JPS5817187B2 - Method for producing 1α,25-dihydroxyvitamin D compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing crystalline 1α,25-dihydroxyvitamin D or its acylate.

It is known that 1α-hydroxyvitamin D derivatives, which also have a 25-hydroxy group, have advantageous biochemical properties that make them quite useful in therapy.

That is, they are more rapidly acting and cleared from the system than the corresponding 1α-unsubstituted compounds, and are therefore more likely to induce vitamin toxicity than normal vitamin D compounds, which are only gradually cleared from the system. becomes smaller.

Additionally, the hydroxylated derivatives are often effective in alleviating symptoms of vitamin D deficiency that apparently do not respond to conventional vitamin treatments.

Such 1α-hydroxyvitamin D derivatives can be prepared by ultraviolet irradiation of 1α,3β-dihydroxysteroid-5°7-dienes, particularly of the cholestane series, by techniques similar to those used for the synthesis of the corresponding 1α-unsubstituted derivatives. can be produced by photochemical decomposition using

A useful precursor to the 1α,3β-dihydroxysteroid-5,thudiene starting material is the corresponding steroid-5-ene.

This is because they can be easily converted into 5,7-dienes, for example by bromination at the 7-position followed by dehydrobromination.

However, the synthesis of such 1α,3β-dihydroxysteroid-5-enes poses a number of problems.

This is because it is generally necessary to introduce a 1α hydroxyl group by a Michael-type addition to a 317g 3-ketosteroid.

That is, the subsequent formation of the desired 5,6-double bond is made difficult by the tendency to remove the 1α-hydroxyl group in the β-position relative to the carbonyl group, whereas the formation of the desired 5,6-double bond is difficult due to the tendency to remove the 1α-hydroxyl group in the 3-β-
Reduction to hydroxy groups is also difficult.

The synthetic route to 1α-hydroxycholesterol has been described by Pelk et al. (J, C3hem.

Soc, 1970(0)1624).

This is 6β-hydroxy-5α-cholest-1-ene-
Epoxidation of the 3-one, reduction of the product to the 1,2-epoxy-3β-hydroxy derivative using sodium borohydride, removal of the 6β-hydroxyl group to form the corresponding Δ steroid and reduction with lithium aluminum hydride. production of 1α,3β-diol by

However, the products obtained by this method do not exhibit the expected physical properties.

That is, the optical rotation is [α]DO+1° (in methanol).

On the other hand, Δ Nuarol is usually characterized by a fairly substantial negative specific rotation, typically around =30°.

In addition, the actual elemental analysis values of 076.2%, Hll, and 1% are also C
27H460□, calculated value for %H20 (078,8
%, Hll, 5%).

The structure of this product must therefore be considered clearly questionable.

One possible source of this error is borohydride reduction of the 3-keto group, which can generate significant amounts of 3α-ol in addition to the desired 3β-ol.

A somewhat similar synthetic route to the nuteroid precursor for 1α,25-dihydroxycholecalciferol was
[See Tetrahedron Letters 4.04147 (1972)].

These researchers epoxidized the appropriate steroid-1-en-3-one-6-(ethylene kecool) and then reduced this product with lithium aluminum hydride to form a mixture and from this 1α, 3α -Only the diol could be separated.

Several additional process steps, including oxidation to 3-one and reduction with sl-IJ borohydride, are therefore required for 1α
.

This is necessary to produce the 3α-diol, which can then be removed by removing the 6-ketal group, reducing and dehydrating the 6-hydroxyl compound to produce the Δ596-steroid. This makes the route somewhat cumbersome.

Therefore, there is a need for a simpler process for preparing 1α,3β-dihydroxysteroid-5-enes that allows easy control of the stereochemistry of the product, especially in the 3-position, and the present invention provides Such a method can be provided.

By this method, a novel crystalline 1α having excellent biochemical properties, which is the object of the present invention, can be obtained.

25-dihydroxyvitamin D derivatives can be produced.

We have identified 1α-hydroxy- and 1α.

2α-Epoxy-steroid-4,6-renin-3-one and the corresponding 6-substituted steroid-4-en-3-one in which the 6-substituent is a reductively removable atom or group are pro-1 It has been found that it can be directly reduced to the corresponding 1α,3β-dihydroxysteroid-5-ene by reaction with alkali metal/liquid ammonia or alkali metal/liquid amine reducing agents in the presence of a source of hydrogen.

Under these conditions, the highly oxidized starting material undergoes a series of reductions, essentially involving double bond isomerization or removal of the substituent in the β-1 position of the 3-carbonyl group. The desired product is obtained without any oxidation.

This 1α,3β-dihydroxysteroid-5-ene becomes a precursor of the 1α-hydroxylated vitamin D derivative targeted by the present invention.

A simple, direct and economical method for producing this intermediate allows the remainder of the vitamin synthesis to be carried out effectively by purification at each step to produce the desired product for the first time in crystalline form.

As used herein, the expression "cholestane series" refers to steroids having the C8 chain characteristic of cholestane at position 17, as well as those in which this chain is unsubstituted or
These include analogs with one or more hydroxy or methyl groups, the 17-side chain found in vitamin D.

Suitable ketone starting materials for the preparation of such 1α-hydroxy steroids of the cholestane series are of the formula forming a group O, R3/\ represents a reductively removable atom or group and R4
represents a hydrogen atom, or R3 and R4 together form a carbon-carbon double bond, and R5 represents a group (wherein R6 and R7 each represent a hydrogen atom or a hydroxyl group or together to form a carbon-carbon double bond or an epoxy group.

and R8 represents a hydrogen atom or a methyl or ethyl group.

Reduction of the compound of formula (1) by the method described above produces a 1α,3β-diol which can be represented by the formula (wherein R5 is as defined for formula I).

Reductively removable substituents which may be present in the 6-position of the starting materials, such as the R3 group of formula I, include, for example, halogen atoms, such as fluorine, chlorine or bromine atoms, and hydrocarbon sulfonate groups, such as aromatic carbon atoms. Mention may be made of hydrogen sulfonate groups such as p-tosylate or aliphatic hydrocarbon sulfonate groups such as mesylate groups.

Alkali metals that can be used in the reducing agent include lithium, calcium, sodium and potassium, with lithium being the preferred metal.

Liquid amines that can be used include, for example, primary, secondary and tertiary alkyl amines, such as primary lower alkyl amines such as methylamine or ethylamine, di(
lower alkyl)amines such as dimethylamine or diethylamine and tri(lower alkyl)amines such as triethylamine, diamines such as lower alkenediamines such as ethylenediamine or propylenediamine,
and saturated heterocyclic amines such as piperidine or piperazine.

Particularly preferred reducing agents are lithium and liquid ammonia.

Proton sources that can be used during the reaction include ammonium and amine salts, such as salts derived from mineral acids, such as halides such as fluorides or chlorides, nitrates or sulfates.

Alcohols such as lower alkanols such as methanol or ethanol can also act as protons.

This reduction is conveniently carried out in a solvent, preferably an inert organic solvent such as a cyclic ether such as tetrahydrofuran or dioxane or a hydrocarbon solvent such as hexane.

It may be advantageous to remove moisture and/or oxygen from the reaction system.

If a solvent is used, the reduction is conveniently carried out cold, at temperatures between the freezing point of the solvent system and 100°C.

Various addition schemes can be used to bring these reaction components together.

Thus, for example, a solution of the steroid can be added in one or more portions to a solution of the alkali metal in liquid ammonia or a liquid amine, and then the proton source can be added in one or more portions.

Alternatively, improved yields and/or easier isolation of reduced steroids may be achieved by first adding a proton source such as solid ammonium chloride to a solution of the steroid starting material and then using an alkali metal/liquid ammonia or liquid amine reducing agent. This can be achieved by adding small amounts of

It is generally preferred that the 1α-hydroxy group in the steroid starting material be protected, for example with a cleavable protecting group.

The reason is that the reduction of steroids with free 1α-hydroxyl groups is Δ
- This is because it results in the formation of steroids.

Suitable protecting groups include silyl groups such as tri(lower alkyl)silyl groups such as trimenalsilyl.

Such protecting groups can be introduced, for example, by reacting a 1α-hydroxysteroid with a suitable hexa(lower alkyl)disilazane.

Steroid-5-ene obtained by the above method is
For example, conventional techniques such as N-bromoamide, imide or hydantoin such as N-bromosuccinimide, N-
By brominating the 7-position using bromophthalimide or dibromodimethylhydantoin as the brominating agent, followed by dehydrobromination using, for example, an amide such as dinaracetamide in the presence of an alkaline earth metal carbonate. It can be converted to the corresponding steroid-5,7-diene.

Alternatively, this dehydrobromination can be induced by treatment with trimethylphosphite or bases such as uridine, pyridine or diazabicyclooctane.

7.8 - Double bonds can also be oxidized using the method of Dobin et al., e.g. 1α,3β-hydroxysteroid-5-ene, using a chromium trioxide oxidizer, preferably a chromium trioxide/pyridine complex. Equivalent steroid-5
-en-7-one, and this ketone is reacted with a sulfonylhydrazine, preferably an aromatic sulfonylhydrazine, e.g. It can also be introduced by subjecting it to Wolf-Kishner reducing conditions using a butoxide and an alkali metal halide such as sodium hydride to produce the desired 5,7-diene.

7.8 - During the series of reactions necessary to introduce the double bond, ζ In order to avoid undesired side reactions, it is possible to
It may be advantageous to protect α- and 3β-hydroxy groups.

This steroidal 5,7-diene obtained from the treatment of a compound of formula (1) by any of the above techniques is
.

□-(wherein R5 is as defined for formula I)
It can be expressed as

Irradiating such a compound of formula (1) with near-ultraviolet light, preferably of a wavelength of e.g. 275-300 nm, firstly irradiates the compound of formula (2).

(wherein R5 is as defined for Formula I).

Further irradiation or treatment with iodine under mild conditions, e.g. at relatively low temperatures using small amounts of iodine, provides compounds of the corresponding formula (wherein R5 is as defined for formula I). Promotes conversion to 1α-hydroxytaxerol derivatives.

This can be optionally reduced with eg lithium/liquid ammonia or sodium/liquid ammonia to provide novel 1α-
Hydroxy-9,10-dihydrotachysterol derivatives can be produced.

This compound of formula ■ is also in thermal equilibrium with the vitamin derivative of formula C, in which R5 is as defined for formula ■, and it is heated, for example in an alcohol or hydrocarbon solvent. Therefore, the vitamin derivatives targeted by the present invention can be converted.

This vitamin has the cis form as shown in formula (■).

The formation of undesirable oxidation by-products during this conversion can be minimized, for example, by converting to a 1,3-diacetquine derivative and thus esterifying its 1α- and 3α-hydroxy groups.

This vitamin ('Vl) can be converted into the corresponding 5,6-transvitamin derivative if desired.

Isomerization of the 5,6-double bond is easily promoted, for example, by treatment with iodine under mild conditions.

The starting material for the reduction process of the present invention can be prepared by any convenient method, such as by oxidizing the appropriate 3-hydroxysteroid-5-ene using, for example, a quinol/quinone oxidizing agent such as dichlorodicyanoquinone, followed by peroxidation. Oxides such as hydrogen peroxide with a base such as sodium hydroxide can be prepared by treatment, conveniently in an aqueous alcoholic medium, to form 1α,2α-yupoxide.

This can be converted if desired to the corresponding 1α-hydroxy compound by reduction, for example with zinc and an acid such as acetic acid.

Said compounds have important prophylactic and therapeutic uses in the prevention and treatment of diseases such as rickets and osteomalacia, and these include vitamin D-responsive diseases such as hypoparathyroidism, It is of value in the treatment of hypophosphatemia, hypocalcemia and/or associated bone disease, renal disease or failure, and hypocalcemic tetany.

Furthermore, compared to conventional 1α-hydrogen vitamin D compounds, 1
The superior activity of α,25-dihydroxyvitamin D compounds is associated with vitamin D-resistant rickets caused by liver, renal or gastrointestinal dysfunction, renal osteodystrophy, and steatorrhea. liver disease, cirrhosis and other resorptive dysfunctions, osteoporosis, secondary hypocalcemia and/or bone disease,
and dilantin, pulpyrate (e.g. ehaphenylbarbitone) and related common compounds such as vitamin D3 have proven to be non-therapeutic.

This makes this 1α-hydroxy compound valuable for the treatment of secondary hypocalcemia or bone disease resulting from drug treatment.

Generally, 1α,25-dihydroxyvitamin D compounds are carried in injectable liquid carriers such as sterile pyrogen-free water, sterile peroxide-free ethyl oleate, dehydrated alcohol, propylene glycol or dehydrated alcohol/propylene glycol). - Can be administered parenterally in combination with a mixture of alcohols.

The injectable compositions are preferably prepared in the form of dosage units, e.g. Contains vitamin ingredients.

Taxisterol compounds require dosages in the higher part of this range.

Usual dosages for adult treatment are generally 0.5 mg/day.
The range is 1 to 200 μg, with lower doses within this range, such as 0.1 to 2 μg, being used for prophylaxis, and higher doses, such as 5 to 50 μg, being used for therapeutic use.

Because of the susceptibility of 1α,25-dihydroxyvitamin D compounds to oxidation, pharmaceutical compositions containing these substances generally contain at least trace amounts of antioxidants such as ascorbic acid, bunallated hydroxyanisole or hydroquinone. It is preferable that it should be included.

Hereinafter, the present invention will be explained in more detail with reference to Reference Examples and Examples.

All temperatures are in °C. J Reference Example 1 a) 25-Hydroxycholenuc-1,4,6-drien-3-one 2 dissolved in purified dioxane (100 m, 1.')
5-Hydroxycholesterol (3,4 g) and dichlorodicyanoquinone (6,5 g) were heated under reflux for 20 hours.

The mixture was filtered and the solvent was evaporated.

The residue was chromatographed on alumina and eluted with ethyl acetate and benzene to give the trienone.

Recrystallization from methanol yields the title compound m, p, 181
~184°, λmaX36001650 and 1600
CrIL was obtained.

b) 1α,2α-Epoxy-25-hydroxycholester-46-renin-3-one The trienone (1,3,9) from (a) in ethanol (50ml) was dissolved in 10% aqueous potassium hydroxide ( 0,5
mA) and 30% aqueous H20□ (3 ml).

After standing at room temperature overnight, the solution was diluted with water and the solid product was collected.

Recrystallization from aqueous methanol gives the title compound, which after one further crystallization m+-0,162
c) The epoxygenone (130°) from (b) in 1α,3β-25-trihydroxycholest-5-ene ethanol (10 ml) was treated with zinc dust (1 g). , then 3
A drop of acetic acid was added.

The mixture was then filtered and the p-liquid was concentrated to dryness.

When chromatography is performed on silica gel, 1α, 2
5-dihydroxy-cholest-46-renin-3-one was obtained.

The latter compound (0,61) was dissolved in tetrahydrofuran (2 m
1. ) and was converted to its trimethylsilyl ether by treating a solution in pyridine (2 ml) with hexamethyldisilazane (1.5 ml) and trimethylchlorosilane (0.6 ml).

The crude trimethylsilyl ether was dissolved in tetrahydrofuran (10 ml) and the solution was mixed with lithium metal (approximately 200 mL LiI) in liquid ammonia ('2
Added dropwise to a stirred solution in 0 ml).

After a few minutes ammonium chloride (2g) was added and the solution was stirred.

Additional lithium metal (approximately 1007729) was added.

The solution was stirred again.

Additional ammonium chloride was then added and the mixture was poured into cold water.

The product was isolated by extraction with ether and methylene dichloride, followed by column chromatography and recrystallization from ethanol to give the title compound.

Example 1 a) Acylation of cholest-5-ene from Reference Example 1 (c) with acetic anhydride/pyridine gives triacet-1-
(0,581 were generated.

This was dissolved in hexane (10ml) and treated with dibromodimethylhydantoin (0,15,9) and heated to reflux for 25 minutes.

After cooling, the mixture was filtered and the p-liquid was concentrated to an oil.

The oil was dissolved in dry xylene ('37711) and added dropwise to a reflux solution (0.4 ml) of trimethylhonupite in xylene (5 ml).

Heating at reflux was continued for 1.75 hours, after which time the solvent was removed under reduced pressure and the residue was crystallized from acetone/methanol to give 1α,3β,25-triacetoxycholesterol after chromatography on silver nitrate-impregnated silica gel. Star-57-diene (m, p, 96-101°, [α)D-
24° (CHCt3), λE120262 (7,90
0), 271 (11,500), 282 (12,400
)294(7,300) nm) was obtained.

b) The cholesta-5,7-diene from (a) above was dissolved in deoxygenated ether (200 ml) and 1 part methanol was dissolved in toluene (24 ml) and C! S2 (4m
Irradiation was performed for 12 minutes using a medium pressure mercury lamp surrounded by a filtrate consisting of 1).

The cold solution was transferred to a flask filled with argon and the ether was removed with 00 to give a mixture of isomers.

This was then chromatographed on silver nitrate-impregnated silica gel to reveal the unchanged cholesta-5,7-
The diene was recovered.

Mostly previtamin triacetate [based on iodine-catalyzed conversion reaction of previtamins to taquinuterol analogs,
max260→λmax272.282,292nm,
100% purity requires a 3x increase in absorption, observed value 1
．． The remainder of this irradiation product, consisting of 9)), was heated in deoxygenated isooctane under argon at 70° for 2 hours to effect equilibration of the previtamin and vitamin triacetates.

Saponification (5% KOH in methanol) yielded a mixture of previtamin and vitamin triols.

The desired vitamin was isolated from this by preparative thin layer chromatography.

1α,25-dihydroxyvitamin Ds E crystallized by precipitation from hexane-containing ether
rn −p −84 to 88°, t O [α), +29° (in ether), λ 2264 (1
8,000), 2m1n228.5 (10,1100)
n, IHNMRO, 57 (3H.

s, C(H)), 1.13(6H,S, 026.C!
.

B-3 (dan, )), 4.85, 5.30 (2H, double thin multiplet C09 (shellfish 2)), 6.20 (2H, A
B Calchit, J-11, 5H2C6, C7 (horse)),
δ:

Elemental analysis actual value 077, 84, Hlo, 53, calculated value (
C27H4403) C77,83, Hl O,65CH
C! When crystallized from A3, it is 1α.

25-dihydroxyvitamin D3 is a monochloroform solvate m, p, 106-112°, λE120
264 (18,000), λmin 228.5 (9
, 900) nm, m/e 416.3291 (calculated value (C27H4403) 416.3290).

Actual elemental analysis value C! 62.19, H8,48, calculated value (027H4403,0HCI3) 062.74,
When treated with H8, 46°■□, this 1α,25~dihydroxyvitamin D3 becomes 1α-hydroxyvitamin D3
It underwent a smooth conversion to the corresponding 5,6-trans isomer, with spectral changes similar to those associated with the conversion of .

Reference Example 2 (a) 1α,2α-Epoxy-25-hydroxycholesta 46-renin-3-one The triene (5,41) from Reference Example 1(a) was dissolved in ethanol (250777) with 50% hydrogen peroxide ( 5 ml.> and 10% aqueous KOH (I TrLl') and the solution was kept at 5° C. for 16 hours (reaction not complete).

This solution was further mixed with 50% hydrogen peroxide (5 ml) and 10%
% KOH (1 ml) and stirred at room temperature for 7 hours (the reaction was followed by thin layer chromatography (TIC)).

The solution was diluted with water, the product collected and recrystallized from aqueous ethanol, resulting in colorless needles of the title compound (
4.1 g, 73%) m, p, 160-162° was obtained.

(b) 1α,25-dihydroxycholesterol lithium metal (0,657') was added to liquid ammonia (10077
11) and to this was added purified tetrahydrofuran (THF) (80 ml).

Epoxygenone (1.24 g, 3 mmol) of above (a) in THE (207711) and solid NH4C
1(9,9) was added slowly (5-10 minutes) and simultaneously to the stirred lithium solution.

The mixture was stirred until the blue color disappeared (5-10 minutes), then additional lithium metal pieces (0.1 g) were added,
This reaction was ensured to completion.

Once the solution was colorless again, the ammonia was evaporated and the remaining mixture was diluted with water and extracted with chloroform.

Evaporation of the chloroform gave a colorless gummy material.

This was subjected to chromatography on alumina (activity 1, 50 g) (the compound was adsorbed on 10 g of alumina 1 and introduced onto the column).

Elution with benzene-ethyl acetate (3:2) gave a less polar impurity followed by the title compound as a colorless solid (0.7
(6 g, 60%) (the yield is actually greater than 60%, since the small amount of impure title compound eluted in the early and final fractions was not recovered).

Recrystallization from acetone-acetonitrile gave colorless needles (0,711) as a semi-acetone hydrate.

Crystalline acetone was observed in NMR (solvent pyridine) at δ 1.97 and IR at 1710 I''.

This acetone is strongly bound and remains at 80°/0 for 2 days.
．． It was completely removed only after heating at 2 rnm.

The melting point of this material varied with heating rate.

When gradually heated above 160℃, it becomes 171-17
3°, then gradually but completely resolidified and the temperature was held near 173° for 2 minutes), and 177° to
Remelted at 179°.

[α] D-35° (CHC ~, actual value C77, 46, H
lo, 98, calculated value (C! HO) C77, 46, H
ll, 08°νm a x (nujol) 3400.
1050cIrL”.

δ (CDC12) 5.60 (1 proton, narrow multiplet, H6), δ 3.86 (2 protons, 1 narrow and 1 broad multiplet, H□ and H3), δ 1.2O (strong singlet , C and 027 methyl), δ 1.02 and 0.67 (singlet, C and 018 methyl).

All reagents were doubled to reduce 2.3 g of epoxide ■, yielding 1.32 g of triol (V).

(c) the trio from above (b) in 1α,25-dihydroxycholesterol-3-benzoate pyridine (0.8ml)
Add benzoic anhydride (0,6
5 g) was added and the solution was kept at room temperature.

After a few days, the reaction mixture consisted of the main monobenzoate, a small amount of dibenzoate and traces of the starting triol.

Preparative thin layer chromatography (silica gel,
3% Me OHC! Separation of the mixture by HOts gave the title monobenzoate (64772P) as a colorless crystalline solid.

When recrystallized from ethanol, colorless prismatic crystals (5571
19) m, p.

An angle of 212 to 216° was obtained (without any modification after recrystallization).

[: α) I) -20° (a (C13). Actual value C77,
87, H9, 42, calculated value (C34H5004) 0
78.12, H9, 64° max (nujo/L/
) 3550.1700cIrL-1oδ(CDC!t
3) 8.3-7.4 (5 protons, multiplet, aromatic proton), δ5.70 (] proton, narrow multiplet, H6), δ5.3 (1 proton, broad multiplet, H3), δ3 .95 (1 proton, narrow multiplet, H□), δ1.21, 1.
07, o, 6s (singlet, C26~
27. C□8menar).

The 1,3-dibenzoate of this triol (10772
9) Also obtained by preparative thin layer chromatography.

Its NMR spectrum showed aromatic protons between δ8.3 and 7.3.

H6 is a narrow multiplet of 5.7, and H
1 and H3 produced one narrow and one broad multiplet at 65.4.

C26t C27 and C□, methyl showed a singlet at 61.2 and C18 menal showed a singlet at δ0.67.

(a) Hydrolysis of monobenzoate Monobenzony 1-(10772?) from (C) above
was dissolved in boiling ethanol (5 ml), the solution was cooled, treated with KOH (1007'2?) in water (a few drops) and left at room temperature overnight.

Then it was neutralized with acetic acid, the solvent was removed under reduced pressure and the residue was extracted with chloroform and washed with water.

Evaporation of the chloroform produced a solid.

When this was recrystallized from acetone-acetonitrile, colorless needle crystals of triol were obtained. p.

171-173° and 177-179° were given.

This was the same as above. (e) 1α, 2
5-dihydroxycholesterol tris-trimethylsilyl ether pyridine (0.2 ml') was treated with TBT (0.2 ml) for 1 hour at room temperature to obtain the title tris-l. -IJ
Methylsilyl ether was produced.

TBT is trimenalsilylimidazole + trimethylsilylacetamide + trimethylchlorosilane (3:3:
2).

Tlc analysis on a 3% QFI column at 212° showed a single peak with a retention time of 5.6 minutes.

(4) The triol (0.51 from above (b)) in 1α,25-dihydroxycholesterol triacetate pyridine (0.5 ml) and acetic anhydride (8 ml) was heated under reflux for 1.5 hours.

The solution was cooled, poured into ice water and stirred to destroy the anhydride.

Extraction with ethyl acetate in the usual manner and after-treatment gave a brown oil, which was mixed with alumina (activity:
, 25 g).

Elution with hexane-benzene (7:3) gave trace amounts of non-polar material.

Benzene-hexane (1:1) produced the title compound (0,58,!i') as a highly soluble colorless oil.

The material was homogeneous on TLC of silica gel, alumina, silica gel, alumina, silica gel-silver nitrate.

νmax (film) 173oCrrL-1, δ(OD
ct3) 5.50 (1 proton, narrow multiplet, H6), 65.2 to 4.6 (2 protons, 1 broad to 1 narrow multiplet, δ5.0
H and H3 as a narrow multiplet of 3 and ζ) (□), δ2.00, 1,98, 1.91 (singlet, acetate), δ1.40, 1.05.0.
67 (singlet, methyl of 026-27.C□9°C08, respectively).

Example 2 The en-triacetate (0,
5M) was treated with dibromodimethylhydantoin (1707ng, 1.1 eq.) in hexane (10ml).

The mixture was heated under reflux for 15 minutes, cooled, filtered and the solvent was evaporated to give a brown oil.

This in xylene (5 TLl)
) to a refluxing solution of trimethyl phosphite (0.6 ml).

The solution was heated to reflux for 1.5 hours and the solvent was evaporated under reduced pressure (oil pump).

Attempts to resolve this mixture by chromatography on a 30 inch column packed with 2% AgNO3-silica gel failed to give any pure 5,7-diene (adsorbent to mixture ratio of 250 :
1).

Preparative tic(1) on silica gel-AgNO3
0 x 200
1α, 3β, 25-1 as more polar bands visible under UV by developing the plate twice in 3.
-lianatoxy-cholester-5, thudiene (175~
, 30%: was produced.

Crystallization from aqueous methanol gave fine colorless needles with m, p, 96-101°, which did not change upon further recrystallization.

[α]-24° (CHCZ3).

Actual value C72, 84, H9, 16, calculated value (C33H5
oO6) 073.03, H9, 29°2 m a x
(Nujol) 1735CrIL-1 (272 and 2
The crude previtamin was heated in deoxygenated isooctane (20 TrLl) at 75° for 2 hours.

During this time the absorption at 260-265 nm increased by 20-25% (isomerization to vitamins).

At this point the mixture is still essentially homogeneous on tlc and at 274, 285 and 298 nm.
The ultraviolet absorption peak still remained.

The isooctane was removed under reduced pressure and the resulting light brown oil was dissolved in deoxygenated 5% methanol [0H (10Tll)].
Hydrolysis was carried out for 16 hours at room temperature.

The mixture was worked up by diluting with water and extracting with ethyl acetate to give a brown oil.

Attempt to partition this mixture on eight 200X200X1 mm silica gel plates (6% MeOH-OHO73
(expanded twice) are approximately 0.2°0.4 and 0.6 respectively.
Three main fractions with Rf of approximately 2:2:1 ratio were generated.

The most polar band (approximately separated into two bands) contained a mixture of the previtamin and the title vitamin and showed a single distinct UV absorption with a maximum of 263 nm and a minimum of 227 nm.

The intermediate fraction had UV maxima at 273, 285 and 298 nm, but it also showed significant absorption in the 220-26 Onm region.

It may contain some partially asenalized vitamins and previtamins.

TR of this fraction showed weak carbonyls at 1720 and 1740.

Further hydrolysis as described above yields an additional 2 //2y
The title vitamin was produced.

The least polar fractions are 275.286 and 299 nm
It exhibits a UV peak in the 220-260 nm region and virtually no absorption in the 220-260 nm range, so it does not contain any of the desired vitamins or previtamins.

This vitamin-previtamin mixture (fraction I) was added to
200×200×] and rechromatographed on man silica gel plates, developed twice with 5% MeOHCHCZ3.

This gave two narrow bands approximately 1 mm apart.

After careful isolation and extraction with 8% MeOH-ether followed by washing with water, drying and evaporation, the title vitamin (12,5772P, 18% conversion) (more non-polar band) was obtained as a colorless gum. Obtained.

Crystallization was carried out by dissolving it in a minimum amount of ether and diluting with pentane to initiate cloud formation and refrigerating to yield an oil.

Aqueous methanol gave the same final results.

By slurrying the ether solution with pentane, the title vitamin was obtained as a colorless powder.

This is m, p, 84-88° and [α), +29° (
CHC! A3).

Actual value 077.84, Hlo, 53, calculated value (0, H4
403) 077, s 3, Hlo, 65oλmax2
64 (18000), 2min228.5nm(1
0100).

Vmax (CHCL3) 3650 (Sharp), 350
0 (broad) 1600-1650CrrL-1°NM
R (D6 in acetone) 6.20 (2 protons, AB caltite, J = 11 ° 5 Hz, H6 and H7),
5, 30 and 4.85 (1 proton, each narrow multiplet, 2H engineering.

), 1.13 and 0.57 (sharp singlet, C and C engineering, respectively, Me26.27 chill).

The mass spectrum is M” at 416, then H20 and C
Peak due to H3, 3x (398.

383,380,365,362,347) and m/
Fragments at e287 (loss of side chain due to cleavage between C□7 and C16) and m/e152 (cleavage between C7 and C8) are shown.

During IR measurements in chloroform, it was observed that the title vitamin began to crystallize.

It was therefore dissolved in a minimum amount of chloroform and after a few minutes it precipitated almost quantitatively as colorless prismatic crystals.

m, p, 106-112°. Actual value C62, 19, H8
, 48, calculated value (C27) - I44030HOL3) 0
62.74, H8,46oλmax264(18,00
0), λm1n228.5nm (9900) (C27H
Calculated for 4403/CHO73).

The mass spectrum shows M + at M 416.3291 [calculated value (C!, H4403') 416.3290
), and the m/e 83/85 pattern is crystalline CHC! ,! It is attributed to 3.

The more polar band from the preparative plate is the previtamin (5,5ttty, 8% conversion) λmaX
260 nm was given.

This showed a large hump at 250 nm.

Additional amounts of vitamins could be obtained by heating previtamins in isooctane.

Claims (1)

[Claims] 11α,25-dihydroxyprevitamin D3 or its acylate is thermally isomerized and then the desired 1α,25
- A method for producing 1α,25-dihydroxyvitamin D3 or its acylate, which comprises recovering dihydroxyvitamin D3 or its acylate in crystalline form.