IE75898B1 - Macrocyclic tetraaza compounds containing a six-membered ring processes for their production and pharmaceutical agents containing the same - Google Patents

Abstract

6-Membered-ring-containing macrocyclic tetraaza compounds of the general formula I <IMAGE> in which ... represents a single or double bond, Q represents a nitrogen atom or the radical NH, X<1> represents a hydrogen atom, -(CH2)n-R<1>- or <IMAGE> group where n denotes the figures 1 to 5, m denotes the figures 0 to 2 and R<1> denotes a hydrogen atom or a hydroxyl group, X<2> represents X<1> or a -(CH2)n-(O)l-(CH2)k-(C6H4)q-R<2> group where k denotes the figures 0 to 4, l and q denote the figures 0 or 1 and R<2> denotes a hydrogen atom, a C1-C4-alkoxy group, a functional group or, bonded by means of this functional group, a bio- or macromolecule, A<1>, A<2>, B<1>, B<2>, C<1>, C<2>, D<1>, D<2>, E<1>, E<2>, F<1> and F<2> independently of one another each represent X<2> G represents R<2> or a second macrocycle, bonded by means of K, of the general formula II <IMAGE> where K denotes a direct bond, a bis(carbonylamino) group (-NH-CO-CO-NH-) or a C1-C14-alkylene group which optionally at the ends carries carbonyl( &rdurule& CO) or carbonylamino (-NH-CO-) groups or oxygen atoms and optionally contains one or more oxygen atom(s), hydroxymethylene (-CH-OH-), CH(X<2>)COOZ, acyl or hydroxyacyl- substituted imino groups or one or two C-C double and/or C-C triple bonds, Z represents a hydrogen atom and/or a metal ion equivalent of an element of atomic number 21-29, 31, 32, 37-39, 42-44, 49 or 57-83, with the proviso that the 12 ring substituents A<1> to F<2> represent at least 8 hydrogen atoms, that X<1> and X<2> only simultaneously represent hydrogen atoms when at least one of the ring substituents A<1> to F<2> does not represent a hydrogen atom and that the macrocycle of the general formula I no longer contains a bio- or macromolecule and that, if desired, the radical of the CO2H groups is present as ester or amide, and their salts with inorganic and/or organic bases, amino acids or amino acid amides are useful diagnostic and therapeutic agents.

Description

The invention relates to the subject-matter characterised in the patent claims, that is to say 6-membered-ringconfcaining macrocyclic tetraaza complex formers, complexes and complex salts, to agents comprising those compounds, to the use thereof as diagnostic and therapeutic agents and also to processes for the preparation of those compounds and agents.

Metal complexes were considered as contrast media for radiology as early as the beginning of the Fifties. The compounds used at that time were, however, so toxic that use in humans was out of the question. It was, therefore, completely surprising that certain complex salts have proved to be sufficiently tolerable that routine administration to humans for diagnostic purposes could be contemplated. The dimeglumime salt of Gd DTPA (gadolinium(lll) complex of diethylenetriaminepentaacetic acid), described in European Patent Application published under no. 71564. was the first example of that class of compounds to be registered, under the name Magnevlst®, as a contrast medium for nuclear spin tomography. The main focus for administration is for disorders of the central nervous system.

A substantial reason for the practical usefulness of Gd DTPA in clinical medicine is its high level of effectiveness in nuclear spin tomography, especially in the case of many brain tumours. By virtue of its being highly effective, cd DTPA can, at 0.1 mmol/kg body weight. be administered at very much lower doses than. for example, X-ray contrast media in many X-ray examinations. » As a further example of the complex salts, the meglumine salt of Gd DOTA (gadolinium(III) complex of 1,4,7,10tetraasacyclododecanetetraacetic acid) described in - 2 75898 German Patent Application 34, 01 052 has also proved its value for diagnostic purposes.

* It is, however, now desirable to use chelates at higher doses also. That is the case especially for detecting » 5 specific disorders outside the central nervous system using nuclear spin tomography (NMR diagnostics), more especially, however, when chelates ©re used as X-ray contrast media.

In order to keep the volume to which the body is subio jected as low as possible, it is necessary to use highly concentrated chelate solutions. The chelates known hitherto are not very suitable for this, above all on account of their osmolality, which is too high.

There is, therefore, a need for chelates that have a 15 lower osmolality than do the previously known chelates.

At the same time, however, the preconditions for the use of those compounds in humans must be met with regard to the separation between the effective dose and the dose established in animal tests as being toxic (the thera20 peutic range), to organ specificity, stability, contrastincreasing action, tolerability and also to the solubility of the complex compounds.

The problem underlying the invention is therefore to provide those compounds and agents and also to provide as simple as possible a process for the preparation thereof.

That problem-is solved by the present invention.

The complex compounds according to the invention and the « solutions prepared therefrom meet the above-mentioned requirements in a surprising manner. They have a reduced osmolality and a more advantageous therapeutic rang® and/or stability and ability of the chemical constituents of the solution to be stored and/or organ specificity and/or contrast-increasing action (for example relaxivity) and/or tolerability (for example lower cardiovascular or allergy-type side effects) than the hitherto customary diagnostic agents.

Even without specific measures, their pharmacokinetics enable an improvement in the diagnosis of many disorders. The complexes remain, for the greater part, unaltered and are eliminated rapidly so that, in particular, even when io relatively toxic metal ions are used, despite a high dosage no damaging effects are observed.

The practical application of the novel complexes and complex formers is facilitated also by their advantageous chemical stability.

A further substantial advantage of the complexes and complex formers described is their outstanding chemical versatility. The properties can be matched to th© requirements in terms of effectiveness, pharmacokinetics, tolerability, solubility, ease of handling and so on by 20 the selection of, in addition to the central atom, a plurality of substituents in the macrocycle and/or of salt formers. Thus, for example, it is possible to obtain compound specificity for structures in th© body, specific biochemical substances, metabolic processes and for conditions of th© tissues or body fluids, which is highly desirable in diagnostics and therapy.

The macrocyclic compounds according to the invention are characterised by the general formula X: •r COOS wherein represents a single or double bond, Q represents a nitrogen atom or the radical NH, X3- represents a hydrogen atom, a group -(CHo^-R1 or -(CH2)m-(CM)n-CH2OH wherein OH represents a number from 1 to 5, represents a number from 0 to 2, and represents a hydrogen atom or a hydroxy group, X2 represents X1 or a group -(CH^JnHOh-iCH^-iCgH^q-R2 wherein k represents a number from 0 to 4, each of 1 and a represents the number 0 or l, and R2 represents a hydrogen atom, a Ci-C^alkoxy group, a functional group or a bio- or macro-molecule bound by way of that functional group, A1, A2, Β1, 32, C1, C2, D1, D2, S1, Ξ2, S’1 and F2 each independently of the other represent X2, G represents R2 or a second macrocycle, bound by way of K, of the general formula II coax wherein K represents a direct bond, a bis(carbonylamino) group (-KH-CO-CO-NH-) or a C|-Ci4alkylene group which optionally carries at its ends carbonyl (>C0) or carbonylamino (-MH-CO-) groups or oxygen atoms and which optionally contains one or more oxygen atom(s), hydroxymethylene (-CH(OH)-) group(s), CH(X2)COO2-, acyl- or hydroxyacyl-substituted imino groups or one or two CC double bonds and/or C-C triple bonds, represents a hydrogen atom and/or a metal ion equivalent of an element of atomic number 21-29, 31, 32, 37-39, 42-44, 49 Or 57-83, with the proviso that the 12 ring substituents A1 to F2 represent at least 8 hydrogen atoms, that X1 and X2 simultaneously represent hydrogen atoms only when at least one of the ring substituents A1 to F2 does not represent a hydrogen atom, at least one of the ring substituents A1 to D2 does not represent (CH2)i-6~S and at least one of the ring substituents B1 to F2 does not represent (CH9)i_5"H, and that the macrocycle of the general formula I contains not more than one bio- or macro-molecule and that, if desired, remaining CO9H groups are present in the form of ester or amide, and also salts thereof with inorganic and/or organic bases amino acids or amino acid amides.

Preferred are tetraaza compounds of the general formula III cooz wherein represents a single or double bond, Q represents a nitrogen atom or the radical NH, χΛ represents a hydrogen atom, a group -(CH-^J^-R1 or -(CH2)m-(CH)n-CH20H wherein OH n represents a number from 1 to 5, m represents a number from 0 to 2, and R1 represents a hydrogen atom or a hydroxy group, X2 represents X1 or a group -(CH2)n-(0)x-(CH2)k-(C6H4)q-R2 wherein k represents a number from 0 to 4, each of 1 and σ represents the number 0 or 1, and R2 represents a hydrogen atom, a Cb-C.alkoxy group, a functional group or a bio- or macro-molecule bound by way of that functional group, A1, , C- and D1 each independently of the other represent X2, G represents R2 or a second macrocycle, bound by way of K, of the general formula iv ea®s wherein K represents a direct bond, a bis(carbonylami.no) J5 group (-NH-CO-CO-NH-) or a Οχ-Chalky lene group which optionally carries at it ends carbonyl (>00) or carbonvlamino (-NH-CO-) groups or oxygen ©toms and which optionally contains on© or more oxygen atom(s), hydroxymethylene i-CH(QH)~, group(s), CH(X2)COOZ-, acyl- or hydroxyacyl-substituted imino groups or one or two C-C double bonds and/or C-C triple bonds, Z represents a hydrogen atom and/or a metal ion equivalent of an element of atomic number 21-29, 31, 32, 37-39, 42-44, 49 or 57-83, with the proviso that X1 and X2 simultaneously represent hydrogen atoms only when at least one of the 4 ring substituents A1, B1, C1 and D1 does not represent a hydrogen atom or (CH2)i_g-H and that, if desired, remaining CQ^H groups are present in the form of ester or amide, and also salts thereof with inorganic and/or organic bases, amino acids or amino acid amides.

Compounds of the general formula I wherein 2 represents hydrogen are referred to herein as complex formers and compounds of the general formula I wherein at least two of the substituents 2 represent a metal ion equivalent are referred to herein as metal complexes.

Th© element of the above-mentioned atomic number which forms the central ion of the physiologically tolerable complex salt may, of course, for the desired purpose of the diagnostic agent according to the invention, also be radioactive.

If the agent according to the invention is intended for use in NMR diagnostics, th® central ion of the complex salt must be paramagnetic. Such ions are especially the di- and tri-valent ions of elements of atomic number 2129, 42, 4< and 58-70. Suitable ions are,, for example, chromium (III), manganese (II), iron(II), cobalt(II), nickel(II), copper(II), praseodymium(III), neodymium(lll), samarium;III) and ytterbium(III). Especially preferred on account of their very strong magnetic moment are the gadolinium(lll), terbium(III), dysprosium(lll), holmium(III), erbium(HI) and iron(III) ions.

If the agents according to the invention are to be used in nuclear medicine, the central ion must be radioactive. For example, radioisotopes of the following elements are suitable: copper, cobalt, gallium, germanium, yttrium, strontium, technetium, indium, ytterbium, gadolinium, samarium and iridium.

If the agent according to the invention is to be used in X-ray diagnostics, the central ion must be derived from an element of relatively high atomic number in order to achieve sufficient absorption of the X-rays. It has been found that diagnostic agents that contain a physiologically tolerable complex salt having a central ion of an element of atomic number 21-29, 42, 44, 57-83 are suitable for that purpose; those are, for example, the lanthanum(III) ion and the above-mentioned ions of the lanthanide series.

There may be mentioned as preferred groups for X1 CH2OH, CH2CH2OH and CHOHCH2OH, and as preferred groups for X2, A1, B1, C1 and/or D1 CH2OH, CH2CH2OH, ch2och2c6h5, chohch2oh, ch2c5h4och3, ch2c6h5, CH2C6H4O(CH2)3COOH and CH2C6H4NCS, the remaining ring substituents A2, B2, C2, D2, E1, E2, F1 and F2 preferably representing hydrogen.

The alkylene chain represented by K, to which the second macrocycle II or IV is bound, optionally carries at its ends carbonyl (CO) groups, carbonylamino (NH-CO) groups or oxygen atoms and contains from l to 14 carbon atoms.

It may be interrupted by one or more oxygen atom(s), hydroxymethylene (-CH(OH)-) group(sp CH(X2)COOZ-, acylor hydroxyacyl-substituted imino groups or by one or two C-C double bonds and/or C-C triple bonds. The two macrocycles may alternatively be linked by a direct bond There come into consideration as optionally hydroxvlated acyl groups acyl radicals having up to 10 carbon atoms. There may be mentioned by way of example the acetyl, propionyl, butyryl, benzoyl and hydroxyacetyl radicals.

The alkylene chain may be straight-chained or branchchained, saturated or unsaturated and may optionally be interrupted as described. It may contain up to 4 oxygen atoms and/or up to 3 carboxymethylimino groups.

Examples of the alkylene chain are: '(CM2l2*· "chz-'°ch2*1 ’(CH?r· -ch2-ch2-o-ch2~ch2-, -«ch2-o-ch2j2 -ICH2-0-CH2)3-, -CH2-CH2-IO-CH2-CH2I3-, -CH2-CH2-(O-CH2-CH2)t~.

-CH-CHII II OH OH II CHX eooz -ch2-ch „„2 C~ ICfrk 5 C002 -ίCM,S„C6<=CH-(i, £ 2 & 2 Preferably the two macrocycles are linked by a direct bond or by the group -(0)o-(CH2)n-(CH)k-(CH2)n~(0)i~. 6« Preferred functional groups, which can be represented by R2, are, for example, maleimidobenzoyl, 3-sulphomale11 Imidobenzoyl, 4-(maleimidomethyl)cyclohexvlcarbonyl, 4(3-sulpho-(maleimidomethyl)Jcvclohexylcarbonyl, 4-(pmaleimidophenyl) butyryl, 3-(2-pyridyldithio)propionyl, methacryloyl(pentamethylene)amido, bromoacetyl, iodo5 acetyl, 3-iodopropvl, 2-bromoethyl, 3-mercaptopropyl, 2mercaptoethyl, phenyleneisothiocyanate, 3-aminopropyl, benzyl ester, ethyl ester, t-butyl ester, amino, hydroxy, Ci-Cgalkylamino, aminocarbonyl, hydrazino, hvdrazinocarbonyl, maleimido, methacrylamido, methacryloyl]q hydrasinocarbonyl, maleimidoamidocarbonyl, halogen, mercapto, hydrazinotrimethylenehydrazinocarbonvl, aminodimethyleneamidocarbonyl, bromocarbonyl, phenylenediazonium, isothiocyanate, semicarbazide, thiosemicarbaside and isocyanate.

A few selected groups are given for clarification: •ch2-CrH,/o2,3-^ / , -CH,-Cg.H;-0(CH2S3MHz>^ . -WH-N CH2-CsH4-0iCH2l5CO2CH2CsH5„ -O-C^-CC^CHjCgHg , -CH2-C5H4-OUH2i5COMHNH2, -COMMNH-^ . -CH^-CgH, - β ( 1 , - SH - 12CH -C.H,-O(CH, J,CONHNH-(CH,J.-NHNH -CH.-NHNH,, -CH,-SM, -CH,CONHNH 2 6 * 25 Z J £ i t i 2 2 (CH I SH, -CH -C.H,-0-CH,COBs·, -C.H, NHCOCH Br . •ϊ ι n j 6 »> 2 CH -C.H,-OCH-C-NH-(CH ),MH -CH ,-C,H,-NH -C H.-M,, -C.HNCS, 2 6* 2 2 2 2 2 6 % 2 6 % 2 6 cHg-CgH,-NH-C-(CH2)2~S-S- 'M'' , -NHCO-HH-NH^, -NHCS-NH-NH 0 0 . /\ 11 11 CH -CH,-O-CH,-CH-CH,P -CH,CPM.-O-CH.-C-NH-(CH_I.-C-NHMH,, £ ® *> 2 Ζ Z ® * & 2 ι D 2 CH, 11 I 3 •CH -C.H-0-CH,-CHOH-CH,~MH(CH,) ..-C-NHNH,, -QCH,~C~H-CH - (CHOH1, -CH.OH, £. 6 % 2 2 2 ι U 2 2 2 ®>2 / \ •CH -CH-CH -CH.-O-ICH,),-N 2 3 CH2-0-(CH2J3-MHNH,, -CH2-Q-CH2-C-MH-NH2„ -CHz-0-CH2-CH,-NH2, CH2-O-CH„-HM-C-5CH? S2-S-$ '^N'' „ CH2-0-CH2-C-HH-(CH2i10~C-NH-NH2> -C.H,-H SO„H SI- / * -C=C-C=C-R, -C=CCH=CRS', g ti§ tccrpk -c-esH, ch9-h. co-CH2-a?B -hh-co-ch2ci„ •C-csh)0-ch2-n SO Μ Ί_ / 3 • c-2i3-csVh II (CH2,3NH2· ~CSHi,SCN* -CC(CH3l=CMr pSH%l3 CiCRR', -CH?3rs -CH^JL , -C-C«2J. -(CH2I SH, u I -c=cRFi'. CgM.cH^er, -OSO^CgH^CHj. -SO2C1. -S0C1, /-N -CHsCH-CMjΒΓ , 0 II II , -C-Hr -C-MI , -CH = CH-C0z8, wherein R and R· are the same or different and each represents a hydrogen atom, a saturated or unsaturated Ci-C2Qalkvl radical that is optionally substituted by a phenyl group, or a phenyl group. Especially preferred are the groups -NCS, -iO2, -OH, -NHNH2, MHCOCH2Br, -KHCOCH2C1, -COoH and -CON30 II 0 Q Ii II II . r _ n - r - is - r . η θ Some or all of the remaining acidic hydrogen atoms, that is to say those that have not been substituted by the central ion, may optionally be replaced by cations of inorganic and/or organic bases or amino acids. Some or all of the corresponding acid groups may also be converted into esters or amides.

Suitable inorganic cations are, for example, the lithium ion, potassium ion, calcium ion, magnesium ion and, especially, th® sodium ion. Suitable cations of organic bases are, inter alia, cations of primary, secondary or tertiary amines, such as, for example, ethanolamine, diethanolamine, morpholine, glucamine, M,N-dimethylglueamine and, especially, N-methylglucamine. Suitable cations of amino acids are, for example, cations of lysine, arginine and ornithine and also amides of otherwise acidic or neutral amino acids.

Suitable esters are, preferably, those having a Ci-Cgalkyl radical; there may be mentioned by way of example the methyl, ethyl and tert-butyl, benzyl and 4-methoxybenzyl radicals.

If at least some of the carboxylic acid groups are to be present in the form of amides, then there come into consideration as radicals saturated or unsaturated, straight-chained or branch-chained or cyclic hydrocarbons having up to 5 C atoms, which are optionally substituted by from 1 to 3 hydroxy or Ch-C^alkoxv groups. The following groups may be mentioned by way of example: methyl, ethyl, 2-hydroxyethyl, 2-hydroxv-l-(hydroxymethyl) ethyl, 1-(hydroxymethyl)ethyl, propyl, isopropenyl, 2-hvdroxvpropyl, 3-hydroxypropyl, 2,3-dihydroxvpropvl, butyl, isobutyl, isobutenyl, 2-hydroxvbutyl, 3-hydroxybutyl, 4-hydroxybutyl, 2-, 3- and The compounds according to the invention have the desired properties described at the outset. They contain, bound stably in the complex, the metal ions required for their use.

Th© osmolality value, which is responsible for side effects such as pain, damage to the blood vessels and heart/circulation disorders, is clearly reduced in comparison with Magnevist (Example lb: 0.55 [osmol/kg) compared with Magnevist 1.96 (osmol/kg], 0.5 mol/1 at 37*C).

The value for the degree of relaxivity, which is a measure of the imaging obtained with MRI, is surprisingly high; for example, in the case of the compound of Example lb, it was possible to double the signal intensification in plasma in comparison with Magnevist.

A further advantage of the present invention lies in the fact that complexes having hydrophilic or lipophilic substituents have now become available. That offers the possibility of controlling the tolerability and pharmaco15 kinetics of those complexes by chemical substitution.

By the selection of suitable bio- or macro-molecules (see below) in R2, complexes according to the invention are obtained that have a surprisingly high tissue and organ specificity.

The compounds according to the invention are prepared as follows: in compounds of the general formula I coosr wherein G' , X1' and X2' represent G, X1 and X2, respectively, wherein the hydroxy groups and functional groups contained therein are present in protected form or in the form of precursor groups, and %' represents a hydrogen atom or an acid-protecting group, the protecting groups are removed, optionally the desired functional group is generated, if desired the resulting complex formers of the general formula I wherein Z represents hydrogen are reacted in a manner known per se with at least one metal oxide or metal salt of an element of atomic number 21-29, 31, 32, 37-39, 42-44, 49 or 57-83, if desired the functional groups are bound to a bio- or macro-molecule, it being possible for the complexing to be effected either before or after removal of the protecting groups for the hydroxy groups and functional groups or either before or after the generation of the functional groups and binding to a macro- or bio-molecule, and then, if desired, any acidic hydrogen atoms that remain are replaced by cations of inorganic and/or organic bases, amino acids or amino acid amides and/or all or some of the corresponding acid groups are converted into esters or amides.

There come into consideration as acid-protecting groups 2' lower alkyl, aryl and aralkyl groups, for example methyl, ethyl, propyl, n-butyl, t-butyl, phenyl, benzyl, diphenylmethyl, triphenylmethyl, bis(p~nitrophenyl)methyl, and also trialkylsilyl groups. 2s may also represent an alkali metal.

The removal of the protecting groups is carried out in accordance with processes known to the person skilled in the art, for example by hydrolysis, hydrogenolysis, alkaline hydrolysis of the esters with alkali in aqueousalcoholic solution at temperatures of from 0 to 50"C, acid hydrolysis with mineral acids or, in the case of, for example, tert-butyl esters, using trifluoroacetic acid.

There come into consideration as hydroxy-protecting groups, for example, benzyl, 4-methoxybenzyl, 4-n.itro10 benzyl, trityl, diphenylmethyl, trimethylsilyl, dimethylt-butylsilyl and diphenyl-t-butylsilyl groups.

The hydroxy groups may also be present, for example, in the form of THP ether, σ-alkoxyethyl ether, MEM ether or in the form of an ester with aromatic or aliphatic carboxylic acids, such as, for example, acetic acid or benzoic acid. In the case of polyols, the hydroxy groups may also be protected in the form of ketals with, for example, acetone, acetaldehyde, cyclohexanone or benzaldehyde.

The hydroxy groups present in X1' and X2' may also be present in a form protected by intramolecular esterification with the carboxy groups in the ©-position to form the corresponding lactones.

The hydroxy-protecting groups may be freed in accordance with methods from the literature known to the person skilled in the art, for example by hydrogenolysis, reductive cleaving with lithium/ammonia, treatment of the ethers and ketals with acid or treatment of'the esters with alkali (see, for example, Protective Groups In Organic Synthesis, T.W. Greene, John Wiley and Sons, 1981).

The synthesis of dimeric compounds, that is to say of compounds that contain a second macrocycle of the general formula II or iv, is carried out in accordance with processes known from the literature, for example by way of an addition/elimination reaction of: an amine with a carbonyl compound (for example an acid chloride, a mixed anhydride, an activated ester, an aldehyde); two amine-substituted rings with a dicarbonyl compound (for example oxalyl chloride, glutardialdehyde); two onitro-substituted nitroxides with bis-alcoholates [cf. Ξ. Klingsberg, The Chemistry of Heterocyclic Compounds, Interscience Publishers New York, p. 514, (1961)]; two rings that each have a nucleophilic group with an alkylene compound carrying two leaving groups or, in the case of terminal acetylenes, by oxidative coupling (Cadiot, Chodkiewicz in viehe Acetylenes, 597-647, Marcel Dekker, New York, 1969).

The chain linking the rings may then subsequently be modified by secondary reactions (for example hydrogenation) .

The synthesis of directly bonded compounds (that is to say K represents a direct bond, see Example 4) may be carried out by cyclisation of tetrahalomethyl-4,4*bispyridines (see below).

The synthesis of the starting materials 18 is, carried out by alkylation of compounds of the general formula v wherein U represents hydrogen and v represents an aminoprotecting group, or U represents amino-protecting groups and v represents 5 hydrogen, it also being possible for U and v to be identical, with compounds of the general formula vi X1' J Mf-CH-COOZ' (VI) or compounds of the general formula vn X2, I Nf-CH-COOZ' (VII) wherein 10 Nf represents a nucleofugal group, such as, for example, Cl, Br, I, CHj-CgH^SOj, CH3SO3, 4-NO2"C6H4SO3 or CF3SO3.

The hydroxy groups optionally contained in X1' and X2' may also, together with the radical 02', form a lactone.

There may be mentioned as examples of an alkylation reagent bromoacetic acid, chloroacetic acid, bromoacetic acid methyl ester, bromoacetic acid t-butyl ester, chloroacetic acid benzyl ester, 2-chloro-3-benzyloxypropanoic acid sodium salt (EP 0 325 762), 2-bromo-3benzyloxvpropanoic acid t-butvl ester (J. Gen. Chem., USSR 36, 52, 1966), 3,4-0-isopropylidene-2-g-tolvl~ sulphonyl-3,4-dihydroxybutvric acid ethyl ester (Synth. Comm. 19,, 3077, 1989) and c-bromo-v-butyrolactone.

There may be mentioned by way of example as aminoprotecting groups U and v formyl, trifluoroacetate, benzoate, 4-nitrobenzoate, acetate, tosylate, mesylate, benzyl, 4-nitrobenzyl, 4-methoxybenzyl, trimethylsilyl and dimethyl-t-butylsilyl.

The alkylation of the compounds of the general formula v with th® compounds of the general formula vi or vn to form the starting materials of the general formula I is carried out in polar aprotic solvents, such as, for example, dimethylformamide, acetonitrile, dimethyl sulphoxide, aqueous tetrahydrofuran, dioxane or hexamethylphosphoric acid triamide in the presence of an acid-acceptor, such as, for example, a tertiary amine (for example, triethylamine, trimethylamine, Ν,Ν-dimethylaminopyridine, 1,5-diazabicyclo[4.3.0]non-5-@ne (DBN), l,5-diazafoicyclo[5.4.0]undec~5-ene (DBU), an alkali metal or alkaline earth metal carbonate, hydrogen carbonate or hydroxide (for example sodium, lithium, magnesium, calcium, barium or potassium carbonate, hydroxide or hydrogen carbonate) at temperatures of from -10C to 120"C, preferably from 0aC to 50C, it optionally being possible for catalytic amounts of iodide or bromide to be added thereto.

After removal of the remaining amino-protecting group(s) in accordance with methods known to the person skilled in the art (for example acid or basic hydrolysis, hydrogenolysis, reductive removal with alkali metals in liquid ammonia, reaction with tetrabutyiammonium fluoride), the remaining amino function(s) is/are reacted in a second alkylation reaction with vn or vi so as to obtain, compounds wherein X1 / X2.

The conversion of a precursor group of the desired 6-membered ring contained in the end product is carried out in accordance with methods known to the person skilled in the art. There may be mentioned by way of example hydrogenation of pyridine (Advan. Catal. 14. 203 (1963)], deoxygenation of nitrogen oxide rings (S. Klingsberg, The Chemistry of Heterocyclic Compounds, Volume 14, part 2, Interscience Publishers Hew York, p. 120 (1961)), conversions and introduction of functional groups on the 6-membered ring, for example freeing of phenolic hydroxy groups (J. Org. Chem. 53. S (1988)), introduction of halogen substituents [E. Klingsberg, The Chemistry of Heterocyclic Compounds, Volume 14, part 2, Interscience Publishers New York, p. 341 (1961), HoubenWeyl, Methoden der organischen Chemie, Volume v/3, SSI (1962)).

The functionalisation of 4-halopyrldine derivatives (for example aside exchange) in the phase transfer process using lQ-crown-6 or tetrabutyiammonium halide as catalyst is described in Phase Transfer Reactions (Fluke Compendium Vol. 2, Walter E. Keller, Georg Thieme verlag Stuttgart, Hew York). In accordance with methods known to the person skilled in the art (for example catalytic hydrogenation (Houben-Wevl Methoden der organischen Chemie, volume 11/1, ρ. 539) or reaction with Raney nickel/hydrazine (German Patent Application 3 150 917)), a resulting azide group may be converted into an amino function. This may be converted into an isothiocyanate group in accordance with methods known from the literature (for example with thiophosgene in a two-phase system, S. Scharma, Synthesis 1978, 803, D. K. Johnson, J. Med. Chem. 1989, Vol. 32, 236).

By reacting an amino function with a haloacetic acid halide, an cr-haloacetamide group may be generated (JACS 1969. vol. 90, 4508; Chem. Pharm. Bull. 29 (1), 128, 1981) which, just as, for example, the isothiocyanate group, is suitable for coupling to bio- and macromolecules .

The synthesis of the compounds of the general formula v is carried out by cyclisation in accordance with methods known from the literature (for example Org. Synth. 58. (1978), Macrocvclic Polyether Syntheses, Springer Verlag Berlin, Heidelberg, Mew York (1982), Coord. Chem. Rev. 3, 3 (1968), Ann. Chem. 1976. 916, J. Org. Chem. 49, 110 (1984)]; one of the two reactants carries, at the ends of the chain, two leaving groups and the other carries two nitrogen atoms that displace those leaving groups in nucleophilic manner.

There may be mentioned by way of example the -reaction of Ai-D2-substituted diethylenetriamines, the terminal nitrogen atoms of which displace the leaving groups of, for example, 2,6-dihalomethylpyridines, 2,6-ditosylmethylpyridxnes or 2,6-dimesylmethylpyridines in nucleophilic manner. For the synthesis of directly bonded dimers, 2,2 ’ , 6,6'-tetrachloromethyl-4,4'-bispyridines (see, for example. Synthesis 552, 1989 ) are used in the cyclisation reaction.

The nitrogen atoms are optionally protected (for example in the form of tosylates or trifluoroacetates) and are freed in accordance with processes known from the literature before the subsequent alkylation reaction (the tosylates, for example, with mineral acids, alkali metals in liquid ammonia, hydrobromic acid and phenol, RedAl®, lithium aluminium hydride, sodium amalgam, see for example, Liebigs Ann. Chem. 1977. 1344, Tetrahedron Letters 1976, 3477; the trifluoroacetates, for example, with mineral acids or ammonia in methanol, see for example, Tetrahedron Letters 1967. 289).

For the preparation of macrocycles that are differently substituted on the nitrogen atoms, in the starting materials those atoms may be provided with different protecting groups, for example with tosylate and benzyl groups. The latter are then removed likewise in accordance with methods known from the literature (preferably by hydrogenation, for example EPA Ho. 232 751).

If diesters ar® used in th® cyclisation, reaction, the resulting diketo compounds must be reduced in accordance with processes known to the person skilled in the art, for example with dlborane.

Suitably substituted terminal bisaldehydes or bisketones, for example 2,6-bisacetylpyridines, may also be cyclised with the desired terminal bisamines in question; th® reduction of the resulting Schiff’s bases is carried out in accordance with methods known from the literature, for example by catalytic hydrogenation (Helv. Chisn. Acta ¢1.. 1376 (1978)3.

The preparation of the amines required as starting materials for the cyclisation is carried out analogously to methods known from the literature (for example EP 299 795).

Starting from an N-protected amino acid, reaction with a partially protected diamine (for example in accordance with the carbodiimide method), removal of the protecting groups and reduction with diborane yield a triamine.

Suitable substituents that may be converted into a functional group that is suitable for binding to a macro- or bio-molecule are, inter alia, hydroxy- and nitro-benzyl, hydroxy- and carboxyl-alkvl and also thioalkyl radicals having up to 20 carbon atoms. They are converted in accordance with processes from the literature known to the person skilled in the art [Chem. Pharm. Bull. 33, 674 (1985), Compendium of Org. Synthesis Vol. 1-5, Wiley and Sons, Inc., Houben-Weyl. Methoden der organischen Chemie, volume VIII, Georg Thieme verlag, Stuttgart, J. Biochem. 92, 1413, (1982)] into the desired substituents (for example having an amino, hydrazino, hydrasinocarbonyl, epoxide, anhydride, methacryloylhydrazinocarbonyl, maleimidoamidocarbonyl, halogen, halocarbonyl, mercapto or isothiocyanate group as the functional group), it being necessary in the case of the nitrobenzyl radical first to carry out catalytic hydrogenation (for example in accordance with Ρ. N. Rylander, Catalytic Hydrogenation over Platinum Metals, Academic Press 1967) to form the aminobenzyl derivative.

Examples of the conversion of hydroxy or amino groups bonded to aromatic or aliphatic radicals are reactions carried out in suitable solvents, such as tetrahydrofuran, dimethoxyethane or dimethyl sulphoxide, two-phase aqueous systems, such as, for example, water/dichloro25 methane, in the presence of an acid-acceptor, such as, for example, sodium hydroxide, sodium hydride or alkali metal or alkaline earth metal carbonates, such as, for example, sodium, magnesium, potassium and calcium carbonate or poly-{4-vinylpyridine) Reille^, at temperatures of from 0®C to the boiling point of the solvent in question, preferably, however, from 20’C to 60°C, with a substrate of the general formula VIII Nf-L-Fu (Viii) wherein L represents an aliphatic, aromatic, arvlaliphatic, branched, straight-chained or cyclic hydrocarbon radical having up to 20 carbon atoms and Pu represents the desired terminal functional group, optionally in protected form (DE-OS 34 17 413).

There may be mentioned as examples of compounds of the general formula vni Br (CH2)2NH2, Br(CH2)3OH, 3rCH2COCCH3, BrCH2C02tBu, ClCH2CONHNH2, Br(CH2)4CO2C2H5, 3rCH2COBr, BrCH2C0NH2, C1CH2COOC2H5, BrCH2CONHNH2, Z \ 3rCH2-CH-CH2, CF3SO3(CH2)3Br, BrCH2OCH, BrCH2CH«CH2 and 3rCH2C6H Conversions of carboxy groups may be carried out, for example, in accordance with the carbodiimide method (Fleser, Reagents for Organic Syntheses 10, 142), by way of a mixed anhydride (iGrg. Prep. Proc. Int. 7, 215 (1375)3 or by way of an activated ester (Adv. Org. Chesrt. Part B, 472).

The resulting complex-forming ligands (and also complexes) may also be bound to bio- or macro-molecules that are known to accumulate to a special degree in the organ or part of the organ to be examined. Such molecules are, for example, enzymes, hormones, polysaccharides, such as dextrans or starches, porphyrins, bleomycins, insulin, prostaglandins, steroid hormones, amino sugars, amino acids, peptides, such as polylvsine, proteins (such as, for example, immunoglobulins, monoclonal antibodies, lectins), lipids (also in the form of liposomes) and nucleotides of the DNA or RNA type. Special mention may be made of conjugates with albumins, such as human serum albumin, antibodies, such as, for example, monoclonal antibodies that are specific for tumour-associated antigens, or antimyosin. Instead of biological macromolecules, suitable synthetic polymers, such as polyethyleneimines, polyamides, polyureas and polyethers, such as polyethylene glycols and polythioureas, may also be attached. The pharmaceutical agents formed therefrom are suitable, for example, for use in tumour and infarction diagnostics and also in tumour therapy. Monoclonal antibodies (for example Nature 256. 495, 1975) have the advantage, in comparison with polyclonal antibodies, that they are specific for an antigenic determinant and have a defined binding affinity, are homogeneous (thus their preparation in pure form is much simpler) and they can be prepared in cell cultures in large amounts. Suitable, for example, for tumour imaging, are monoclonal antibodies or the Fab and F(ab’)2 fragments thereof that are, for example, specific for human tumours of the gastrointestinal tract, breast, liver, bladder, gonads and melanomas [Cancer Treatment Repts. 6£, 317, (1984), Bio Sci 34, 150, (1984)] or are directed against Carcinoma Embryonic Antigen (CEA), human chorionic gonadotropin (β-ViCG) or other tumour antigens, such as glycoproteins, [New Engl. J. Med. 298, 1384, (1973), US-P 4,331,647). Suitable, inter alia, are also anti-myosin, anti-insulin and anti-fibrin antibodies (US-P 4,036,945).

Carcinoma of the colon can be detected by NMR diagnostics using the antibody 17-1A (Centocor, USA) with the aid of conjugates complexed by gadolinium(III) ions.

Suitable for liver examinations or for tumour diagnosis 5 are, for example, conjugates or inclusion compounds with liposomes, which are used, for example, in the form of uni- or multi-lamellar phosphatidylcholine cholesterol vesicles.

In the case of antibody conjugates, the binding of the 10 antibody to the complex or ligand must not result in the loss or reduction of binding affinity and binding specificity of the antibody for the antigen. That can be achieved either by binding to the carbohydrate portion in the Pc part of the glycoprotein or in the Fab or P(ab')2 fragments or by binding to sulphur atoms of the antibody or antibody fragments.

In the former case, firstly oxidative cleaving of sugar units must be carried out to generate couplable formyl groups. That oxidation may be carried out by chemical means using oxidising agents, such as, for example, periodic acid, sodium metaperiodate or potassium metaperiodate, in accordance with methods known from the literature (for example J, Histochem and Cytochem. 22, 1084, 1974) in aqueous solution in concentrations of from 25 1 to 100 mg/ml, preferably of from 1 to 20 mg/ml, and a concentration of the oxidising· agent of from 0.001 to 10 mmol, preferably of from I to 10 mmol, within a pH range of approximately from 4 to 8 at a temperature of from 0 to 37 *C and with a reaction duration of from minutes to 24 hours. The oxidation can also be carried out by enzymatic means, for example using galactose oxidase, in an enzyme concentration of from io to 100 units/ml, a substrate concentration of from 1 to mg/ml at a pH value of from 5 to 8, with a reaction duration of from 1 to 8 hours and at a temperature of from 20 to 40eC (for example, J. Biol. Chem. 234. 445, 1959) .

Complexes or ligands having suitable functional groups, such as, for example, hydrazine, hydrazide, hydroxylamine, phenylhvdrazine, semicarbazide and thiosemicarbazide, are bound to the oxidation-generated aldehydes by reaction at from 0 to 37 eC and of a duration of from 1 to 65 hours at a pH value of approximately from 5.5 to 8, an antibody concentration of from 0.5 to 20 mg/ml and a molar ratio of complex former to antibody aldehyde of from 1:1 to 1000:1. The subsequent stabilisation of the conjugate is carried out by reduction of the double bond, for example with sodium borohydride or sodium cyanoborohvdride; the reduction agent is used in an excess of from 10- to 100-fold (for example J. Biol. Chem. 254, 4359, 1979).

The second possibility for forming antibody conjugates starts from a gentle reduction of the disulphide bridges of the immunoglobulin molecule; the more susceptible disulphide bridges between the H-chains of the antibody molecule ar® cleaved whilst the S-S bonds of the antigenbinding region remain intact, with the result that there is practically no decrease in the binding affinity and specificity of the antibody (Biochem. 18, 2226, 1979, Handbook of Experimental Immunology, vol. 1, Second edition, Blackwell Scientific Publications, London 1973, Chapter 10). Those free sulphhydryl groups of the interH-chain regions are then reacted with suitable functional groups of complex formers or metal complexes at from 0 to 37C, at a pH value of approximately from 4 to 7 and with a reaction duration of from 3 to 72 hours, a covalent bond being formed which does not affect the antigen29 binding region of the antibody. There may be mentioned by way of example as suitable reactive groups haloalkyl, haloacetyl, g-mercuric benzoate, isothiocyanate, thiol and epoxide groups and also groups that are to be subjected to a Michael addition reaction, such as, for example, maleimides and methacrylo groups (for example J, Amer, Chem. Soc. 101, 3097, 1979).

For the purpose of binding the antibody fragments to the complexes or ligands there is, additionally, a range of suitable, often also commercially available, bifunctional linkers'· (see, for example. Pierce, Handbook and General Catalogue 1986) that are reactive both towards the SH groups of the fragments and towards the amino and hydrazino groups of the complexes.

There may be mentioned by way of example: m-maleimidobenzoyl N-hydroxysuccinimide ester (MBS), m-rnaleimidohenzovl N-sulphosuccinimide ester (sulphoMBS), N-succinimidyl (4-{iodoacetyl)amino)benzoic acid ester (SXAB), succinimidyl 4-(N-maleimidomethyl)cyclohexane-l-carboxylic acid ester (SMCC), succinimidyl 4-(g-maleimidophenyl)butyric acid ester (SHPB), N-succinimidyl 3-(2-pyridyldithio)propionic acid ester (SDPD), 4-[ 3- (2,5-dioxo-3-pvrrolinyl)propionyloxy)-3-oxo-2,5d ipheny 1- 2,3-d ίhyd rothiophene-1, l -d iox ide, acetylalanwlleucylalanylaminobenzyl, acetamldo-g-thioureidobenzyl.

Bonds of a non-covalent type may also be used for coupling, it being possible for both ionic and van der Waals and hydrogen bridge bonds to contribute to th® bond in varying proportions and strengths (lock and key principle) to the bond (for example, avidin-biotin, antibody-antigen). Inclusion compounds (host-guest) of smaller complexes in larger cavities in the macromolecule are also possible.

The coupling principle consists firstly of preparing a bifunctional macromolecule, either by fusing an antibody hybridoma that is directed against a tumour antigen with a second antibody hybridoma that is directed against a complex according to the invention or by binding the two antibodies to one another chemically by way of a linker (for example, in the manner given in J. Amer. Chem. Soc. 101. 3097, (1979)) or by binding the antibody that is directed against the tumour antigen to avidin (or biotin), optionally by way of a linker, [D. J. Hnatowich et al., J. Nucl. Med. 28, 1294, (1987)]. Instead of the antibodies, the corresponding F(ab) or P(ab')2 fragments thereof may be used. For pharmaceutical administration, firstly the bifunctional macromolecule, which accumulates at the target site, is injected and then, after an interval, the complex compound according to the invention (optionally bound to biotin (or avidin)] which is coupled in vivo at the target site and can take its diagnostic or therapeutic effect there. In addition, other coupling methods, such as, for example, Reversible Radiolabelling described in Protein Tailoring Food Med. Uses (Am. Chem. Soc. Symp.) (1985), 349, may be used.

So-called solid phase coupling provides’ an especially simple method for preparing antibody conjugates or antibody fragment conjugates. The antibody is coupled to a stationary phase (for example an ion exchanger) which is located, for example, in a glass column, very high yields of conjugate are obtained by successive rinsing of th® column with a solution that is suitable for gene31 rating aldehyde groups, washing, rinsing with a solution of the functionalized complex and finally elution of the conjugate.

That process allows the automatic and continuous prepara5 tion of any desired amount of conjugate.

Other coupling steps may also be carried out in that manner.

Thus, for example, fragment conjugates may be prepared by the following sequence: papain reduction/bifunctional linker/functionalized complex or ligand.

The resulting compounds are then purified preferably by chromatography over ion exchangers on a fast protein liquid chromatography apparatus.

The preparation of the metal complexes according to the invention is carried out in the manner disclosed in DE-OS 34 01 052, by dissolving or suspending the metal oxide or a metal salt (for example the nitrate, acetate, carbonate, chloride or sulphate) of an element of atomic number 21-29, 42, 44, 57-83 in water and/or a lower alcohol (such as methanol, ethanol or isopropranol) and then reacting the solution or suspension with a solution or suspension of the equivalent amount of the complexforming ligand and then, if desired, replacing any acidic hydrogen atoms by cations of inorganic and/or organic bases or amino acids.

The introduction of the desired metal ions may take place either before or after removal of the protecting groups for the hydroxy and functional groups or before or after the generation of the functional groups ©nd binding to a macro- or bio-molecule.

Neutralisation of any free carboxy groups still present is carried out using inorganic bases (for example hydroxides, carbonates or bicarbonates) of, for example, sodium, potassium, lithium, magnesium or calcium, and/or using organic bases, such as, inter alia. primary, secondary and tertiary amines, such as, for example, ethanolamine, morpholine, glucamine, N-methyl- and N,Ndimethyl-glucamine, and also basic amino acids, such as, for example, lysine, arginine and ornithine, or amides of originally neutral or acidic amino acids.

For the preparation of the neutral complex compounds, for example, there may be added to the acid complex salts in aqueous solution or suspension as much of the desired bases as is required to reach the neutral point. The resulting solution may then be concentrated to dryness in vacuo. It is often advantageous to precipitate out the resulting neutral salts by adding water-miscible solvents, such as, for example, lower alcohols (methanol, ethanol, isopropanol and others), lower ketones (acetone and others), polar ethers (tetrahvdrofuran, dioxane, 1,2dimethoxyethane and others), and thus to obtain crystallisates that can be isolated readily and purified satisfactorily. It has proved especially advantageous to add the desired base to the reaction mixture even during the formation of the complex and thus to dispense with one process step.

If the acid complex compounds contain several free acid groupsit is often advantageous to prepare neutral mixed salts that contain both inorganic and organic cations as counter-ions.

That can be done, for example, by reacting the complexforming ligand in aqueous suspension or solution with the oxide or salt of the element providing the central ion and half the amount of an organic base required for neutralisation, isolating the resulting complex salt, if desired purifying it, and then adding the required amount of inorganic base to complete the neutralisation. The order in which the bases are added may also be reversed.

Another possibility for obtaining neutral complex compounds consists of converting all or some of the acid groups remaining in the complex into, for example, esters or amides. That may be done by subsequent reaction on the finished complex (for example, by exhaustive reaction of the free carboxy groups with dimethyl sulphate).

Before in vivo administration, the conjugates of antibody and complex are dialysed after incubation with a weak complex former, such as, for example, sodium citrate or sodium ethylenediaminetetraacetic acid, in order to remove weakly bound metal atoms.

The preparation of the pharmaceutical agents according to th© invention is likewise carried out in a manner known per se by suspending or dissolving the complex compounds according to the invention, optionally with the addition of additives customary in galenic pharmacy, in an aqueous medium and then optionally sterilizing the suspension or solution. Suitable additives are, for example, physiologically acceptable buffers (such as, for example, tromethamineJ, complex formers (such as, for example, dlethylenetriaminepentaacetic acid) or, if required, electrolytes, such as, for example, sodium chloride, or, if required, antioxidants, such as, for example, ascorbic acid.

If suspensions or solutions of the agents according to the invention in water or physiological saline solution are desired for enteral administration or for other purposes, they are mixed with one or more excipient(s) customary in galenic pharmacy (for example methylcellulose, lactose, mannitol) and/or surfactant(s) (for example lecithin, Tween®, Myrj®) and/or flavouring(s) to adjust the taste (for example ethereal oils).

In principle, it is also possible to prepare the pharmaceutical agents according to the invention also without isolating the complex salts. In every case special care must be taken to carry out the chelate formation in such a manner that the salts and salt solutions according to the invention are virtually free of non-complexed metal ions, which have a toxic effect.

That can be achieved, for example, with the aid of colour indicators, such as xvlenol orange, by titration monitoring during the preparation process. The invention therefore relates also to processes for the preparation of the complex compounds and the salts thereof. As an ultimate safety measure, the isolated complex salt may be purified.

The pharmaceutical agents according to the invention comprise preferably from 0.1 pmol to 1 mol/litre of the complex salt and are usually administered in doses of from 0.1 pmol to 5 mmol/kg. They are intended for enteral and parenteral administration. The complex compounds according to the invention are used: 1. for NMR and X-ray diagnostics, in the form of their complexes with the ions of elements of atomic number 21-29, 42, 44 and 57-83; 2. for radiodiagnostics and radiotherapy, in the form of their complexes with the radioisotopes of elements of atomic number 27, 29, 31, 32, 37-39, 43, 49, 62, 64, 70, and 77.

The agents according to the invention satisfy the many preconditions for suitability as contrast media for nuclear spin tomography. Thus, after oral or parenteral administration, they are outstandingly suitable for improving the information value of the image obtained by nuclear spin tomography by increasing the signal intensity. They also demonstrate the high level of effectiveness that is required for the body to be subjected to as small amounts of foreign substances as possible and the good tolerability that is required in order for the noninvasive nature of the examinations to be maintained.

The good solubility in water and low osmolality of the agents according to the invention makes it possible to prepare highly concentrated solutions so that the volume to which the circulation is subjected is kept within acceptable limits and dilution with body fluid is compensated for, that is to say NMR diagnostic agents must be from 100 to 1000 times more soluble in water than is the case for NMR spectroscopy. Furthermore, the agents according to the invention demonstrate not only high stability in vitro but also surprisingly high stability in vivo so that the release or exchange of the ions that are not covalently bonded in the complexes, which ions are per se toxic, within the time taken for the novel contrast media to be completely eliminated, takes place only extremely slowly.

For use as NMR diagnostic agents, the agents according to the invention are generally administered in amounts of from 0.0001 to 5 mmol/kg, preferably from 0.005 to 0.5 rauol/kg. Details of their use are discussed, for example, in H. J. weinmann et al., Am. J. of Roentgenology 142, 619 (.1984) .

Especially low doses (less than 1 mg/kg body weight) of organ-specific NMR diagnostic agents may be used, for example, to detect tumours and myocardial infarction.

Furthermore, the complex compounds according to the invention can advantageously be used as susceptibility reagents and as shift reagents for in vivo NMR spectroscopy .

The agents according to the invention are suitable also as radiodiagnostic agents by virtue of their favourable radioactive properties and the good stability of the complex compounds contained therein. Details of their use and dosage are described, for example, in Radiotracers for Medical Applications, CRC-Press, Boca Raton, Florida.

A further imaging method using radioisotopes is positron emission tomography which uses positron-emitting isotopes, such as, for example, 43Sc, 44’Sc, 52Fe, 55Co and 6®Ga (Heiss, w. D.; Phelps, Μ. E.; Positron Emission Tomography of Brain, Springer Vsrlag Berlin, Heidelberg, New York 1983).

The compounds according to the invention may be used also in radioimmunotherapy or radiotherapy. This differs from the corresponding diagnostics only by the amount and type of isotope used. Th© object is to destroy tumour cells by high-energy short-wave radiation having as small a range as possible. Suitable ^-emitting ions are, for example, 45Sc, t7Sc, 4®Sc, 72Ga, 73Ga and 90ϊ. Suitable ©-emitting ions having a short half-life are, for example, 211Bi, 212Bi, 213Bi and 21^Bi, 212Bi being preferred. A suitable photon- and electron-emitting ion is 1 ^8(^3 which can be obtained from 157Gd by neutroncapture.

If the agent according to the invention is intended for use in the variant of radiotherapy proposed by R. l.

Mills et al. [Nature vol. 336, (1988), p. 787] then the central ion must be derived from a Hofbauer isotope, such as, for example, 57Fe or 151Eu.

For the in vivo administration of the therapeutic agents according to the invention, they may be administered together with a suitable carrier, such as, for example, serum or a physiological saline solution and together with a different protein, such as, for example, human serum albumin. The dosage depends on the type of cell disorder, the metal ion used and the type of method, for example, brachytherapy.

The therapeutic agents according to the invention are administered parenterally, preferably i.v..

Details of the use of radiotherapy agents are discussed, for example, in R. W. Kozak et al.. TI3TEC, October 1986, 262.

The agents according to the invention are outstandingly suitable as X-ray contrast media, it being especially noteworthy that with those agents there is no sign, in biochemical pharmacological tests, of the anaphylactictype reactions known of iodine-containing contrast media. They are especially valuable for digital subtraction techniques on account of their favourable absorption properties in ranges of relatively high tube voltages.

For use as X-ray contrast media, the agents according to the invention are generally dosed analogously to, for example, meglumine diatrizoate, in amounts of from 0.1 to 5 mmol/kg, preferably from 0.25 to 1 mmol/kg.

Details of the use of X-ray contrast media are discussed, for example, in Barke, Rontgenkontrastmittel, G. Thieme, Leipzig (1970) and P. Thurn, E. BOcheler Einfilhrung in die Rontgendiagnostik", G. Thieme, Stuttgart, New York (1977).

In summary, novel complex formers, metal complexes and metal complex salts that open up new possibilities in diagnostic and therapeutic medicine have been synthesized successfully. Above all, the development of new types of imaging processes in medical diagnostics renders that development desirable.

The following Examples serve to illustrate the subjectmatter of the invention in greater detail.

Example 1 a) 3,6„9-Tris(dihydro-2(3K)-furanoja-3-yl]|-3,6,9,3L5tetraazabicyclo(9.3.1 )pentadeca-l (15), 11,13-trieae g (242.38 mmol) of σ-bromo-y-butyrolactone are added to 10 g (48.48 mmol) of 3,6,9,15-tetraazabicyclo[9.3.1)pentadeca-1(15),11,13-triene, 33.5 g (242.38 mmol) of potassium carbonate and 805 mg (4.85 mmol) of potassium iodide in 200 ml of acetonitrile. The mixture is heated under reflux for 48 hours. The mixture is concentrated to dryness by evaporation in vacuo. The residue is taken up in 500 ml of methylene chloride and extracted 3 times with 150 ml of water. The organic phase is dried over magnesium sulphate and concentrated by evaporation in vacuo. The residue is purified by chromatography on silica gel. (Eluant: methylene chlorlde/methanol = 15:1). Yield: 7.11 g (32% of the theoretical yield) of a slightly yellow-coloured oil that solidifies when left to stand.

Analysis: C 60.25 H 6.59 N 12.22 (calc.) C 60.18 H 6.64 N 12.17 ( found) fe) Gadolinium complex of 3„6,9,15-tetraazabicyclo[9.3.1)pentadeca-3L(15) ,ll,13-triene-3-5-9-tris(cr-(2-hydroxyethyl)acet ic acid 3 6.7 g (14.61 mmol) of the title compound of Example la are dissolved in 50 ml of de-ionized water and the pH is •° brought to 5.5 by the addition of IN hydrochloric acid. 2.65 g (7.3 mmol) of gadolinium oxide ar© added thereto and the mixture is boiled under reflux for 3 hours.

The cooled solution is stirred with 10 ml of acidic ion exchanger (IR 120) and 10 ml of basic exchanger (IRA 410) for one hour. The exchanger is removed by filtration and the filtrate is boiled for 1 hour with activated charcoal. After filtration and freeze-drying, 9.25 g (95% of the theoretical yield) of an amorphous, colourless powder (contains 8.3% water according to analysis) are obtained. Analysis (corrected for water): C 41.43 H 4.99 N 8.40 Gd 23.58 (calc.) C 41.35 H S.09 N 8.34 Gd 23.50 (found, c) Europium complex of 3,6,9,, 15-tetraazabicyclo[9.3.1)pentadeca-i(15),11,13-fc.rxene-3-S-9-t.ris [c-(2-hwdroxyethyl)acetic acid] The corresponding europium complex is obtained analogously with 151Eu2O3.

Analysis (corrected for water): C 41.76 H 5.03 N 8.47 Eu 22.97 (calc.) C 41.68 H 5.12 N 8.39 Eu 22.88 (found) Example 2 a> 3„6„S,15-Tetraazabicyclo[9.3.1]pentadeca-I(15J,11,13trieme-3-6-9-fcris[or-(benzyloxymethyl)acetic acid] g (48.48 mmol) of 3,6,9,l5-tetraazabicvclo[9.3.1]pentadeca-1(15),11,13-triene and 114.71 g (484.8 mmol) of the sodium salt of 2-chloro-3-benzyloxypropicnic acid in 200 ml of water are heated at 70 ®C for 48 hours. The solution is diluted with 400 ml of water, and 300 ml of 2N hydrochloric acid are added.

Extraction is carried out 5 times each time with 200 ml of methylene chloride. The aqueous phase is concentrated by evaporation in vacuo. The residue is dissolved in 300 ml of ethanol and the sodium chloride is removed by filtration. Concentration by evaporation is carried out ini vacuo and the oil which remains is chromatographed on silica gel (eluant: ethanol/water « 20:1). The main fractions ar© concentrated by evaporation in vacuo and dissolved in 50 ml of 5% hydrochloric acid. The solution is poured onto a column filled with Reillex® (= poly-4vinylpyridine) and the product is eluted with a mixture of water/methanol 3:1. Concentration by evaporation of th© main fractions yields 12.93 g (36% of the theoretical yield) of a strongly hygroscopic solid (9.1% water according to analysis).

Analysis (corrected for water): C 66.47 H 6.53 N 7.56 C 66.38 H 6.60 N 7.48 (calc.) ( found) b) 3, ί6,9,15-Tetraazabicyclo(9 -3.1] pentadeca-1 (15),11,13triesie-3-6-9-tris(G-hydroxymethyl)acetic acid] 12.6 g (17.01 mmol) of the title compound of Example 2a are dissolved in a mixture of 200 ml of methanol/100 ml of water, and 4. g of palladium catalyst are added thereto (10% Pd on activated charcoal). Hydrogenation is carried out at 50C for 5 hours. The catalyst is removed by filtration and concentration by evaporation is carried out in vacuo.

Yield: 7.84 g (98% of the theoretical yield) of a glassy solid (6.9% water according to analysis).

Analysis (corrected for water): C 51.06 H 6.43 N 11.91 (calc.) C 50.97 H 6.51 N 11.81 (found) c) GadoliJQiUB complex of 3,6,9,15-tetraazabicyclo(9.3.1 )penfcadeca-X (15),11,13-triene- 3,6,9-tris (o- (hyd roxymetby 1J acet ic ac id J 7.5 g (15.94 mmol) of the title compound of Example 2b ©re dissolved in 50 ml of de-ionized water, and 2.89 g (7.97 mmol) of gadolinium oxide are added thereto. The mixture is heated at 90C for 3 hours. The cooled solution, is stirred at room temperature for one hour with 2 ml of acidic ion exchanger .(IR 120) and 2 ml of basic exchanger (IRA 410). The exchanger is removed by filtration and the filtrate is briefly boiled up with 2 activated charcoal. After filtration and freeze-drying, 9.56 g (96% of the theoretical yield) of a colourless, amorphous powder (8.1% water according to analysis) are obtained.

Analysis (corrected for water): C 38.45 H 4.36 N 8.97 Gd 25.17 (calc.) C 38.37 H 4.43 N 8.89 Gd 25.06 (found) Example 3 a > 3,6,9,15-Tetraazabicyclo (9.3.1) pentadeca-l (15),11,13triene-3-6-9-tiris[c(li, 2-O-isopropylidene-l, 2 -dihvdro xyetfeyl)acetic acid ethyl ester) A mixture of 15 g (72.71 mmol) of 3,6,9,15-tetraazabicyclo(9.3.1]pentadeca-l(15),11,13-triene, 156.38 g (436.28 mmol) of 3,4-0-isopropylidene-2-(p-tolylsulphonyl)-3,4-dihydroxybutyric acid ethyl ester, 60.3 g (436.28 mmol) of potassium carbonate and 2.41 g (14.54 mmol) of potassium iodide in 400 ml of acetonitrile is heated under reflux for 48 hours. The mixture is concentrated by evaporation in vacuo and the residue is taken up in 500 ml of methylene chloride. Extraction is carried out 3 times with 200 ml of water and the organic phase is dried over magnesium sulphate. After concentration by evaporation, the oil which remains is chromatographed on silica gel (eluant: methylene chloride/hexane/methanol ~ 20:4:1). yield: 17.24 g (31% of the theoretical yield ) of a yellow viscous oil.

Analysis: C 59.67 H 7.91 N 7.32 (calc.) C 59.59 H 7.98 K 7.27 (found) b) 3,6,9,15-Tetraazabicyclo(9.3.1Jpentadeca-l(15),11,13triene-3,6,9-cris(c(l,2-dihydroxyethyl>acetic acid] 16.5 g (21.57 mmol) of the title compound of Example 3a are dissolved in 100 ml of ethanol, and 50 ml of 5N sodium hydroxide solution are added thereto.

The mixture is heated under reflux for 10 hours and concentrated by evaporation in vacuo. The residue is dissolved in 250 ml of methanol and the sodium chloride is removed by filtration. The filtrate is concentrated by evaporation in vacuo and the residue is purified by ion exchanger as follows: the product is dissolved in 50 ml of water and the solution is poured onto a cation exchanger column (IR 120). After rinsing with water, the ligand is eluted with 0.5H aqueous ammonia solution. The main fractions are concentrated by evaporation, taken up in a small amount of water and poured over an ion exchanger column (IRA 67). After first washing with water, elution is then carried out with 0.5N formic acid. Concentration by evaporation is carried out in vacuo and the residue is dissolved in a small amount of hot methanol. 3v the careful addition of acetone and cooling in an ice bath, the title compound crystallises out. Yield: 0.22 g (68% of the theoretical yield) of a glassy solid (9.2% water according to analysis).

.Analysis (corrected for water): C 49.28 H 6.47 N 9.99 (calc.) C 49.17 H 6-56 N 9.88 (found) c) Gadotjuaiurn cosplex of 3,6,9,15-tetraazabicyclo[9.3.1 ]pentadeca-l {15), 11,13-triene-3,6,9-tris [σ( 1,230 dihydroxyethyl)acetic acid] g (14.27 mmol) of the title compound of Example 3b are dissolved in 60 ml of de-ionized water, and 2.58 g 4 (7.135 mmol) of gadolinium oxide are added thereto. The mixture is heated at 90’C for 3 hours. The cooled solution is stirred at room temperature for one hour with 2 ml of acidic ion exchanger (IR 120) and 2 ml of basic exchanger (IRA 410). The exchanger is removed by filtration and the filtrate is boiled up with activated charcoal. After filtration and freeze-drying, 9.89 g (97% of the theoretical yield) of a colourless amorphous powder (contains 7.3% water according to analysis) are obtained.

Analysis (corrected for water): C 38.65 H 4.65 N 7.84 Gd 22.00 (calc.) C 38.54 H 4.74 N 7.78 Gd 21.92 (found) Example 4 aj 2,2,6,65-Tetra(hydroxymethylJ-4,4'-bipyridine g (128.77 mmol) of 2,2',6,6'-tetra(methoxycarboxyl)4,4 ’-bipyridine are dissolved in a mixture of 400 ml of dioxane/400 ml of water, and 48.71 g (1.28 mol) of sodium borohydride are added in portions thereto. The mixture is stirred at room temperature overnight. The solution is acidified with 5N hydrochloric acid and concentrated to dryness by evaporation. The residue is suspended in 1 litre of IN sodium hydroxide solution and extraction is carried out 3 times with 250 ml of chloro25 form. The organic phases are dried over magnesium sulphate and concentrated by evaporation in vacuo., The residue is recrvstallised from ethanol/ether. yield: 29.53 g (83% of the theoretical yield) of colourless crystals.

Analysis : C 60.86 H 5.84 N 10.14 (calc .) C 60.77 H 5.93 N 10.06 ( found ) b) 2,2',6,6'-Tetra(chloromethyl)-4,4'-bipvridine g (104.96 mmol) of the title compound of Example 4a are heated in 250 g (2.1 mol) of thionyl chloride under reflux for 5 hours. The mixture is concentrated to dryness by evaporation and the residue is taken up in 200 ml of concentrated sodium carbonate solution. Extraction is carried out twice with 150 ml of methylene chloride. The organic phase is dried over magnesium sulphate and concentrated by evaporation in vacuo. The residue is crystallised from ether/hexane.

Yield: 35.54 g (94% of the theoretical yield) of colourless crystals.

Analysis: C 48.03 H 3.45 N 8.08 Gd 40.51 (calc.) C 48.10 H 3.40 N 7.96 Gd 40.59 (found) c) 13,13'-Bis(3,6,9-tris (p-tolylsulphonyl)-3,8,9,15tetraazabicyclo[9.3.1)pentadeca-X(15),11,13-triene] A solution of 34 g (97.12 mmol) of the title compound of Example 4b (dissolved in 700 ml of dimethylformamide) is added dropwise at 100aC in the course of 4 hours to 118.43 g (194.25 mmol) of N,N',N-tris(o-tolylsulphonyl)diethylenetriamine-M,N'"-disodium salt in 1600 ml of dimethylformamide. The mixture is stirred at 100°C overnight. 2 litres of water are added dropwise to the hot solution and the mixture is cooled to 0®C. The precipitate is removed by filtration with suction and washed with water. After drying in vacuo (60"C), th© product is reerystallised from acetonitrile. 79-13 g (61% of the theoretical yield) of a cream-coloured powder are obtained.

Analysis : C 57.55 H 5.28 N 8.39 S 14.40 (calc.) C 57.47 H 5.35 N 8.31 S 14.32 (found) d) 13,135 -Bis [3,6,9, 15-tetraazabicycl©[ 9.3.1] pentadeca1 (15>,11,13-triene] octahydrosulphate g (59.15 mmol) of the title compound of Example 4c are added to 270 ml of concentrated sulphuric acid and the mixture is stirred at 100eC for 48 hours. The mixture is cooled to 0®C and 1.35 litres of absolute ether are added dropwise thereto. The precipitate is removed by filtration with suction and stirred in 500 ml of methanol. Filtering off and drying in vacuo yield 65.74 g (93% of the theoretical yield) of a solid that deliquesces upon exposure to air. Analysis : C 22.11 H 4.22 N 9.38 S 21.46 (calc., C 22.04 H 4.33 fc? 9.29 S 21.38 (found) e) 13,13'-Bis[3,6,9,1 S- tetr aazabicyclo [9.3.1] pentadecaΪ(Ι5>,11,13-trienej 65.S g (54.80 mmol) of the title compound of Example 4d are dissolved in 100 ml of water and the pH value is adjusted to pH 13 with 32% sodium hydroxide solution. Extraction is carried out 3 times with 250 ml of hot toluene. The combined toluene phases are heated under reflux with 20 g of finely powdered sodium hydroxide for 1 hour. Filtration is carried out and the filtrate is concentrated to dryness by evaporation. yield: 21.6 g (96% of the theoretical yield) of a slightly yellow-coloured solid . Analysis : C 64.36 H 8.35 N 27.29 (calc.) C 64.27 H 0.44 N 27.22 ( found) f) 13,13'-Bis[3,6,9,15-tetraazabicyclo(9.3.JLJpentadeca1(15), 11,13-triene-3,6,9-tris(σ(benzyloxymethyl) acetic acid j 21.5 g (52.37 mmol) of the title compound of Example 4e and 247.8 g (1.05 mol) of the sodium salt of 2-chloro-310 benzvloxypropionic acid in 400 ml of water are heated at 70"C for 48 hours. The solution is diluted with 800 ml of water, and 600 ml of 2N hydrochloric acid are added. Extraction is carried out 5 times each time with 300 ml of methylene chloride. The aqueous phase is concentrated by evaporation in vacuo. The residue is dissolved in 500 ml of ethanol and the sodium chloride is removed by filtration. Concentration by evaporation is carried out in vacuo and the residue is chromatographed on silica gel (eluant: ethanol/water = 20:1). The main fractions are concentrated by evaporation in vacuo and dissolved in 100 ml of 5% hydrochloric acid. The solution is poured onto a column that is filled with Reille>® (~ poly-4vinylpyridine) and the product is eluted with a mixture of water/methanol 2:1. After concentration of the main fractions by evaporation, 20.92 g (27% of the theoretical yield) of a strongly hygroscopic solid (®.1% water according to analysis) are obtained.

Analysis (corrected for water): C 66.56 H 6.40 N 7.57 (calc.) 30 C 66.47 H 6.51 N 7.48 (found) g) 13,13’-Bis[3,6,9,15-tetraazabicyclof9.3.1]pentadeca1(15),11,13-triene-3,6, 9-tris[o(hydroxymethyl) acetic acid]] .5 g (13.85 mmol) of the title compound of Example 4f are dissolved in a mixture of 300 ml of methanol/150 ml of water, and 7 g of palladium catalyst (10% Pd on activated charcoal) are added thereto. Hydrogenation is carried out at 50'C for 5 hours. The catalyst is removed by filtration and concentration by evaporation is carried out in vacuo.

Yield: 12.62 g (97% of the theoretical yield) of a glassy solid (8.5% water according to analysis).

Analysis (corrected for water): C 51.17 H 6.23 N 11.93 (calc.) C 51.07 H 6.31 N 11.87 (found) h) Gadolinium complex of 13,13'-bis[3,6,9,15-tetraazabicyclo[ 9.3.1 ]pentadeca-l (15),11,13-triene-3,6,9-tris (ar(hydroxymethyl> acetic acid)] g (12.78 mmol) of the title compound of Example 4g are dissolved in 80 ml of de-ionized water, and 4.63 g (12.78 mmol) of gadolinium oxide are added thereto. The mixture is heated at 90'C for 3 hours. The cooled solution is stirred at room temperature for 1 hour with S ml of acidic ion exchanger (IR 120) and 5 ml of basic exchanger (IRA 410). The exchanger is removed by filtration and the filtrate is boiled up briefly with activated charcoal. After filtration and freeze-drying, 15.3 g (96% of the theoretical yield) of a colourless amorphous powder (contains 9.3% water according to analysis ) are obtained. Analysis (corrected for water) • C 38.52 H 4.20 N 8.98 Gd 25.21 (calc.) C 38.46 H 4.28 N 8.91 Gd 25.14 ( found) Example 5 a) Trans-5-(o-tolylsulphonyl) -amino-6- (o-tolyljsulpfaonyloxy) -2,2-dimethyl-l., 3-dioxepane 295.67 g of g-toluenesulphochloride are added, in portions, with stirring at from -5° to 0C, to a solution of 100 g of trans-6-amino-2,3-dimethvl-l,3-dioxepan~5-ol in 903 ml of pyridine. The mixture is left to stand at +4'C for 72 hours and is then stirred into 10 litres of ice-water. After filtration with suction and washing of the precipitate with water, the residue is dried in a drying chamber at 50aC and 200 torr for 48 hours. For purification, the crude product is recrystallised from 5 litres of dioxane. 196 g of the title compound are obtained in the form of a white powder.

M.p. 200-202®C. b) Monosodium salt of N*-(2-(N-tolylsulphonylamino)» ethyl jj -jj-tolylsulphonasnide ISO g of N-[2~(M-tolylsulphonylamino)ethylJ-g-toiylsulphonylamide are suspended in 1.25 litres of ethanol, the suspension is heated under reflux and a solution of 10.3 g of sodium in 300'ml of ethanol is added dropwise thereto, resulting in a solution. As the solution cools, the title compound precipitates out. Filtration with suction is carried out and the precipitate is washed with ethanol and dried at 50 *C and 200 torr. 119 g of the title compound are obtained in the form of a white powder . c) Cis-2.2-ciime chyl-5- (N-p-tolylsulphonyl} amino J -6- [N- (gtolylsulphonyl) -Ν- (N " -2-g-tolylsulphonyl aminomethyl) ]1,3-dioxepane 116 g of the monosodium salt of Example 5b are suspended in 2.66 litres of dimethylformamide. At 100eC, a solution of 141 g of trans-5-( p-tolylsulphonvl)amlno-S-(p-toIylsulphonyloxy )-2,2-dimethyl-l,3-dioxepane in 1.5 litres of dimethylformamide is added dropwise thereto and the mixture is stirred at a bath temperature of 120C for 5 hours. The reaction solution is then concentrated In vacuo to 1 litre and diluted with 10 litres of icewater. Filtration with suction is carried out and the precipitate is washed with water and dried at 50C and 200 torr. 182 g of the crude title compound are obtained which, for purification, are boiled with 1.85 litres of ethanol. After filtration with suction and drying, 125 g of the title compound are obtained in the form of a white powder.

M.p. 190~194®C. d, Bisodium salt ©f cis-2,2-dimethyl-5-[N- (p-tolylsulphony 1) -aaiiiao ) - 6 - [ N- (p- tolylsulphonyl > -N- (Ν ® -2-βtolylsulphonylaminomethyl ))-1,3-dioxepane 87.8 g of the compound prepared in accordance with Example 5c are suspended in 410 ml of ethanol, the suspension is heated to boiling and a solution of 6.67 g of sodium in 200 ml of ethanol is added dropwise thereto. The mixture is cooled in an ice bath, 450 ml of ether are added and the precipitate which forms is removed by filtration with suction and dried at 80*C and 200 torr. g of the title compound are obtained in the form of a whit© powder. e) Acetonide of 4,5-bis( hydroxymethyl)-3,6,9-tritosylsuiphonvl-3,5,3,15-tetraazabicyclo(9.3.1]pentadeca1(15),11,13-triene 78.75 g of the disodium salt of Example 5d are dissolved in 880 ml of dimethylformamide, heated to 100"C and a solution of 19.53 g of bis-(2,5-chloromethyl)pyridine in 360 ml of dimethylformamide is added dropwise thereto, the mixture is heated at 120‘C for a further 5 hours and concentrated in vacuo to 300 ml. The solution is stirred into 5 litres of ice-water, and the precipitate which forms is separated off by filtration with suction, washed with water and dried. The crude product is recrystallised from 700 ml of dioxane, and 45 g of the title compound are obtained in the form of a white powder. l5 M.p. 244-250°C. f] Acetonide of 4,5-bis( hydroxymethyl)-3,6,9,15-tetraazabicyclof 9.3. IJpentadeca-l (15),11,13-triene A suspension of 20 g of the compound obtained in accordance with Example 5e in 140 ml of tetrahydrofuran is added to 260 ml of liquid ammonia, the mixture is stirred in a cooling bath at -50’C, and a total of 14.4 g of sodium is added in portions. The mixture is stirred at -60 "C for a further 5 hours, the cooling bath is then, removed, 50 ml of ethanol are added dropwise thereto and the ammonia is allowed to evaporate; evaporation t© dryness is carried out in vacuo and the residue is purified by chromatography on silica gel. Elution is carried out with chloroform/ethanol/conc. ammonia solution (3:1:0.5); 5.30 g of the title compound are 3o obtained in the form of an oil.

Analysis: C 62.72 H 8.55 N 18.29 (calc.) C 62.51 H 8.41 N 18.45 (found) g) Acetonide of 4,5-bis(hydroxymethyl)-3,6,9,15-tetraazabicvclo[9.3.1]pentadeca-1(15),11,13-triene-3,6,9-trisacetic acid tert-butyl ester .51 g of anhydrous sodium carbonate and 10.2 g of bromoacetic acid tert-butvl ester are added to a solution of 4 g of the compound prepared in accordance with Example 5f in 100 ml of tetrahydrofuran and 10 ml of water, and the mixture is stirred at 50*C for 5 hours. Filtration and concentration by evaporation in vacuo are carried out and the oily residue is stirred with 50 ml of hexane and decanted. The residue is purified by chromatography on 100 g of silica gel with dichloromethane (from 1 to 10% ethanol). 5.7 g of the title compound are obtained in the form of a light-yellow oil. h) 4,5-Bis (hydroxymethyl )-3,6,9,15-tetraazabicyclo[ 9»3«1 i) pentadeca-1 (15),11,13-triene-3,6,9-tris-acetie acid A mixture of 5.3 g of the ester prepared in accordance with Example 5g and 50 ml of trifluoroacetic acid is stirred at 50BC for 3 hours. 10 ml of water are then added thereto, and the mixture is stirred at 50®C for a further 2 hours and then evaporated to dryness in vacuo. The residue is dissolved in 20 ml of water and the solution is run through a column containing 100 ml of Reillex (poly-4-vinylpyridine) and eluted with 100 ml of water, end the eluate is concentrated by evaporation in vacuo. An amorphous powder is obtained that still contains 8.5% water . Yield: 2.90 g. Analysis: C 51.81 H 6.41 N 12.72 (calc.) C 51.63 H 6.70 N 12.51 (found) i) Gadolinium complex of 4,5-bis(hydroxymethyl)-3,S,9,X5 tetraazabicyclo[9.3.1 }pentadeca-1 (15). 11,13-trieae-3 ,.,6,9tris-acetic acid g (water content 8.5%, corresponds to 1.83 g = 4.29 mmol) of 4,5-bis(hydroxymethyl)-3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-3,6,9-fcrisacetic acid (for preparation, see Example 5h) and 778 mg of gadolinium oxide are stirred with 50 ml of water at 90"C for 5 hours. Once the mixture has cooled, 10 ml of anion exchanger IRA-410 and 10 ml of cation exchanger IRC-50 are stirred in in succession, filtration is carried out and the solution is subjected to freezedrying. 2.35 g of the title compound are obtained in the form of a loose white powder; water content according to K. Fischer titration: 7.3%.

Analysis (after correction for the water content):c19h25g<^n4°8 • C 38.38 H 4.24 N 9.42 Gd 26.44 (calc.) C 38.51 H 4.31 N 9.36 Gd 26.19 (found) Example β a) Acetonide of 4,5-bis(hydroxymethyl)-3,6,9-tris[dihydro-2 (3H)-furanon-3-yl)-3,6,9,15-tetraazabicyclo[9-3.1]pentadeca-1(15),11,13-triene g of potassium carbonate, 260 mg of potassium iodide and 13.50 g of c-bromo-y-butyrolactone are added to a solution of 5 g (16.34 mmol) of acetonide of 4,5-bis(hydroxymethyl )-3,6,9,15-tetraazabicyclo(9.3.1]pentadeca 1(15),11,13-triene in 100 ml of acetonitrile, and the mixture is heated at boiling for 48 hours. Concentration by evaporation is carried out in vacuo, the residue is dissolved in methylene choride and shaken several times with water, and the organic phase is dried over sodium sulphate and concentrated by evaporation in vacuo. The oily residue is chromatographed on 150 g of silica gel 5 with methylene chloride/methanol (15:1). 5.3 g of the title compound are obtained in the form of a light-yellow viscous oil. fe) 4„5-Bis(hydroxymethyl)-3,6,9,15-fcetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-3,6,9-tris-[σ- (210 hydroxyethyl) J acet ic acid g of the compound prepared in accordance with Example 6a are dissolved in 50 ml of water and the pH value is adjusted to 2 by the addition of hydrochloric acid. The mixture is heated under reflux for s hours, cooled to room temperature and the solution is run through a column containing 10 g of Reillex (polv-4vinylpyridine), the column is then washed with 20 ml of water and the combined eluates are subjected to freezedrying. 4.05 g of the title compound are obtained in the ° form of a loose powder having a water content of 7.2%.

Analysis (after correction for the water content): C25H40^Pll C 52.44 H 7.04 N 9.78 (calc.) C 52.61 H 7.33 N 9.62 (found) 5 c) Gadoli&dbian complex of 4,5-bis(hydroxyi®ethyl>-3,6,S»,lStetraazahicyclo( 9.3.13 peatadeca-1 (15),11,13-trlene-3,6,9tr is- [cr- (2-hydroxyethyl) ] acetic acid 1.50 g (2.68 mmol) of 4,5-bis(hydroxymethyl)-3,6,9,15~ tetraasabicvclo[9.3.l)pentadeca-l£15),11,13-triene-3,6,90 tris-(σ-(2-hydroxyethyl))acetic acid are stirred in 25 ml of water with 487 mg of gadolinium oxide at 90*C for hours. After cooling, the solution is stirred, in succession, with 5 ml of anion exchanger IRA-410 and ml of cation exchanger IRC-50, filtered and subjected to freeze-drying. 1.69 g of the title compound are obtained in the form of a white powder having a water content of 4.3%.

Analysis (after correction for the water content): C25H37GdN4O11 C 4.1.31 H 5.13 N 7.71 Gd 21.63 (calc.) C 41.07 H 5.33 N 7.61 Gd 21.89 (found) Example 7 a> 4-Hydroxymethyl-3,6,9-tritosyl-3,5,3,15-tetraazabicyclo[ 3.3.1)pentadeca-l (15),11,13-triene 9.60 g of a 50% suspension of sodium hydride in mineral oil are added, in portions, to a solution of 59.57 g of 3-aza-l-hydroxymethyl-l,3,5-tritosylpentanediamine (for preparation, see International Patent Application PCT/DE 88/00200, WO 88/08422, page 45) in 500 ml of dimethylformamide, and the mixture is heated at 80 eC for 1 hour. 17.61 g of 2,6-bis(chloromethyl)pyridine dissolved in 150 ml of dimethylformamide are added dropwise to that solution and the mixture is heated at H0*C for hours. The mixture is concentrated in vacuo to approximately 220 ml, and 1 litre of water is added dropwise thereto; the precipitate is separated off by filtration with suction, washed with water and dried at 50°C and 200 mbar overnight. The crude product is recrystallised from 500 ml of ethanol and yields 45 g of the title compound in the form of a yellow solid. b) 4-Hydroxymethyl-3,6,9,15-tetraazabicycloj9.3.1)peotadeca-1(15),11,13-iriene g of the compound obtained in accordance with Example 7a are heated with 120 ml of concentrated sulphuric acid at 100®C for 48 hours. The mixture is cooled to 0"C and 350 ml of diethyl ether are added dropwise thereto. The salt of the title compound precipitates out. Filtration with suction is carried out, the residue is dissolved in 100 ml of water, 40 g of sodium hydroxide are added and extraction is carried out several times with dichloromethane. The combined organic phases are dried over sodium sulphate and concentrated by evaporation in vacuo. 13.3 g of the title compound are obtained in the form of a viscous oil. c) 4-Hydroxymethyl-3,6,9,15-tetraazabicyclo[9.3-1)peatadeca-1(15>,11,13-triene-3,6,9-triacetic acid g of the amine prepared in accordance with Example 7b are dissolved in 100 ml of water, and 13.21 g of chloroacetic acid are added. The mixture is stirred at 60 °C for 20 5 hours and the pH value is maintained at 9.0 during that time by the addition of 10N sodium hydroxide solution.

The mixture is cooled to 0’C, 100 ml of ethanol are added and the mixture is acidified to pH 1 with concentrated hydrochloric acid, the precipitate which forms is separated off by filtration with suction and dissolved in 50 ml of water, and the solution is poured over a column containing 30 ml of Reillex (poly-<-vinylpyridine) followed by washing with 50 ml of water, and the eluates are combined and subjected to freeze-drying. 16.8 c of the title compound are obtained in the form of an amorphous powder having a water content of 9.3%.

Analysis (after correction for the water content): C18H26N4°7 C 52.68 H 6.39 N 13.65 (calc.) C 52.49 H 6.54 N 13.81 (found) d) Gadolinium complex of 4-hy<3roxymethyl-3,6»9„15tetraazabicyclo[ 9.3. J.) pentadeca-l (15),11,13-triene-3,6,9triacetic acid 1.015 g of gadolinium oxide are added to a solution of 2.3 g of 4-hydroxymethyl-3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-l(15),ll,13-triene in 30 ml of water and the mixture is heated at 90°C for 1 hour. The small amount of oxide that has not reacted is removed by filtration, the solution is run, in succession, through ml of anion exchanger IRA-410 and 10 ml of cation exchanger IRC 50 followed by washing with 30 ml of water, and the combined eluates are subjected to freezedrying. 3.05 g of the title compound are obtained in the form of a powder having a water content of 7.5%.

Analysis (after correction for the water content): C 38.29 H 4.11 N 9.92 Gd 27.85 (calc.) C 38.44 n 4.32 N 9.68 Gd 27.71 (found) Example S a) 4-Benzyloxymethyl- 3,6,9,15-tetraazabicyclo( 9.3.1]25 peatadeca-l(lS),ll,l3-triene-3,6„9-trlacetic acid 0.5 g of potassium iodide, 4.17 g of benzyl bromide and 5 g of sodium carbonate are added to a solution of 10 g (= 24.36 mmol) of 4-hydroxymethyl-3,6,9.15-tetraazabicyclof 9.3 .1 ] pentadeca-1 (15),11,1 3- trises-3,6,9-triacetic acid (prepared in accordance with Example zb) in 150 ml of dimethylformamide. The mixture is heated at 60®C for 20 hours, concentrated in vacuo, 100 ml of water and 300 ml of ethanol are added and the pH value is adjusted to 2 by the addition of concentrated hydrochloric acid. The precipitate which forms is separated off by filtration with suction and dissolved in 100 ml of water, the solution is poured over a column containing 50 g of Reillex (poly-4-vinylpyridine), the column is washed with 50 ml of water and the combined aqueous phases are subjected to freeze-drying. 8 g of the title compound are obtained in the form of an amorphous powder.

Analysis : C 59.99 H 6.44 N 11.19 (calc.) C 59.71 H 6.49 M 11.38 (found) b) Gadolinium complex of 4-benzyloxymethy 1-3,6,9,15tetraazabicyclo [9.3.1) pentadeca-1 (15),11,13-tr£euae-3,6,9triacetic acid 1.81 g of gadolinium oxide are added to a solution of 5 g of 4-benzvloxymethyl-3,6,9,15-tetraazabicvclo[9.3.1)pentadeca-l(lS) ,ll,13-triene-3,6,9-triacetic acid in 100 ml of water, the mixture is heated at from 80 to 90’C for 3 hours, filtration is carried out and the solution is run, in succession, through columns containing 15 ml of anion exchanger IRA-410 and 15 ml of cation exchanger IRC-50; the columns are then washed with 75 ml of water and the combined aqueous phases are subjected to freezedrying. 5.85 g of the title compound are obtained in the form of an amorphous powder; water content 7.4%.

Analysis (after correction for the water content): C 45.86 H 4.46 N 8.56 Gd 24.02 (calc.) C 45.69 H 4.71 N 8.72 Gd 23.81 (found) Example 9 Gadolinium complex of 3,6,9,15-tetraazabicyclo[9.3.1)pentadecane-3,6,9-tris(a(hydroxymethyl)acetic acid] 4.5 g (7.2 mmol) of the title compound of Example 2c are dissolved in 150 ml of de-ionized water and hydrogenated IQ in an autoclave over a rhodium catalyst (5% Rh/C) at bar and 40*C. After 12 hours the catalyst is removed by filtration and the filtrate is stirred with 3 ml of cation exchanger (IR 120) and 3 ml of anion exchanger (IRA 410) for one hour. The exchanger is removed by filtration and freeze-drying is carried out.

Yield: 4.18 g (92% of the theoretical yield) of a colourless amorphous powder (contains 6.7% water according to analysis).

Analysis (corrected for water): C 30.08 H 5.27 N 8.88 Gd 24.93 (calc.) C 30.01 H 5.34 N 8.78 Gd 24.86 (found) Example 10 Preparation of a solution of the gadolinium(III) complex of 3,6,9,15-tetraazabicyclo(9.3.1]pentadeca-l(15),11,1325 triene-3,6,9-tris[a~(2-hydroxyethyl)acetic acid] a) 361 g (0.5 mol) of the complex obtained in accordance with Example lb (water content: 8.3 %) are dissolved, with gentle heating, in 500 ml of water pro injectione (p.i. ), After the addition of 0.8 g of tromethamine, the solution is made up to 1000 ml with water p.i.. The solution is ultrafiltered and introduced into bottles.

After heat sterilization, the solution is ready to use for parenteral administration for diagnostic purposes. b) The ultrafiltered solution obtained in Example 10a is introduced, under sterile conditions, into multivials and lyophilized. After the addition of the desired amount of water p.i., the administration dose suitable for intrastitial injection for the purpose of radiotherapy is obtained.

Claims (20)

1. Patent claims

1. Macrocyclic compounds of the general formula X wherein coox represents a single or double bond, represents a nitrogen atom or the radical NH, X 1 represents a hydrogen atom, a group or -(CH 2 ) m -(CH) n -CH 2 OH wherein OH n represents a number from 1 to 5, m represents a number from 0 to

2. , and R 1 represents a hydrogen atom or a hydroxy group, X 2 represents or a group H CH 2 )n~ < O) x -< CH 2 ) k -< C S H 4 ) qR 2 **herein k represents a number from 0 to 4, each of I and g represents the number 0 or 1, and R 2 represents a hydrogen atom, a C£-C 4 alkoxy group, a functional group or a bio- or macro-molecule bound by way of that functional group, A 1 , A 2 , Β 1 , B 2 , C 1 , C 2 , D 1 , D 2 , E 1 , E 2 , F 1 and F 2 each independently of the other represent X 2 , 5 G represents R 2 or a second macrocycle, bound by wav of K, of the general formula II cooz wherein K represents a direct bond, a bis(carbonylamino) group (-NK-CO-CO-NH-) or a C^-C l4 alkylene group which optionally carries at its ends carbonyl (>C0) or carlo bonylamino (-NH-CO-) groups or oxygen atoms and which optionally contains one or more oxygen atom(s), hydroxymethylene (-CH(OH)-) group(s), CH(X 2 )CGOZ~, acyl- or hydroxyacyl-substituted imino groups or one or two C-C double bonds and/or C-C triple bonds, 15 Z represents a hydrogen atom and/or a metal ion equivalent of an element of atomic number 21-29, 31, 32, 37-39, 42-44, 49 or 57-83, with the proviso that the 12 ring substituents A~ to F 2 represent at least 8 hydrogen atoms, that X 1 and X 2 20 simultaneously represent hydrogen atoms only when at least one of the ring substituents A 1 to P 2 does not represent a hydrogen atom, at least one of the ring substituents A 1 to D 2 does not represent (CH2)j_g-H and at least one of the ring substituents E 3 to P 2 does not represent (CH2)i_ 5 -H, and that the macrocycle of the 5 general formula I contains not more than one bio- or macro-molecule and that, if desired, remaining CO 2 H groups are present in the form of ester or amide, and also salts thereof with inorganic and/or organic bases, amino acids or amino acid amides. 10 2. Macrocyclic compounds of the general formula III COOS wherein represents a single or double bond, Q represents a nitrogen atom or the radical NH, X 1 represents a hydrogen atom, a group -(CH 2 ) n “R~ or 15 =(CH 2 ) m -(CH) n ~CH 2 OK wherein OH n represents a number from 1 to 5, m represents a number from 0 to 2, and R- represents a hydrogen· atom or a hydroxy group, X 2 represents X 1 or a group -(CH 2 ) n -(0)1-(CH 2 ) k -(C 6 H 4 ) q -R 2 wherein k represents a number from 0 to 4, each of 1 and g represents the number 0 or 1, and R- represents a hydrogen atom, a Ci-C^alkoxy group, a functional group or a bio- or macro-molecule bound by way of that functional group, A 1 , B 3 ·, C 3 · and D 3 · each independently of the other represent X 2 , G represents R 2 or a second macrocycle, bound by way of K, of the general formula IV (IV) coos wherein K represents a direct bond, a bis(carbonylamino) group (-NH-CO-CO-NH-) or a Ci-Ci^alkylene group which optionally carries at its ends carbonyl (>C0) or carbonylamino (-NH-CO-) groups or oxygen atoms and which optionally contains one or more oxygen atom(s), hydroxymethylene (-CH(OH)-) group(s), CH(X 2 )CCOS-, acyl- or hydroxyacyl-substituted imino groups or on© or two C-C double bonds and/or C-C triple bonds. Z represents a hydrogen atom and/or a metal ion equivalent of an element of atomic number 21-29, 31, 32, 37-39, 42-44, 49 or 57-83, with the proviso that X 1 and X 2 simultaneously represent hydrogen atoms only when at least one of the 4 ring substituents a 1 , B 1 , C 1 and D 1 does not represent a hydrogen atom or (CK 2 and that, if desired, remaining CO 2 K groups are present in the form of ester or amide, and also salts thereof with inorganic and/or organic bases, amino acids or amino acid amides.

3. Compounds according to claim 1, characterised in that Z represents hydrogen atoms.

4. Compounds according to claim 1, characterised in that at least 2 of the substituents 2 are metal ion equi valents of at least one element of atomic number 21-29, 42, 44 or 57-83 or of at least one radionuclide of an element of atomic number 27, 29, 31, 32, 37-39, 43, 49, 62, 64, 70 or 77.

5. Compounds according to claim 1, characterised in that K represents a group -(Q) c -(CB 9 ) n -(CH)$,(C« 2 )-,-(0)] 6 OH or a direct bond.

6. Compounds according to claim 1, characterised ia that the functional group represented by R 2 is NCS, N02, OH, NHNH2, NH2, NHGOCH2Br, NHCOCH2C1, °°2 H C0N3.

7. Compounds according to claim 1, characterised in that the bio- or macro-molecule optionally contained in R 2 is an antibody or antibody fragment.

8. Compounds according to claim 1, characterised in that the bio- or macro-molecule optionally contained in R 2 is a protein, such as albumin, globulin or lectin.

9. Compounds according to claim 1, characterised in that the bio- or macro-molecule optionally contained in R 2 is a polysaccharide, such as a starch, dextran or dextrin.

10. Compounds according to claim 1, characterised in that X 1 represents CH 2 OK, CH 2 CH 2 OH or CHOHCH 2 OK.

11. Compounds according to claim 2, characterised in that X 2 , A 3 ·, B 3 -, C 1 and/or D 3 · represent(s) CH 2 OH, CH 2 CH 2 OH, ch 2 och 2 c 5 h 5 , chohck 2 oh, ch 2 c 6 h 4 och 3 , ch 2 c 6 h 5 , CH 2 C g H 4 O(CH 2 ) 3 cooh or ch 2 c 6 h 4 ncs.

12. Use of at least one physiologically tolerable compound according to claim 4 for the preparation of agents for NMR-, X-ray- or radio-diagnostics or for radioimmuno- or radio-therapy.

13. Process for the preparation of macrocyclic compounds of the general formula I C©02 wherein represents a single or double bond, 0 represents a nitrogen atom or the radical NH, X 1 represents a hydrogen atom, a group -(CH 2 ) n -R~ or 5 ~(CH 2 ) m -(CH) n -CH 2 OH wherein “ 5 OH n represents a number from 1 to S, m represents a number from 0 to 2, and R- represents a hydrogen atom or a hydroxy group, 0 X 2 represents X 1 or a group -(CH 2 ) n -(O) 1 -(CH 2 ) k -(C 6 H 4 ) q -R 2 wherein k represents a number from 0 to 4, each of 1 and g represents the number 0 or 1, and R 2 represents a hydrogen atom, a C^-C^alkoxv 5 group, a functional group or a bio- or macro-molecule bound by way of that functional group, A 1 , A 2 , Β 1 , B 2 , C 1 , C 2 , D 1 , D 2 , Ε 1 , E 2 , F 1 and F 2 each independently of the other represent X 2 , represents R 2 or a second macrocycle, bound by way of K, of the general formula II CQOZ wherein K represents a direct bond, a bis (carbonylarnino) group (-NH-CO-CO-NH-) or a C ? -C 14 alkvlene group which optionally carries at its ends carbonyl (>C0) or carbonylamino (-NH-C0-) groups or oxygen atoms and which optionally contains one or more oxygen atom(s), hydroxymethylene (-CH(OH)-) group(s), CH(X 2 )COOZ~, acyl- or hydroxyacvl-substituted imino groups or one or two C-C double bonds and/or C-C triple bonds, Z represents a hydrogen atom and/or a metal ion equivalent of an element of atomic number 21-29, 31, 32, 37-39, 42-44, 49 or 57-83, with the proviso that the 12 ring substituents A 1 to F 2 represent at least 8 hydrogen atoms, that X 1 and X 2 simultaneously represent hydrogen atoms only when at least one of th® ring substituents A 1 to F 2 does not represent a hydrogen atom, at least one of the ring substituents A 1 to D 2 does not represent (CH2)£_g~H and at least one of the ring substituents E 1 to F 2 does not represent (CH2)?_g-Hz and that the macrocycle of the general formula I contains not more than one bio- or macro-molecule, and also salts thereof with inorganic and/or organic bases and, if desired, remaining CO 2 H groups are present in the form of ester or amide, amino acids or amino acid amides, characterised in that, in a manner known per se, in compounds of the general formula I' (X' ), coor wherein G', X 1 ' and X 2 ' represent G, X 1 and X 2 , respectively, wherein the hydroxy groups and functional groups contained therein are present in protected form or in the form of precursor groups, and z' represents a hydrogen atom or an acid-protecting group, the protecting groups are removed, optionally the desired 5 functional group is generated, if desired the resulting complex formers of the general formula 1 wherein Z represents hydrogen are reacted in a manner known per s® with at least one metal oxide or metal salt of an element of atomic number 21-29, 31, 32, 37-39, 42-44, 49 or 5770 83, if desired the functional groups are bound to a bioor macro-molecule, it being possible for the complexing to be effected either before or after removal of the protecting groups for the hydroxy groups and functional 5 groups and either before or after the generation of the functional groups and binding to a macro- or biomolecule, and then, if desired, any acidic hydrogen atoms that remain are replaced by cations of inorganic and/or organic bases, amino acids or amino acid amides and/or 0 all or some of the corresponding acid groups are converted into esters or amides.

14. Pharmaceutical agents comprising at least one compound according to claim 1, optionally with additives customary in galenic pharmacy. ]5

15. Pharmaceutical agents comprising at least one compound according to claim 1 in the form of liposomes.

16. Process for the preparation of the pharmaceutical agents according to claim 14, characterised in that the complex compound, which is dissolved or suspended in 20 water or physiological saline solution, optionally with additives customary in galenic pharmacy, is rendered into a form that is suitable for enteral or parenteral administration.

17. A compound substantially as hereinbefore described Ί with reference to the Examples.

18. A process substantially as hereinbefore described with reference to the Examples.

19. A method substantially as hereinbefore described with reference to the Examples.

20. A pharmaceutical agent substantially as hereinbefore described with reference to the Examples. CRUICKSHANK & CO.