GB1579029A - Synthetic aminoglycosides - Google Patents

Description

(54) SYNTHETIC AMINOGLYCOSIDES (71) I, ANTONIO CANAS-RODRIGUEZ, a British Citizen, of 8 Saint Martin's Place, Canterbury, Kent, CTl 1QD, England, do hereby declare the invention, for which I pray that a Patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to aminoglycosides. In particular the invention relates to pseudotrisacchardies having antibiotic activity.

The well known antibiotics of the Kanamycin, Gentamycin and Apramycin types are amino-pseudotrisaccharides. The known antibiotics have activity against a wide variety of bacteria. However, strains of bacteria are becoming prevalent which have resistance to these types of antibiotics. This is a significant problem because the resistant strains of bacteria tend to produce more dangerous toxins than the non-resistant strains. The present invention is based on the discovery that by substituting at least partly deoxy rings for the normal rings in these antibiotics can give compounds which have significantly increased activity as compared with the corresponding known antibiotics against such resistant microorganisms.

Antibiotics of the Kanamycin, Gentamycin and Apramycin types are pseudotrisacchardies based on 2-deoxystreptamine:

In Kanamycin and Gentamycin antibiotics this ring is substituted with monosaccharide (or pseudomonosaccharide) rings in the 4- and 6-positions and in Apramycin antibiotics this ring is substituted with a disaccharide (or pseudodisaccharide) ring in the 4- or 5-position. In antibiotics of this type the glycosidic bands are a, and the substituents in the rings are equatorial.

In antibiotics of this invention the pseudomonosaccharide residues other than streptamine residues can be either in their D- or L-forms. Generally, for convenience, in this specification the compounds will be described and illustrated in their D-forms but it is to be understood that such references include the L-forms and mixtures, such as racemic mixtures, of the two forms.

The present invention provides a compound being a pseudotrisaccharide of the general formula: [A]-[B]-[C] or [A]-[C1]-[A1] where [A] is a group of the formula:

where R, is H, F, OH or SH; R2 is H or NH2; and R3 is H or -CH2-R4 where R4 is OH or NH2: provided that when R2 is H, R3 is -CH2-NH2, and when R3 is H or -CH2-OH R2 is NH2; [A'] is a group of the formula:

where R5 is H, OH, SH or halogen, preferably F; R6 is H, OH or NHR8 where R8 is H or CH3; and R7 is H or -CH2-R9 where R9 is H, OH or NH2; provided that when R6 is H or OH R, is -CH2-NH2 and when R7 is H or -CH2-OH R6 is NHR8; [B] is a group of the formula:

where R2 and R3 are as defined for [Al; [C] is a group of the formula

where R10 is H or OH and R11 is H, CH3 or -CO. ). CHOH-CH2-CH2-NH2; and [C'] is a group of the formula:

where R10 and R" are as defined for [C] wherein both glycosidic bonds are cr-glycosidic bonds, and the pharmaceutically acceptable acid addition salts thereof. The invention includes a pharmaceutical composition comprising as an active ingredient a compound of the invention in combination with a pharmaceutically acceptable excipient, diluent or carrier.

The compounds of the invention can be made by reacting together, in a manner known per se for analogous compounds, corresponding protected precursor monosaccharides or pseudomonosaccharides to form a protected pseudotrisaccharde wherein the glycosidic linkages are a-glycosidic and subsequently removing the protecting groups to liberate the compound of the invention. This method can be performed in two stages, by first reacting together two protected monosaccharide units to give a protected disaccharide unit and subsequently reacting this with a further monosaccharide unit to give the protected pseudotrisaccharide. This method is generally applicable to the compounds of the invention. A further possibility particularly applicable to Kanamycin analogues where the two terminal monosaccharide residues in the eventual protected pseudotrisaccharide are the same is to react a difunctional protected pseudomonosaccharide corresponding to the middle residue in the product with two molar equivalents of a monofunctional protected monosaccharide corresponding to the terminal residues. Usually an excess of the monofunctional compounds will be used in order to drive the reaction more in favour of the trirather than di-saccharide possible products.

As will be apparent to the man skilled in the art some of the compounds of the invention are interconvertible with other compounds of the invention. In particular -OH groups can be converted into NH2 or SH groups or halogen atoms by procedures known in the art. Also compounds directly corresponding to compounds of the invention but having OH groups in some places where the compounds of the invention have NH2 groups can be converted into compounds of the invention by procedures known in the art. In this situation the OH groups are for the purpose of the invention considered to be protecting groups.

The Kanamycin analogues of the invention have an NH2 group in the 3"position can be converted into Gentamycin analogues by N-methylation of this amino group by procedures known in the art. The compounds of the invention where R" is other than hydrogen can also be made from the corresponding free amino compounds by known methods.

As will be apparent from the formulae given above the compounds of the invention contain a minimum of 4 and a maximum of 6 amino groups. The preferred compounds of the invention have 5 amino groups. In particular in the group A' the radical R6 is very preferably an amino group.

The most preferred compounds of the invention are those set out below:

R8, R10 and R11 are as defined above.

[C] as defined above.

The compounds of the invention can be made by general synthetic procedures which are well understood in carbohydrate chemistry. Many of the compounds used as intermediates are believed to be novel. The synthetic routes can be considered in two parts, first the synthesis of the intermediate monosaccharides or pseudomonosaccharides and second the reaction of these compounds to give the pseudotrisaccharides of the invention. In both parts of the overall syntheses it will be necessary or desirable to stereoselectively protect various of the reactive groups in the molecule in order to react others of the groups unambiguously. As is understood in the art, protecting groups used during the syntheses must be able to adequately mask the reactive group to which they are attached and must also be removable under relatively mild conditions in particular such as will not affect the glycosidic bond, e.g. alkaline hydrolysis, hydrogenolysis or very mild acid treatment.

Suitable groups for protecting hydroxyl functions include the following groups: acetyl, benzoyl, trifluoroacetyl, 2-chloroacetyl, methoxycarbonyl, 2,2,2trichloroethoxycarbonyl, benzyl and any nuclear substituted benzyl group, methylthio-methyl and allyl.

Suitable groups for protecting amino functions include the following groups (named including the amino nitrogen atom): N,N-dibenzyl; N- benzyl - Nalkoxycarbonyl, preferably where the alkyl group is methyl, benzyl or 2,2,2trichloroethyl; N-phthalimido; N-succinimido; N - 0 - benzoyloxymethylbenzoyl; N-acetyl; N-2,2,2-trifluoroacetyl; N-benzyloxycarbonyl and N- 2,2,2 - trichloroethoxycarbonyl.

For vicinal diol groups or a-amino alcohol functions suitable protecting systems include forming a cyclic carbonate or carbamate or a 1,3-dioxolane ring, e.g. in a cyclohexylidene or isopropylidene system, this latter being particularly preferred because of the ease with which it can be hydrolysed under mildly acidic conditions and the commercial availability of the reagent, 2,2-dimethoxypropane.

As will be appreciated by the man skilled in the art the individual reactions in the schemes below are well known. Further, the schemes set out below exemplify the production of the relevant compounds and are not exhaustive. Equivalent reactions for many of the stages will be apparent to the man skilled in the art and are not included or discussed in detail here to avoid undue lengthening of the description.

The ring system common to all the compounds of the invention is the deoxystreptamine ring either in the form of 2-deoxystreptamine or 2,5dideoxystreptamine. For glycosidic coupling these compounds are provided with only the 4-, 5- (if present) or 6-hydroxyl group remaining unprotected. These compounds can be synthesised from 2-deoxystreptamine itself or compounds containing it as a residue, e.g. Kanamycin or Neomycin.

A suitably protected 4 - hydroxy - 2 - deoxystreptamine can be prepared from the known compound 5,6 - 0 - cyclohexylidene - tetra - Nmethoxycarbonylenamine by the sequence described below and illustrated in Scheme 1 a. This compound upon periodate oxidation gives a dialdehyde which can be degraded by an alkali, e.g. an alkali or alkaline earth metal alcoholate, e.g.

NaOCH2, or triethylamine to give a substituted 2-deoxystreptamine which can be isolated from the reaction mixture by column chromatography on silica gel with ethyl acetate/chloroform containing ca. 1 /n triethylamine. Hydrolysis with an alkali or alkaline earth metal hydroxide, or with 90V, hydrazine hydrate, removes the Nmethoxycarbonyl groups.

The two amino groups in this compound can be protected by reacting it with N-ethoxycarbonylphthalimide in the presence of triethylamine or aqueous sodium carbonate. The product is 5,6 - 0 - cyclohexylidene - 2- deoxy - 1,3 diphthalimidostreptamine. An alternative method is to benzylate the product of the degradation reaction rather than to hydrolyse it, e.g. with benzyl bromide-sodium hydride in dimethylformamide followed by mild hydrogenolysis (Pd-charcoal, 1 atm) to give 5,6 - 0 - cyclohexylidene - 1,3 - di - N - benzyl - 2 - deoxy - 1,3 di - N - methoxycarbonylstreptamine.

The cyclohexylidene protecting group may be difficult to remove in the final products. It can be converted to the more labile isopropylidene group by mild acid hydrolysis followed by treatment with 2,2-dimethoxypropane and catalytic amounts of toluene - p - sulphonic acid. In this sequence the 4-hydroxyl group should be protected, e.g. by benzylation. The benzyl group can be removed by catalytic hydrogenation after the exchange of protecting groups.

Suitably protected 4- and 6 - hydroxy - 2 - deoxystreptamines can be made by the sequence described below. This sequence starts with 2-deoxystreptamine which is monobenzylated on each nitrogen atom and then methoxycarbonylated with, e.g., methyl-chloroformate. The resulting product is reacted with 1,1dimethoxycyclohexane. The resulting racemic mixture can be resolved by fractional crystallisation techniques, e.g. using optically active seed from ethereal solution. Repetition of the fractional crystallization gives satisfactory separation of the 4-hydroxy and 6-hydroxy isomers.

Synthesis of protected 5 - hydroxy - 2 - deoxystreptamine can be accomplished by the sequence described below and illustrated in Scheme lb. This sequence starts with 2-deoxystreptamine, which is reacted with benzaldehyde under reducing conditions, e.g. using sodium borohydride, sodium cyanoborohydride, hydrogen and palladium-on-charcoal or hydrogen and Raney nickel, to give the di-N-benzylated streptamine. This compound is transformed into a dicyclic carbamate by reaction with phosgene, phenyl chloroformate, pnitrophenyl chloroformate or methyl chloroformate, in the presence of a base such as Amberlite 400 (OH-), sodium or potassium carbonate, alk li metal alcoholates or sodium hydride. (The word "Amberlite" is a Registered Trade Mark). This intermediate, 2 - deoxy - 1,3 - di - N - benzylstreptamine - 1,6:3,4 - dicarbamate, is a key intermediate for the synthesis of 5-O-glycosidic bonds with 2-deoxystreptamine.

This cyclic dicarbamate can also be used in the synthesis of other intermediates such as is illustrated in reaction Schemes lc and. Id. In Scheme ld the cyclic dicarbamate is reacted with an halogenating agent, preferably bromine or iodine, in the presence of a trivalent phosphorus compound such-as-triphenylphosphine or a trialkylphosphite. The resulting 5-halogeno compound (the 5-bromo compound is illustrated) can be reduced, e.g. by catalytic hydrogenation in the presence of a base, to give a cyclic dicarbamate protected 2,5-dideoxystreptamine. In Scheme le the 5-hydroxy group in the cyclic dicarbamate is benzylated or allylated to protect the 5-hydroxyl groups. The cyclic dicarbamate intermediate obtained in Schemes Ic and Id can be ring opened (as illustrated) by reaction with sodium methoxide in methanol or, preferably, by saponification followed by methoxy-carbonylation or benzoxy-carbonylation. The products of these two sequences are 4,6-dihydroxy protected streptamines. The product of sequence lc is important because it is a 2,5dideoxystreptamine. Where it is desired to have the 4- or 6-monohydroxy derivatives corresponding to these products, i.e. with the 4- or 6-hydroxyl group respectively protected, they can be made by standard protection reactions, e.g. benzylation followed by resolution of the isomers or changing one of the Nprotecting groups to a cyclic group with the hydroxyl group adjacent, e.g. a cyclic carbamate, followed by resolution of the isomers.

The synthesis of the remaining intermediates needed in the production of the pseudosaccharides of the invention can be effected from known compounds by methods similar to those described above for the preparation of intermediates containing the 2-deoxy- or 2,5-dideoxystreptamine ring. Scheme 2 briefly sets out a series of reaction schemes for the synthesis of some of these intermediates. Suitable reagents and reaction conditions will be apparent to the man skilled in the art.

The coupling reaction for the synthesis of a-glycosides from the monocyclic intermediates can be readily achieved with excellent yields via two procedures known per se. The first one takes advantage of the reaction by which glycals can add alcohols through the catalytic action of boron trifluoride-etherate in an inert solvent of low dielectric constant, such as benzene, carbon tetrachloride or chloroform. During this type of reaction any amino functions must be protected by such groups as phthaloyl, succinyl or alkyloxy-carbonyl, e.g. to give

If secondary or tertiary amines, secondary amides or secondary carbamates are present, the catalyst reacts with them forming insoluble by-products and no glycoside can be isolated. The reactants should be soluble in the solvents mentioned above (benzene, Cm14, CHCl2). The reaction between glycals and alcohols is fast (5 to 15 minutes) and takes place at room temperature and the proportion of p-glycosides is negligible.

The second procedure is a modified Koenigs-Knoor glycosylation reaction between a glycosyl halide and an alcohol function, which takes advantage of the non-participating neighbouring group at carbon 2, adjacent to the reaction centre (anomeric carbon). The catalyst used could be silver oxide or silver carbonate but preferably the mixture of mercuric cyanide and mercuric bromide or a quaternary ammonium bromide such as tetrabutyl bromide or Amberlite IR-400 (Bf form), or a sulphide (tetrahydrothiophene) and a proton acceptor such as 2,6-lutidine, mercuric cyanide, anhydrous sodium bicarbonate or Amberlite IR-400 (CN-), which increases the proportion of a-glycoside obtained at the expense of the A- anomer. The formation of pseudo-trisaccharides of 2-deoxy-streptamine can be effected stepwise, by the addition of one glycosyl moiety at a time, i.e. first forming a disaccharide with a protected 2-deoxystreptamine, then reacting another glycosyl moiety with the already formed disaccharide as depicted below, where X is a halide or represents the reactive .1:2 double bond of a glycal.

Z=cyclohexylidene or isopropylidene ['A] and ['B] are protected residues corresponding to [A] and [B] defined above, Bn is benzyl and Me is methyl.

Alternatively the trisaccharide can be synthesized by the reaction of a disaccharide derivative, [A]-[B]-X, with a suitably protected 2deoxystreptamine (Scheme 4).

where 'A, 'B, X, Z, Bn and Me are as defined above in Scheme 3.

Once the protected trisaccharides have been obtained the sequences of reactions which follow are directed towards the removal of the trisaccharide protective groups, thus liberating the amino and hydroxyl functions.

Schemes 5 and 6 summarize some of the possible routes to synthesize the 4-0 and 5-O-glycosides of 2-deoxystreptamine.

When the glycosylation is carried out simultaneously at carbons 4 and 6 of the aminocyclitol ring, whether the glycal or the glycosyl halide method is used, and in spite of the presence of an excess of glycosylating agent, a small percentage of the disaccharides formed remain unreacted at the end of the reaction period. Their separation, however, from the trisaccharides is easily accomplished by filtration through silica gel and elution with solvents. These disaccharides (4-O-glycoside and 6-O-glycoside of either 2-deoxystreptamine or 2, 5-dideoxystreptamine) which are present to the maximum extent of l5-20V of the total reaction products, can, once separated from the trisaccharides, be glycosylated again to furnish more trisaccharides.

The fully protected trisaccharides obtained in this way are then subjected to a series of chemical operations designed to remove the protective groups, thus liberating the trisaccharide. Removal of esters, carbamates, and amide functions is achieved by alkaline hydrolysis with hydroxides of the alkali or alkaline earth metals, or, preferably, with 8090% hydrazine hydrate in a suitable solvent such as methanol, ethanol or propanol. N- and O-benzyl groups are removed by catalytic hydrogenation over palladium-on-charcoal or Raney nickel catalysts. Any azido functions present are reduced simultaneously to amino groups during this operation.

Some of the trisaccharides included in this invention can be obtained, apart from the general method of glycosylation with the appropriate glycosyl halide or glycal, through chemical transformation of the intermediates 4,6 - di - 0 - (2,3 dideoxy - a - D - erythro - hexopyranosyl) - 2 - deoxy - 1,3 - di - N - benzyl 1,3 - di - N - methoxycarbonylstreptamine and 4,6 - di - 0 - (2,3 - dideoxy - a D - erythro - hexopyranosyl) 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N - - methoxycarbonylstreptamine. When either of these trisaccharides is reacted with carbon tetrachloride, hexamethylphosphorous acid triamide and sodium azide, replacement of the primary alcohol functions by the azido group at carbons 6' and 6" is achieved. These transformations, followed by the removal of the groups protecting the trisaccharides, lead to the obtention of 4,6 - di - 0 - (6 - amino 2,3,6 - trideoxy - a - D - erythrohexopyranosyl) - 2 - deoxystreptamine and 4,6 di - 0 - (6 - amino - 2,3,6 - trideoxy - a - D - erythro - hexopyranosyl) - 2,5 dideoxystreptamine.

An alternative route to the compounds mentioned above is embodied in the following sequence of reactions: selective tosylation of the primary alcohol functions in the partially protected trisaccharides, i.e. [4,6 - di - 0 - (2,3 dideoxy - a - D - erythro - hexopyranosyl) - 1,3 - di - N - benzyl 2,5 - dideoxy 1,3 - di - N- methoxycarbonylstreptamine (a), and 4,6 - di - 0 - (2,3 - dideoxy - a - D - erythro - hexopyranosyl) - 2 - deoxy - 1,3 - di - N - methoxycarbonyl - 1 - N,3 - N, - 5 - 0 - tribenzylstreptamine (b)] is followed by the nucelophilic displacement of the tosyl group by sodium azide to give the 6', 6"diazido protected trisaccharides. These are then treated under saponification conditions in ethanol or propanol (80/900/, hydrazine hydrate, sodium potassium or barium hydroxide) to remove the N-methoxycarbonyl groups, then submitted to hydrogenation (hydrogen, palladium-on-charcoal) to reduce the azido functions to amino ones with concomitant hydrogenolysis of the N-benzyl groups.

The inconvenience of this route to the azido intermediates is that during the selective tosylation step the separation of by-products is difficult, making it impossible to obtain yields greater than 6065% of the ditosylated derivative.

In a similar fashion 4,6 - di - 0 - [4,6 - diamino - 2,3,4,6 - tetradeoxy - a D - (threo or erythro) - hexopyranosyl] - 2 - deoxystreptamine or 4,6 - di - 0 [4,6 - diamino - 2,3,4,6 - tetradeoxy - a - D - (threo or erythro) - hexopyranosyl] - 2,5 - dideoxystreptamine can be obtained from the abovementioned intermediate trisaccharides (a) and (b) by permesylation of the four hydroxyl functions, displacement of the mesyl groups by azido in dimethylformamide or hexamethylphosphoric acid triamide, saponification of the protective groups (N-COOMe), followed by hydrogenation over palladium-oncharcoal catalyst. Schemes 7 and 8 illustrate the sequence of steps in the preparation of some of the trisaccharides of the invention.

The pseudotrisaccharides of the invention possess excellent antibacterial activity which, in some cases, appears superior to that of Kanamycin A itself.

Illustrated below is a table showing the minimal inhibitory concentrations (MIC's) of kanamycin A together with those of one of the trisaccharides synthesized (Example LI) against a variety of Gram-positive and Gram-negative bacteria as obtained by the Steers agar-dilution method with Mueller-Hinton agar medium.

TABLE I Micrococcus pyogenes aureus 6539 P Staphylococcus pyogenes Smith A Escherichia coli R 1513 Salmonella tiphymurium Proteus mirabilis Pseudomonas aeruginosa s.p.

Pseudomonas aeruginosa I.A.

Salmonella sui-pestifer Pseudomonas aeruginosa D 15 Proteus rettgeri Proteus morganii

MIC (ug/ml) Kanamycin A Example LI 0.8 0.4 0.8 0.4 100 32 100 32 2 0.4 100 16 100 32 - 32 32 25 8 0.4 0.2 0.8 0.2 In vitro activity of Kanamycin A and compound (Example LI).

MIC's in Mueller-Hinton broth pH 7.2.

In addition the pseudotrisaccharides of the invention are less susceptible to deactivation by, and are therefore effective against, bacteria which are resistant to Kanamycin and Apramycin.

Acids from which pharmaceutically acceptable addition salts of the compounds of the invention can be prepared are those which form non-toxic addition salts containing pharmaceutically acceptable anions, such as the hydrochloride, hydrobromide, hydroiodide, sulphate or bisulphate, phosphate or acid phosphate, acetate, maleate, fumarate, lactate, tartrate, citrate, gluconate, saccharate and p-toluene-sulphonate salts.

The compounds of the invention can be administered alone, but will generally be administered in admixture with a pharmaceutical carrier selected with regard to the intended route of administration and standard pharmaceutical practice. For example, they may be administered orally in the form of tablets containing such excipients as starch or lactose, or in capsules either alone or in admixture with excipients, or in the form of elixirs or suspensions containing flavouring or colouring agents. They may be injected parenterally, for example, intramuscularly or subcutaneously. For parenteral administration, they are best used in the form of a sterile aqueous solution which may contain other solutes, for example, enough salts or glucose to make the solution isotonic.

The invention is illustrated by the following Examples of the preparation and characterisation of compounds of the invention. In these Examples, all temperatures are given in "C, the organic solutions are dried over anhydrous Na2SO4 and concentrated at 350C (10 Torr), and the PMR data follow the general practice adopted in the scientific journals. First the position in the spectrum for a particular signal or signals is given in (p.p.m.) with respect to the internal standard tetramethylsilane. In brackets the types of signals are given, i.e. singlet (s), doublet (d), triplet (t), multiplet (m) and this is followed by the number of protons responsible for those signals together with the molecular position or functional group whose signals are reported.

EXAMPLE I A solution of methyl 4,6 - 0 - benzylidene - 2,3 - dideoxy - a - D - erythro hex - 2 - enopyranoside (50 g, 0.2 mol) in dry methanol (11.) containing 10% palladium-on-charcoal (9.0 g) was hydrogenated.at 4 atm. at room temperature for 48-72 h. The catalyst was filtered off and the filtrate was concentrated in vacuo to yield syrupy methyl 2,3 - dideoxy - a - D - erythro - hexopyranoside (32 g, 98%).

[cr]54G,+155 (c 1.61, chloroform). TLC: R, 0.37 (ethyl acetate-ethanol, 8:1).

PMR data (CDCl2): Xl.20 (m, 4 H, H-2,2', 3,3'), 3.20 (bm, 2 H, 2-OH), 3.55 (m, 2 H, H-4,5), 3.80 (m 2 H, H-6,6') and 4.67 (m, 1 H, H-la) Analysis: Calculated for C7H14O4: C, 51.86; H, 8.70 Found: C, 51.95; H, 8.80% EXAMPLE II To a solution of methyl 2,3 - dideoxy - a - hexo - erythro - pyranoside (31 g, 0.191 mol) in dry pyridine (150 ml) toluene-p-sulphonyl chloride (36.29 g, 0.191 mol) was added and the mixture was allowed to stand at room temperature for 0.5 h. A small amount of water was then added, after which the solution was concentrated, giving a syrup which was poured into water and extracted with ether.

The extracts were dried and concentrated to a small volume. After standing in the refrigerator the solution precipitated a solid which was filtered, washed with petroleum ether (40-60 ) and dried in vacuo at 450. Recrystallization from benzene-petroleum ether (4060 ) gave pure methyl 2,3 - dideoxy - 6 - 0 toluene - p - sulphenyl - a - D - erythro - hexopyranoside as a colourless solid (36 g, 60%), m.p.: 101020. [a]020+780 (c 1, chloroform). TLC: Rf 0.55 (ethyl acetate).

PMR data (CDCl3): a 1.75 (m, 4 H, H-2,2',3,3'), 2.43 (s, 3 H, Ph-Me), 3.27 (s, 3 H, OMe), 3.60 (m, 2 H, H-4,5), 4.27 (m, 2 H, H-6,6'), 4.60 (m, I H, H-la), 7.35 (m, 2 H, aromatic) and 7.80 (m, 2 H, aromatic).

Analysis: Calculated for C14H20O8S: C, 53.16; H, 6.37; S, 10.12 Found: C, 53.26; H, 6.57; S, 10.39% EXAMPLE III Method I A mixture of methyl 6 - 0 - toluene - p - sulphonyl - 2,3 - dideoxy - a - D erythro - hexopyranoside (1 g, 3.16 mmol) and sodium azide (0.6 g, 9.2 mmol) in dry N,N-dimethylformamide (12 ml) was heated at 800 and stirred for 12 h. The solvent was removed in vacuo and the residue was treated with ice-water and extracted into chloroform. The extracts were washed with water, dried and evaporated to yield a syrup (0.52 g, 88%) which was purified by distillation at 100110 /0.1 mm. Methyl 6 - azido - 2,3,6 - trideoxy - a - D - erythro - hexopyranoside was obtained as a colourless oil. [α]D20+118 (c 1, chloroform). TLC: R, 0.62 (ethyl acetate).

PMR data (CDCl3): a 1.80(m, 4 H, H-2,2',3,3'), 2.23 (bs, 1 H, OH), 3.16 (s, 3 H, OMe), 3.50 (m, 2 H, H-6,6'), 3.60 (m, 2 H, H-4,5) and 4.70 (t, 1 H, H-la, width 3 Hz).

Analysis: Calculated removed from the syrupy residue by repeated extraction with petroleum ether. The colourless syrup methyl 6- azido - 2,3,6- trideoxy - a - D - erythro- hexopyranoside which resulted (5.80 g, 48%) had an Rf 0.62 in TLC (ethyl acetate).

Analysis: Calculated for C7H12N2O2: C, 44.91; H, 7.00; N, 22.44 Found: C, 44.70; H, 6.80; N, 22.31% EXAMPLE V A solution of methyl 6 - azido - 2,3,6 - trideoxy - a - D - erythro hexopyranoside (1 g) in 0.1 M hydrochloric acid (20 ml) was heated at 1000 for 0.5 h, then cooled and neutralized with Amberlite IR-400 (carbonate form) resin.

Filtration and evaporation of the reaction mixture yielded a syrup (0.9 g, 97%) which was purified by chromatography on silica-gel using chloroform-ethanol (93:7) as eluant. 6 - Azido - 2,3,6 - trideoxy - D - erythro - hexose was obtained as a colourless syrup (TLC, R, 0.06 (chloroform-ethanol, 93:7), which gave a positive Fehling test. [α]546125+56 , [a],25+410 (c 0.6, water).

Analysis: Calculated for C8H11N2O2: C, 41.61; H, 6.40; N, 24.26 Found: C, 41.75; H, 6.29; N, 24.350/, EXAMPLE VI 6 - Azido - 2,3,6 - trideoxy - D - erythro - hexose (1.73 g, 10 mmol) was acetylated in acetic anhydride (8 ml) with a few drops of 70% perchloric acid as catalyst. After 1 h at room temperature the solution was saturated with dry hydrogen bromide and the mixture was allowed to stand for 2 h. It was then poured into ice-water and extracted with ice-water, ice-cold saturated sodium bicarbonate solution and water. Finally the extracts were dried (Na2SO4) and concentrated to yield 4 - 0 - acetyl - 6 - azido - 2,3,6 - trideoxy - D - erythro - hexopyranosyl bromide as a colourless syrup (2.2 g), which was used immediately for the next step.

Analysis: Calculated for C8H12N2O2Br: C, 34.55; H, 4.35; N, 15. 11; Br, 28.7 Found: C, 34.20; H, 4.65; N, 14.92; Br, 29.0 EXAMPLE VII 4 - O - Acetyl - 6 - azido - 2,3,6 - trideoxy - D - erythro - hexopyranosyl bromide (2.78 g, 10 mmol) in dry nitromethane (30 ml), mercuric cyanide (0.5 g), silver carbonate (3 g), methanol (1 ml) and Drierite (5 g) was shaken in the dark at room temperature for 48 h. The mixture was filtered and the solids were washed with dichloromethane. The combined organic liquids were washed with water, dried and evaporated to dryness to give a syrup (2.1 g, 91.7%). Examination of the syrup by TLC (ethyl acetate) showed a main component, Rf 0.65, which was separated by chromatography on silica gel using benzene-ethyl acetate as eluant.

The yield of methyl 4 - 0 - acetyl - 6 - azido - 2,3,6 - trideoxy - a - D - erythro hexopyranoside was 1.37 g, 60%. [a]022+l220, [a]250461+1650 (c 1, chloroform).

PMR data (CDCl2): S 1.84 (m, 4 H, H-2,2',3,3'), 2.02 (s, 3 H, OAc), 3.30 (m, 2 H, H-6,6'), 3.38 (s, 3 H, -OMe), 3.86 (q, 1 H, J45=9, J56=J56,=5 Hz, H-5), 4.60 (m, I H, H-4), 4.69 (t, 1 H, H-la, with 4 Hz).

Analysis: Calculated for C9H15N2O4: C, 47.15; H, 6.60; N, 18.33 Found: C, 47.07; H, 6.75; N, 18.50% EXAMPLE VIII Methyl 6 - azido - 2,3,6 - trideoxy - a - D - erythro - hexopyranoside (1.5 g, 8 mmol) in dry methanol (100 ml) was hydrogenated over 10% palladium-oncharcoal (0.4 g) at room temperature under a pressure of 2.5 atm. for 5 h. The catalyst was removed and the solution evaporated to give a colourless syrup (1.2 g), which showed a positive ninhydrin reaction. This syrup in methanol (3 ml) was treated with ethereal hydrogen chloride solution whereupon a crystalline hydrochloride precipitated immediately. This was filtered, washed with ether and recrystallized from methanol-ether to yield pure methyl 6- amino - 2,3,6 - trideoxy - a - D - erythro - hexopyranoside hydrochloride (1.25 g, 79). M.p.: 153154 dec. [α]546122+130 , [α]D22+96.3 (c 1, water). TLC: Rf 0.65 (chloroform-methanolammonia, 20:6:1).

PMR data (D2O): a 1.80 (m, 4 H, H-2,2',3,3'), 3.10 (m, 2 H, H-6,6'), 3.38 (s, 3 H, OMe), 3.5-3.9 (m, 2 H, H-4,5) and 4.80 (m, 1 H, H-la).

Analysis: Calculated for C7H16NO3Cl: C, 42.53; H, 8.15; N, 7.08; Cl, 17.93 Found: C,42.68; H,8.04; N,7.00; Cl, 18.20% EXAMPLE IX Methyl 6 - azido - 2,3,6 - trideoxy - a - D - erythro - hexopyranoside (3.0 g, 16 mmol) in methanol (100 ml) containing acetic anhydride (2 ml) was hydrogenated over 10% palladium-on-charcoal (0.4 g) at room temperature under a pressure of 2.5 atms. for 5 h. The catalyst was filtered off and the filtrate was evaporated to dryness giving a syrupy residue which crystallized upon treatment with ether to yield 3.18 g, 98%. The product was recrystallized from chloroformether to give pure methyl 6 - acetamido - 2,3,6 - trideoxy - α - D - erythro hexopyranoside. M.P.: 117-118 . [α]546121-13 (c 1, chloroform). TLC: Rf 0.83 (chloroform-methanol-ammonia, 20:6:1).

PMR data (CDCl3): # 1.8 (m, 4H, H-2,2',3,3'), 2.04 (s, 3 H,-NAc), 3.08 (dq, 2 H, J6.6'=14 Hz, J5.6=3.0 Hz, J5.6,=3.5 Hz, H-6,6'), 3.29 (s, 3 H, OMe) 3.51 (dt, 1 H, J4.5=9.0 Hz, H-5), 3.98 (dq, 1 H, J3.4=3.0 Hz, J3'.4=12 Hz, H-4), 4.4 (bs, 1 H, OH), 4.63 (t, 1 H, width 5 Hz, H-1) and 6.50 (bs, 1 H, NH).

Analysis: Calculated for CgH17NO4 C, 53.18; H, 8.43; N, 6.89 Found: C, 53.12; H, 8.56; N, 7.01% EXAMPLE X Methyl 6 - acetamido - 2,3,6 - trideoxy - a - D - erythro - hexopyranoside (1.5 g) in 0.1 M aqueous hydrochloric acid (30 ml) was heated at 1000 for 0.5 h. The solution was neutralized with Amberlite IR-400 (carbonate form) resin and evaporated in vacuo to yield a syrup, 1.46 g. This syrup showed the presence of two components by TLC (ether-methanol, 9:1): A) Rf 0.08 and b) R, 0.05. The separation of these two components was achieved by chromatography on a silicagel column using mixtures of ether-methanol as eluants. Compound a), 6 acetamido - 2,3,6 - trideoxy - D - erythrohexopyranose (Rf 0.08) was obtained as a colourless syrup (0.75 g, 50%) which reduced Fehling's reagent. [α]546125+50 , [α]D25+36 (c 0.5, water).

Analysis: Calculated for C8H,5NO4: C, 50.78; H, 7.99; N, 7.40 Found: C, 50.89; H, 8.10; N, 7.10% The chromatographic fractions from the previous preparation containing compound b), Rf 0.05, were pooled and evaporated to yield a syrup (negative test with Fehling's reagent) which crystallized on standing. Pure 6 - acetamido - 1,6 anhydro - 2,3,6 - tndeoxy - ss - D - erythrohexopyranose was obtained (0.16 g, 12%) as a colourless crystalline solid. M.p.: 125-126 . [α]546124-32 (c 0.5, water).

PMR data (CDCl3); a 1.82 (bm, 4 H, H-2,2',3,3'), 2.04 and 2.07 (2 s, 3 H, - NAc, two rotational isomers), 2.91 (s, 1 H, OH), 3.51 (m, 3 H, H-5,6,6'), 4.52 (unresolved multiplet, 1 H, width 10 Hz, H-4), 5.44 and 5.71 (2 s broad, 1 H, width 4 Hz, ratio 7:9, H-l of two rotational isomers).

Mass spectrum: M/e 171 (calculated for C8H,3NO3: M+ 171).

Analysis: Calculated for C8H,3NO3: C, 56.12; H, 7.65; N, 8.18 Found: C, 56.11; H, 7.92; N, 7.93.

EXAMPLE XI 6 - Acetamido - 2,3,6 - trideoxy - D - erythro - hexopyranose (1.89 g, 10 mmol) was treated with acetic anhydride-acetic acid, 2:1 (10 ml) and 70% perchloric acid (0.2 ml) for 2 hours after which the solution was saturated at 0 with dry hydrogen bromide. The mixture was allowed to stand for 2 h, then poured into ice-water and extracted with dichloromethane (4x50 ml). The extracts were successively washed with ice water (2x50 ml), cold aqueous NaHCO2, water (2x50 ml), and finally they were dried (Na2SO4) and evaporated. The syrupy residue, 6 acetamido - 4 - 0 - acetyl - 2,3,6 - trideoxy - D - erythro - hexopyranosyl bromide 2.64 g, 90%) was pure enough for further reactions but it decomposes on standing at room temperature.

Analysis: Calculated for Cl0Hl6NO3Br: C, 40.83; H, 5.48; N, 4.76; Br, 27.16 Found: C, 40.95; H, 5.88; N, 4.80; Br, 26.80 EXAMPLE XII A mixture of 6 - acetamido - 4 - 0 - acetyl - 2,3,6 - trideoxy - D - erythro hexopyranosyl bromide (1.47 g, 5 mmol), mercuric cyanide (2.5 g), mercuric bromide (3 g), methanol (1.0 ml), Drierite (5 g) and dry nitromethane (20 ml) was shaken in the dark at room temperature for 48 h. The mixture was filtered and the solids were washed with dichloromethane. The combined organic liquids were washed with water, dried and evaporated to dryness to furnish a syrup (1.16 g, 95%). Examination of this syrup by TLC (chloroform-acetone, 3: 1) showed a main compound (Rf 0.60) which was separated from the crude reaction product by column chromatography on silica gel using chloroform-ethyl acetate mixtures as eluant. The crystalline product, methyl 6 - acetamido - 4 - 0 - acetyl - 2,3,6 trideoxy - D - a - erythro - hexopyranoside, was recrystallized from ether-hexane (yield: 0.80 g, 65%). M.p. 9798C. [α]546120+135 , [α]D0+98 (c 0.5, chloroform).

PMR data (CDCl3): a 1.82 (bm, 4 H, H-2,2',3,3'), 1.96 and 2.04(2s,6 H -NAc and'-OAc), 3.52 (s, 3 H, -OMe), 3.58 (bm. 3 H, H-5,6,6'), 4.52 (m, 1 H, H-4), 4.64 (t, 1 H, width 4 Hz, H-la) and 5.82 (bs, 1 H, -NH).

Analysis: Calculated for C11H19NO5: C, 53.86; H, 7.81; N, 5.71 Found: C, 54.05; H, 7.98; N, 5.52% EXAMPLE XIII Methyl 2,3 - dideoxy - a - D - erythro - hexopyranoside (6 g, 37 mmol) in dry pyridine (50 ml) was treated with toluene-p-sulphonyl chloride (15.2 g, 80 mmol) at 0 with stirring. The reaction mixture was stored at 22C for 12 h, and after the addition of water (1 ml) it was concentrated. The syrupy residue was poured into ice-water, the oil which separated was extracted with CHCl3,and the extracts were washed with water, dried and evaporated. The solid thus obtained (12 g, 70%) was recrystallized from methanol to give pure methyl 2,3 - dideoxy - 4,6 - di - 0 toluene - p - sulphonyl - a - D - erythro - hexopyranoside. M.p.: lllll.5a.

[α]D22+80.8 (c 1, chloroform). TLC: Rf 0.62 (benzene-ethyl acetate, 9:4).

PMR data (CDCL2): #1.5-2.1 (m, 4H, H-2,2',3;3'), 2.45 (s, 6 H, 2 C113-PH-), 3.2 (s, 3 H, -OMe), 3.70-4.40 (m, 4 H, H-4,5,6,6'), 4.55 (t, 1 H, H-la), 7.55 (q, 8 H, -Ph-).

Analysis: Calculated for C21H26O8S2: C, 53.60; H, 5.57; S, 13.62 Found: C, 53.98; H, 5.59; S, 13.8% EXAMPLE XIV A cooled solution (00) of methyl 6 - azido - 2,3,6 - trideoxy - a - D erythro - hexopyranoside (3 g, 16 mmol) in dry pyridine (10 ml) was treated dropwise with methanesulphonyl chloride (2.29 g, 20 mmol) with stirring for 1 h.

Water (1 ml) was then added to the reaction mixture and the solvents were removed in vacuo at 300. The residual syrup was poured into ice-water, producing a precipitate which was filtered, washed with water and dried. The solid was recrystallized from benzene-petroleum ether (40-60 ) to give methyl 6 - azido 4 - 0 - methanesulphonyl - 2,3,6 - trideoxy - (x - D - erythro - hexopyranoside (3.5 g, 83 /á) as a colourless solid. M.p.: 54-56 . [α]D22+42 (c 1, chloroform). TLC: Rf 0.55 (chloroform).

PMR data (CDCl3): #1.70-2.30 (m, 4 H, H-2,2',3,3'), 3.05 (s, 3 H, -SO2Me), 3.40 (s, 3 H, -OMe), 3.45 (d, 2 H, H-6,6'), 3.75-4.0 (m, 1 H, H-5), 4.4 4.60 (m, 1 H, H-4), 4.70 (t, 1 H, H-1α).

Analysis: Calculated for C8H15N3O5S: C, 36.22; H, 5.70; N, 15.84; S, 12.08 Found: C, 36.06; H, 5.75; N, 15.89; S,11.77 EXAMPLE XV A mixture of methyl 2,3 - dideoxy - 4,6 - di - 0 - toluene - p - sulphonyl a - D - erythro - hexopyranoside (5 g, 10.6 mmol), sodium azide (10 g, 0.16 mol) and dimethylformamide (50 ml) was stirred and heated at 1000 for 24 h. The solvent was evaporated in vacuo and the residue was partitioned between water-ether (1:1, 200 ml). The aqueous layer was extracted with ether and the combined organic liquors were washed with water, dried and evaporated to give a syrup which was distille dat 110-120 /1 Torr. Methyl 4,6 - di - azido - 2,3,4,6 - tetradeoxy - α - D threo - hexopyranoside (1.9 g, 90%) was obtained as a colourless oil [α]D21+15.3 (c 2, chloroform). TLC: Rf 0.7 (benzene-ethyl acetate, 9:4).

PMR data (CDCl3): 6 1.5-2.20 (m, 4 H, H-2,2',3,3'), 3.0-3.30 (m, 2 H, H 6,6'), 3.40 (s, 3 H, OMe), 3.50 (m, 1 H, H-4), 4.85-5.05 (m, 1 H, H-5), 5.75 (t, 1 H, H-1α).

Analysis: Calculated for C7H,2N802: C, 39.62; H, 5.70; N, 39.60 Found: C, 39.75; H, 5.87; N, 39.30% EXAMPLE XVI A mixture of methyl 6 - azido - 4 - 0 - methanesulphonyl - 2,3,6 - trideoxy a - D - erythro - hexopyranoside (2.65 g, 10 mmol), sodium azide (5 g, 80 mmol) and dimethylformamide (30 ml) was heated at 1000 for 24 h. The solvent was removed in vacuo and the residue was partitioned between ether-water (1:1, 100 ml). The aqueous layer was extracted with ether and the combined organic liquids were washed with water, dried and evaporated. The syrup thus obtained was purified by distillation at 110-120 C/1 Torr. Yield: 1.80 g, 85% of methyl 4,6 - di azido - 2,3,4,6 - tetradeoxy - a - D - threo - hexopyranoside as a colourless oil [a]D1+15.3 (c 1, chloroform) TLC: Rf 0.7 (benzene-ethyl acetate 9:4).

Analysis: Calculated for C7H12N6O2: C, 39.62; H, 6.70; N, 39.60 Found: C, 39.51; H, 5.72; N, 39.76% EXAMPLE XVII Methyl 4,6 - di - azido - 2,3,4,6 - tetradeoxy - a - D - threo - hexopyranoside (1.9 g, 8.9 mmol) in methanol (30 ml) was hydrogenated over 10% palladium-on-charcoal catalyst (0.2 g) under a pressure of 4 atms. for 3 h. The catalyst was removed and the filtrate was evaporated in vacuo to yield a syrup (1.35 g, 95%). The syrup was dissolved in methanol (3 ml) and a solution of oxalic acid in dry ether was added until precipitation was complete. The solid was filtered, washed with dry ether and dried in vacuo. It was recrystallized from waterisopropanol to yield 2 g (90 /a) of methyl 4,6 - di - amino - 2,3,4,6 - tetradeoxy - a D - threo - hexopyranoside - dihydrogen dioxalate as a colourless solid. M.p.: 2500 decomposition. [α]D25+55.3 (c 1, water). TLC: Rf 0.2 (chloroform-methanolammonium hydroxide, 100:30:3).

PMR data (CDCl3): 6 1.6-2.3 (m, 4 H, H-2,2',3,3'), 2.8-3.30 (m, 2 H, H-6,6'), 3.40 (s, 3 H, -OMe), 3.60 (m, 1 H, H-4), 4.204.40 (m, 1 H, H-5), 4.90 (m, 1 H, H-la).

Analysis: Calculated for C11H20N2O10: C, 38.82; H, 5.92; N, 8.23 Found: C, 38.79; H, 5.88; N, 8.35% EXAMPLE XVIII A mixture of potassium thiolobenzoate (1.87 g, 10 mmol), methyl 6 - azido 4 - 0 - methanesulphonyl - 2,3,6 - trideoxy - a - D - erythro - hexopyranoside (1.5 g, 5.6 mmol) and dry dimethylformamide (40 ml) was stirred and heated at 1000 for 5 h under nitrogen. The solvent was then removed in vacuo and the residue was partitioned between water-ether (1:2, 100 ml). The ethereal layer was separated and the aqueous phase was extracted with ether (2x25 ml). The combined ethereal liquors were washed with water (2x25 ml), dried and concentrated in vacuo to give a syrup which was purified by chromatography on silica gel using mixtures of benzene-chloroform as eluant. Methyl 6- azido - 4 - S- benzoyl - 2,3,4,6 - tetradeoxy - 4 - thio - a - D - threo - hexopyranoside (1.32 g, 80%) was a syrup presenting a single spot in TLC (chloroform) Rf 0.75. [α]D22+91.3 (c 1, chloroform).

PMR data (CDC13): a 1.7-2.60 (m, 4 H, H-2,2',3,3'), 3-3.60 (m, 2.H, H-6,6'), 3.40 (s, 3 H, OMe), 4.05 (m, 1 H, H-4), 4.30 (m, 1 H, H-5), 4.80 (dt, 1 H, H 1α), 7.80 (m, 5 H, -Ph).

Analysis: Calculated for C13H17N2O3S; C, 52.86; H, 5.80; N, 14.22; S, 10.85 Found: C, 53.01; H, 5.90; N, 14.40; S, 10.72 EXAMPLE XIX Methyl 6 - azido - 4 - 5 - benzoyl - 2,3,4,6 - tetradeoxy - 4 - thio - a - D - threo - hexopyranoside (0.3 g, 1 mmol) in dry methanol (10 ml) was treated with sodium (20 mg) in methanol (2 ml) and the mixture was stored for 12 h at 220. It was then neutralized with CO2 and concentrated. The residue was extracted with chloroform and the extracts, upon concentration, gave a syrup (0.18 g, 90%) which was purified by preparative TLC (benzene-ethyl acetate, 4:1). A clear syrup of pure bis (methyl 6 - azido - 2,3,4,6 - tetra - deoxy - ar - D - threo - hexopyranoside - 4) bisulphide was obtained by aerial oxidation of its thiol precursor. [α]D23-46.2 (c 0.8, methanol). TLC: Rf 0.3 (benzene-chloroform, 3:1), Rf 0.65 (benzene-ethyl acetate, 4:1).

IR vmaxCHCL3 2100 (N3) cm-'.

PMR data (CDCl3): a 1.26-2.30 (m, 4 H, H-2,2',3,3'), 2.94 (d, 1 H, H-4), 3.38 (s, 3 H, OMe), 3.14-3.70 (m, 2 H, H-6,6'), 4.16 (m, 1 H, H-5), 4.73 (d, 1 H, H-la).

Analysis: Calculated for C,4H24N604S2: C, 41.56; H, 5.98; N, 20.77; S, 15.83 Found: C, 41.70; H, 6.03; N, 20.91; S, 15.60 EXAMPLE XX A mixture of methyl 6 - azido - 4 - S - benzoyl - 2,3,4,6 - tetradeoxy - 4 thio - a - D - threo - hexopyranoside (0.72 g, 3.5 mmol), acetone-deactivated Raney nickel (5 g) and alcohol (20 ml) was stirred at room temperature for 5h. The catalyst was removed and the filtrate was concentrated to give an oil which was purified by distillation at 70-80 /1 Torr. Yield: 0.36 g (85 /n) of pure methyl 6 azido - 2,3,4,6 - tetradeoxy - a - D - glycero - hexopyranoside as a colourless oil.

Analysis: Calculated for C7H13N3O2: C, 49.11; H, 7.65; N, 24.54 Found: C, 49.30; H, 7.78; N, 24.38% EXAMPLE XXI A mixture of methyl 6 - azido - 4 - S - benzoyl - 2,3,4,6 - tetradeoxy - 4 thio - a - D - threo - hexopyranoside (0.2 g, 0.65 mmol) and partially deactivated Raney nickel (10 g) in ethanol (20 ml) was stirred at 220 for 12 h and then filtered.

The solids were washed with ethanol and the organic solution was concentrated to give a syrup which was purified by silica gel column chromatography (eluant: chloroform). A clear syrup of pure methyl 6 - benzamido - 2,3,4,6 - tetradeoxy - a D - glycero - hexopyranoside was obtained. [α]D23+72.2 (c 1.7, methanol). TLC: Rf 0.55 (chloroform-ethyl acetate, 1:1), Rf 0.25 (chloroform).

IR VmaxCHCl3 3330 (NH), 2940, 1650 (NCOPh), 1605 (Ph), 1585, 1545 (Amide II) cm-1.

PMR data (CDCl3, 110 ): # 1.30-2.52 (m, 6 H, H-2,2',3,3',4,4'), 3.33 and 3.42 (2 s, 6 H, 2 OMe), 3.57 (m, 2 H, H-6,6'), 4.80 (m, 1 H, H-5), 5.76 (m, 1 H, H-la), 6.70 (b. band, 1 H, -NHCO), 7.45 and 7.80 (2 sets of multiplets, 5 H, -Ph).

Analysis: Calculated for C14H19NO3: C, 67.44; H, 7.68; N, 5.62 Found: C, 67.68; H, 7.40; N, 5.41% EXAMPLE XXII A mixture of methyl 6 - azido - 4 - 0 - mesyl - 2,3,6 - trideoxy - a - D erythro - hexopyranoside (0:265 g, 1 mol) and anhydrous sodium benzoate (.72 g, 5 mmol) in hot N,N-dimethylformamide (35 ml) was heated at 110 for 4 h, then poured into ice-water. Extraction of the mixture with ether, followed by washing of the organic phase with water and concentration of the dried extracts gave a syrup (0.25 g, 890/,) which was purified by silica gel chromatography using benzenechloroform mixtures as eluant. Pure methyl 6 - azido - 4 - 0 - benzoyl - 2,3,6 trideoxy - α - D - threo - hexopyranoside was obtained as a syrup, b.p.: 120 140 /0.1 Torr. [α]D21+68 (c 0.4, chloroform). IR vmaxCHCl3 2100 (N3) 1710 (OCOPh), 1600 (Ph), cm-'.

PMR data (CDCl2): a 1.75 (m, 4 H, H-2,2',3,3'), 3.52 (m, 2 H, H-6,6') 3.45 (s, 3 H, OMe), 4.12 (m, 1 H, H-S), 4.86 (s, 1 H, H-la), 5.13 (s, 1 H, H-4), 7.50 and 8.08 (2 m, total intensity 5 H, -Ph).

Analysis: Calculated for C16H21NO6: C, 55.91; H, 6.14; N, 15.05 Found: C, 56.00; H, 6.06; N, 14.85% EXAMPLE XXIII A mixture of methyl 4 - 0 - mesyl - 6 - methoxycarbonylamino - 2,3,6 trideoxy - a - D - erythro - hexopyranoside (0.16 g, 0.6 mmol) and anhydrous sodium benzoate (0.72 g, 55 mmol) in hot N,N-dimethylformamide (15 ml) was heated at 110 for 4 h. The solution was poured into ice-water and extracted with ether. The organic layer was washed with water, dried and concentrated to give a syrup which was purified by silica gel column chromatography using benzenechloroform mixtures as eluant.

Pure, syrupy methyl 4 - 0 - benzoyl - 6 - methoxycarbonylamino - 2,3,6 trideoxy - α - D - threo - hexopyranoside (0.13 g, 0.66 g) had the following analytical characteristics: [α]D21+32 (c 0.23, chloroform). TLC: Rf 0.5 (chloroform-ethyl acetate, 1:1).

IRvmaxCHCl3 3100 (NH), 2930, 1710 (OCOPh), 1690 (NCOOMe), 1600 (Ph), 1520 cm-l (Amide II).

PMR data (CDCI3): a 1.76 (m, 4 H, H-2,2',3,3'), 3.39 (s, 3 H, OMe) 3.61 (s, 3 H, NCOOMe), 4.04 (m, 1 H, H-S), 4.83 (s, 1 H, H-la), 5.20 (bm, 2 H, H-4) and NH), 7.50 and 8.09 (2 m, 5 H total intensity, -Ph).

Analysis: Calculated for C16H21NO6: C, 59.43; H, 6.55; N, 4.33 Found: C, 59.20; H, 6.40; N, 4.21% EXAMPLE XXIV 5,6 - O - cyclohexylidene - tetra - N - methoxycarbonylneamine (S.

Umezawa et al., Bull. Chem. Soc. Japan, 46, 3507, 1973) (15 g, 23.7 mmol) in tetrahydrofuran (100 ml) was treated with a solution of sodium metaperiodate. The solution was concentrated, the residue was extracted with hot chloroform, and the combined extracts were washed with water, dried and concentrated. The residue (15 g) was recrystallized from water-ethanol to give the pure dialdehyde: 5,6 - O cyclohexylidene - 2 - deoxy - 4 - O [(1R, 2R) - 1 - [(1R) - 1 - formyl - 2 (methoxycarbonylamino)ethoxy] - 2 - formyl - 2 - (methoxycarbonylamino) - ethyl] 1,3 - bis - N - methoxycarbonylstreptamie (13.2 g, 88%) M.p.: 127-133 , [α]D20α4 (c 0.57, N,N-dimethylformamide). TLC: Rf 0.60 (ethyl acetate-ethanol, 8:1), Rf 0.3 (ethyl acetate).

IR vmaxNujol 3290 (broad NH,OH), 1710 (-CHO), 1695 (NCOOMe), 1530 cm- (Amide II). (The word "Nujol" is a Registered Trade Mark).

PMR data (methylsulphoxide-d6): a 1.55 (bm, 12 H, H-2,2 and cyclohexylidene protons), 3.52 (m, 12 H, 4 NCOOMe), 5.62 (m, 1 H, H-1'α), 6,80-7.50 (4 H, NH), 8.30 and 9.12 (2s, 1.5, CHO).

Analysis: Calculated for C26H40N4O14#0.5 H2O: C, 48.66; H, 6.44; N, 8.73 Found: C,48.75; H, 6.53; N, 8.60% The product isolated in the previous step described above (2 g, 3.1 mmol) in methanol (30 ml) was treated with NaOMe (0.2 g) at 220 for 24 h. Sodium borohydride (0.3 g) in water (10 ml) was added and the mixture was stored at 220 for 12 h. The solution was concentrated to dryness and the residue was extracted with acetone. Concentration of the extracts left a solid which was purified by silica gel column chromatography using chloroform-ethyl acetate-1% triethylamine as eluant. The isolated product was recrystallized from ethyl acetate to give 0.38 g (34%) of pure 5,6- Q - cyclohexylidene- 2- deoxy - 1,3- di - N methoxyearbonylstreptamine. M.p.: 109-111 . [a]022+140 (c 1, chloroform);+100 (c 1, methanol).

IR vmaxNujol 3390 (OH), 3260 (NH), 1690 (NCOOMe), 1550 cm-l (Amide II).

PMR data (methylsulphoxide-d6): 6 1.48 (bm, 12 H, H-2,2 and cyclohexylidene protons), 3.52 (s, 6 H, 2 NCOOMe), 5.14 (m, 1 H, OH), 7.38 (b. band, 2 H, 2 NH).

Analysis: Calculated for C16H26N2O7: C, 53,62; H, 7.31; N, 7.81 Found: C, 53.52; H, 7.20; N, 7.53% EXAMPLE XXV A mixture of 5,6 - 0 - cyclohexylidene - 2- deoxy - 1,3 - di - Nmethoxycarbonylstreptamine (0.3 g)in pyridine (3 ml) and acetic anhydride (0.5 ml) was stored at 220 for 10 h. It was then concentrated to a small volume and poured into ice-water The oily material was extracted with chloroform and the extracts were washed with saturated NaHCO3 solution and water, then dried. On evaporation they gave a solid (0.31 g, 93 /n) which was crystallized from ethyl acetate-petroleum ether 4060 to give pure 4- 0 - acetyl - 5,6 - 0 - cyclohexylidene - 2 - deoxy -1,3 - di - N - methoxycarbonylstreptamine, m.p.: 1647 166. [α]D23-4.6 (c 1.2, chloroform). TLC: Rf 0.5 (ethyl acetate).

PMR data (CDCI3): a 1.43 (bm, 12 H, 10-cyclohexylidene protons and H-2,2), 2.10 (s, 3 H, -OAc), 2.65 (bm, 2 H, H-1,3), 3.63 and 3.68 (2 s, 6, 6 H, 2 NCOOMe), 4.85-6.40 (bm, 3 H, H-4 and 2 NH).

Analysis: Calculated for C18H28N2O8: C, 53,99; H, 7.05; N, 6.99 Found: C, 54.01; H, 6.97; N, 6.52% EXAMPLE XXVI A mixture of the dialdehyde obtained in the first part of Example XXIV (16 g, 25.2 mmol), ethanol (250 ml) and triethylamine (25 ml) was stirred at 220 for 24 h, then concentrated. A solution of the syrupy residue in water (150 ml) was treated with a solution of NaBH4 (2 g) in water (20 ml) for 12 h. The mixture was concentrated, the solid residue was extracted with chloroform (3x30 ml) and the extracts were washed with water, dried and concentrated. The residue was acetylated with acetic anhydride (S ml) and pyridine (50 ml) for 24 h, and the solid obtained after concentration of the mixture was eluted from silica gel with ethyl acetate to give 4.84 g, (48%) of 4 - 0 - acetyl - 5,6-- 0 - cyclohexylidene - 2 deoxy I

EXAMPLE XXVII A solution of 4 - 0 - acetyl - 5,6 - 0 - cyclohexylidene - 2 - deoxy - 1,3 di - N - methoxycarbonylstreptamine (0.2 g, 0.05 mmol) in methanol (4 ml) was stirred with a solution of Ba(OH)2 . BH2O (0.6 g) in water (3 ml) at 800 for 24 h, then neutralized with CO2 and centrifuged. The supernatant was concentrated to dryness, the residue was extracted with methanol and the filtered extracts were concentrated to a syrup which was eluted from Amberlite CG 50 (NH4+) resin with 0.1-0.2 N aqueous methanolic ammonia (1:1). Evaporation of the eluates gave a syrup which was dissolved in water (0.5 ml) and neutralized with 0.5 N H2SO4. The sulphate of 5,6 - 0 - cyclohexylidene - 2 - deoxystreptamine was obtained by precipitation with dioxan (83 mg, 48%). M.p.: 212 (decomp.). [α]D20-9 (c 0.57, water). TLC: Rf 0.4 (chloroform-methanol-conc. ammonia, 100:30:3), Rf 0.65 (methanol-conc. ammonia, 8:1).

Analysis: Calculated for C12H22N2O3 . H2SO4: C, 43.34; H, 7.10; N, 8.23 Found: C, 42.45; H, 7.20; N, 8.17% EXAMPLE XXVIII Sodium hydride (60% oil dispersed, 0.16 g, 6.2 mmol, 23% excess) was added gradually, with stirring, to a solution of 5,6 - 0 - cyclohexylidene - 2 - deoxy 1,3 - di- N- methoxycarbonylstreptamine (0.62 g, 1.7 mmol) in N,Ndimethylformamide, cooled at 0-5 . After 1 h, benzyl bromide (1 g, 6.7 mmol, 20% excess) was added with vigorous stirring. The reaction was stored at 250 for 24 h, after which pyridine (3 ml) was added and the mixture was stored for a further hour. Concentration of the solution in vacuo (1 Torr) left a syrup which was poured into ice-water and extracted with chloroform. The extracts were washed with water, dried, concentrated and azeotroped with toluene to give a syrup which was fractionated by silica gel column chromatography using benzene and chloroform as eluants. Among other components separated, compound a): 5,6- 0 - cyclohexylidene - 2 - deoxy - 1,3 - di - N - methoxycarbonyl - 1 - N, 3 - N, 4 0 tribenzylstreptamine was isolated in 18% yield. M.p: 8-87", [d]2-40 (c 1, chloroform). TLC: Rf 0.4 (benzene-ethyl acetate, 9:1).

IR: vmaxCHCl3 1695 (NCOOMe), 1600 (Ph), 1500 (benzyl) cm-l.

PMR data (CDCl3, 80 ): a 1.56 (bm, 11 H, H-2ax and 10 cyclohexylidene protons), 3.56 and 3.64 (2 s, 6 H, 2-NCOOMe), 7.19 and 1.27 (2 s, 15 H, 3 Ph).

Analysis: Calculated for C37H44N2O7: C, 70.70; H, 7.00; N, 4.45 Found: C, 70.53; H, 7.14; N, 4.56% EXAMPLE XXIX Another component (compound b), was isolated from the chromatographic fractionation carried out in Example XXVIII.

The yield of compound b): 5,6 - 0 - cyclohexylidene - 2 - deoxy - 1,3 - di - N benzyl - I - N - methoxycarbonylstreptamine - 3:4 carhamate, was 50%. M.p.: 100- 1030. [α]D22-35 (c 1, chloroform). TLC: Rf 0.3 (benzene-ethyl acetate, 9:1).

IR: vmaxCHCl3 1760 (NCOO cyclic), 1690 (NCOOMe), 1605 (Ph), cm-1.

PMR data (CDCl3): a 1.58 (bm, 12 H, H-2,2 and 10 cyclohexylidene protons), 3.72 (s, 3 H, NCOOMe), 7.25 (m, 10 H, 2 Ph).

Analysis: Calculated for C29H34N2O: C, 68.75; H, 6.76; N, 5.52 Found: C, 69.00; H, 7.03; N, 5.25% EXAMPLE XXX Method I A solution of 5,6 - 0 - cyclohexylidene - 2 - deoxy - 1,3 - di - N - benzyl 1 - N - methoxycarbonylstreptamine - 3:4 - carbamate (0.15 g, 0.3 mmol) in dry methanol (15 ml) was treated at 700 for 2 h with sodium methoxide (20 mg). The mixture was neutralized with CO2 and concentrated. The residue was then extracted with chloroform and the extracts were concentrated to give 5,6 - 0 cyclohexylidene - 2- deoxy - 1,3 - di - N- benzyl - 1,3 - di - N methoxycarbonylstreptamine (0.13 g, 81%). M.p.: 130-132.5 (from ether).

[α]D22-9.5 (c 1, chloroform).

IR: vamxCHCl3 3520 (OH), 1695 (NCOOMe), 1605 (Ph) cm-1.

PMR data (CDCl3): # 1.55 (bm, 12 H, H-2,2 and 10 cyclohexylidene protons), 2.54 (s, 1 H, OH), 3.66 and 3.69 (2 s, 6 H, 2 NCOOMe), 4.42 (m, 4 H, 2 CH2 Ph), 7.23 (m, 10 H, 2 Ph).

Analysis: Calculated for C30H38N2O,: C, 66.89; H, 7.11; N, 5.20 Found: C, 66.70; H, 7.10; N, 5.20% Method II A solution of 5,6 - 0 - cyclohexylidene - 2- deoxy - 1,3 - di - N methoxycarbonyl - I - N, 3 - N, 4 - 0 - tribenzylstreptamine (0.314 g, 0.5 mmol) in methanol (15 ml) was hydrogenated over 10% palladium-on-charcoal catalyst (50 mg) at 3 atmos., 20 for 10 h. The catalyst was filtered and washed with methanol and the combined organic liquids were concentrated to give a solid which was recrystallized from ether, 5,6 - 0 - cyclohexylidene - 2 - deoxy - 1,3 - di - N benzyl -1,3 - di - N - methoxycarbonylstreptamine. Yield: 95% (0.26 g). M.p.: 130- 132.5 . [a]2-9.50 (c 1, chloroform).

The chromatographic mobilities of this compound, as well as the IR and PMR spectra, were identical with those of the compound described under Method I. No depression of the melting point occurred when both products were mixed.

Analysis: Calculated for C20H28N2O7: C, 66.89; H, 7.11; N, 5.20 Found: C,66.92; H,7.03; N, 5.35% EXAMPLE XXXI Kanamycin sulphate (20 g) in water (100 ml) was basified with 20% NaOH solution to pH 12. Benzaldehyde (15 ml) was added and the mixture was shaken for 3 h. The precipitated solid was filtered, washed with water, dried and dissolved in methanol (100 ml). Chloroform (100 ml) and benzaldehyde (7 ml) were added to the solution and the mixture was stirred for 12 h., concentrated to a small volume and poured into ether (100 ml). The resulting solid was washed with ether and water and dried in vacuo to give tetra - N - benzylidenekanamycin (26 g), m.p. 205-206 .

This material was dissolved in ethanol (700 ml) and treated with sodium borohydride (5 g) in water (25 ml). The mixture was stirred for 12 h, filtered and concentrated. The glassy residue, thus obtained, (36 g) was dissolved in 6N hydrochloric acid (500 ml) and the solution was heated on a water-bath (90 ) for 1 h. The filtered solution was concentrated to a syrup, treated with methanolic HCI and evaporated, this operation being repeated several times to remove boric acid.

The residue was finally treated with methanol and the inorganic salts were filtered off. The solution, upon concentration, and storing at 00, deposited pure 2 - deoxy 1,3 - di - N - benzylstreptamine dihydrochloride (8.33 g). M.p.: 258260 . TLC: Rf 0.45 (chloroform-methanol-ammonia, 100:30:5).

PMR data (D2O): a 2.05 (t, 1 H, H-2ax), 2.60 (m, 1 H, H-2eq), 3.35 (m, 2 H, H 1,3), 3.75 (m, 3 H, H-4,5,6), 4.43 (m, 4 H, 2 CH2 -Ph), 7.57 (m, 10 H, 2 Ph).

Analysis: Calculated for C2oH2aN2O3Cl2: C, 57.83; H, 5.79; N, 6.74; Cl, 17.07 Found: C, 57.90; H, 5.84; N. 6.55; cl,l6-;93- Cl, The starting material for this Example is a commerically available kanamycin sulphate. The kanamycin is typically 85% kanamycin A with the remainder being approximately equal proportions of kanamycin B and kanamycin C.

EXAMPLE XXXII A mixture of 2 - deoxy - 1,3 - di - N - benzylstreptamine dihydrochloride (5 g, 12 mmol) and sodium carbonate (5 g) in water (250 ml) and acetone (50 ml) was treated dropwise with methyl chloroformate (3 ml, 39 mmol) in acetone (100 ml) at 0 for 3 h, and stored at 50 for 12 h. It was then concentrated and the residue was extracted with chloroform. The extracts were concentrated to give a syrup which was recrystallized from chloroform-ether. 2 - Deoxy -1,3 - di - N - benzyl -1,3 di - N - methoxycarbonylstreptamine was obtained in 86.7% yield (5.18 g), with m.p.

176-180 . TLC: Rf 0.76 (chloroform-methanol-ammonia, 100:30:5).

Analysis: Calculated for C24H30N2O7: C, 62.86; H, 6.59; N, 6.11 Found: C, 62.98; H, 6.72; N, 6.04% EXAMPLE XXXIII A mixture of 2 - deoxy - 1,3 - di - N- benzyl - 1,3 - di - Nmethoxycarbonylstreptamine (2 g, 4.3 mmol), dry N,N-dimethylformamide (60 ml), anhydrous toluene - p - sulphonic acid (0.1 g) and 1,1 - dimethoxycyclohexane (3 ml) was stirred at 1000 for 2 h. An addition of 1,1 - dimethoxycyclohexane (1 mol) was followed by further stirring and heating for 1.5 h, after which the mixture was neutralized with solid sodium bicarbonate (0.8 g) and concentrated to a syrup. This was extracted into chloroform, the extracts were washed with water, dried and concentrated to give a solid (2 g, 86%) which was recrystallized ten times successively from ether. 5,6 - 0 - Cyclohexylidene - 2 - deoxy - 1,3 - di - Nbenzyl - 1,3 - di - N - methoxycarbonylsteptamie (0.4 g) was obtained, with an optical purity of 79%. M.p.: 129-131 . [α]D21-7.5 (c 2, chloroform). TLC: Rf 0.55 (benzene0ethyl acetate, 1:1); Rf 0.5 (chloroform-ethyl acetate, 3:1).

IR: vamxCHCl3 3520 (OH), 2940, 1695 (NCOOMe), 1605 (Ph) cm-1.

PMR data (CDCl3): # 1.55 (bm, 12 H, H-22, and 10 cyclohexylidene protons), 2.54 (s, 1 H, OH), 3.66 and 3.69 (2 s, 6 H, 2 NCOOMe), 4.42 (m, 4 H, 2 CH2 Ph), 7.23 (m, 10 H, 2 Ph).

Analysis: Calculated for C30H38N2O7: C, 66.89; H, 7.11; N, 5.210 Found: C, 66.94; H, 6.96; N, 5.04% Upon concentration of the mother liquors from the previous preparation, the residue was recrystallized six times and 4,5 - 0 - cyclohexylidene -2 - deoxy - 1,3 di - N - benzyl - 1,3 - di - N - methoxycarbonylstreptamine (0.3 g) was obtained with an optical purity of 63%, [α]D21+6 (c 1, chloroform). TLC: Rf 0.55 (benzene-ethyl acetate, 1:1); Rf 0.5 (chloroform-ethyl acetate, 3:1).

The IR and PMR spectra were identical with those of the isomer isolated above.

Analysis: Calculated for C20H28N2O7: C, 69.89; H, 7.11; N, 5.20 Found: C, 69.68; H, 7.01; N, 5.06% EXAMPLE XXXIV A solution of 5,6 - 0 - cyclohexylidene - 2- deoxy - 1,3 - di - N methoxycarbonyl - 1 - N, 3 - N, 4 - 0 - tribenzylstreptamine (0.628 g, 1 mmol), in 50 /n aqueous acetic acid was heated at 800 for 20 minutes and concentrated in vacuo. The residue was azeotroped with benzene, dissolved in 2,2 dimethoxypropane (4 ml) containing toluene - p - sulphonic acid (50 mg), and heated at 700 for 5 h. After neutralization of the mixture with triethylamine (1 ml) and concentration, a syrup was obtained which was extracted into chloroform. The extracts were washed with water, dried and concentrated and the residue, dissolved in methanol (10 ml) was hydrogenated over 5% palladium-on-charcoal (0.1 g) at 1 atmos. for 6 h. The filtered reaction mixture was concentrated and the solid, upon recrystallization from aqueous ethanol, gave pure 2 - deoxy - 1,3 - di - N - benzyl 1,3 - di - N - methoxycarbonyl - 5,6 - O - isopropylidenestreptamine (0.35 g, 70%), m.p. 137 [α]D23-10 (c 1, chloroform). TLC: Rf 0.57 (ethyl acetate).

PMR data (CDCl3): # 1.15 (m, 1 H, H-2ax), 1.35 (s, 6 H, 2 Me, isopropylidene), 1.75 (m, 1 H, H-2eq), 2.55 (b band, 1 H, OH), 3.30 (m, 4H, H01,3,4,5), 3.68 (2 s, 6 H, 2 NCOOMe), 4.27 (m, 1 H, H-6), 4.48 (m, 4 H, 2-CH2 PH), 7.23 (m, 10 H, 2 Ph).

Analysis: Calculated for C27H24N2O7 C, 65.04; H, 6.87; N, 5.61 Found: C, 65.18; H, 6.99; N, 5.74% EXAMPLE XXXV A mixture of 2 - deoxy - 1,3 - di - N - benzylstreptamine (10 g, 24 mmol), anhydrous Na2CO3 (15 g) in 50% aqueous acetone (50 ml) was treated with benzyl chloroformate for 0.5 h at 0 with vigorous stirring, which was continued for a further 3 h. The mixture was concentrated to a small volume and extracted with chloroform. Concentration of the extracts gave a syrup of 2 - deoxy - 1,3 - di - N benzyl - 1,3 - di - N - benzyloxycarbonylstreptamine (11.2 g. 85%) [TLC: Rf 0.17 (ethyl acetate).] This syrup (4 g, 7.4 mmol) was dissolved in dry N,N-dimethylformamide (60 ml) containing toluene-p-sulphonic acid (.15 g) and 1,1-dimethoxycyclohexane (6 ml).

The mixture was stirred and heated at 1000 for 2 h, then neutralized with solid NaHCO3 (1 g) and concentrated (1 Torr) to a syrup. This was extracted into ether, and the extracts, after being washed with water and dried, were concentrated to give a solid. Recrystallization of this from benzene gave the racemic mixture containing 5,6 - 0 - and 4,5 - 0 - cyclohexylidene - 2 - deoxy - 1,3 - di - N benzyl - 1,3 - di - N - benzyloxyearbonylstreptamine (4.15 g, 88%), m.p.: 147-150 .

TLC: R, 0.35 (chloroform), Rf 0.45 (chloroform-ethyl acetate, 15:1).

IR: nCHcl3 3430 (OH), 1690 (NCOOCH2), 1600 (Ph), 1585 (Ph) cm-1.

PMR data (CDCI3, 80 ): a 1.55 (m, 12 H, H-2ax, 2eq and 10 cyclohexylidene protons), 2.15 (broad, 1 H, OH), 4.40 (m, 4 H, 2-O-CH2 Ph), 5.12 (s, 4 H, 2 NCH2 Ph), 7.23 (m, 20 H, 4 Ph).

Analysis: Calculated for C40H46N2O7: C, 72.04; H, 6.95; N, 4.15 Found: C, 71.82; H, 7.07; N, 4.20% EXAMPLE XXXVI A solution of methyl 6 - azido - 2,3,6 - trideoxy - a - D - erythro hexopyranoside (0.187 g, 1 mmol) and 6 - azido - 6 - deoxy - 3,4 - di - 0 acetyl - D - glucal (0.255 g, 1 mmol) in dry benzene (18 ml) was treated with boron trifluoride etherate (0.05 ml) and stirred at 200 for 0.5 h. Triethylamine (1 ml) was added and the stirring was continued for a further 25 minutes. The reaction mixture was washed with water, dried and concentrated to give a syrup (0.325 g, 85%) which, after purification by silica gel column chromatography using benzene as eluant, gave pure syrupy methyl 4 - 0 - (4 - 0 - acetyl - 6 - azido - 2,3,6 - frideoxy - a - D - erythro - hex - 2 - eno - pyranosyl) - 6 - azido - 2,3,6 - trideoxy a - D - erythro - hexopyranoside. [a]022+810 (C 0.28, chloroform). TLC: R, 0.4 (benzene-ethyl acetate, 10:1); Rf 0.25 (benzene-chloroform, 1:1).

IR aCHCl3 2100 (N3), 1735 (OAc) cm-'.

PMR data (CDC12): a 1.75 (m, 4 H, H-2,2,3,3), 2.09 (s, 3 H, OAc), 3.39 (s, 3 H, OMe), 3.42 (bm, 4 H, H-6,6,6',6'), 3.80 (m, 3 H, H-4,5,5'), 4.73 (s, I H, H la), 5.21 (s, 1 H, H-l'a), 5.30 (m, 1 H, H-4'), 5.78 (m, 1 H, H-3'), 5.85 (m, 1 H, H, H-2').

Analysis: Calculated for C1H22N6O6: C, 47.11; H, 5.80; N, 21.98 Found: C,47.03; H, 5.94; N, 22.10% EXAMPLE XXXVII A mixture of 5,6 - 0 - cyclohexylidene - 2 - deoxy - 1,3 - di - N - benzyl 1,3 - di - N - methoxycarbonylstreptamine (1.03 g, 1.91 mmol), tri - 0 - acetyl D - glucal (0.8 g, 2.9 mmol) and dry benzene (20 ml), was treated with boron trifluoride etherate (0.03 ml) and stirred at 20 for 0.5 h. Triethylamine (1 ml) was added and the stirring was continued for a further 20 minutes. The reaction mixture was washed with water, dried and hydrogenated over 10% palladium-on-charcoal (20 mg) at 2 atmos. for 3 h. After filtering the suspension, and washing the catalyst with methanol, the combined organic liquids were concentrated to give a glassy product (1.53 g, 85%). This product, dissolved in methanol (20 ml), was catalytically deacetylated with sodium methoxide (20 mg) for 12 h at 220. Neutralization of mixture with CO2 was followed by concentration to give a syrup which was extracted into chloroform. The extracts, once filtered, were concentrated to a solid residue which was purified by silica gel column chromatography using chloroformethyl acetate as eluant. 4 - Q - (2,3 - dideoxy - a - D - erythro hexopyranosyl) - 5,6 - O - cyclohexylidene - 2 - deoxy - 1,3 - di - N - benzyl -1,3 di - N - methoxycarbonylstreptamine was obtained (1.35 g) as a crystalline product.

M.P.: 153-159 [α]D23+42.7 (c 1, chloroform).

IR: DmaxCHCl 3450 (OH), 1690 (NCOOMe), 1605 (Ph) cm-1.

PMR data (CDCl3, 80 ): a 1.15-2.00 (bm, 16 H, H-2,2,2',2',3',3' and 10 cyclohexylidene protons), 2.21 (b. band, 2 H, 20 H), 3.65 and 3.66 2 s 6 H, 2 NCOOMe), 5.24 (m, 1 H, H-l'a), 7.20 (m, 10 H, 2 Ph).

Analysis: Calculated for C26H48N2O10: C, 64.65; H, 7.23; N, 4.18 Found: C,64.62; H,7.35; N, 4.15% EXAMPLE XXXVIII A mixture of 5,6 - 0 - cyclohexylidene - 2 - deoxy - 1,3 - di - N - benzyl 1,3 - di - N - methoxycarbonylstreptamine (0.306 g, 0.57 mmol), tri - 0 - acetyl D - glucal (0.24 g, 0.9 mmol) and dry benzene (10 ml) was treated with boron trifluoride etherate (0.03 ml) and stirred at 200 for 0.5 h. Triethylamine (1 ml) was added and the stirring continued for a further 20 minutes. The reaction mixture was washed with water, dried and concentrated to give a glassy product. This was catalytically deacetylated in methanol (10 ml) with sodium methoxide (15 rngWat 22 for 12 h. Neutralization of the mixture with CO2 was followed by concentration to give a syrup which was extracted with chloroform. The extracts, washed with water, dried and concentrated, gave a residue which was eluted from silica gel with benzene-chloroform mixtures. 4 - O - (2,3 - Dideoxy - α - D - erythro - hex - 2 enopyranosyl - 5,6 - O - (cyclohexylidene - 2 - deoxy - 1,3 - di - N - benzyl - 1,3di - N - methoxyearbonylstreptamine (0.4 g. 95%) was obtained as a colourless solid, M.p.: 114-118 . [α]D23+36 (c 0.86, methanol). TLC: Rf 0.3 (chloroform-ethyl acetate, 1:1); Rf 0.55 (ethyl acetate).

IR: vaxCHCl3 3440 (OH), 1695 (NCOOMe), 1605 (Ph), 1590 (Ph) cm-1.

PMR data (CDCl3): # 1.56 (m, 12 H, H-2ax, 2eq and 10 cyclohexylidene protons), 2.88 (b. band, 2 H, 2 OH), 3.66 (bs, 6 H, 2 NCOOMe), 5.42 (m, 1 H, H-l'a), 5.89 (m, 2 H, H-2',3'), 7.25 (m, 10 H, 2 Ph).

Analysis: Calculated for C36H46N2O10; C, 64.84; H, 6.95; N, 4.20 Found: C, 64.98; H, 7.04; N, 4.15% EXAMPLE XXXIX A benzenic solution (25 ml) of 4,5 - 0 - cyclohexylidene - 2 - deoxy - 1,3 di - N - benzyl - 1,3 - di - N - methoxycarbonylstreptamine (0.5 g, 0.92 mmol) and tri - 0 - acetyl - D - glucal (0.4 K, 1.5 mmol) was treated with boron trifluoride etherate (0.06 ml) and stirred for 0.5 h at 220. Triethylamine (1 ml) was added and after 20 minutes stirring period, the mixture was washed with water, hydrogenated over 10% palladium-on-charcoal (70 mg) at 2 atmos. for 3 h. The catalyst was filtered and washed with methanol, the combined organic liquids were concentrated to give a glassy residue (0.76 g, 85). This was deacetylated with sodium methoxide (20 mg) in methanol (25 ml) for 12 h at 220. Neutralization (CO2) and concentration left a residue which was extracted into chloroform. The extracts were filtered and concentrated, and the solid thus obtained was purified by silica gel column chromatography using benzene-chloroform mixtures as eluant. The crystalline solid obtained, 6 -Q - (2,3 - dideoxy - 2 - D - erythro - hexopyranosyl) 4,5 - O - cyclohexylidene - 2 - deoxy - 1,3 - N - benzyl - 1,3 - di - N methoxyearbonylstreptamine (0.447 g, 72%), had m.p.: 121-125 . [α]D21+36.7 (c 0.7, chloroform). TLC: Rf 0.65 (chloroform-ethyl acetate, 1:1).

IR: vmaxCHCl3 3480 (OH), 1695 (NCOOMe), 1600 (Ph) cm-1 PMR data (CDCl3, 80 ): # 1.55 (bm, 16 H, H-2,2,2',2',3',3' and 10 cyclohexylidene protons), 2.25 (bm, 2 H, 20 H), 3.66 (m, 6 H, 2 NCOOMe), 5.32 (m, 1 H, H-l'a), 7.20 (m, 10H, 2 Ph).

Analysis: Calculated for C38H48N2O10: C, 64.65; H, 7.23; N, 4.18 Found: C, 64.71; H, 7.20; N, 4.07% EXAMPLE XL A mixture of 5,6 - 0 - cyclohexylidene - 2 - deoxy - 1,3 - di - N - benzyl 1,3 - di - N- methoxycarbonylstreptamine (0.5 g, 0.92 mmol) and tri - 0 acetyl - D - glucal (0.4 g, 1.5 mmol) was treated with boron trifluoride etherate (0.06 ml) and stirred for 0.5 h at 22 . The reaction mixture was processed as in Example XXXIX, except for the deacetylation procedure which was not carried out in this Example. The crude syrupy residue was chromatographed on silica gel.

Elution with benzene-chloroform mixtures gave a solid which was recrystallized from ethanol-petroluem or ether-petroleum to give pure 4 - O - (4,6 - di - 0 acetyl - 2,3 - dideoxy - a - D - erythro - hexopyranosyl) 5,6 - 0 - cyclohexylidene 2 - deoxy - 1,3 - di - N - benzyl - 1,3 - di - N - methoxycarbonylstreptamine, m.p.: 70-75 . [α]D23+51 (c 1, chloroform). TLC: Rf 0.55 (chloroform-ethyl acetate, 5:1).

IR: vmaxCHCl3 1730 (OAc); 1690 (NCOOMe).

PMR data (CDC13, 95 ): a 1.26-1.89 (bm, 16 H, H-2,2,2',2',3',3' and 10 cyclohexylidene protons), 1.96 and 1.99 (2 s, 6 H, 2 OAc), 3.63 and 3.65 (2 s, 6 H, 2 NCOOMe), 5.27 (m, 1 H, H-l'a), 7.15 (m, 10 H, 2 Ph).

Analysis: Calculated for C40H52N2O12: C, 63.82; H, 6.91; N, 3.72 Found: C, 63.51; H, 7.16; N, 3.48% EXAMPLE XLI Method I A mixture of 2 - deoxy - 1,3 - di- N- benzyl- 1,3 - di- Nmethoxycarbonyl - 5,6 - 0 - isopropylidenestreptamine (0.4 g, 0.8 mmol), tri - 0 acetyl - D - glucal (0.24 g, 0.9 mmol) and dry benzene (10 ml) was treated with boron trifluoride etherate (0.02 ml) with stirring, at 22 , for 0.5 h. It was neutralized with triethylamine (1 ml), washed with water and hydrogenated over 10% palladium-on-charcoal (50 mg) at 2 atmos. for 3 h. The catalyst was filtered off and washed with methanol, the combined organic liquids were concentrated and the residue was dissolved in chloroform (10 ml) containing toluene-p-sulphonic acid (20 mg) and methanol (2 ml). The mixture was heated at 55-60 for 2 h, neutralized with triethylamine (0.5 ml) and concentrated to dryness. The residue, after extraction with chloroform, was purified by silica gel column chromatography using chloroform-ethyl acetate mixtures as eluant. The yield of pure syrupy 4 -Q (4,6 - di - O - acetyl -2,3 - dideoxy - a - D - erythro - hexopyranosyl) -2 - deoxy 1,3 - di - N - benzyl - 1,3 - di - N - methoxycarbonylstreptamine was 0.37 g (68.7%).

[α]D20+38 (c 1, chloroform). TLC: Rf 0.3 (ethyl acetate).

PMR data (CDCl3): # 1.55 (m, 6H, H-2,2,2',2'3',3'), 2.02 (2 s, 6 H, 2 OAc), 3.64 (m, 6 H, 2 NCOOMe), 4.10 (m, 2 H, H-6',6'), 4.43 (m 4 H, 2 CH2 Pb), 5.40 (m, I H, H-l'a), 7.23 (m, 10 H, 2 Ph).

Analysis: Calculated for C34H44N2O12: C, 60.70; H, 6.59; N, 4.16 Found: C, 60.62; H, 6.30; N, 4.29% Method II A chloroformic solution (20 ml) of 4 - 0 - (4,6 - di - 0 - acetyl - 2,3 dideoxy - α - D - erthro - hexopyranosyl) - 5,6 - O - cyclohexylidene - 2 deoxy - 1,3 - di - N - benzyl - 1,3 - di - N - methoxycarbonylstreptamine (0.15 g, 0.2 mmol), toluene-p-sulphonic acid (20 mg) and methanol (3 ml) was heated at 5060 for 2h, and then neutralized with triethylamine (0.5 ml). Concentration of the reaction mixture and chromatography of the residual syrup as in Method I gave pure amorphous, glassy 4 - 0 - (4,6 - di - 0 - acetyl - 2,3 - dideoxy - a - D erythro - hexopyranosyl)- .'- deoxy - 1,3 - di - N - benzyl - 1,3 - di - N - methoxyearbonylstreptamine (0.117 g, 87%). [α]D20+38 (c 1, chloroform). TLC: R, 0.30 (ethyl-acetate).

IR: vmaxCHCl3 3440 (OH), 1745 (OAc), 1695 (NCOOMe) cm~1.

The PMR spectrum of this product was identical to that of the compound prepared according to Method I.

Analysis: Calculated for C34H44N2012: C, 60.70; H, 6.59; N, 4.16 Found: C, 60.75; H, 6.47; N, 4.07% EXAMPLE XLII When 6 - 0 - (4,6 - di - D - acetyl - 2,3 - dideoxy - a - D - erythro hexopyranosyl) - 4,5 - O # cyclohexylidene - 1,3 - di - N - benzyl - 1,3 - di - -N - methoxycarbonylstreptamine was reacted under the same conditions and with identical quantities of reagent as in the case of the 4-O-isomer described in Example XLI, Method II, the corresponding 6 - O - (4,6 - di - O - acetyl - 2,3 dideoxy - a - D - erythro - hexopyranosyl) - 2 - deoxy - 1,3 - di - N - benzyl -1,3 di - N - methoxycarbonylstreptamine (99.5 mg, 74%) was obtained as a glassy product. [α]D20+21.5 (c 1, chloroform). TLC: Rf 0.40 (ethyl acetate).

IR: vmaxCHCl3.3440 (OH), 1745 (OAc), 1695 (NCOOMe) cm-1.

PMR data (CDCl3, 100 ): # 1.40-1.90 (m, 6 H, H-2,2,2',2',3',3'), 2.00 (2. s, 6 H, 2 OAc), 3.65 (2 s, 6 H, 2 NCOOMe), 4.65 (m, 1 H, H-l'a), 7.17 (m, 10 H, 2 Ph).

Analysis: Calculated for C34H44N2O12: C, 60.70; H, 6.59; N, 4.16 Found: C, 60.90; H, 6.64; N, 4.26$ EXAMPLE XLIII Carbon tetrachloride (0.5 ml) and hexamethylphosphorous acid triamide (0.6 ml) were added to a solution of 4 - O - (2,3 - dideoxy - α - D - erythro hexopyranosyl) - 5,6 - O - cyclohexylidene - 2 - deoxy - 1,3 - di - N - benzyl 1,3 - di - N- methoxycarbonylstreptamide (0.64 g, 0.95 mmol) in dry N,Ndimethylformamide (4 ml). The mixture was stirred at -45 under nitrogen for 1.5 h. Sodium azide (0.8 g) was then added, the mixture was stirred at 800 for 12 h, and it was poured into ice-water and ether extracted. The extracts were washed with water, dried and concentrated to give a glassy residue which was purified by silica gel column chromatography using benzene-chloroform mixtures as eluant. The solid isolated was recrystallized from ether-petrol to give pure 4 - O - (6 - azido 2,3,6 - trideoxy - a - D - erythro - hexopyranosyl) - 5,6 - O - cyclohexylidene - 2 deoxy - 1,3 - di - N - benzyl - 1,3 - di - N - methoxycarbonylstreptamine (0.5 g, 7 EXAMPLE XLV A mixture of 4 - 0 - (6 - azido - 2,3,6 - trideoxy - a - D - erythro hexopyranosyl) - 5,6 - O - cyclohexylidene - 1,3 - di - N - benzyl - 1,3 - di - N methoxycarbonyl - 2 - deoxystreptamine (0.12 g, 0.18 mmol), isopropanol (4 ml), 90% hydrazine hydrate (5 ml) and 10% palladium-on-charcoal (30 mg) was boiled under redlux and nitrogen for 24-36 h. the solution was filtered, the catalyst was washed with ethanol and the combined organic liquids were concentrated and repeatedly azeotroped with water to remove excess of hydrazine. The syrupy residue was extracted with chloroform, the extracts, after concentration, gave a solid which was purified by preparative TLC. Pure 4 - 0 - (6 - amino - 2,3,6 trideoxy - α - D - erythro - hexopyranosyl) - 5,6 - O - cyclohexylidene - 2 - deopxy 1,3 - di - N - benzylstreptamine (68 mg, 67%) was obtained. M.p.: 182-186 (sinters at 89 ) [α]D24+60 (c 0.9, methanol). TLC: Rf 0.25 (methanol-acetone, 6:1).

IR: vmaxCHCl3 3300 (OH, NH, NH2), 1600 (Ph) cm-1 PMR data (CDCl3): # 1.58 (bm, 16 H, H-2,2,2',2',3',3' and 10 cyclohexylidene protons), 3.85 (bm, 4 H, 2 CH2 Ph), 4.80 (b. band, 5 H, 10 H, 2 NH, 1 NH2), 5.37 (m, I H, H-l'a), 7.26 (m, 10 H, 2 Ph).

Analysis: Calculated for C32H45N3O5: C, 69.66; H, 8.22; N, 7.62 Found: C, 69.80; H, 8.04; N, 7.74% EXAMPLE XLVI Carbon tetrachloride (1 ml) and hexamethylphosphorous acid triamide were added to a solution of 4 - 0 - (2,3 - dideoxy - a - D - erythro - hexopyranosyl) 5.6 - O - cyclohexylidene - 2 - deoxy - 1,3 - di - N - benzyl - 1,3 - di - N methoxycarbonylstreptamine (0.64 g, 0.95 mmol) in dry N,N-dimethylformamide (4 ml). The mixture was stirred at -20 under nitrogen for 1.5 h after which sodium azide (1.0 g) was added and the mixture was stirred at 800 for 12 h. It was then poured into ice-water and extracted with ether. The extracts were washed with water, dried and concentrated to give a glassy residue which was recrystallized from ether-petroleum. 4 - O -(4,6 - diazido - 2,3,4,6 - tetradeoxy - a - D - threo hexopyranosyl) - 5,6 - O - cylohexyylidene - 2 - deoxy - 1,3 - di - N - benzyl - 1,3 di - N - methoxycarbonylstreptamine was obtained in 83% yield (0.57 g). M.p.: 118121 (sinters at 108 ). [α]D21+36.7 (c 0.74, chloroform). TLC: Rf 0.5 (chloroformethyl acetate, 3:2).

IR: vmaxCHCl3 2105 (N3), 1690 (NCOOMe), 1600 (Ph) cm-1.

PMR data (CDC3, 100 ): # 1.57 (m, 16 H, H-2,2,2',2',3',3' and 10 cyclohexylidene protons), 3.66 (s, 6 H, NCOOMe), 4.43 (m, 4 H, 2 CH2 Ph), 5.34 (m, I H, H-l'a), 7.19 (m, 10 H, 2 Ph).

Analysis: Calculated for C26H46N8O8: C, 60.52; H, 6.43; N, 15.55 Found: C, 60.71; H, 6.32; N, 15.65% EXAMPLE XLVII A mixture of 4 - O - (4,6 - di - azido - 2,3,4,6 - tetradeoxy - α - D - threo hexopyranosyl ) - 5,6 - O - cyclohexylidene - 2 - deoxy - 1,3 - di - N - benzyl 1,3 - di - N - methoxycarbonylstreptamine (0.1 g, 0.14 mmol), chloroform (6 ml), toluene-p-sulphonic acid (20 mg) and methanl (3 ml) was heated at 55-60 for 2 h. Triethylamine (0.5 ml) was then added and the mixture was stirred for a further 15 minutes and concentrated to dryness. The residue was extracted with chloroform, the extracts were washed with water, dried and concentrated to give a syrup which was purified by silica gel column chromatography (benzenechloroform as eluant). 4 - O - (4,6 - diazido - 2,3,4,6 - tetradeoxy - α - D - threo hexopyranosyl ) - 1,3 - di - N - benzyl - 1,3 - di - N - methoxycarbonyl - 2 deoxystreptamine was obtained as a colourless solid (85 mg, 95%). M.p.: 134-137 (softens at 119 ). [α]D24+20 (c 0.28, chloroform). TLC: Rf 0.2 (chloroform-ethyl acetate, 1:1).

IR: vmaxCHCl3 3420 (OH), 2105 (N3) 1690 (NCOOMe), 1605 (Ph) cm-1.

PMR data (CDCl3, 80 ): # 1.29 (s, 1 H, H-2ax), 1.90 (m, 5 H, H-2eq, 2',2',3',3'), 2.85 (bm, 2 H, 2-OH), 3.68 and 3.72 (2 s, 6 H, 2 NCOOMe), 5.40 (m, 1 H, H-l'a), 7.21 (m, 10 H, 2 Ph).

Analysis: Calculated for C30H38N8O8: C, 56.42; H, 5.99; N, 17.54 Found: C, 56.60; H, 6.04; N, 17.68% EXAMPLE XLVIII A mixture of 4 - 0 - (6 - azido - 2,3,6 - trideoxy - a - D - erythro hexopyranosyl) - 5,6 - 0 - cyclohexylidene - 2 - deoxy - 1,3 - di - N - benzyl 1,3 - di - N - methoxycarbonylstreptamine (0.344 g, 0.5 mmol) and tri - 0 acetyl - D - glucal (0.204 g, 0.75 mmol) in dry benzene (15 ml) was treated with boron trifluoride etherate (0.05 ml) and the mixture was stirred for 25 minutes at 22 . Triethylamine (1 ml) was added and the stirring was continued for 20 minutes.

The mixture was washed with water, dried and concentrated to yield a glassy material which was dissolved in dry methanol (10 ml) and catalytically deacetylated with sodium methoxide (20 mg) for 12 h at 220. Neutralization of the mixture with CO2 was followed by concentration to give a syrup. This was extracted with chloroform, and the extracts were concentrated and eluted from silica gel (benzenechloroform) to give pure 4 - 0 - [4 - 0 - (2,3 - dideoxy - a - D erythro - hex - 2 - enopyranosyl) - 6 - azido - 2,3,6 - trideoxy - a - D - erythro hexopyranosyl] - 5,6 - O - cyclohexylidene - 2 - deoxy - 1,3 - di - N - benzyl - 1,3 di - N - methoxycarbonylstreptamine, (0.312 g, 76%). M.p.: 126-130 (decomp.) [α]D23+48 (c 0.4, chloroform). TLC: Rf 0.2 (ethyl acetate-chloroform, 2:1).

IR: vmaxCHCl3 3430 (CH), 2100 (N3), 1695 (NCOOMe), 1600 (Ph) cm-1.

PMR data (CDCl3, 80 ): # 1.58 (m, 16 H, H-2,2,2',2',3',3' and 10 cyclohexylidene protons), 2.25 (b band, 2 H, 2 OH), 3.70 (m, 6 H, 2 NCOOMe), 4.48 (m, 4 H, 2 CH2-Ph), 5.33 (m, 1 H, H-l'a), 5.50 (m, 1 H, H-l"a), 5.94 (m, 2 H, H-2",3"), 7.26 (m, 10 H, 2 Ph).

Analysis: Calculated for C42H55N5O12: C, 61.37: H, 6.74; N, 8.52 Found: C, 61.53; H, 6.51; N, 8.47% EXAMPLE XLIX A mixture of 4 - O - (6 - azido - 2,3,6 - trideoxy - α - D - erythro hexopyranosyl) - 5,6 - O - cyclohexylidene - 2 - deoxy - 1,3 - di - N - benzyl 1,3 - di - N - methoxycarbonylstreptamine (0.35 g, 0.55 mmol) and 6 - azido - 6 deoxy - 3,4 - di - 0 - acetyl - D - glucal (0.167 g, 0.65 mmol, 20% excess) in dry benzene (15 ml) was treated with boron trifluoride etherate (0.05 ml) and stirred at 22 for 25 minutes. Triethylamine (0.5 ml) was added and the mixture, after stirring for 15 minutes, was washed with water, dried and concentrated to give a solid. This was purified by silica gel column chromatography (benzene-chloroform as eluant) to give pure, amorphous, glassy, 4 - 0 - [4 - 0 - (4 - 0 - acetyl - 6 - azido - 2,3,6 trideoxy - a - D - erythro - hex - 2 - enopyranosyl) - 6 - azido - 2,3,6 - trideoxy a - D - erythro - hexopyranosyU - 5,6 - O - cyclohexylidene - 2 - deoxy -1,3 - di N - benzyl - 1,3 - di - N - methoxyearbonylstreptamine (0.46 g, 880/,). [a]22+42.5 (C 0.46, chloroform). (TLC: Rf 0.3 (benzene-ethyl acetate, 5:1).

* IR: vmaxCHCl3 2210 (N3), 1740 (OAc), 1700 (NCOOMe), 1605 (Ph) cm-1.

PMR data (CDCl3, 80 ): # 1.58 (m, 16 H, H-2,2,2',2',3',3' and 1 cyclohexylidene protons), 2.08 (s, 3 H, OAc), 3.67 (s, 6 H, 2 NCOOMe) 5.23 (m, 1 H, H-l'a), 5.34 (m, 1 H, H-l"a), 5.84 (m, 2 H, H-2", 3"), 7.21 (m, 10 H, 2 Ph).

Analysis: Calculated for C44H56N8O12: C, 59.45; H, 6.35; N, 12.60 Found: C, 59.31; H, 6.52; N, 12.59% EXAMPLE L A solution of 4 - 0 - [4 - 0 - (4 - 0 - acetyl - 6 - azido - 2,3,6 - trideoxy α - D - erythro - hex - 2 - enopyranosyl) - 6 - azido - 2,3,6 - trideoxy - α - D - erythro - hexopyranosyl] - 5,6 - O - cyclohexylidene - 2 - deoxy - 1,3 - di - N benzyl - 1,3 - di - N - methoxycarbonylstreptamine (0.25 g, 0.28 mmol) in dry methanol (10 ml) was catalytically deacetylated with sodium methoxide (20 mg) at 20 for 12 h. Neutralization of the mixture with CO2 followed by concentration to dryness led to a residue which was extracted with chloroform. The extracts, washed with water and dried, gave a solid which was eluted from silica gel (benzenechloroform mixtures) to give 0.23 g (96%) of pure 4 - O - 4 - O - (6 - azido - 2,3,6 trideoxy - α - D - erythro - hex - 2 - enopyranosyl) - 6 - azido - 2,3,6 - trideoxy α - D - erythro - hexopyranosyl] - 5,6 - O - cyclohexylidene - 2 - deoxy - 1,3 - di N - benzyl - 1,3 - di - N - methoxycarbonylstreptamine, M.p.: 126-132 [α]D22+34 (c 0.68, chloroform). TLC: R, 0.5 (benzene-ethyl acetate, 1:1); Rf 0.3 (benzeneethyl acetate, 2:1); Rf 0.25 (chloroform).

IR: vmaxCHCl3 3420 (OH), 2100 (N3), 1690 (NCOOMe), 1600 (Ph) cm-1.

PMR data (CDCl3): # 1.55 (bm, 16 H, H-2,2,2',2',3',3' and 10 cyclohexylidene protons), 2.40 (b, 1 H, OH), 3.65 (bm, 6 H, 2 NCOOMe), 5.15 (m, 1 H, H I'cr); 5.31 (m, 1 H, H-l"a), 5.85 (m, 2 H, H-2",3"), 7.25 (m, 10 H, 2 Ph).

Analysis: Calculated for C42H54N8O": C, 59.56; H, 6.43; N, 13.23 Found: C, 59,65; H,6.63; N, 13.29 EXAMPLE LI A mixture of 4 - 0 - [4 - 0 - (4 - acetyl - 6 - azido - 2,3,6 - trideoxy - a D - erythrohex - 2 - eno - pyranosyl) - 6 - azido - 2,3,6 - trideoxy - a - D - erythro - hexopyranosyl] - 5,6 - 0 - cyclohexylidene - 2 - deoxy - 1,3 - di - N benzyl - 1,3 - di - N - methoxycarbonylstreptamine (111 mg, 0.125 mmol), 90% hydrazine hydrate (3 ml), isopropanol (2 ml) and 10% palladium-on-charcoal (20 mg) were heated under nitrogen at 110 for 20 h. The mixture was evaporated (2 Torr.) and redisslved in methanol (10 ml), neutalized with 1N HCl and hydrogenated with fresh palladium catalyst (30 mg) at 3 atmos, for 7 h. The catalyst was filtered off and washed with methanol. The combined organic liquids were acidified to pH 4 with HCI, heated at 4500 for 1 h, and then tested for the presence of cyclohexylidene protecting group by evaporating an aliquot of the solution to dryness, spotting a drop of the residue in a TLC plate and spraying with anisaldehyde reagent (anisaldehyde in acetic acid containing 5% H2SO4) and heating at 1100. The absence of a carmine coloured spot showed that the hydrolysis of the cyclohexylidene group had taken place. The solution was evaporated, taken in 1 ml of water and eluted from CG 50 Amberlite (NH+) resin column with water, then with 1N and 1.5N aqueous ammonia. The eluates were evaporated to a small volume, neutalied with the 1N H2So4 and treated with 3 volumes of methanolacetone (1:1). The precipitate was redissolved in water (1 ml) and reprecipitated as before. 4 - 0 - [4 - 0 - (6 - amino - 2,3,6 - trideoxy - a - D erythrohexopyranosyl) - 6 - amino - 2,3,6 - trideoxy - α - D - erythro hexopyranolsyl] - 2 - deoxystreptamie disulphate (50 mg, 65%) was obtained as an amorphous hygroscopic powder. M.p.#250 decomposition. [α]D24+135 (c 1, water). TLC: Rf 0.35 (methanol-NH4OH, 8:1). Equivalent weight: (in galcial acetic acid): Calcd. 154. Found, 153.

Mass spectrum M/e 421 Calculated for C,8H38N407 M+.' 421 Analysis: Calculated for C18H36N4O7 . 2H2SO4: C, 35.06; H, 6.54; N, 9.08 Found: C, 35.42; H, 6.69; N, 8.93% EXAMPLE LII A mixture of 2 - deoxy - 1,3 - di - N - benzylstreptamine - 1,6:3,4 dicarbamate (500 mg, 1.27 mmol) and tri-O-acetylglucal (700 mg, 2.57 mmol) in freshly prepared dry chloroform (200 ml) was treated with boron trifluoride etherate (1 ml) for 10 minutes at 220 with stirring. Triethylamine (3 ml) was added and the reaction mixture was washed with water, dried and concentrated to yield a syrup. This was extracted with light petroleum and the extracts were discarded.

The residue was then dissolved in benzene, ether was added to precipitate the starting material and the solution, after filtration, was concentrated to a syrup. This was crystallized from benzene-light petroleum to give 0.75 g of a product which showed two spots on TLC examination (chloroform-ethyl acetate, 2:1), Rf 0.35 (main component) and R, 0.25 (minor component). A sample of the main component (50 mg) was purified by silica gel column chromatography using benzene-chloroform (1:1) as eluant followed by recrystallization from benzene-petroleum ether to give colourless, pure 5 - 0 - (4,6 - di - 0 - acetyl - 2,3 - dideoxy - a - D - erythro hex - 2 - enopymnosyl - 2 - deoxy - 1,3 - di - N - benzylstreptamine - 1,6:3,4 dicarbamate. M.p.: 75-80 . [α]D23+72 (c 1, chloroform). TLC: Rf 0.35 (chloroformethyl acetate, 2:1); IR: vmaxCHCl3: 1760 (-NCOO), 1730 (OAc), 1600 (Pb), 1585 (Ph), 1495 (Ph) cm-'.

PMR data (CDCl3): # 1.25 (m, 1 H, H-2ax), 1.91 (m, 1 H, H-2eq), 1.99 and 2.07 (2 s, 6 H, 2 OAc), 2.4 (dt, 2 H, H-1,3, J1.6=J3.4=11 Hz, J1,2eq=J3,2eq=3 Hz), 3.85 (t, 2 H, H-4,6, J1,6=J2,3=11 Hz), 4,16 (m, 1 H, H-5), 4.22 (m, 2 H, H 6',6'), 4.37 (q, 4 H, 2 CH2), 5.28 (m, 1 H, H-1'α), 5.88 (m, 2 H, H-2',3'), 7.25 (m, 10 H, 2 Ph).

Analysis: Calculated for C32H34N2O10: C, 63.36; H, 5.65; N, 4.62 Found: C, 63.41; H, 5.89; N, 4.85% EXAMPLE LIII The crude solid (0.72 g) isolated in the previous Example in methanol (50 ml), was hydrogenated for 3 h at atmospheric pressure over 10% palladium-on-charcoal catalyst (0.2 g). After filtering off the catalyst the combined filtrate and washings were concentrated to give a syrup (0.72 g) which was purified by silica gel column chromatography using benzene-chloroform (1:1) as eluant. Two components were separated in this way: (TLC chloroform-ethyl acetate, 2:1): a) main component R, 0.35 b) minor component, Rf 0.25.

The main component (a) was recrystallized from benzene-light petroleum to give 600 mg) 77%) of 5 - O - (4,6 - di - O - acetyl - 2,3 - di\deoxy - α - D - erythro hexopyranosyl) - 2 - deoxy - 1,3 - di - N - benzylstreptamine - 1,6:3,4 - dicarbamate, m.p.: 91-93 . [α]D23+82.5 (c 0.67, chloroform). TLC: Rf 0.35 (chloroform-ethyl acetate, 2:1).

IR: vmaxCHCl3: 1760 (-NCOO-), 1730 (OAc), 1495 (Ph) cm-1.

PMR data (CDCl3): # 1.25 (m, 1 H, H-2ax), 1.86 (m, 5 H, h-2',2',3',3' and 2 eq), 1.98 and 2.02 (2 s, 6 H, 2-OAc), 2.94 (dt, 2 H, J1,6=J3,4=11 Hz, J1,2eq=J3,2eq=J3,2eq=3 Hz, H-1,3), 3.84 (dt, 2 H, H-4,6), 4.13 (m, 2 H, H 6',6'), 4,35 (q, 4 H, 2 CH2-Ph), 4,75 (m, 1 H, H-4'), 5.11 (m, 1 H, H-1'α), 7,23 (m, 10 H, 2 Ph).

Analysis: Calculated for C32H36N2O10: C, 63,15; H, 5.96; N, 4.60 Found: C, 63.25: H, 6.17; N, 4.54% EXAMPLE LIV Component (b) isolated from the chromatographic column in the previous Example was identified as the pure 5 - O - (4,6 - di - O - acetyl - 2,3 - dideoxy - D - erythro - hexopyranosyl) - 2 - deoxy 1,3 - di - N - benzylstreptamine 1,6:3,4 - dicarbamate. It was recrystallized from benzene-light petroleum and from methanol to give 45 gm 6% of a colourless product. M.p.: 196-197 . [α]D20-1 (c 1, chlorooform).

IR: vmaxCHCl3: 1760 (-NCOO-), 1730 (OAc), 1495 (Ph) cm-1.

PMR data (CDCl3): # 1.25 (m, 1 H, H-2ax), 1.50-2.00 (m, 5 H, H-2',2',3',3', and 2eq), 2.02 (s, 6 H, 2 OAc), 2.95 (m, 2 H, N-1,3), 3.84 (t, 2 H, J1.6=J3,4=10.5 Hz, H-4,6), 4.17 (m, 2 H, H-6',6'), 4.35 (q, 4 H, 2CH2Ph), 4.65 (m, 2 H, H-1' , 4'), 7.25 (m, 10 H, 2 Ph).

Analysis: Calculated for C32H36N2O10: C, 63.15; H, 5.96; N, 4.60 Found: C, 63.31: H, 6.03; N, 4.53% EXAMPLE LV 5 - O - (4,6 - Di - O - acetyl - 2,3 - didexoy - α - D - erythro - hexoyranosyl) - 1,3 - di - N - benzyl - 2 - deoxystreptamine - 1,6:3,4 dicarbamate (176 (mg, 0.29 mmol) was heated under reflux in 1N methanolic soluton of sodium hydroxide (10 ml) overnight. TLC examination revealed a single spot, Rf 0.18 (benzene-methanol, 2:1) ninhydrin positive. The mixture was neutralized with CO2 adn solvent were removed in vacuo. The residue was dissolved in acetone-water (1:1) and sodium carbonate (300 mg) was added. The mixture was cooled at 0 and benzyl chloroformate (0.1 ml, 0.7 mmol) was added.

The mixture was stirred at room temperature overnight, after which the solvents were removed under diminished pressure. The residue was dissolved in water and extracted with chloroform, the extracts were washed with water, dried and concentrated to a syrup. This was crystallized from benzene-light petroleum to give 167 mg (78%) of 5 - O - (2,3 - dideoxy - α - D - erythro - hexopyranosyl) - 2 deoxy - 1,3 - di - N - benzyl - 1,3 - di - N - benzyloxycarbonylstreptamine, m.p.: 70-75 . [α]D24+62.5 (c 1, chloroform). TLC: Rf 0.20 (ethyl acetate); Rf 0.55 (benzene-methanol, 2:1).

IR: vmaxCHCl3: 3420 (OH), 1685 (-NCOO), 1605, 1585 and 1495 (Ph) cm-1.

PMR data (CDCl3, 80 ): # 1.40-1.90 (m, 6 H, 2 H-2', 2 H-3', H-2ax and H- 2eq), 2.40 (bm, 4 H, 4 OH, disappears with D2O), 3.20-3.85 (m, 9 H, H 1,3,4,5,6,4',5',6',6'), 4.41 (m, 4 H, 2 NCH2-Ph), 5.10 (m, 5 H, H-1'α and 2-COOCH2-Ph), 7.20 (m, 20 H, 4 Ph).

Analysis: Calculated for C42H48N2O10: C, 68.09; H, 6.54; N, 3.78 Found: C, 68.00; H, 6.70; N, 3.64% EXAMPLE LVI 5 - 0 - (4,6 - Diacetyl - 2,3 - dideoxy - a - D - erythro - hexopyranosyl) 2 - deoxy - 1,3 - di - N - benzylstreptamine - 1,6:3,4 0 dicarbamate (1.40 mg, 0.23 mmol) in 1N methanolic sodium hydroxide (5 ml) was heated under reflux for 12 h.

The mixture was concentrated to dryness after neutralization with CO2. The residue was extracted with methanol, the extracts were concentrated to yield a glassy product, and this was extracted with chloroform. The residue left after removal of the solvent was recrystallized from chloroform-light petroleum to yield 97 mg (89%) from which the hydrochloride of 5 - O - (2,3 - dideoxy - α - D erythro - hexopyranosyl - 2 - deoxy - 1,3 - di - N - benzylstreptamne water to pH 6. [α]D22+60 (c 0.9, methanol). TLC: Rf 0.18 (benzene-methanol, 2:1); Rf 0.70 (chloroform-methanol 35% ammonia, 20:6:1).

IR: vmaxnujol: 3340 (OH, NH), 1050 (glycoside), 700 (Ph) cm-1.

PMR data (D2O): # 1.60-2.15 (m, 5 H, H 2',2',3',3',2ax), 2.55 (m, 1 H, 2-2eq), 3.20 (m, 2 H, H-1,3), 3.50-4.00 (m, 7 H, H-4,4',5,5'6,6',6'), 4.38 (m, 4H, 2 CH2-Ph), 5.25 (m, 1 H, H-l'a), 7.56 (m, 10 H, 2 Ph).

Analysis: Calculated for C26H26N2O8: C, 66.08; H, 7.68; N, 5.93 Found: C, 66.20; H,7.80; N, 6.04% EXAMPLE LVII 5 - O - (2,3 - Dideoxy - α - D - erythro - hexopyranosyl) - 2 - deoxy - 1,3 di - N - benzylstreptamine dihydrocholoide (50 mg, 0.092 mmol) in dry methanol (5 ml) was hydrogenated over 10% palladium-on-charcoal catalyst (70 mg) at atmospheric pressure overnight. The catalyst was filtered and washed with methanol and water. Evaporation of the combined filtrate and washings gave 31 mg (92%, calc. on dihydrochloride salt) of a hygroxscopic 5 - O - (2,3 dideoxy - α - D erythro - hexopyranosyl) - 2 - deoxystreptamine dihydrochloride. M.p.: > 250 [α]D24+74.5 (c 1.5, methanol). TLC: Rf 0.20 (methanol-35% ammonia, 8:1); Rf 0.40 (methanol-35% ammonia, 2:1).

PMR data (D2O): # 1.60-2.00 (m, 5 H, H-2',2',3',3',2ax), 2.45 (m, 1 H, H-2eq), 3.10-4.00 (m, 9 H, H-1,3,4,5,6,4',5',6',6'), 5.27 (m, 1H, H-1'α).

Analysis: Calculated for C12H26Cl2N2O6: C, 39.45; H, 7.17; N, 7.67; Cl, 19.41 Found: C, 39.60; H, 7.09; N, 7.75; Cl, 19.80 EXAMPLE LVIII Carbon tetrachloride (0.1 ml) and hexamethyl-phosphorous acid triamide (0.2 ml) were added to a solution of 5 - O - (2,3 - dideoxy - α - D - erythro hexopyranosyl) - 2 - deoxy - 1,3 - di - N - benzyl - 1,3 - di - N benzyloxycarbonylstreptamine (120 mg, 0.162 mmol) in dry N,Ndimethylformamide (2.0 ml). The mixture was stirred at -50 under nitrogen for 10 minutes. Sodium azide (130 mg, 2.0 mmol) was then added and the mixture was stirred at 800 for 8 h. It was then poured into ice and water and extracted with ether. The ethereal extracts were washed with water, dried and concentrated to give a syrup which crystallized from benzene-light petroleum. The crude product (119 mg) was eluted from a dry silica gel column (20 cmxl cm) with chloroform.

The major component was isolated as a glassy solid which crystallized from benzene-petroleum ether. 5 - 0 - (6 - Azido - 2,3,6 - trideoxy - a - D - erythro hexopyranosyl)- 2 - deoxy - 1,3 - di - N- benzyl - 1,3 - di - N - methoxycarbonylstreptamine (80 mg, 65%) had m.p.: 60-62 . [α]D23+28 (c 0.8, chloroform). TLC: Rf 0.53 (ethyl acetate); Rf 0.50 (benzene-methanol, 4: 1); Rf 0.20 (chloroform-ethyl acetate, 1:1).

IR: vmaxCHCl3: 3420 (OH), 2100 (N3), 1690 (NCOOMe), 1610, 1590 and 1500 (Ph) cm-' MR data (CDCl3, 80 ): # 1.25-1.90 (m, 6 H, H-2ax, 2eq, 2',2',3',3), 3.23.90 (m, 9 H, H-1,3,4,5,6,4',5',6',6'), 4,40 (m, 4 H, 2 CH2-Ph), 5.10 (m, 5 H, H 1'α and 2 COOCH2-Ph), 7.20 (m, 20 H, 4 Ph).

Analysis: Calculated for C42H47N5Og: C, 65.86; H, 6.19; N, 9.15 Found: C, 65,74; H, 6.20; N, 9.30% EXAMPLE LIX 2 - Deoxy - 1,3 - di - N - benzylstreptamine dihydrochloride (3.0 g, 7.2 mmol) and sodium carbonate (5 g) were dissolved in water-acetone (2:1, 150 ml).

Phenyl chloroformate (2.1 ml, 16.5 mmol, 140/, excess) in acetone (50 ml) was added dropwise to the mixture at - 10 with stirring. After 3 h the reaction mixture was evaporated and the product which separated upon the addition of water was filtered and washed with water. Recrystallization from chloroform-etherpetroleum ether yielded 3.2 g (76 /n) of pure 2 - deoxy - 1,3 - di - N - benzyl - 1,3 di - N phenyloxycarbonylstreptamine. M.p.: 96-100 . TLC: Rf 0.30 (ethyl acetate).

Analysis Calculated for C24H34N2O7: C, 70.17; H, 5.88; N, 4.80 Found: C, 70.20; H, 5.96; N, 4.83% EXAMPLE LX A mixture of 2- deoxy - 1,3 - di- N- benzyl - 1,3 - di- Nphenyloxycarbonylstreptamine (3.0 g, 5.1 mmol), sodium hydride (60% oil dispersed, 0.66 g, 16.5 mmol) and N,N-dimethylformamide was stirred at 0 for 4 h, after which solid CO2 was added to neutralize it and the solvents were evaporated in vacuo. The residue was treated with water, thus obtaining a precipitate which was filtered off and dried. Two recrystallizations from hot methanol gave 0.84 g (41%) of pure 2 - deoxy - 1,3 - di - N - benzylstreptamine - 1,6:3,4 - dicarbamate. M.p.: 243-248 . TLC: Rf 0.65 (ethyl acetate).

Analysis Calculated for C22H22N2O5: C, 66.99; H, 5.62; N, 7.10 Found: C, 70.15; H, 5.60; N, 7.01% EXAMPLE LXI 2 - Deoxy - 1,3 - di - N - benzylstreptamine 1,6:3,4 - dicarbamate (2.0 g, 5.1 mmol) was dissolved in triphenylphosphite (20 ml) with heating. Bromine (1 ml, 19 mmol) was then added and the warm mixture was shaken for a few minutes.

After standing overnight at room temperature, the mixture was diluted with chloroform (200 ml) and washed with 10% Na2CO3 solution (4x50 ml) and water.

The orgainc phase was dried (Na2SO4) and evaporated to give an oily residue. This was dissolved in benzene, petroleum ether (60-80 ) was added to slight turbidity and it was allowed to crystallize in the refrigerator overnight. The solid was recrystallized from hot benzene to yield 1.9 g (82 /n) of pure 5 - bromo - 1,3 - di N- benzyl - 2,5 - dideoxystreptamine - 1,6:3,4 - dicarbamate. M.p.: 175-177 TLC: Rf 0.50 (chloroform-ethyl acetate, 1:1).

PMR data (CDCl3): a 1.5-1.90 (m, 2 H, H-2,2), 3.60 (m, 2 H, H-l ,3), 4.05 (m, 2 H, H-4,6, J3,4=J1,6=10 Hz, J4,5=J5,6=2.2 Hz), 4.33 (m, 4 H, 2 CH2-Ph), 4.90 (m, 1 H, H-5), 7.10-7,40 (m, 10 H, 2 Ph).

Analysis Calculated for C22H2,N204Br: C, 57.78; H, 4.63; N, 6.12; Br, 17.

Found: C, 57.84; H,4.51; N,6.00; Br, 17.

EXAMPLE LXII 5 - Bromo - 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,6:3,4 - dicarbamate (3 g, 6.54 mmol) in absolute ethanol (200 ml) containing triethylamine (S ml) was hydrogenated over 10% palladium-on-charcoal (2 g) for 2 h at 2 atmos. The filtrate, after removal of the catalyst, was concentrated tb a small volume and stored at 0 for 12 h. The precipitated product was recrystallized from hot ethanol giving 1,3 di - N - benzyl - 2,5 - dideoxystreptamine - 1,6:3,4 - dicarbamate (1.83 g, 73%). M.p.: 193-194 . TLC: Rf 0.65 (ethyl acetate); Rf 0.47 (chloroform-ethyl acetate, 1:1).

PMR data (CDCL3): # 1.17 (q, 1 H, H-2ax, J=11 Hz), 1.90 (m, 2 H, H-2eq, 5ax).

2.73 (dt, 1 H, H-Seq), 2.95 (td, 2 H, H-1,3), 3.87 (td, 2 H, H-4,6), 4.33 (m, 4 H, 2 CH2Ph), 7.25 (m, 10 H, 2 Ph).

Analysis CalculatedforCHNO: C,69.82; H,5.86; N,7.40 Found: C, 70.01; H, 5.73; N, 7.63 EXAMPLE LXIII 1,3 - Di - N - benzyl - 2,5 - dideoxystreptamine - 1,6:3,4 - dicarbamate (0.4 g, 1.06 mmol) in 0.5 N methanolic sodium methoxide (16 ml) was heated under reflux for 2 h. Water (S ml) was added and the heating under reflux was continued for a further 2 h.

TLC (CHCl2-MeOH-NH4OH, 100:30:3) examination of the mixture revealed only one spout, Rf 0.55, ninhydrin positive, corresponding to 1,3 - di - N benzyl - 2,5 - dideoxystreptamine. Sodium carbonate (0.3 g) was added to the mixture followed by the dropwise addition of methyl chloroformate (0.2 ml, 2.6 mmol) in acetone (S ml) over period of 15 minutes while the mixture was stirred and cooled to 00. This stirring was continued for 2 h at 00, after which the mixture was concentrated and the residue was extracted with chloroform. The extracts were washed with water, dried and concentrated to give a syrup which was extracted with ether. Evaporation of the ethereal solution gave pure, glassy, 1,3 - di - N benzyl - 2,5 - dideoxy - 1,3 - di - N - methoxycarbonylstreptamine (0.414 g, 88%).

TLC: Rf 0.35 (ethanol-ethyl acetate, 1:8).

The analytical sample was purified by column chromatography on silica gel using ethyl acetate as eluant.

PMR data (CDCl2): a 1.25 (m, I H, H-2ax), 1.55 (m, 2 H, H-2eq, Sax), 2.15- 2.45 (m, 3 H, 2 OH and H-Seq), 3.60 (m, 4 H, H-1,3,4,6), 3.70 (m, 6 H, 2 NCOOMe), 4.38 (m, 4 H, 2 CH2Ph), 7.23 (m, 10 H, 2 Ph).

Analysis Calculated for C24H20N2O6: C, 65.14; H, 6.83; N, 6.33 Found: C, 65.27; H, 6.70; N, 6.42% EXAMPLE LXIV A mixture of 1,3 - di - N- benzyl - 2- deoxystreptamine ml) was stirred and heated under reflux for 24 h. This was followed by the addition, at 0 , of sodium carbonate (0.3 g) and methyl chloroformate (0.2 ml). The solution was stirred at 0 for 1 h, then at 250 overnight. Concentration of the mixture and addition of water produced a crystalline precipitate (0.228 g, 91). It was recrystallized from benzene to give pure 5 - 0 - allyl - 2 - deoxy - 1,3 - di - N benzyl -1,3 - di - N - methoxycarbonylstreptamine. M.p.: 155-158 . TLC: Rf 0.40 (ethyl acetate); Rf 0.70 (ethyl acetate, ethanol, 8:1).

PMR data (CDCI3): a 1.20-1.80 (bm, 2 H, H-2ax, 2eq), 2.59 (bm, 2 H, 2 OH), 3.11 (m, 1 H, H-5), 3.68 (s, 6 H, 2 NCOOMe), 4.30 (m, 2 H, -OCH2 allyl group), 4.38 (s, 4 H, 2 CH2-Ph), 5.14 and 5.28 (2 dd, 2 H, C=CH2 allyl group), 5.73-6.16 (m, I H, -CH=C, allyl group), 7.22 (m, 10 H, 2 Ph).

Analysis Calculated for C27H34N2O7: C, 65.31; H, 6.87; N, 5.62 Found : C, 65.25; H, 6.93; N, 5.69% EXAMPLE LXVI A solution of 2 - deoxystreptamine - 1,6:3,4 - dicarbamate (0.1 g, 0.5 mmol) in dry N,N-dimethylformamide (4 ml) was treated with sodium hydride (0.1 g, 4 mmol). The suspension was stirred for 1 h at 250 and cooled to 0 while benzyl bromide (2 ml) was added, stirring of the reaction mixture being continued for 24 h at 22 . Dry methanol (2 ml) was then added and the solution was concentrated to dryness. The residue was extracted with chloroform and the extracts were washed with water, dried, filtered and concentrated to yield a syrup which crystallized upon the addition of ethanol. Recrystallization of the solid from ethanolchloroform gave pure 2 - deoxy - 1 - N,3 - N,5 - 0 - tribenzylstreptamine 1,6:3,4 - dicarbamate (0.19 g, 60%). M.p.: 192-193 . TLC: R, 0.75 (ethyl acetateethanol, 8:1); Rf 0.40 (chloroform).

PMR data (CDCl3): os 1.25 (m, 1 H, H-2ax), 1.90 (dt, 1 H, J2eq2aX=11.5 Hz, J2eq.1=J2eq.3=3.5 Hz, H-2eq), 2.93 (m, 2 H, H-1,3), 3.90 (m, H, H-4,5,6), 4.37 (m, 4 H, 2 NCH2-Ph), 4.82 (s, 2 H, O-CH2Ph), 7.30 (m, 15 H, 3 Ph).

Analysis Calculated for C29H28N2O5: C, 71.88; H, 5.82; N, 5.78 Found: C, 71.90; H, 5.75; N, 5,80% EXAMPLE LXVII A mixture of 2 - deoxy - I - N,3 - N,S - 0 - tribenzylstreptamine - 1,6:3,4 dicarbamate (I g, 2.6 mmol) in methanol (100 ml) and barium hydroxide octahydrate (7.5 g) in water (25 ml) was heated under reflux with stirring for 24 h, after which it was neutralized with solid CO2 and centrifuged to remove the inorganic salts. The supernatant was concentrated to dryness, and the residue was dissolved in chloroform (25 ml), filtered and treated with an ethereal solution of HCl until pH 2 was reached. Ether was then added to effect complete precipitation.

The solid (1.012 g, 97%) was recrystallized from methanol-ether to give pure 2 deoxy - I - N,3 - N,5 - 0 - tribenzylstreptamine dikydrochloride as a white solid.

M.p.: 185-190 . TLC: Rf 0.35 (ethyl acetate-methanol, 3:1); Rf 0.05 (ethyl acetate).

PMR data (D2O free base): # 2.10 (t, 1 H, H-2ax), 2.65 (m, 1 H, H-2eq), 4.45 (bm, 5 H, H-1,3,4,5,6), 4.50 (d, 4 H, 2-N-CH2-Ph), 4.93 (s, 2 H, -0- CH2-Ph), 7.55 (d, 15 H, 3 Ph).

Analysis Calculated for C27H24N2O3Cl2: C, 64.1 5; H, 6.78; N, 5.54 Found: C, 64.22; H, 6.84; N, 5.48% EXAMPLE LXVIII To an ice-cold solution of 2- deoxy - 1 - N- 3 - N,S - 0 - tribenzylstreptamine hydrochloride (505 mg, 1 mmol) and sodium carbonate (0.5 g) in water (25 ml) and acetone (50 ml), methyl chloroformate (0.25 ml, 3.2 mmol) in acetone (15 ml) was added dropwise, with stirring. After 5 h, the inorganic salts were removed by filtration. The solution was concentrated, water was added and the insoluble residue was filtered, washed with water and dried. It was recrystallized from hot benzene to give 400 mg (73 /") of pure 2 - deoxy - 1,3 - di N- methoxyearbonyl - I - N,3 - N,5 - 0 - tribenzylstreptamine. M.p.: 185.5-' 186.5 . TLC: Rf 0.62 (ethyl acetate); Rf 0.37 (chloroform-ethyl acetate, 1:1).

IR: vmaxCHCl3 3420 (OH), 1690 (NCOOMe), 1600 (Ph) cm-'.

PMR data (CDCI2): a 1.55 (m, 1 H, H-2ax), 1.80 (m, 1 H, H-2eq), 2.60 (m, 2 H, 2 OH), 3.55 (bm, S H, H-1,3,4,5,6), 3.66 (s, 6 H, 2 NCOOMe) 4.37 (s, 4 H, 2 N-CH2Ph), 4.82 (s, 2 H, -O-CH2-Ph), 7.25 (m, 15 H, 3 Ph).

Analysis Calculated for C31H36N2O7: C, 67.86; H, 6.61; N, 5.10 Found: C, 67.70; H, 6.71; N, 5.03% EXAMPLE LXIX 2 - Deoxy - 1,3 - di - N - benzylstreptamine - 1,6:3,4 - dicarbamate (1.182 g, 3 mmol) and sodium hydride (0.2 g, 5 mmol, 60% oil dispersed) in N,Ndimethylformamide (15 ml) was stirred at 0 for 0.5 h. Chloromethylmethyl sulphide (0.5 ml) was added dropwise at 00, and the mixture was stirred at 220 for 14 h, then dropped into ice-water containing sodium bicarbonate, pH7-7.5. The precipitate was filtered off, washed with water, dried and purified by silica gel column chromatography using benzene as eluant. 2 - Deoxy - 1,3 - di - Nbenzyl - 5 - 0 - methylthiomethylstreptamine -1,6:3,4 - dicarbamate (0.983 g, 72%) thus obtained was recrystallized from ethanol. M.p.: 160-162 , TLC: Rf 0.5 (chloroform-ethyl acetate, 1:1).

IR: i'mcoacxl2: 1760 (NCOO), 1500 (Ph) cm-'.

PMR data (CDCl3): # 1.28 (m, 1 H, J28x, 26q=11 Hz, H-2ax), 1.93 (dt, 1H, J28x, 2eq-11 Hz, J2eq1=J2eq3=3.5 Hz, H-2eq), 2.16 (s, 3 H, S-Me), 3.02 (m, 2 H, J1.6=J3.4=11 hz, H-1,3), 3.90(q, 2H, J4.5=J6.5=9 Hz, H-4.6), 4.38 (q, 4 H, 2CH2Ph), 4.42 (t, 1 H, J5.4=J5.6=9 Hz, H-5) 4.87 (s, 2 H, -OCH2S)2 7.30 (m, 10 H, 2 Ph).

EXAMPLE LXX A suspension of 2- deoxy - 1,3 - di- N- benzyl - S - 0 - methylthiomethylstreptamine - 1,6:3,4 - dicarbamate (0.84 g, 1.85 mmol) in IN sodium methoxide in methanol (25 ml) was boiled under reflux for 0.5 h. Water (25 ml) was then added and boiling under reflux was continued for 24 h. The solution was neutralized with CO2, concentrated, and the residue dissolved in aqueous acetone (2:1, IS ml). This solution was cooled at 00, and sodium carbonate (1 g) was added with stirring followed by the dropwise addition of methyl chloroformate (0.8 ml) in acetone (2 ml). The stirring was continued for 4 h, the solvents were removed in vacuo, and the precipitate obtained after the addition of water was collected, washed with water and dried (0.956 g). The solid was recrystallized from benzene to give 0.38 g (92%) of crystalline 2 - deoxy - 1,3 - di - N - benzyl - 1,3 di - N - methoxycarbonyl - 5 - 0 - methylthiomethylstreptamine. M.p.: 173.5- 174.5 . TLC: Rf 0.42 (ethyl acetate).

IR: vmaxCHCl3: 3420 (OH), 1685 (NCOOMe), 1600 (Ph) cm-'.

PMR data (CDCI3): a 1.40-1.90 (m, 2 H, H-2ax, 2eq), 2.20 (s, 3 H, SCH2), 2.72 (b, 2 H, 2 OH), 3.204.00 (m, 11 H, skeleton protons), 3.70 (s, 6 H, 2 COOMe), 4.40 (s, 4 H, 2 CH2Ph), 4.90 (s, 2 H, OCH2S), 7.23 (m, 10 H, 2 Ph).

EXAMPLE LXXI A mixture of 1,3 - di - N- benzyl - 2,5 - dideoxy - 1,3 - di - Nmethoxycarbonylstreptamine (0.51 g, 1.15 mmol) and tri - 0 - acetyl - D - glucal (0.78 g, 2.8 mmol) in dry benzene (20 ml), boron trifluoride etherate (0.02 ml) was stirred for 0.5 h. Triethylamine (I ml) was added, and the mixture was washed with water, dried and concentrated. The syrupy residue showed three components on TLC (ethyl acetate): a) Rf 0.57 (major), b) Rf 0.40 and c) Rf 0.28. These were separated by silica gel column chromatography using chloroform-benzene mixtures as eluant. Component a) was a low melting solid (35-37 from ether-petroleum ether) and was identified as 4,6 - di - 0 - (4,6 - di - 0 - acetyl - 2,3 - dideoxy - a D - erythro - hex - 2 - enopyranosyl) - 1,3 - di - N - benzyl - 2,5 - dideoxy -1,3 di - N - methoxycarbonylstreptamine (0.75 g, 75.3%), TLC: Rf 0.57 (ethyl acetate); Rf 0.43 (benzene-ethyl acetate, 1:1).

IR: vmaxCHCl3: 1735 (OAc), 1690 (NCOOMe), 1600 (Ph) cm-1.

PMR data (CDCI2): a 1.40 (m, 3 H, H-2ax, 2eq, S ax), 2.07 (q, 12 H, 4 OAc), 3.67 (m, 6 H, 2 NCOOMe), 4.25 (bm, 14 H, 4 CH2Ph, H 1,3,4,6,5',5",6',6",6"), 5.20 (m, 2 H, H-1"α, 1"α), 5.36 (m, 2 H, H-4',4"), 5.77 (m, 4 H, H-2',2",3',3"), 7.20 (m, 10 H, 2 Ph).

Analysis Calculated for C44H54N2O16: C, 60.96; H, 6.21; N, 3.23 Found: C, 61.10; H, 6.41; N, 3.10% EXAMPLE LXXII 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N methoxycarbonylstreptamine (442 mg, 1 mmol) and tri - 0 - acetyl - D - glucal (820 mg, 3 mmol) in benzene (25 ml) were treated with boron trifluoride etherate (0.1 ml) for 0.5 h at room temperature with stirring. Triethylamine (0.5 ml) was added and the reaction mixture was washed with water, dried and concentrated to yield a syrup (1.2 g). This was dissolved in methanol (20 ml) and hydrogenated over 10% palladium-on-charcoal (0.2 g) at atmospheric pressure for 2 h. After filtering the catalyst the reaction mixture was concentrated to give a syrup (1.13 g) which was purified by silica gel column chromatography using benzene-chloroform (1:2) as eluant. Three components were separated in this way: (TLC: benzene-ethyl acetate, 1:1): a) main component, Rf=0.30 (trisaccharide) b) minor component, Rf=0.09 (disaccharide) c) minor component, Rf=0.05 (disaccharide).

The main component (a) was recrystallized form ether-petroleum ether 6080 to give 560 mg (65%) of pur 4,6 - di - O =- (4,6 - di - O - acetyl - 2,3 dideoxy - α - D - erythro - hexopyranosyl) - 1,3 - di - N - benzyl - 2,5 - dideoxy 1,3 - di - N - methoxycarbonylstreptamine. M.p.: 63-65 . [α]D24+71.5 (c 0.7, chloroform). TLC; Rf 0.65 (ethyl acetate); Rf 0.3 (benzene-ethyl acetate, 1:1); Rf 0.2 (chloroform-ethyl acetate, 3:1).

PMR data (CDCl3, 90 ): # 1.10-1.80 (series of multiplets, 12 H, H 2,2,2',2',2",2",3',3',3",3",5,5), 1.95 (3 s, 12 H, 4 OAc), 3.62 (2 s, 6 H, 2 NCOOMe), 3.70-4.45 (series of multiplets, 2-CH2-Ph, H 1,3,4,4',4",5',5",6,6',6",6"), 4.60 (m, 1 H, H-1"α), 4.91 (m, 1 H, H-1'α), 7.13 (m, 10 H, 2 Ph).

Analysis Calculated for C44H58N2O16: C, 60.68; H, 6.71; N, 3.21 Found: C, 60.,81; H, 6.52; N, 3.05% EXAMPLE LXXIII Component (b) (Rf 0.15, [benzene-ethyl acetate, 1:1]) separated from the chromatographic column in the previous Example was identified as pure 6 - 0 (4,6 - di - O - acetyl - 2,3 - dideoxy - α - D - erythro - hexopyranosyl) - 1,3 - di - N benzyl - 2,5 - dideoxy - 1,3 - di - N - methoxycarbonylstreptamine, [α]D25+32 (c 0.7, chloroform). TLC; Rf 0.45 (ethyl acetate).

IR: vmaxCHCl3 3440 (-OH), 1725 (-OAc), 1680 (-NCOOMe), 1487 (-Ph), 1235 (C-O), 1037 (-O-glycoside) cm-'.

PMR data (CDCl3): # 1.25 (m, 1 H, H-2ax), 1.65 (m, 4 H, H-2',2',3',3'), 2.02 (s, 6 H, 2 OAc), 2.40 (m, 1 H, H-5eq), 3.68 (2 s, 6 H , 2 NCOOMe), 4.10 (m, 4 H, 2 CH2Ph), 4.65 (m, I H, H-l'a), 7.24 (m, 10 H, 2 Ph).

Analysis Calculated for C34H44N2O11: C, 62.18: H, 6.75; N, 4.26 Found: C, 62.05; H, 6.60; N, 4.33% EXAMPLE LXXIV Component (c) (TLC: Rf 0.10, benzene-ethyl acetate, 1:1) separated from the chromatographic column in Example LXXII was identified as pure, glassy, 4 - 0 (4,6 - di - O - acetyl - 2,3 - dideoxy - α - D - erythro - hexopyranosyl) - 1,3 - di N - benzyl - 2,5 - dideoxy - dimethoxycarbonyl - 2,5 - dideoxystreptamine.

[α]D25 + 75.5 (c 0.6, chloroform). TLC: Rf 0.35 (ethyl acetate).

IR: vmaxCHCl3 3440 (-OH), 1725 (-OAc), 1680 (-NCOO), 1487 (-Ph), 1240 (C O), 1027 (-O-glycoside).

PMR data (CDCl3): # 1.25 (m, 1 H, H-2ax), 1.70-1.90 (m, 6 H, H 2',2',3',3',2eq,5ax), 2.02 (s, 3 H, OAc), 2.06 (s, 3 H, OAc), 3.68 (s, 6 H, 2 NCOOMe), 3.43.90 (bm, 4 H, H-1,3,4,6), 4.00--4.80(m, 10 H, 2 CH2Ph and skeleton protons), 4.94 (m, 1 H, H-l'a), 7.23 (m, 10 H, 2 Ph).

Analysis Calculated for C34H44N2O11: C, 62.18; H, 6.75; N, 4.26 Found: C, 62.28; H, 6.87; N, 4.20% EXAMPLE LXXV 6 - O - (4,6 - Di - O - acetyl - 2,3 - dideoxy - α - D - erythro hexopyranosyl) - 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N methoxycarbonylstreptamine 65 mg, 0.1 mmol) in methanol (2 ml) was deacetylated for 12 h with sodium methoxide (10 mg). The mixture was neutralized (CO2) and concentrated. The chloroformic extracts of the residue were evaporated and the solid was recrystallized from chloroform-ether to yield 54 mg (95%) of pure 6 - O - (2,3 - dideoxy - α - D - erythro - hexopyranosyl) - 1,3 - di - N - benzyl 2,5 - dideoxy - 1,3 - di - N - methoxycarbonylstreptamine, m.p.: 87 , [α]D21+29 (c 0.9, chloroform).

IR: vmaxCDCl3 3400 (OH), 1685 (NCOOMe), 1500 (Ph), cm-3, PMR data (CDCl3, 95 ): # 1.20-1.90 (m, 7 H, H-2ax, 2eq, 5ax, 2',2',3',3',).

2.25-2.60 (bm, 4 H, H-5eq, 3 OH), 3.70 (m, 6 H, 2 NCOOCH3), 4.40(m, 4 H, 2 CH2 - Ph), 4.63 (m, 1 H, 1-1"α), 7.23 (m, 10 H, Ph).

Analysis Calculated for C30H40N2Og: C, 62.92; H, 7.04; N, 4.89 Found: C, 63.02; H, 7.16; N, 5.04% EXAMPLE LXXVI 4 - 0 - (4,6 - Di - 0 - acetyl - 2,3 - dideoxy - a - D - erythro hexopyranosyl) - 1,3 - di - N - benzyl - 1,3 - di - N - methoxycarbonyl - 2,5 dideoxystreptamine (50 mg, 0.076 mmol) in methanol (2 ml) was catalytically deacetylated with 0.2 ml of methanolic 0.1N sodium methoxide for 12 h. The mixture was neutralized with solid CO2 and concentrated to give a solid which was extracted with chloroform. The organic extracts were filtered and concentrated, the residue was recrystallized from chloroform-ether to yield 39 mg (90%) of 4 - 0 (2,3 - dideoxy - a - D - erythro - hexopyranosyl) - 1,3 - di - N - benzyl - 2,5 dideoxy -1,3 - di - N - methoxycarbonylstreptamine. M.p.: 950 (sinters). [α]D21+58 (Q.5, chloroform). TLC: Rf 0.20 (benzene-methanol, 3:1); Rf 0.20 (ethyl acetate-ethanol, 8:1).

IR: vmaxCDCl3 3400 (OH), 1685 (NCOO), 1500 (Ph), 1250, 1125, 1070, 1030, 700 cm-1.

PMR data (CDCl3, 100 ): # 1.20-1.65 (m, 3 H, H-2ax, 2eq, 5ax.), 1.75 (m, 4 H, H-2',2',3',3') 2.10 (bb, 3 H, 3 OH), 2.40 (m, 1 H, H-5eq), 3.70 (2 s 6 H, 2 COOme), 4.37 (m, 4 H, 2 CH2-Ph), 4.89 (m, 1 H, H-1'α), 7.23 (m, 10 H 2 Ph).

Analysis Calculated for C30H40N2O9: C, 62.92; H, 4.04; N, 4.89 Found: C, 62.84; H, 6.08; N, 4.78% EXAMPLE LXXVII 4,6 - Di - 0 - (4,6 - di - 0 - acetyl - 2,3 - dideoxy - a - D - erythro - hexopyranosyl) 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N methoxycarbonylstreptamine (360 mg, 0.41 mmol) in methanol (10 ml) was treated with sodium methoxide (20 mg) for 12 h. The mixture was neutralized (CO2) and concentrated to give a solid which was extracted with chloroform. The organic extracts were evaporated and the residue was recrystallized from chloroform-ether to yield pure 4,6 - di - 0 - (2,3 - dideoxy - a - D - erythrohexopyranosyl) - 1,3 - di N - benzyl - 2,5 - dideoxy - 1,3 - di - N - methoxyearbonylstreptamine (280 mg, 96%), M.p.: 72 [α]D25+66 (c 1.1, chloroform). TLC; Rf 0.12 (ethyl acetate-ethanol, 8:1); Rf 0.50 (ethyl acetate-ethanol, 2:10.

IR: vmaxCHCl3 3400 (OH), 1675 (NCOOMe), 1595 (Ph) cm-1, Analysis Calculated for C36H50N2O12: C, 61.52; H, 7.17; N, 3.98 Found: C, 61.64; H, 7.02; N, 4.02% EXAMPLE LXXVIII A mixture of 4,6 - di - O - (2,3 - dideoxy - α - D - erythro hexopyranosyl) - 1,3 - di - N - benzyl - 2,5 = dideoxy - 1,3 - di - N methoxycarbonylstreptamine (0.2 g, 0.28 mmol), 90% hydrazine hydrate (2 ml) and ethanol (1 ml) was heated under reflux.for 24 h in an oil bath at 1300. The solvent were removed in vacuo and the residue was purified by chromatography (silica gel/chloroform-methanol mixtures as eluant) to give pure, glassy 4,6 - di - 0 (2,3 - dideoxy - α - D - erythro - hexopyranosyl) - 1,3 - di - N - benzyl - 2,5 dideoxystreptamine (0.147 g, 90%), [α]D25+93.5 (c 1.0, methanol). TLC: Rf 0.50 (chloroform-methanol-ammonia, 100:30:5), ninhydrin positive.

PMR data (D2O): # 1.95 (bm, 12 H, H-2,2,2',2',2",2",3',3',3",3",5,5), 3.70 (bm, 16 H, skeleton protons and 2 CH2-Ph), 4.98 (m, 2 H, (H-1'α and H-1"α), 7.22 (m, 10 H, 2 Ph).

Analysis Calculated for C22H46N2O8: C, 65.50; H, 7.90; N, 4.77 Found: C, 65.65; H,8.10; N, 4 85% EXAMPLE LXXIX A mixture of 4,6 - di - O - (4,6 - di - O - acetyl - 2,3 - dideoxy - α - D erythrohexopyranosyl) - 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N methoxycarbonylstreptamine (87 mg, 0.1 mmol), 90% hydrazine hydrate (1 ml) and ethanol (I ml) was heated under reflux for 24 h in an oil bath (130 ). The solvents were evaporated in vacuo and the glassy residue was purified by chromatography on silica gel, using chloroform-methanol mixtures as eluant. 4,6 - Di - 0 - (2,3 dideoxy - a - D - erythro - hexopyranosyl)- 1,3 - di - N - henz4 - 2,5 dideoxystreptamine was obtained pure as a glassy solid (55 mg, 94%). [a]5+950 (c 1.0 methanol). TLC: Rf 0.5 (chloroform-methanol-ammonia, 100:30:5).

The PMR spectrum (D2O) of this compound is identical with that of the product isolated in the previous example.

Analysis Calculated for C32H46N2O8: C, 65.50; H, 7.90; N, 4.77 Found: C, 65.40; H, 7.95; N, 4.68% EXAMPLE LXXX 4,6 - Di - 0 - (2,3 - dideoxy - a - D - erythro - hexopyranosyl) - 1,3 - di N - benzyl - 2,5 - dideoxystreptamine (117 mg, 0.2 mmol) in methanol (20 ml) was hydrogenated overnight at 2 atmos. over 10% palladium-on-charcoal catalyst (100 mg). After filtering and washing the catalyst, the combined liquids were concentrated to give pure 4,6 - di - 0 - (2,3 - dideoxy - a - D - erythro hexopyranosyl) - 2,5 - dideoxystreptamine as a white glassy solid (74.8 mg, 92%).

[α]D25+109.5 (c 0.6, methanol). TLC: Rf 0.06 (chloroform-methanol-ammonia, 100:30:5); Rf 0.32 (methanol-ammonia, 8:1); Rf 0.55 (Whatman (Registered Trade Mark) No. I chromatographic paper/propanol-pyridine-acetic acid-water, 15:10:3:12), ninhydrin positive.

Mass spectrum: M/e 407: calculated M+.: 407.

Analysis Calculated for C18H34N2O8: C, 53.18; H, 8.43; N, 6.89 Found: C, 53.02; H, 8.35: N, 7.01% EXAMPLE LXXXI 4,6 - Di - 0 - (4,6 - di - 0 - acetyl - 2,3 - dideoxy - α - D - erythro - hexopyranosyl) - 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N methoxycarbonylstreptamine (866 mg, 1 mmol) dissolved in a 1:1 mixture of 90% hydrazine hydrate and ethanol (S ml) was heated under reflux for 24 h (130 oil bath). The mixture was then cooled, 10% palladium-on-charcoal (150 mg) and ethanol (25 ml) were added and the suspension was hydrogenated under 2 atm. pressure for 8 h. The catalyst was filtered and washed with methanolic ammonia, all the organic liquids were combined, evaporated to dryness and the residue was extracted with methanol (20 ml) and again evaporated. The glassy residue was purified by chromatography on silica gel with methanol-ammonia (8:1) as eluant to give 370 mg (91%) of pure 4,6 - di - O - (2,3 - dideoxy - α - D - erythro hexopyranosyl) - 2,5 - dideoxystreptamine as an amorphous solid. [α]D25+110 (c, 1, methanol). TLC: Rf 0.32 (methanol-ammonia, 8:1); Rf 0.55 (Whatman No. 1 chromatographic paper/propanol-pyridine-acetic acid-water, 15:10:3:12), ninhydrin positive.

Analysis Calculated for C,8H24N2O8: C, 53.18; H, 8.43; N, 6.89 Found: C, 53.40; H, 8.20; N, 6.75 EXAMPLE LXXXII A mixture of 5 - 0 - Allyl - 2 - deoxy - 1,3 - di - N - benzyl - 1,3 - di - N methoxycarbonylstreptamine (0.1 g, 0.2 mmol) and tri - 0 - acetyl - D - glucal (0.163 g, 0.6 mmol) in dry benzene (10 ml) was treated with boron trifluoride etherate (0.05 ml) for 0.5 h at 220. Triethylamine was added (0.3 ml) and the solution was washed with water, dried and concentrated. The resulting syrup was fractionated by preparative TLC (chloroform-ethyl acetate, 4:1). The fraction with Rf 0.35 was isolated (40 mg) and identified as amorphous 5 - 0 - allyl - 4,6 - di 0 - (4,6 - di - 0 - acetyl - 2,3 - dideoxy - a - D - erythrn - hex - 2 - enopyranosyl) 2 - deoxy - 1,3 - di - N - benyl - 1,3 - di - N - methoxycarbonylstreptamine.

[α]D24+82.5 (c, 0.66, chloroform). TLC: Rf 0.35 (chloroform-ethyl acetate, 4:10; Rf 0.35 (benzene-ethyl acetate, 1:1).

IR: vmaxCHCL3 1735 (OAc), 1690 (NCOOMe), 1490 (Ph) cm-1, PMR data (CDCl3, 110 ): # 1.10-1.40 (m, 2 H, H-2ax, 2eq), 2.03 (s, 12 H, 4 OAc), 3.30 (m, 2 H, H-1,3), 3.68 (2 s, 6 H, 2 NCOOMe), 3.80-4.80 (m, skeleton protons and CH2Ph), 5.05 (m, 1 H, H-1'α), 5.10-5.50 (m, 4 H, H 4',4" and C=CH2, allyl), 5.80 (m, 5 H, H-2',2",3',3" and CH=C allyl), 7.15 (m, 10 H, 2 Ph).

Analysis Calculated for C47H58N2O17: C, 61.16; H, 6.33; N, 3.03 Found: C, 61.30; H, 6.40; N, 3.15% EXAMPLE LXXXIII A mixture of 2 - deoxy - 1,3 - di - N - methoxycarbonyl - 1N,3N,5 - 0 tribenzylstreptamine (0.7 g, 1.27 mmol) and tri - 0 - acetyl - D - glucal (1.04 g, 3.8 mmol) in dry benzene (100 ml) was treated with boron trifluoride etherate (0.1 ml) for 0.5 h at 22 . Triethylamine (0.5 ml) was added, the mixture was washed with water and concentrated. The syrup (1.93 g) was deacetylated in methanol (20 ml) with sodium methoxide (50 mg) for 12 h at 220. The neutralized solution (CO2) was concentrated and the residue was extracted. The extracts were concentrated and the syrup thus obtained was purified by silica gel column chromatography using benzene-chloroform and benzene-methanol mixtures as eluants. The man fraction was Precipitated from chloroform solution with petroleum 40-60 as an amorphous solid (376 mg, 45%) and was identified as pur 4,6 - di - O - (2,3 dideoxy - α - D - erythro - hex - 2 - enopyranosyl) - 2 - deoxy - 1,3 - di - N methoxycarbonyl - 1 - N,3 - N,5, - O - tribenzylstreptamine. M.p.: 105 (sinters).

[α]D22+37 (c 0.43, chloroform). TLC: Rf 0.27 (benzene-methanol, 4:1); Rf 0.43 (ethyl acetate-ethanol, 10:1), Rf 0.08 (ethyl acetate).

IR: vmaxCHCl33420 (OH), 1690 (NCOOMe), 1600 (Ph), 1580 (Ph) cm-1.

PMR data (CDCl3, 95 ): # 1.30 (m, 2 H, H-2ax, 2 eq), 2.10 (b.b, 4 H, 4 OH), 3.70 (m, 6 H, 2 NCOOMe), 5.40-5.95 (m, 5 H, H-1',2',3',2",3"), 7.20 (m, 15 H, 3 Ph).

Analysis Calculated for C42H52N2O12: C, 64.16; H, 6.51; N, 3.48 Found: C, 64.28; H, 6.70; N, 3.56% EXAMPLE LXXXIV A solution of 4,6 - di - 0 - (2,3 - dideoxy - a - D - erythro - hex - 2 enopyranosyl) - 2 - deoxy - 1,3 - di - N - methoxycarbonyl - 1 - N, 3 - N, S - 0 - tribenzylstreptamine (0.3 g, 0.35 mmol) in methanol (20 ml) was hydrogenated over 10% palladium-on-charcoal (50 mg) at atmospheric pressure for 2 h. The filtered solution was concentrated and the residue was purified by silica gel column chromatography (benzene-methanol mixtures as eluant) and by precipitation from an ethereal solution with petroleum 4600. The amorphous solid (0.25 g, 83%) was identified as 4,6 - di - 0 - (2,3 - dideoxy - α - D - erythro - hexopyranosyl) 2 - deoxy - 1,3 - di - N - methoxycarbonyl - I - N,3 - N,5 - U - tribenzylstreptamine, M.p.: 1050 (sinters).

IR: vmaxCHCl3 3420 (OH), 1690 (NCOOMe), 1605 (Ph), 1590 (Ph) cm-'.

PMR data (CDCI3, 95 ): at 1.20-1.80 (m, 10 H, H-2,2,2',2',2",2",3',3",3",3"), 3.67 (2 s, 6 H, 2 NCOOMe), 4.32 (m, 4 H, 2 NCH2Ph), 4.85 (m, 1H, H-l"a), 4.88 (m, 2 H, -OCH2Ph), 5.27 (m, 1 H, H-l'a), 7.20 (m, 15 H, 3 Ph).

Analysis Calculated for C43H56N2O13: C, 63.84; H, 6.98; N, 3,46 Found: C, 63.97; H, 7.03; N, 3.50% EXAMPLE LXXXV Carbon tetrachloride (0.2 ml) and hexamethylphosphorous acid triamide (0.2 ml) were added to a solution of 4,6 - di - 0 - (2,3 - dideoxy - a - D erythrohexopyranosyl) - 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N - methoxycarbonylstreptamine (0.351 g, 0.5 mmol) in dry dimethylformamide (2 ml).

The mixture was stirred at -45 for 1 h. Sodium azide (0.26 g, 4 mmol) was added and the solution was stirred at 800 for 18 h. It was then poured into ice-water and extracted with ether. The extracts were washed with water, dried and concentrated to give a glassy product (0.373 g) which was purified by chromatography on silica gel (chloroform). The eluted product (0.26 g, 70"/,) was pure, glassy 4,6 - di - 0 (6 - azido - 2,3,6 - tndeoxy - a - D - erythro - hexopyranosyl) - 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N - methoxyearbonylstreptamine. [α]D24.4+44.7 (c, 0.78, chloroform). TLC: Rf 0.11 (benzene-ethyl acetate, 1:1); Rf 0.50 (ethyl acetate).

PMR data (CDCI3, 80 ): # 1.20-1.80 (m, 11 H, H 2,2,2',2',2",2",3',3',3",3",5ax), 1.98 (s, 2 H, 2) H), 2.65 (m, 1 H, H-Seq), 3.46 (m, 4 H, H-6',6',6",6"), 3.66 (2 s, 6 H, 2 NCOOMe), 4.30 (m, 4 H, 2 CH2- Ph), 4.59 (m, 1 H, H-1"a), 4.96 (m, 1 H, H-l'a), 7.17 (m, 10 H, 2 Ph).

Analysis Calculated for C36H46N8O10: C, 57.43; H, 6.42; N, 14.88 Found: C, 57.30: H, 6.50; N, 14.74% EXAMPLE LXXXVI A mixture of 4,6 - di - 0 - (2,3 - h. After the addition of water (0.03 ml) the mixture was concentrated to give a residue which was triturated with water and recrystallized from ethanol-water (23 - mg, 71 /n) Pure 4,6 - di - 0 - (4 - 0 - acetyl - 6 - 0 - toluene - p - sulphonyl - 2,3 dideoxy - α - D - erythro - hexopyranosyl - 1,3 - di - N - benzyl - 2,5 - dideoxy 1,3 - di - N - methoxycarbonylstreptamine thus obtained had an m.p. of 85-88 .

TLC: R, 0.68 (benzene-ethyl acetate, 1:2); R, 0.50 (chloroform).

PMR data (CDCl2): a 1.25 (m, 1 H, H-2ax), 1.50-2.00 (m, 10 H, H-2eq, 2',2',2",2",3',3',3",3", and 5ax), 1.95 (2 s, 6 H, 2 OAc), 2.43 (2 s, 6 H, CH2- tosyl groups), 2.65 (m, 1 H, H-Seq), 3.67 (2 s, 6 H, 2 NCOOMe), 3.904.70 (b. band, the remaining protons), 5.02 (m, 1 H, H-l'a), 7.20 (m, 10 H, 2 Ph), 7.32 and 7.78 (2 m, 8 H, 2-Pb-, tosyl).

Analysis Calculated for C54H66N2O,6S2 C, 59.32; H, 6.06; N, 2.55; S, 5.83 Found: C, 59.20; H,6.15; N, 2.70; S, 5.95% EXAMPLE LXXXVIII A mixture of 4,6 - di - 0 - (6 - 0 - toluene - p - sulphonyl - a - D erythro - hexopyranosyl) - 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N - methoxycarbonylstreptamine (0.48 g, 0.475 mmol) and sodium azide (0.3 g, 4.6 mmol) in dry N,N-dimethylformamide (5 ml) was heated and stirred at 80C for 24 h.

The mixture was poured into ice-water and extracted with ether. The extracts were washed with water, dried and concentrated to give a glassy residue (0.31 g, 87%) of pure 4,6 - di - 0 - 06 - azido - 2,3,6 - trideoxy - a - D - erythro - hexopyranosyl) 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N - methoxycarbonylstreptamine.

[a]25+450 (c 0.8, chloroform). TLC: R, 0.11 (benzene-ethyl acetate, 1:1), Rf 0.50 (ethyl acetate).

The PMR spectrum of this material was identical with that of the product described in Example LXXXV.

Analysis Calculated for C36H48N8O10: C, 57.43; H, 6.42; N, 14.88 Found: C,57.60; H, 6.50; N, 15.01% EXAMPLE LXXXIX A mixture of 4,6 - di - 0 - (6 - azido - 2,3,6 - trideoxy - a - D - erythro hexopyranosyl)- 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N - methoxycarbonylstreptamine (0.2 g, 0.265 mmol) and 10% palladium-on-charcoal (0.05 g) in methanol (10 ml) was hydrogenated at atmospheric pressure for 20 h.

The catalyst was filtered and washed with methanol containing ammonia and the organic liquids were concentrated to give a glassy material (0.192 g). TLC: R, 0.25 (chloroform-methanol-ammonia, 100:30:5).

This product was heated under reflux (48 h) with ethanol-90% hydrazine hydrate (1:3, 2 ml), and the mixture was evaporated to dryness. The chloroformic extracts of the residue, on evaporation, yielded a glassy product (0.148 g, 95%) of pure 4,6 - di - 0 - (6 - amino - 2,3,6 - trideoxy - a - D - erythro - hexopyranosyl) 1,3 - di - N - benzyl - 2,5 - dideoxystreptamine. [α]D24+54.2 (c 0.166, methanol).

TLC: Rf 0.10 (chloroform-ethanol-ammonia, 100:30:5); Rf 0.55 (methanolammonia, 8:1).

Analysis Calculated for C32H48N4O8: C, 65.73; H, 8.27; N, 9.58 Found: C, 65.91; H, 8.40; N, 9.63% EXAMPLE XC A mixture of 4,6 - di - 0 - (6 - amino - 2,3,6 - trideoxy - a - D - erythro hexopyranosyl) - 1,3 - di - N - benzyl - 2,5 - dideoxystreptamine (0.23 g, 0.39 mmol) and 10% palladium-on-charcoal (65 mg) in methanol (25 ml) was hydrogenated at atmospheric pressure for 16 h. Filtration of the catalyst and concentration of the clear solution gave a glassy residue of pure 4,6 - di - 0 - (6 amino - 2,3,6 - trideoxy - a - D- erythro - hexopyranosyl) - 2,5 - dideoxystreptamine (0.16 g, 100%). [α]D24+139.35 (c 0.37, methanol). TLC: Rf 0.48 (methanol-ammonia, 4:1) (cf Kanamycin A, Rf: 0.25); paper chromatography: Rglucosamine: 0.26 (n - butanol - pyridine - water - acetic acid, 6:4:3:1).

PMR data (D2O): # 1.10-2.20 (bm, H-2eq H-5ax 2 H-2', 2 H-2", 2 H-3' and 2 H-3"), 2.70-3.05 (m, 4 H, H-6',6',6",6"), 3.30-3.70 (m, 8 H, skelton protons), 5.04 (m, 1 H, H 1"α), 5.06 (m, 1 H, H-1'α).

Analysis Calculated for C,8H36N406: C, 53.45; H, 8.97; N, 13.85 Found: C, 53.16; H, 8.74; N, 1390 /n EXAMPLE XCI A mixture of 4,6 - di - 0 - (6 - azido - 2,3,6 - trideoxy - a - D - erythro hexopyranosyl) - 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N methoxycarbonylstreptamine (0.7 g, 1 mmol), 90% hydrazine hydrate (3 ml), 10% palladium-on-charcoal (50 mg) and ethanol (2 ml) was heated under reflux for 6 h.

After evaporating the mixture, ethanol (10 ml) and more palladium catalyst (50 mg) were added and the suspension was hydrogenated at 25 , 2 atmos. for 6 h. The mixture gave. upon filtration and concentration, a glassy residue (0.4 g, 99%) of pure 4,6 - di - O - (6 - amino - 2,3,6 - trideoxy - α - D - erythro - hexopyranosyl) 2,5 - dideoxystreptamine. [α]D24+139 (c 0.5, methanol). TLC: Rf 0.47 (methanolammonia, 4:1), (cf Kanamycin A, Rf: 0.25.

The PMR spectrum of this compound was identical with that of the product prepared in the previous Example.

Analysis Calculated for C18H25N4O6: C, 53.45; H, 8.97; N, 13.85 Found: C, 53.56; H, 9.09; N, 13.76 EXAMPLE XCII A mixture of 4 - 0 - acetyl - 6 - azido - 2,3,6 - trideoxy - D - erythro hexopyranosyl bromide (0.56 g, 2 mmol) and 1,3 - di - N - benzyl - 2,5 - dideoxy 1,3 - di - N - methoxycarbonylstreptamine (0.443 g, 1 mmol), mercuric cyanide (1.5 g), mercuric bromide (1.5 g), dry Amberlite IR-400 (Br-), (3 g) and Drerite (5 g) in nitromethane (15 ml) and benzene (10 ml), was shaken for 2 days in the dark. The mixture was filtered, the solids were washed with chloroform and all the combined organic liquids were concentrated to give a syrupy material which was purified by chromatography on silica gel using mixtures of chloroform-benzene as eluant.

4,6 - Di - 0 - (4 - 0 - acetyl - 6 - azido - 2,3,6 - frideoxy - a - D - erythro hexopyranosyl)- 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N methoxycarbonylstreptamine (0.394 g, 470/,) was obtained as a glassy material.

[α]D24.5+69 (c 0.55, chloroform). TLC: Rf 0.58 (benzene-ethyl acetate, 1:1).

PMR data (CDCl3, 70 ): # 1.30 (m, 10 H, H-2eq, 5ax, 2',2',2",2",3',3',3",3"), 2.00 (s, 6 H, 2 OAc), 2.65 (m, 1 H, H-5eq), 3.27 (m, 4 H, H-6',6',6",6"), 3.67 (2 s, 6 H, 2 NCOOMe), 3.804.75 (broad band of multiplets, 12 H, skeleton protons), 5.01 (m, 1 H, H-l'a), 7.20 (m, 10 H, 2 Ph).

Analysis Calculated for C40H52N8O12: C, 57.40; H, 62.6; N, 13.39 Found: C, 57.62; H, 5.31; N, 13.45% EXAMPLE XCIII Methylsulphonyl chloride (0.5 ml) was added to a solution of 4,6 - di - 0 (2,3 - dideoxy - a - D - erythro - hexopyranosyl) - 1,3 - di - N - benzyl - 2,5 dideoxy - 1,3 - di - N - methoxycarbonylstreptamine (0.5 g, 0.71 mmol) in dry pyridine (5 ml) and the mixture was stored at 220 for 12 h. Water (0.5 ml) was added and the mixture was poured onto ice. The solid which separated was recrystallized from chloroform-ether to give pure 4,6 - di - 0 - 4,6 - di - 0 - methylsulphonyl 2,3 - dideoxy - α - D - erythro - hexopyranosyl) 1,3 - di - N - benzyl - 2,5 dideoxy - 1,3 - di - N - methoxycarbonylstreptamine (0.41 g, 50%). M.p.: 108-110 (sinters at 100 ). [α]D27+60 (c 0.714, chloroform). TLC: Rf 0.25 (benzene-ethyl acetate, 1:1); Rf 0.60 (ethyl acetate).

PMR data (CDCl3, 100 ): # 1.33 (m, 1 H, H-2ax), 1.65 (m, 2 H, H-2",2"), 1.83 (m, 2 H, H-2',2'), 1.90-2.30 (bm, 4 H, H-3',3',3",3"), 2.52 (m, 1 H, J5ax, 5eq=13 Hz, H-5eq), 3.02 (s, 12 H, 4-SO2Me), 3.37 (m, 2 H, H-1,3), 3.68 (s, 6 H, 2 NCOOMe), 4.00 (m, 2 H, H-4,6), 4.32 (m, 4 H, 2 CH2Ph), 4.62 (m, 1 H, H-1"a), 5.00 (m, 1 H, H-l'a), 7.20 (m, 10 H, 2 Ph).

Analysis Calculated for C40H58N2O20S4: C, 47.34; H, 5.76; N, 2.76; S, 12.61 Found: C,47.10; H,5.81; N,2.94; S, 12.79 EXAMPLE XCIV A mixture of 4,6 - di - 0 - (4,6 - di - 0 - methylsulphonyl) - 2,3 - dideoxy a - D - erythro - hexopyranosyl) - 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 di - N - methoxycarbonylstreptamine (0.35 g, 0.34 mmol) and sodium azide (0.3 g, 4.6 mmol) in dry dimethylformamide (10 ml) was stirred at 900 for 25 h. The solvent was removed in vacuo, the residue was treated with ice-water and the precipitate thus obtained was filtered, washed (water) and dried. This product was purified by chromatography (silica gel, benzene-ethyl acetate) to give pure, amorphous 4,6 di - O - (4,6 - di - azido - 2,3,4,6 - tetradeoxy - a - D - threo - hexopyranosyl) -1,3 di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N - (methoxycarbonylstreptamine (0.137 g, 49.5%). [α]D23+13.4 (c 0.73, chloroform). TLC: R, 0.70 (benzene-ethyl acetate, 1:2); Rf 0.43 (chloroform-ethyl acetate, 3:1).

PMR data (CDCl3): # 1.20-1.60 (bm, 5 H, H-2ax, 2',2',2",2"), 1.70-2.10 (m,6 H, H-2eq, 5ax, 3',3',3",3"), 2.65 (m, 1 H, H-5eq), 3.00 3.50 (m, 6 H, H 4',4",6',6',6",6"), 3.67 (m, 6 H, 2 NCOOMe), 5.01 (m, 1 H, H-l'a), 7.20 (m, 10 H, 2 Ph) Analysis Calculated for C36H46N14O8: C, 53.95; H, 5.76; N, 24.37 Found: C, 54.07; H, 5.64; N, 24.48% WHAT I CLAIM IS:- 1. A compound being a pseudotrisaccharide of the general formula: [A]-[B]-[C] or [A]-[C1]-[A1] where [A] is a group of the formula:

where R, is H, F, OH or SH; R2 is H or NH2; and R3 is H or -CH2-R4 where R4 is OH or NH2; provided that when R2 is H, R3 is -CH2-NH2, and when R2 is H or -CH2-OH R2 is NH2; [A'] is a group of the formula:

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   5eq=13 Hz, H-5eq), 3.02 (s, 12 H, 4-SO2Me), 3.37 (m, 2 H, H-1,3), 3.68 (s,

   6 H, 2 NCOOMe), 4.00 (m, 2 H, H-4,6), 4.32 (m, 4 H, 2 CH2Ph), 4.62 (m, 1 H, H-1"a), 5.00 (m, 1 H, H-l'a), 7.20 (m, 10 H, 2 Ph).

   Analysis Calculated for C40H58N2O20S4: C, 47.34; H, 5.76; N, 2.76; S, 12.61 Found: C,47.10; H,5.81; N,2.94; S, 12.79 EXAMPLE XCIV A mixture of 4,6 - di - 0 - (4,6 - di - 0 - methylsulphonyl) - 2,3 - dideoxy a - D - erythro - hexopyranosyl) - 1,3 - di - N - benzyl - 2,5 - dideoxy - 1,3 di - N - methoxycarbonylstreptamine (0.35 g, 0.34 mmol) and sodium azide (0.3 g, 4.6 mmol) in dry dimethylformamide (10 ml) was stirred at 900 for 25 h. The solvent was removed in vacuo, the residue was treated with ice-water and the precipitate thus obtained was filtered, washed (water) and dried. This product was purified by chromatography (silica gel, benzene-ethyl acetate) to give pure, amorphous 4,6 di - O - (4,6 - di - azido - 2,3,4,6 - tetradeoxy - a - D - threo - hexopyranosyl) -1,3 di - N - benzyl - 2,5 - dideoxy - 1,3 - di - N - (methoxycarbonylstreptamine (0.137 g, 49.5%). [α]D23+13.4 (c 0.73, chloroform). TLC: R, 0.70 (benzene-ethyl acetate, 1:2); Rf 0.43 (chloroform-ethyl acetate, 3:1).

   PMR data (CDCl3): # 1.20-1.60 (bm, 5 H, H-2ax, 2',2',2",2"), 1.70-2.10 (m,6 H, H-2eq, 5ax, 3',3',3",3"), 2.65 (m, 1 H, H-5eq), 3.00 3.50 (m, 6 H, H 4',4",6',6',6",6"), 3.67 (m, 6 H, 2 NCOOMe), 5.01 (m, 1 H, H-l'a), 7.20 (m,

   10 H, 2 Ph) Analysis Calculated for C36H46N14O8: C, 53.95; H, 5.76; N, 24.37 Found: C, 54.07; H, 5.64; N, 24.48% WHAT I CLAIM IS:- 1. A compound being a pseudotrisaccharide of the general formula: [A]-[B]-[C] or [A]-[C1]-[A1] where [A] is a group of the formula:

   where R, is H, F, OH or SH; R2 is H or NH2; and R3 is H or -CH2-R4 where R4 is OH or NH2; provided that when R2 is H, R3 is -CH2-NH2, and when R2 is H or -CH2-OH R2 is NH2; [A'] is a group of the formula:

   where R5 is H, OH, SH or halogen; R6 is H, OH or NH R8 where R8 is H or CH3; and R7 is H or-CH2-R9 where R9 is H, OH or NH2; provided that when R6 is H or OH R7 is -CH2-NH2 and when R7 is H or -CH2-OH, R6 is NH R8; [B] is a group of the formula:

   where R2 and R3 are as defined for [A]; [C] is a group of the formula:

   where R10 is H or OH and R11 is H, CH3 or -CO#CHOH-CH2-CH2-NH2; and [C1] is a group of the formula;

   where R10 and R11 are as defined for [C]; wherein both glycosidic bonds are α- glycosidic bonds, and the pharmaceutically acceptable acid addition salts thereof.
2. 2. A compound as claimed in claim 1 of the formula: [A]-[B]-[C] wherein R, is H or OH, R2 is H or NH2 and R2 is CH2NH2.
3. 3. A compound as claimed in claim 1 of the formula: [A]-[C]-[A1] wherein R1, is H or OH, R2 is H or NH2, R3 is CH2 # NH2, R5 is H or OH, R6 is H, NH2 or NHCH3 and R7 is -CH2NH2 or -CH2OH.
4. 4. A compound as claimed in any one of claims I to 3 and substantially as hereinbefore described.
5. 5. A method of making a compound as claimed in any one of claims 1 to 4 substantially as hereinbefore described.
6. 6. Pseudotrisaccharides whenever made by the method claimed in claim 5.
7. 7. A pharmaceutical composition comprising as an active ingredient a compound as claimed in any one of claims 1 to 4 and 6 in combination with a pharmaceutically acceptable excipient, diluent or carrier.