DK154563B - PROCEDURE FOR PREPARING A RACEMIC OR OPTICAL ACTIVE (+) - THIOLACTON OR (+) - BIOTON - Google Patents

Description

DK 154563 B

The present invention relates to a particular process for the preparation of the racemic or optically active (+) thiolactone of formula I

0

A

R-N 1 3 M

, Wherein R and A are cis-linked and R represents a benzyl group, or (+) - biotin.

This thiolactone (the racemate and (+) form) is a valuable intermediate in the synthesis of biotin or (+) - biotin.

The optically active (+) - thiolactone is a novel substance.

The process of the invention is characterized in that at elevated temperature the racemic or optically active (+) - lactone of formula II 15 is reacted

A

R-ΪΓ M \ A / in which rings A and B are cis-linked and R has the above meaning, with a salt of a thio derivative of a carboxylic acid, and to produce (+) - biotin in and for In a known manner, the carboxybutyl side chain enters the (+) - thiolactone obtained and cleaves the benzyl groups.

DK 154563 B

2

By (+) - thiolactone is meant the antipode which is right-turning in chloroform.

The racemic lactone of the above formula II used as a starting material is a known substance and can be prepared by known methods. It can be obtained, for example, by reacting cis-bis-benzylamino acid with phosgene in the presence of alkali, after which the reaction product is treated with a dehydrating agent and reduced.

The optically active (+) - lactone also used as a starting material is a novel substance which can be prepared, for example, by converting a racemic trion of formula A by means of cholesterol or cyclohexanol

0

A

R-ΕΓ ΕΓ-R

Λ-ώ »• · \ /"

15 in which R represents a benzyl group, to the corresponding haloesters of general formulas B and C

Island Island

E-ITIT-R E-jf ^ Nr-R

- ^ | H H * ^ -

H00C C00R! R'OOC C00H

B C

in which R is as defined above, and R 'represents a cyclohexyl or cholesteryl group, separates the cholesterol halves from fractional crystallization of their triethylamine salts, or separates the cyclohexyl halves from fractionated

DK 154563 B

3 crystallizes their ephedrine salts and converts the salts thus obtained of the desired antipode into the (+) - lactone of formula A.

The conversion of the trion of formula A to the corresponding half esters of formulas B and C by cholesterol or cyclohexanol 5 is conveniently carried out in an inert organic solvent, preferably at the reflux temperature of the reaction mixture.

The cleavage of the racemic half-esters of formulas B and C with triethylamine or ephedrine is conveniently carried out in a lower alkanol such as ethanol or isopropanol or in a lower ketone such as acetone at a temperature between about 40 ° C and the boiling point of the reaction mixture.

The salts thus obtained of the desired antipode can be directly converted to the (+) - lactone of formula II by means of lithium borohydride in an inert organic solvent.

If the process according to the invention uses as a starting material a racemic lactone of formula II, the racemic thio-lactone of formula I is obtained, and if the optically active (+) - lactone of formula II is used as starting material, the optically active ( +) - thiolactone of formula I.

The reaction of the lactone of formula II, both of the racemate and of the optically active (+) form, with a salt of a carboxylic acid thio derivative is conveniently carried out in an inert organic solvent at temperatures ranging from ca. 100 ° C and approx. 200 ° C, preferably between ca. 140 ° C and approx. 185 ° C.

Preferably, as a solvent, high boiling solvents are used, especially high boiling amides, tertiary amines, ethers and the like. Examples of such solvents include diethylaniline, collidines, lutidines, phenylethyl ether and preferably dimethylacetamide, dime thylformamide and quinoline. However, solvents with a lower boiling point, such as carbon disulfide or cyclic ethers such as tetrahydrofuran or dioxane or tertiary, can also be used.

DK 154563 B

4 amines such as pyridine, triethylamine and the like, in which case the reaction is conveniently carried out under pressure.

The reaction can also be carried out without solvent in a melt.

The reaction is conveniently carried out in an atmosphere of inert gas, for example under nitrogen.

As salts of carboxylic acid thio derivatives, salts of strong bases, e.g., alkali metal or alkaline earth metal salts, preferably sodium or potassium salts, are suitably used.

The nature of the carboxylic acid moiety is not critical within the scope of the present invention. Both aliphatic and aromatic carboxylic acids can be used if they are stable at temperatures above 100 ° C. Preferred salts of carboxylic acid thio derivatives are the sodium and potassium salts of thioacetic acid and thiobenzoic acid. Particularly preferred is potassium thioacetate.

The conversion of the optically active (+) - thiolactone to (+) - biotin takes place by the introduction of the carboxybutyl side chain in a manner known per se. For example, the conversion can take place according to one of the following reaction schemes I, II and III:

DK 154563 B

5

Scheme I

0 0 RI ^ V ^ NR R-N '^^ TR 111 \ / XMgCE-CE-CH ^ OR1 \ / <+> r \ —----- 1 - »r \ oh 1 Vs> ° ^ \ VC ^ ch OR1 xS ^ _H20 s CH20r · O o

N-R R - ^^ H-R

+ H + cat. \ _ / V

17 Μ / \ HBr / ^

ISLAND ISLAND

I ^ I

R-N N-R. ^ COOR1 f-R

VI) - (AC ^ coor1, W f0Rl \ jA / Xs ^ - ^^ OOOE1 ar \ /.

T "HBr / ^ VII

Λ ^

H-N N-H

vm) - (

\ PXX / \ / \ COOH

(+) - biotin

DK 154563 B

6 In the formulas I, III and IV shown, the rings A and B are cis-linked, in the formulas V, VI, VII and VIII the hydrogen atoms are in positions 6a, 3a and 4 in the cis position. The symbol R represents a benzyl group, represents alkyl of 1-4 carbon atoms, and X represents chlorine or bromine. A represents the alkali metal atom.

The optically active compounds of formulas III, IV, V and VI shown are novel compounds.

According to Scheme I, the (+) - thiolactone of formula I is converted to the optically active compound of formula III by a Grignard reaction. The conversion of this compound to a compound of formula IV may be carried out by means of a water decomposing agent, e.g., glacial acetic acid, or by means of a dilute mineral acid, e.g., sulfuric acid. The compound of formula IV is converted to the compound of formula V by catalytic hydrogenation using, for example, Raney nickel as catalyst. Of the compound of formula V, the compound of formula VI is obtained by cleavage of the methoxy group, for example with hydrochloric acid. The compound of formula VII is obtained from the compound of formula VI by treating it with an alkali metal dialkyl malonate, for example sodium diethyl malonate. The compound of formula VII is hydrolyzed and after decarboxylation 20 and debenzylation (+) - biotin of formula VIII is obtained.

SCHEME II

7

DK 154563 B

1 λ

R./^N-R R-ØØ-R

(+) \ - / l) XMgCHOCH? CH CHpMgX} - (

Xs ^ x COOH

'H2 ° / 0 I o

R-N A y-R R-tiT ^ tf-R

x) - (Hp + cat.) - / XI

V

Xsx σοοΗ xs ^^ gooh f

H-N N-H

v "" Ow ^ xsx x: ooh (+) - biotin

DK 154563 B

8 In formulas I, IX and X, rings A and B are cis-linked. In formulas XI and VIII, the hydrogen atoms are in positions 6a, 3a and 4 in the cis position. The symbol R represents a benzyl group and X represents chlorine or bromine.

The optically active compounds of formulas IX and X are novel compounds.

According to Scheme II, the (+) - thiolactone of formula I is converted to the optically active compound of formula IX by a Grignard reaction and subsequent treatment with carbon dioxide. The conversion of the compound 10 of formula IX to the compound of formula X is carried out by means of a water scavenging agent such as glacial acetic acid or a dilute mineral acid such as dilute sulfuric acid. The compound of formula X is converted to the compound of formula XI by catalytic hydrogenation using, for example, Raney nickel as catalyst. (+) - Biotin of formula VIII is obtained from the compound of formula XI by debenzylation.

SCHEME III

9

DK 154563 B

ISLAND ISLAND

A A

R-N N-R R-N N-R

\ A / XMgCH CH CELCILOR2 A / w A- hi * I Vs / - "

XII

-H20 .A

0 Yes 9 Λ A Λ

Η Α / "R Η? 4th cat. R-Η n-R

(Β A ^ \ / ch OP2

\ g / AA 2 XSX AA

XIII> A XIV

0 y / 'O

Λ A Λ

R-N N-R „R-N N-R

(, NaCN_ \ / (A ^ XV> A χνΐ

HBr> A

island

H-N ^^ \ - H

(+) - Biotin

VIII

DK 154563 B

In the formulas I, XII and XIII shown, the rings A and B are cis - joined. In formulas XIV, XV, XVI and VIII shown, the hydrogen atoms are in positions 6a, 3a and 4 in the cis position. The symbol R represents a benzyl group, R 4 represents benzyl or alkyl of 1-4 carbon atoms, and 5 X represents chlorine or bromine.

The optically active compounds of formulas XII, XIII, XIV, XV and XVI are novel compounds.

According to Scheme III, the (+) - thiolactone of formula I is converted to the optically active compound of formula XII by a Grignard reaction.

The conversion of the compound of formula XII to the compound of formula XIII is carried out by means of a water-scavenging agent, for example glacial acetic acid or a dilute mineral acid such as sulfuric acid. The compound of formula XIII is converted to the compound of formula XIV by catalytic hydrogenation using, for example, Raney nickel as catalyst. The conversion of the compound of formula XIV to the compound of formula XV is carried out by treatment with hydrochloric acid in glacial acetic acid. The conversion of the compound of formula XV to the compound of formula XVI is carried out by means of an alkali metal cyanide, for example sodium cyanide. The compound of formula XVI is then converted to (+) - biotin 20 of formula VIII by hydrolysis and debenzylation.

The process of the invention is further illustrated by the following examples: EXAMPLE 1 50 g (+) - cis-1,3-dibenzyl-hexahydro-1H-furo [3,4-d] imidazole-2,4-dione 25 and 20 g of potassium thioacetate are stirred. in 50 ml of dimethylacetamide for 30 minutes at 150 ° C under a nitrogen atmosphere. The reaction mixture is cooled and partitioned between water and benzene. The aqueous phase is extracted once more with benzene and the benzene phases are washed once more with water. After evaporation of the organic extracts, the residue is recrystallized from isopropanol to give 47.4-48.4 g (+) - cis-1,3-dibenzyl-hexahydro-1H-thieno [3,4-d] imidazole -2,4-dione; mp 125-127 ° C; [α] g 5 - + 92.2 ° (c = 1 in chloroform).

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11

The (+) - cis-1,3-dibenzyl-hexahydro-1H-furo [3,4-d] imidazole-2,4-dione used as starting material can be prepared as follows: 77.5 g of cholesterol is suspended in 500 ml benzene. To remove moisture, distribute 135 ml of benzene. 45 g of cis-5 1,3-dibenzyl-hexahydro-1H-furo [3,4-d] imidazole-2,4,6-trione are then added and the mixture is refluxed for 18 hours. The mixture is cooled and evaporated in vacuo. To remove the benzene, the residue is dissolved twice in 50 ml of acetone, the solvent being re-equilibrated each time. The residue is then dissolved in 450 ml of acetone at 40 ° C and 10.9 g of triethylamine are added. The temperature rises to 50 ° C,

The mixture is allowed to cool slowly to 23 ° C and the crystals (40 g) are filtered off. After recrystallization from 650 ml of ethanol, 30 g of pure (+) - cis-1,3-dibenzyl-5- (3'-cholesteryloxycarbonyl) -2-oxo-4-imidazolidine-carboxylic acid triethylamine salt are obtained. [α] mp = + 8.4 ° (c = 5.0 in CHCl13).

5.9 g of potassium borohydride and 6.075 g of lithium chloride are stirred overnight in 73 ml of tetrahydrofuran under a nitrogen atmosphere. The mixture is then heated to 30-35 ° C, followed by a solution of 30 g of (+) - cis-1,3-dibenzyl-5- (3'-cholesteryloxycarbonyl) -2-oxo-4-imidazolidine-carboxylic acid triethylamine salt in 160 ml of tetrahydrofuran are dropped over a period of 2 hours at a maximum temperature of 50 ° C. The mixture is then refluxed for 2 hours, after which 65 ml of tetrahydrofuran is distilled off at atmospheric pressure. To the residue is then slowly added 73 ml of methanol, then the mixture is boiled for 1/2 hour under reflux. 18.25 ml of concentrated hydrochloric acid is added and refluxed for an additional 1/2 hour, after which, at atmospheric pressure, solvents are distilled to a volume of 75 ml. 250 ml of methanol are added and the mixture is refluxed for 15 minutes and left overnight at 15 ° C. The precipitated cholesterol 30 is filtered off, washed with water and ethanol and dried. 13.75 g are recovered. The filtrate is evaporated in vacuo to 60 ml, mixed with 75 ml of water and extracted three times with chloroform. The extracts are washed with water, dried and evaporated in vacuo. The residue is taken up in 15 ml of ether and left overnight at 8 ° C. The crystals are filtered off

DK 154563 B

12 and washed with ether. 11.2 g (+) - cis-1,3-dibenzyl-hexahydro-1H-furo [3,4-d] imidazole-2,4-dione are obtained. [a] §® = + 57.2 ° (c = 1 in benzene).

EXAMPLE 2 50 g of (+) - cis-1,3-dibenzyl-hexahydro-1H-furo [3,4-d] imidazole-2,4-dione 5 is stirred with 20 g of potassium thioacetate in 50 ml of dimethylformamide for 10 minutes at 145 -150 ° C. After working up as described in Example 1, 47.1 g of (+) - cis-1,3-dibenzyl-hexahydro-1H-thieno [3,4-d] imidazole-2,4-dione are obtained. [α] β · + - 91.4 ° (c = 1 in chloroform). 0.7 g of the mother liquor can be further obtained. [A] + = + 89.3 °.

EXAMPLE 3 10 g (+) - cis-1,3-dibenzyl-hexahydro-1H-furo [3,4-d] imidazole-2,4-dione, 12 ml of quinoline and 4 g of potassium thioacetate are stirred under a nitrogen atmosphere at 175 ° C. At 30 minute intervals, a further two portions of potassium thioacetate are added on each 2 g, after which the mixture is stirred after another 15 minutes for a further 30 minutes at 175 ° C.

After cooling the mixture, add 100 ml of benzene and 50 ml of water. The benzene phase is separated and washed with water, then with 20% hydrochloric acid and finally with water. The aqueous solutions are extracted separately once more with benzene. The benzene solutions are evaporated in vacuo to dryness and the residue is crystallized in 50 ml of isopropanol; 7.05 g of (+) - cis-1,3-dibenzyl-hexahydro-1H-thieno [3,4-d] imidazole-2,4-dione are obtained; mp 124-125 ° C. [α] D + 89.0 (c - 1 in chloroform). Evaporation of the mother liquor gives an additional 1.2 g; mp 122-124 ° C; [cr] g5 - + 86.6®.

EXAMPLE 4 10 g (+) - cis-1,3-dibenzyl-hexahydro-1H-furo [3,4-d] imidazole-2,4-dione is reacted analogously to the manner described in Example 3, however, in 10 ml diethylamine instead of quinoline. 8.0 g of (+) - cis-1,3-dibenzyl-hexahydro-1H-thieno [3,4-d] imidazole-2,4-dione are obtained; mp 126-13

DK 1S4563B

127 ° C. [<*] $ - * = +90.1 "(c = 1 in chloroform). 0.12 g can be further crystallized from the mother liquor.

EXAMPLE 5 10 g (+) - cis-1,3-dibenzyl-hexahydro-1H-furo [3,4-d] imidazole-2,4-dione is stirred with 4 g of potassium thioacetate in 12 ml of 2,4,6 trimethylpyridine 1 1 1/2 hours under nitrogen atmosphere at 175 ° C. After working up according to Example 1, 6.9 g of (+) - cis-1,3-dibenzyl-hexahydro-1H-thieno [3,4-d] -imidazole-2,4-dione are obtained; mp 125-126 ° C.

EXAMPLE 6 5 g (+) - cis-1,3-dibenzyl-hexahydro-1H-furo [3,4-d] imidazole-2,4-dione, 2 g of potassium thioacetate and 6 ml of phenylethyl ether are stirred together under a nitrogen atmosphere at 175 ° C. At 30 minute intervals, an additional 2 portions are added to each 1 g of potassium thioacetate, after which the mixture, after the last addition, is stirred for an additional 30 minutes at 15 175 ° C. The reaction mixture is then cooled, 150 ml of benzene is added and washed 3 times with 100 ml of water each time. The solvent is juxtaposed in vacuo and the residue is crystallized by isopropanol and 2.7 g of (+) - e: is-1,3-dibenzyl-hexahydro-1H-thieno [3,4-d] imidazole-2 are obtained. 4-dione. [<*] § * - + 86.1 ° (c = 1 in chloroform).

EXAMPLE 7 5 g (+) - cis-1,3-dibenzyl-hexahydro-1H-furo [3,4-d] imidazole-2,4-dione, 2 g sodium thioacetate and 6 ml diethylaniline are stirred together under a nitrogen atmosphere at 175 ° C. At 30-minute intervals, an additional 2 portions of sodium thioacetate are added to each 1 g, after which the mixture is stirred, after the last addition, for a further 30 minutes at 175 ° C. The reaction mixture is cooled and added to water and benzene, then the benzene extract is washed first with 20% hydrochloric acid, then with sodium hydrogencarbonate solution and finally with water, then the benzene is evaporated. The residue is crystallized by isopropanol and more

DK 154563 B

14 is obtained 2.98 g (+) - cis-1,3-dibenzyl-hexahydro-1H-thieno [3,4-d] imidazole-2,4-dione.

EXAMPLE 8 10 g (+) - cis-1,3-dibenzyl-hexahydro-1H-furo [3,4-d] imidazole-2,4-dione, 6.2 g of potassium thiobenzoate and 10 ml of dimethylacetamide are stirred together for 20 minutes. minutes at 140 ° C under nitrogen atmosphere. The reaction mixture is worked up as described in Example 1 to give 7.8 g of (+) - cis-1,3-dibenzyl-hexahydro-1H-thieno [3,4-d] imidazole-2,4-dione, m.p. 124eC.

EXAMPLE 9 5 g (+) - cis-1,3-dibenzyl-hexahydro-1H-furo [3,4-d] imidazole-2,4-dione and 2 g of potassium thioacetate are heated in 100 ml of carbon disulfide to 171-181 ° C. a stirring autoclave under nitrogen atmosphere for 12 hours. The reaction mixture is evaporated in vacuo to dryness and the residue is taken up in benzene and water. The phases are separated and the aqueous phase is extracted once more with benzene. The benzene extracts are then washed twice with saturated sodium chloride solution and then evaporated in vacuo to dryness. The residue is crystallized from isopropanol to give 3.62 g (+) - cis-1,3-dibenzyl-hexahydro-1H-thieno [3,4-d] imidazole-2,4-dione, m.p. 124-126 ° C.

EXAMPLE 10 2.5 g of (+) - cis-1,3-dibenzyl-hexahydro-1H-furo [3,4-d] imidazole-2,4-dione and 1.0 g of potassium thioacetate are stirred under a nitrogen atmosphere at 180 ° C.

30, 60 and 90 minutes after the beginning of the heating, a further portion of potassium thioacetate of 0.5 g is added. After a further 1/2 hour the mixture is cooled. The reaction product is taken up in benzene and dilute hydrochloric acid and the organic phase is washed with water for neutral reaction. The benzene is distilled off in vacuo and the residue is crystallized by 25 ml of isopropanol. An initial portion is available

DK 154563B

1.52 g, and, after evaporation of the mother liquor, a second portion of 0.12 g (+) - cis-1,3-dibenzyl-hexahydro-1H-thieno [3,4-d] imidazole-2,4- dione.

EXAMPLE 11 240 ml of dimethyl acetamide, 238 g of rac. -cis-1,3-dibenzyl-hexahydro-1H-furo [3,4-d] imidazole-2,4-dione and 95 g of potassium thioacetate are heated to 150 ° C for 30 minutes. The mixture is cooled to 80 ° C and 2.5 liters of benzene and later 2.5 liters of water are added. The phases are separated and the aqueous phase is extracted twice with 0.5 liters of benzene each time, after which the benzene extracts are evaporated together. The residue is dissolved in the heat in 600 ml of isopropanol. The mixture is allowed to stand for 12 hours at room temperature to give 215 g of rac-cis-1,3-dibenzyl-hexahydro-1H-thieno [3,4-d] imidazole-2,4-dione, m.p. 128 ° C.

Example 12 A solution of Grignard reagent is prepared in 18.2 ml of tetrahydrofuran at 60-70 ° C of 1.03 g of magnesium shavings and 4.05 g of 1-chloro-3-methoxypropane. This solution is dripped to a preheated solution of 45 g of (+) - cis-1,3-dibenzyl-hexahydro-1H-thieno [3,4-d] imidazole-2,4-dione in 110 ml of toluene. The temperature rises to approx. 62 ° C. The solution is allowed to cool to room temperature over 2 hours, after which it is added 22 ml of water and 5.5 ml of concentrated hydrochloric acid under ice-cooling. The bags are separated, then the aqueous phase is washed once more with toluene and the organic extracts are washed several times with water. The combined toluene extracts are diluted with 25 ml of methanol, adjusted to an alkaline reaction (pH 11) with 28¾ aqueous sodium hydroxide solution and allowed to stand for 30 minutes at room temperature. The reaction mixture is added to water, after which the aqueous phase is separated and extracted several times with toluene. The toluene extracts are washed with water for neutral reaction, dried and evaporated in vacuo to dryness. 9.98 g of crude (+) - cis-1,3-dibenzyl-4-hydroxy-4- (3-methoxypropyl) hexahydro-1H-thieno [3,4-d] imidazol-2-one are obtained. . The substance can be crystallized by acetone

DK 154563 B

16 / ether / petroleum ether: mp 114-116 ° C, [α] D + 89.2 ° (c - 1.0 in chloroform).

The 9.98 g of crude product is boiled in 100 ml of glacial acetic acid for 2 hours at reflux. The glacial acetic acid is distilled off in vacuo, after which the residue 5 is taken up in benzene and this solution is washed with sodium hydrogen carbonate solution and with water. After evaporation of the solvent, 9.45 g of cis-1,3-dibenzyl-4- (3-methoxypropylidene) -hexahydro-1H-thieno [3,4-d] imidazol-2-one is obtained. [.alpha.] D @ + + 222 DEG (c - 1 in chloroform).

This substance is dissolved in 56 ml of methanol and hydrogenated for approx. 40 10 atmospheric hydrogen pressure in the presence of approx. 9 g Raney nickel at 35-40 ° C. After removing the catalyst, the solution is evaporated in vacuo. 8.6 g of (-) - cis-1,3-dibenzyl-4- (3-methoxypropyl) -hexahydro-thieno [3,4-d] imidazol-2-one are obtained as an oil. [<*] $ -> - -42.4 ° (c »* 1.0 in chloroform).

This compound is heated to 90-95 ° C with 14.5 ml of 48% aqueous hydrochloric acid under intense stirring for 2 hours. A brownish-colored solution is formed. This is cooled and extracted with toluene.

The aqueous phase is evaporated in vacuo. The residue is taken up in 50 ml of acetone. 6.78 g of (-) - cis, cis-1,3-dibenzyl-2-oxo-20-decahydro-imidazo [4,5-c] thieno [1,2-a] thiolium bromide crystallize. Melting point (dec.) 206-207 ° C; [α] β - -18.0 ° (c - 1.0 in methanol-water 1: 1). By evaporation of the mother liquor, 0.23 g of this substance can be further obtained in crystalline form.

To a heated suspension of 2.2 g of sodium methylate in 40 ml of toluene, drop 8.74 g of diethyl malonate into a heated suspension at 80 ° C. The suspension is stirred for 1 hour at this temperature and then cooled to 60 ° C and 6.16 g of (-) - cis, cis-1,3-dibenzyl-decahydro-imidazo [4,5-c] thieno [1,2 -a] thiolium bromide, then boil for 3 hours under reflux.

The mixture is cooled to room temperature and 20 ml of water is added, after which the phases are separated. The organic phase is dried and the solvent removed in vacuo. The residue is heated to boiling with stirring with 90 ml · 48% hydrochloric acid. Ethyl bromide, acetic acid and benzyl bromide formed during the course of the reaction are distilled off together with a small amount of aqueous hydrobromic acid. In total, the reaction mixture is heated.

DK 154563B

17 the mixture to 120-126 ° C for approx. 3 1/2 hours. Then, the aqueous hydrochloric acid is removed in vacuo. The residue is boiled in 90 ml of water. The hot solution is decanted from the oily insoluble material, cooled and left to stand overnight in ice cream. The crystals of the crude (+) - 5 biotin are filtered off and washed with water and acetone. There is (+) - biotin which is recrystallized from water. Melting point 230-232 ° C, [a] §® = + 90 ° ± 1 ° (c - 1 in 0.1N NaOH).

EXAMPLE 13

11.0 g of magnesium is poured with 70 ml of diethyl ether and 70 ml of toluene.

To this solution, a solution of 24.9 g of 1,2-dibromo-ethane in 36 ml of diethyl ether is then dropped over a period of approx. 20 minutes under cooling. (The temperature of the reaction mixture: 20-28 ° C). After 45 minutes, a solution of 16.9 g of 1,4-dichlorobutane in .36 ml of diethyl ether and 75 ml of toluene is added dropwise over 25 minutes. Stir for an additional 105 minutes, after which the obtained suspension is cooled to -30 ° C - -40 ° C, and at this temperature a solution of 14.65 g (+) - cis-1,3-dibenzyl-hexahydro-hydroxide is added dropwise. 1H-thieno [3,4-d] imidazole-2,4-dione in 260 ml of toluene. Stir for an additional 1 hour at -30 ° C -40 ° C, then carbon dioxide is quenched, first for 1 hour 20 at -30 ° C -40 ° C and then for 1 hour at room temperature. The reaction mixture is then separated with ice and hydrochloric acid. The organic phase is separated, washed with water and evaporated to dryness. The residue is shaken for 40 minutes with 150 ml of 5% sodium carbonate solution. Undissolved neutral proportions are extracted with ethyl acetate. The aqueous qp-25 solution is adjusted to pH 5.5 with hydrochloric acid and extracted with ethyl acetate. The ethyl acetate extracts are washed with water, dried and evaporated in vacuo. 13.28 g of crude cis-5- (1,3-dibenzyl-4-hydroxy-2-keto-hexahydro-1H-thieno [3,4-d] imidazolyl-4) -valeric acid are obtained as a chloroform right-turning oil . 11.6 g of this oil is boiled in 60 nil 30 glacial acetic acid for 2 hours at reflux. The glacial acetic acid is distilled off in vacuo and the residue is dissolved in toluene and this solution is evaporated in vacuo. The residual oily, chloroform right-turning cis-1,3-dibenzyl-4- (4-carboxybutylidene) hexahydro-1H-thieno [3,4-a] imidazol-2-one is dissolved in 80 ml of methanol and hydrogenated in presence of Raney nickel at 35-40 ° C peaks 38-40 atmospheric hydrogen.

DK 154563 B

18

The catalyst is filtered off and the filtrate is evaporated. 10.3 g of oily crude Ν, Ν-dibenzyl-biotin are obtained which are left-turning in chloro- form.

10.3 g of crude Ν, Ν-dibenzyl-biotin are heated for 5 hours under reflux in 100 ml of 48% hydrochloric acid. 60 ml is then distilled off under partial vacuum, after which the residual solution is diluted with 230 ml of water and refluxed for 10 minutes. The hot solution is decanted from a dark brown insoluble oil. This oil is boiled again with 80 ml of water and then decanted. 2.9 g of oil remain as insoluble residue. The aqueous solutions are combined, evaporated to 50 ml and left for 24 hours at + 5 ° C. 0.61 g (+) - biotin crystallizes, mp 225-228 ° C; [e] + - 86.0 (c - 1.0 in 0.1N NaOH). The filtrate is evaporated to dryness and boiled again for 3 1/2 hours in 100 ml of 48% hydrochloric acid under reflux. The hydrochloric acid is removed in vacuo and the residue is taken up in 50 ml of water. After standing for 24 hours at + 5®, 0.72 g of (+) biotin crystallizes, mp 223-225 ° C; [α] D + 83.2 (c - 1.0 in 0.1N NaOH). The filtrate is added 2 g of sodium carbonate and at ca. 10 ° C is phosgene fed to this solution until pH 1. From this reaction mixture, overnight, crystallizes 0.58 g (+) - biotin, mp 224-226 ° C; [α] β + - + 85.5 (c - 1.0 in 0.1N NaOH).

EXAMPLE 14

Prepare a solution of Grignard reagent in 65 ml of ether of 1.8 g of magnesium and 9.18 g of 4-bromo-1-methoxybutane, then drop over a period of 25 minutes to a heated solution of 50 ° C. 9 g (+) - cis-1,3-dibenzyl-hexahydro-1H-thieno [3,4-d] imidazole-2,4-dione in 200 ml of benzene. Stir for a further 1 hour, after which the solution is cooled and the reaction mixture is separated with ice and dilute hydrochloric acid.

The organic phase is separated and washed with water for neutral reaction. After distilling off the solvents in vacuo, 23.7 g of cis-1,3-dibenzyl-4-hydroxy-4- (4-methoxybutyl) hexahydro-1H-thieno- [3,4-d] imidazol-2-one are obtained. and oil. This is refluxed for 1 hour in a mixture of 200 ml of methanol and 2 ml of concentrated sulfuric acid. The methanol is distilled off in vacuo and the residue is taken up

DK 154563B

19 benzene and water. The benzene solution is washed for neutral reaction, dried and evaporated to dryness. 21.4 g of cis-1,3-dibenzyl-4- (4-methoxybutylidene) -hexahydro-1H-thieno [3,4-d] imidazol-2-one is obtained as a benzene right-turning oil. 16.1 g of this oil is dissolved in 160 ml of methanol and hydrogenated in the presence of ca. 30 g Raney nickel under a hydrogen pressure of 25-30 atmospheres. The catalyst is filtered off and the methanol is distilled off in vacuo. The residue is crystallized by isopropyl ether. 11.6 g (-) - cis-1,3-dibenzyl-4- (methoxybutyl) hexahydro-1H-thieno [3,4-d] imazol-2-one is obtained; mp 87-89 ° C. 10 -41.4 ° (c - 1 in benzene).

10 g (-) - cis-1,3-dibenzyl-4- (4-methoxybutyl) hexahydro-1H-thieno [3,4-d] imidazol-2-one is dissolved in 100 ml of 33% bromine solution hydrochloric acid in glacial acetic acid and leave for 60 hours at room temperature.

The solution is then evaporated in vacuo to dryness, after which the residue is taken up in benzene and this solution is washed several times with water, dried over sodium sulfate and ehromatographed over 150 g of alumina, activity step III. Benzene elutes 8.4 g of substance. After dissolving this eluate in isopropyl ether, 5.0 g of (-) - cis-1,3-dibenzyl-4- (4-bromobutyl) hexahydro-1H-thieno [3,4-d] imidazol-2-one crystallize . Mp 78-79 ° C; [is] - - 49.7 ° (c - 1 in benzene). 5.0 g of (-) -cis-1,3-dibenzyl-4- (4-bromobutyl) hexahydro-1H-thieno [3,4-d] imidazol-2-one is dissolved in 25 ml of dimethyl sulfoxide and stirred. for 3 hours at 80 ° C with 1.53 g of sodium cyanide. After cooling the reaction mixture, benzene and water are added and the phases are separated and the benzene solution is washed several times with water. After evaporation of the solvent in vacuo, the residue is dissolved in isopropanol. After addition of n-hexane, overnight, 4.35 g of (-) - cis-1,3-dibenzyl-4- (4-cyanobutyl) hexahydro-1H-thieno [3,4-d] imidazole-2 crystallize -on. Melting point 95-97 ° C. [α] D = -56.8 ° (c * = 1 in benzene).

4.25 g of (-) -cis-N, N-dibenzyl-bie-tin tril is heated to boiling temperature for 3 hours with 125 ml of 48% hydrochloric acid, continuously distilling off the benzyl bromide formed. The reaction mixture is extracted with benzene. The aqueous phase is evaporated in vacuo and the residue is dissolved in the heat in 300 ml of water and extracted in the heat with 1,2-dichloroethane.

The aqueous solution is evaporated and two portions of 1.25 and 0.30 g (+) - biotin are obtained.

Claims (10)

A process for the preparation of the racemic or optically active (+) - thiolactone of formula I DK 154563 BOA R-IT1 3 RR \ 1 / \ 6aV in é 5 9 = 0 \ 5 / xs in which rings A and B are e - linked, and R represents a benzyl -5 group, or (+) - biotin, characterized in that at elevated temperature the racemic or optically active (+) lactone of formula II 0 A RI A Ή-R T_ is reacted W 10 in which the rings A and B are cis-linked and R represents a benzyl group, with a salt of a thio derivative of a carboxylic acid, and to introduce (+) - biotin in a manner known per se the carboxybutyl side chain in the water (+) - thiolactone and decomposes the benzyl groups. Process according to claim 1, characterized in that the reaction is carried out at a temperature between 100 ° C and approx. 200 ° C, preferably between ca. 140 ° C and about 185 ° C. Process according to claim 1 or 2, characterized in that the reaction is carried out in a high boiling solvent. DK 154563 B Process according to claim 3, characterized in that as a high boiling solvent. a high boiling amide, a high boiling tert amine or a high boiling ether are used. Process according to claim 3 or 4, characterized in that dimethylacetamide, dimethylformamide, quinoline, diethylaniline are used. collidins, lutidines or phenylethyl ether. Process according to claim 1, 10, characterized in that the reaction is carried out in a low boiling solvent under pressure. Process according to any one of claims 1-6, characterized in that as an salt of a thio derivative of a carboxylic acid an alkali metal or alkaline earth metal salt is used. Process according to claim 7, characterized in that a sodium or potassium salt is used. Process according to any one of claims 1-8, characterized in that as a thio derivative of a carboxylic acid 20 a thiocarboxylic acid is used. Process according to any one of claims 1-9, characterized in that potassium thioacetate is used as the salt of a thio derivative of a carboxylic acid.