HU179782B - Process for preparing ether and thioether derivatives of mercapto-acyl-prolines - Google Patents

Description

USA

Process for the preparation of ether and thioether derivatives of mercaptoacyl proline

2

The present invention relates to novel ether and thioether derivatives of mercaptoacylproline I and their salts.

In the general formula I, X-R! group is in the 3- or 4-position of the ring and X is oxygen or sulfur,

R is hydrogen or lower alkyl,

R j is lower alkyl or phenyl optionally substituted by halogen, lower alkyl or lower C 10 alkoxy,

R _{2 is} hydrogen or lower alkyl; and

R _{3 is} hydrogen, lower alkanoyl or benzoyl.

U.S. Patent 4,105,776 discloses mercaptoacyl proline derivatives having antihypertensive activity.

The lower alkyl group used in the general formula I for the definition of R, R ₁ and R _{2 is a} straight or branched chain hydrocarbon group containing up to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl-. , tert-butyl and the like. means. Methyl and ethyl are preferred.

The term "substituted phenyl group" used to define R 1 signifies a group containing one or two, preferably one, substituents on the phenyl ring. Suitable substituents include C 1-4 alkyl, especially methyl; lower C 1-4 alkoxy, especially methoxy, containing from 1 to 4 carbon atoms, tar179782; halogen, especially chlorine or fluorine.

The term halogen includes four halogen atoms, namely chlorine, bromine, fluorine and iodine, of which chlorine, bromine and fluorine are preferred.

Examples of lower alkanoyl groups include acetyl, propionyl, butyryl, isobutyryl, preferably acetyl.

In Formula I, the asterisk represents the asymmetric carbon atom in the proline ring. Of course, there may be additional asymmetric carbon atoms in the mercapto side chain depending on the R ₂ substituent. Consequently, the compounds of formula I may exist in stereoisomeric form or as racemic mixtures thereof. All of these isomers are within the scope of the invention. In the process described below, the starting material may be a racemate or one of the enantiomers. The group -X-R can be a source of cis-trans isomerism.

The asymmetric carbon atom in the proline ring is preferably in the L configuration and, if the mercaptoacyl side chain is asymmetric, it is preferably in the D configuration.

Preferred compounds are those compounds of formula I wherein R is hydrogen, R 1 is C 1-3 alkyl, R _{2 is} hydrogen or methyl. Also preferred as intermediates are those compounds wherein R _{3 is} acetyl or benzoyl, especially acetyl.

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Most preferred of the above compounds are those wherein X is O; R is methyl or ethyl, especially methyl; R _{2 is} hydrogen or methyl, especially methyl; R _{3 is} hydrogen;

the -XRj group is in the 4-position of the proline ring and the -XRj group is primarily in the cis configuration.

The ethers and thioethers of Formula I may be prepared by reacting a proline or thioether of Formula II, wherein X, R and Rj are as defined above, with an acid or reactive derivative of Formula III, wherein R _{3 is a} hydrogen atom. C szén-C alk alkanoyl or benzoyl. Thus, compounds of formula IV of formula I are obtained wherein R, R _b , R ₁ , R ₂ and X are as defined above.

This reaction is carried out with a condensing agent such as dicyclohexylcarbodiimide and the like. or in the presence of either acid by converting the acid into a mixed anhydride, a symmetric anhydride, an acid halide, a reactive ester, or Woodward K reagent, N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline and the like. used. For a detailed review of the methods of acylation, see Methoden der Organic Chemie (Houben-Weyl) XV. Volume II. section,

Pages 1 et seq. (1974). Preferably, the halide, especially the acid chloride, of the acid of formula III is reacted with the acid of formula II.

The ester of a compound of formula IV (i.e., when R is alkyl) can be converted to the free acid (i.e., when R is hydrogen) by conventional means. For example, when R represents a tert-butyl group, it is reacted with trifluoroacetic acid and anisole to give the free acid.

Preferably, the compound of Formula IV can be isolated and purified by crystallization, for example, converting it into a dicyclohexylamine salt and reacting the salt with an aqueous solution of an acid such as potassium hydrogen sulfate to give the free acid.

The compound of formula IV containing R 1 alkanoyl or benzoyl can be converted by conventional hydrolysis or ammonolysis to a compound of formula I wherein R _{3 is} hydrogen.

Esters of Formula I wherein R is lower alkyl may be prepared from carboxylic acid compounds, i.e. compounds containing R as hydrogen, by standard esterification procedures such as diazoalkane such as diazomethane or 1-alkyl-3-p-tolyltriazine. such as n-butyl-3-ρ-tolyltriazine and the like. esterification.

The starting proline derivatives of formula II can be prepared by various methods. For example, hydroxy or mercapto-proline of formula V may be used with an acylating agent such as acetic anhydride, acetyl chloride, propionic anhydride, butyric anhydride, chloroformate, and the like. acylating the nitrogen atom to protect it. The R 1 group is then introduced by reacting a protected nitrogen form of the compound of formula V with a halide of the formula R (-hal), wherein the halogen atom is preferably iodine, in the presence of silver oxide, sodium hydride, sodium hydroxide, etc .; This intermediate is basically hydrolyzed with a base such as barium hydroxide, sodium hydroxide, potassium hydroxide, etc. to give the free acid (-COOH) and then to obtain the compound of formula II.

II. In another process for the preparation of compounds of the formula (VII), the tosyloxyproline ester of formula VII containing the protected nitrogen atom, preferably the methyl ester, is reacted with the sodium salt of formula VIII to give the intermediate of formula IX. In Formula VII, Ts represents a p-toluenesulfonyl group and the nitrogen atom is preferably protected with a benzyloxycarbonyl group or other commonly used acylating group. When the tosylate group is in the cis configuration in this reaction, the -XR group is in the trans configuration, and if the tosyl group is in the trans configuration, the -XR _t group will be in the cis configuration. The alkyl ester group of intermediate IX is then removed and then reacted with hydrogen bromide to form the hydrobromide salt of proline II and then reacted with an acid of formula III, preferably acid chloride.

The starting proline compounds of formula II wherein X is sulfur and the group -XR 1 is in the 3-position of the proline ring may also be prepared by reacting a 1,2-dehydroproline ester of formula X, preferably butyl ester with an acylating agent such as benzyl chloroformate, acetyl chloride and the like. and the resulting

The 4,5-dehydro compound of formula XI is then reacted with a mercaptan of formula R1SH

Preparing a compound of formula XII; in this case the substituent -S-Rj is in the trans configuration. After removal of the nitrogen protecting group and the alkyl group, the desired starting material is obtained.

The starting proline compounds of formula II wherein R _(represents phenyl or substituted phenyl) may also be prepared by the protected nitrogen-containing benzyl ester of formula V in the presence of triphenylphosphine and diethyl azodicarboxylate according to Bittner et al., Chem. 281] with an alcohol of formula R, OH Removing the nitrogen protecting group and benzyl ester to give the starting compound of formula II.

The preparation of starting and intermediate compounds is described in the following publications; U.S. Patent Nos. 4,046,889, 4,105,776 and 4,154,935 to Neuberger, J. Chem. Soc. 1945, pp. 429-432; Patchett et al., J. Am. Chem. Soc., 79, 185-192 (1957); Baer et al., Can. J. Biochem. and Pbys. 37, 583-587 (1959); Sheehan et al., J. Am. Chem. Soc. 85, 3863-3865 (1963); Magerlein, J. Med. Chem., 10, 1161-1163 (1967). The methods described in the publications can be used as general methods for preparing the compounds useful in the process of the invention and stereochemically converting the compounds.

The compounds of the present invention form basic salts with a variety of inorganic or organic bases. The salt-forming ion derived from such bases may be a metal ion such as an aluminum, an alkali metal such as sodium or potassium, an alkaline earth metal such as calcium or magnesium; obsession

-2179782 corresponding amines such as aralkylamines such as dibenzylamine, amin, Ν-dibenzylethylenediamine; lower alkylamines such as methylamine, tert-butylamine; procaine; lower alkylpiperidines, such as N-ethylpiperidine; cycloalkylamines such as cyclohexylamine, dicyclohexylamine, 1-adamantanamine; benzathine; or amino acids such as arginine, lysine, etc. resulting salts. Physiologically acceptable salts, such as sodium and potassium salts, can be advantageously used for therapeutic purposes. These salts, and other salts which are not necessarily physiologically acceptable, may be used for isolation or purification of the product as exemplified in the Examples for the dicyclohexylamine salt and the cyclohexylamine salt. Salts are prepared by reacting the acid form of the compound with an equivalent amount of the base providing the desired basic ion in a medium from which the salt precipitates, or lyophilizing the solution in an aqueous medium. The salt can be acidified by a conventional neutralization method such as potassium hydrogen sulfate, hydrochloric acid, and the like. by reaction.

The compounds of the present invention inhibit the conversion of the angiotensin I decapeptide to angiotensin Π and are therefore useful in reducing or eliminating hypertension. The compounds of the invention inhibit the renin-angiotensinogen-angiotensin-I-angiotensin-II process by interfering with the action of the angiotensin-converting enzyme and with hypertension.

reducing the production of angiotensin IT causing or Example number ₅₀ (µg / ml) terminated. Thus, one or more of the general formula (I) 30 or a physiologically acceptable salt thereof. Second 0,028 administration of high blood pressure 4th 0,007 reduces or eliminates. 6th 0,013 Amint S. L. Engel, R. T. Schaeffer, Μ. H. Waugh and 8th 0.0007 B. Rubin's method [Proc. Soc Exp Bioi. Med., 143, 35 11th 0,012 483 (1973)] 21st 0,008 showed that the compounds of the present invention 25th 0,009 0.1 to 100 mg per kilogram and per day, preferably 27th 1.0 Single dose or pre-dose of 1-50 mg 30th 0.011 daily dose is divided into 2 to 4 parts, suitable for 40 31st 0,009 to reduce pressure. The compound is preferably oral. 32nd 0,006 but parenterally, for example subcutaneously, intramuscularly. 33rd 0,006 ramus, intravenous or intraperitoneal administration 34th 0,001 can also be used. 35th 0.35 The compounds of the invention are used in the treatment of hypertension. 45 36th 0,012

For oral administration, they may be formulated into pharmaceutical compositions such as tablets, capsules or elixirs, or into sterile solutions or suspensions for parenteral administration.

10-500 mg of a compound of Formula I or a mixture of several such compounds or a physiologically acceptable salt thereof is a physiologically acceptable tablet base, carrier, diluent, binder, preservative, stabilizer, flavor, and the like. it is mixed into 55 units according to accepted pharmaceutical practice. These mixtures or formulations contain sufficient amounts of the active ingredient to produce an effective dose within the indicated limits,

Excipients that may be included in tablets, capsules, and the like may include a binder such as gum tragacanth, gum arabic, corn starch, or gelatin; a tablet base such as dicalcium phosphate or microcrystalline cellulose; disintegrants such as corn starch, potato starch, alginic acid, etc .; a lubricant such as magnesium stearate; a sweetening agent such as sucrose, milk sugar or saccharin; a flavoring agent such as mint oil, galanter oil or cherry flavor. When encapsulated in a unit dose, it may contain, in addition to materials of the above type, a liquid carrier such as vegetable oil. A variety of materials can be used as coatings or to form the unit dosage form. The tablets may be coated with, for example, shellac or sugar, or both. The syrup or elixir may contain the active ingredient, sucrose as a sweetening agent, methyl and propylparaben as a preservative, a coloring agent and a flavoring agent such as cherry or orange.

Sterile injectable compositions are prepared according to accepted pharmaceutical practice by incorporating the active ingredient in a solvent such as water for injection or a natural vegetable oil such as sesame oil, coconut oil, peanut oil, cottonseed oil and the like. dissolved or suspended.

The blood pressure lowering effect of the compounds of Formula I was determined by the inhibition of the angiotensin converting enzyme by Cushman and Cheung, Biochem. Pharmacol. 20, 1637 (1971)]. In the following table ( ₅₀ µg / ml), 25 is the dose that inhibits the efficiency of the angiotensin converting enzyme by 50%. The data always refer to a compound containing R ₃ = = hydrogen.

The following examples illustrate the process of the invention in more detail. Temperature data is given in degrees Celsius.

Example 1 1- (3-Acetylthio-1-oxopropyl) -trans-4-methoxy-L-proline

a) N-Acetyl-trans-4-hydroxy-L-proline

To a suspension of trans-4-hydroxy-L-proline (26.2 g, 0.2 mol) in acetic acid (400 ml) was added acetic anhydride (26 ml) with stirring. After stirring at room temperature for 2 hours, the solid gradually dissolves. The solution was transferred to a 2 liter flask and the solvent removed in a rotary evaporator in a 45 ° water bath. To the resulting residue (57.5 g) was crystallized by adding 100 ml of diethyl ether.

-3179782 solid precipitated. After cooling overnight, the solid product was collected by filtration, washed with cold diethyl ether and dried in a desiccator. The product (35.7 g) was pulverized, suspended in 100 ml of diethyl ether, cooled and filtered to give 33.8 g (98%) of N-acetyl trans-4-hydroxy-L-proline. 128-131 ° C. Recrystallization of 0.5 g of this product from 5 ml of acetonitrile gives 0.45 g of a colorless solid. 130-132 °. [α] D = -92 ° (c = 1% in ethanol).

b) N-Acetyl-trans-4-methoxy-L-propoline methyl ester

A mixture of N-acetyl-trans-4-hydroxy-L-proline (30.0 g, 0.17 mol) and silver oxide (130 g) was pulverized in a mortar and placed in a 1 liter flask containing 300 ml of acetone. Methyl iodide (130 mL) was added portionwise to the resulting suspension with stirring so that the temperature in the cold water bath was kept below 40 ° and allowed to stand overnight after stirring for 7 hours. The solid is then filtered off, washed with acetone and the filtrate is concentrated in a rotary evaporator. The resulting residue (38.3 g) was re-dissolved in 350 ml of acetone and reacted with 130 g of silver oxide and 130 ml of methyl iodide to give 41 g of product. This residue was distilled to give 32.2 g of distillate. Boiling point 130-140 ° at 0.3 Torr. Trituration with 30 ml of cyclohexane gave 31.4 g of N-acetyl-trans-4-methoxy-L-proline methyl ester as an almost colorless product. Melting point 71-75 °. Recrystallization from ethyl acetate (31 mL) gave 25.1 g (66%) of a colorless solid. Melting point 76-77 °. [α] D = -83 ° (c = 1% in ethanol).

c) trans-4-Methoxy-L-proline

To a solution of about 3.3 N of crystalline barium hydroxide (27.0 g, 0.085 mol) in water (525 ml) was added N-acetyl trans-4-methoxy-L-proline methyl ester (11.0 g, 0.05 mol) with stirring. . The resulting solution was stirred at 18-20 ° C for 3 hours, cooled and a solution of 8.8 g of concentrated sulfuric acid in 20 ml of water was added. The acidic suspension was allowed to stand overnight and then filtered through a thick pad of Celite to give a milky filtrate. The filtrate was concentrated in a rotary evaporator using a high vacuum pump at 50 ° to give 121 g of a milky residue. To this residue was added a solution of concentrated sulfuric acid (19.0 g) in water (75 mL), and the mixture was stirred and refluxed for 3 hours. After cooling the reaction mixture to 30 °, 48 g of crystalline barium hydroxide are added portionwise, and the pH is adjusted from 6.0 to 4.0 with dilute sulfuric acid and left to stand overnight. The reaction mixture was filtered through a thick pad of Celite, and the milky filtrate was evaporated to give 50 g of a colorless dry residue. This residue was triturated with 200 mL of hot chloroform and filtered through a pad of Celite to remove barium sulfate. The slightly turbid filtrate was concentrated by rotary evaporation to give 17.7 g of a gelatinous product; this was suspended in 100 ml of diethyl ether and separated by filtration to give 7.5 g (94%) of an almost colorless solid. 185-190 °. (Dec). This material was suspended in 30 mL of warm acetonitrile, cooled and filtered to give 4.0 g (50%) of trans-4-methoxy-L-proline as a colorless solid. M.p. 209-211 ° (dec.). [α] D = -75 ° (c = 1% in ethanol).

d) 1- (3-Acetylthio-1-oxopropyl) -trans-4-methoxy-L-proline

To a solution of trans-4-methoxy-L-prohn (3.5 g, 0.024 mol) in water (50 ml) was added sodium carbonate (3 g) with stirring and cooling at 5 °. A solution of 4.0 g (0.024 mol) of 3-acetylthiopropionyl chloride in 5 ml of diethyl ether was then added over 10 minutes, and additional 3 g of sodium carbonate was added to maintain the pH at about 8.0. The reaction mixture was stirred in an ice-water bath for an additional hour, 25 ml of water was added, followed by 5 ml of concentrated hydrochloric acid in 25 ml of water, whereupon carbon dioxide evolution occurred. The strongly acidic solution was saturated with sodium chloride and extracted with ethyl acetate (4 x 50 mL). The organic phases were combined, dried over magnesium sulfate, filtered and evaporated to give 6.0 g (90%) of 1- (3-acetylthio-1-oxopropyl) -trans-4-methoxy-L-proline as a colorless syrup. This acid was dissolved in ethyl acetate (25 mL); 4.7 g of dicyclohexylamine were added and the solution solidified rapidly. An additional 15 mL of ethyl acetate was added and the solution was triturated in a water bath and then cooled and filtered to give 8.7 g of dicyclohexylamine salt. 170-172 °. Recrystallized from 60 ml of acetonitrile,

8.3 g (75%) of a colorless solid are precipitated. 171-173 °. [α] D = -35 ° (c = 1% in ethanol),

The dicyclohexylamine salt was converted to 1- (3-acetylthio-1-oxopropyl) -trans-4-methoxy-L-proline by suspending 8.0 g of the product obtained in 60 ml of ethyl acetate cooled in an ice-water bath. % potassium hydrogen sulfate solution. The clear layers were separated, the aqueous layer was extracted twice with 60 mL each of ethyl acetate, the combined organic layers dried over magnesium sulfate, filtered and the filtrate evaporated to give 4.6 g (80%) of a colorless syrup.

Example 2 1- (3-Mercapto-1-oxopropyl) -trans-4-methoxy-L-proline

To a solution of 1- (3-acetylthio-1-oxopropyl) -trans-4-methoxy-L-proline (4.6 g, 0.017 mol) prepared in Example 1 was added a cold solution of 9 ml of concentrated ammonia in 22 ml of water. The base dissolves in about 30 minutes and the resulting solution is allowed to stand under argon at room temperature for 2 hours. The solution was cooled, extracted with ethyl acetate (2 x 25 mL) and the ethyl acetate extract discarded. Ethyl acetate (25 mL) was added to the aqueous layer, acidified with aqueous hydrochloric acid (1: 1, 17 mL), shaken, separated and the aqueous layer was extracted with ethyl acetate (3 x 25 mL). The organic extracts were combined, dried over magnesium sulfate, filtered and the filtrate evaporated in a rotary distillate to give 1- (3-mercapto-1-oxopropyl) -trans-4-methoxy-L-proline (2.3 g, 59%) as a colorless syrup. we get. [α] D = -60 ° (c = 1% in ethanol). Rf = 0.49 (eluted in methanol on silica gel with nitroprusside reagent).

An additional 1.1 g of product was obtained by saturating the aqueous phase with sodium chloride and extracting with ethyl acetate (2 x 25 mL).

The sodium salt is prepared by reacting the syrup-like product with aqueous sodium bicarbonate solution and freeze-drying.

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Example 3 Trans-1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -4-methoxy-L-proline

A solution of 4.3 g (0.029 mol) of trans-4-methoxy-L-proline in 50 ml of water was cooled at 5 ° C and 3 g of sodium carbonate was added with stirring. A solution of 5.2 g (0.029 mol) of D-3- (acetylthio) -2-methylpropionyl chloride in 5 ml of diethyl ether is added over 10 minutes, while 3 g of sodium carbonate is added in portions to maintain a pH of 8.0. . The reaction mixture was stirred in an ice-water bath for 1.5 hours, water (25 ml) was added and then a solution of concentrated hydrochloric acid (6 ml) in water (25 ml) was added while developing carbon dioxide. The resulting strongly acidic solution was extracted four times with 50 mL of ethyl acetate. The organic layers were combined, dried over magnesium sulfate, filtered, and the filtrate evaporated to give 6.1 g (73%) of trans-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] as a pale yellow syrup. ] -4-methoxy-L-proline is obtained. This acid is dissolved in 50 ml of ethyl acetate and a solution of 4.0 g of dicyclohexylamine in 20 ml of ethyl acetate is added. After about one minute the product begins to crystallize out. After standing overnight, the almost colorless solid was collected by filtration and dried to give 6.7 g of product. 175-177 °. [α] ²⁵ = -55 ° (c = 1% in ethanol).

The product was recrystallized from 60 ml of acetonitrile to give an almost colorless dicyclohexylamine salt weighing 5.6 g (41%). 179-181 ° C. [<χ] ^> ⁵ = -62 ° (c = l%, ethanol).

The dicyclohexylamine salt was acidified by dissolving 5.5 g of the salt in 50 ml of ethyl acetate, cooling in an ice-water bath and adding 50 ml of 10% potassium hydrogen sulfate solution. The layers were separated and the aqueous phase was extracted twice with 50 mL of ethyl acetate. The organic extracts were combined, dried over magnesium sulfate, filtered and evaporated to give the filtrate as an almost colorless syrup (3.4 g, 41%) of trans-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl]. -4-methoxy-L-proline is obtained.

Example 4 Trans-4-Methoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline

To a solution of 3.4 g of trans-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-methoxy-L-proline is added a cold solution of 8 ml of concentrated ammonia in 20 ml of water. The base was dissolved in about 10 minutes, and the resulting solution was allowed to stand under argon at room temperature for 2 hours, cooled and extracted with ethyl acetate (2 x 20 mL). Ethyl acetate (20 mL) was added to the aqueous layer and acidified with aqueous hydrochloric acid (1: 1, 15 mL). The reaction mixture was saturated with sodium chloride, the layers were separated and the aqueous layer was extracted with ethyl acetate (3 x 20 mL). The organic extracts were combined, dried over magnesium sulfate, filtered, and the filtrate evaporated to give 2.9 g (100%) of trans-4-methoxy-1- (D-3-mercapto-2-methyl-oxopropyl) as an almost colorless product. L-proline is obtained. [α] D = -80 ° (c = 1% in ethanol). Rf = 0.53 (eluted with methanol on silica gel with nitroprusside reagent).

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Example 5 Trans- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -4-ethoxy-L-proline

In the same manner as in Example 3, but trans-4-methoxy-L-proline is equivalent to trans-4-ethoxy-L-proline [J. Med. Chem. 10, 1161 (1967)] to give trans-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-ethoxy-L-proline. The product is purified by conversion to the dicyclohexylamine salt. Recrystallized from isopropyl alcohol, m.p. 170-172 ° [α] D = -64 ° (c = 1%, in ethanol).

The resulting salt (7.75 g) was converted to the free acid by reaction with potassium hydrogen sulfate solution as in Example 4. 4.85 g of trans-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-ethoxy-L-proline are obtained as an almost colorless syrupy liquid.

EXAMPLE 6 Trans-4-Ethoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline

To 4.85 g of the product obtained in Example 5 is added a solution of 9 ml of concentrated ammonia in 22 ml of water under argon. The reaction mixture was reacted as in Example 4 to give 4.2 g (100%) of the title compound as an almost colorless syrup. [afe ⁵ = -80 ° (c = l%, ethanol). Rf value = 0.64 (eluted with methanol, silica gel, nitroprusside reagent).

Example 7 Cis-1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -4-methoxy-L-proline

a) N-Benzyloxycarbonyl-cis-4-hydroxy-L-proline g (0.038 mol) of N-benzyloxycarbonyl-4-oxo-L-proline was dissolved in 300 ml of methanol and 5.8 g (0.15 mol) of sodium borohydride were added. Reduced with a solution of 20 ml of water according to the method described in J. Am. Chem. Soc. 79, 189 (1957). The foam product (8.7 g) was dissolved in ethanol (30 ml), reacted with 3.5 g of cyclohexylamine in a small amount of ethanol and diluted with 500 ml of diethyl ether. After inoculation and rubbing, the cyclohexylamine salt crystallizes rapidly from the reaction mixture. This cyclohexylamine salt (10.8 g, m.p. 163-165 ° C) was treated with 30 ml of 2N hydrochloric acid and extracted with ethyl acetate (4 x 50 ml) to give 8 g of N-benzyloxycarbonylcis-4-hydroxy-L-proline as a glass product.

b) N-Benzyloxycarbonyl-cis-4-methoxy-L-proline methyl ester

In the same manner as in Example 1 (b), a solution of 13.9 g (0.052 mol) of N-benzyloxycarbonylcis-4-hydroxy-L-proline in 40 g of silver oxide and 40 ml of acetone was added, followed by a solution of the same reagents in 120 ml of acetone. of ethyl acetate to give 17.5 g (100%) of N-benzyloxycarbonylcis-4-methoxy-L-proline methyl ester as a yellow oil.

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c) N-Benzyloxycarbonyl-cis-4-methoxy-L-proline

To a solution of 17.5 g (about 0.052 mol) of N-benzyloxycarbonyl cis-4-methoxy-L-proline methyl ester in 135 ml of methanol is added dropwise 32 ml (0.064 mol) of 2N sodium hydroxide solution at -1 ° to + 4 °. and the reaction mixture was allowed to stand at 0 ° C for one hour and then at room temperature overnight. About half of the solvent was removed by rotary distillation, the remaining solution was diluted with water (300 mL), washed with diethyl ether (the diethyl ether washes were discarded), acidified to pH 2 with 12.5 mL of 1: 1 hydrochloric acid and 150-150 mL of ethyl acetate. extracted. The organic extracts were combined, dried over magnesium sulfate, filtered and the filtrate evaporated to give 15 g of product as an orange syrup. This was dissolved in ethanol (60 mL), a solution of cyclohexylamine (6 g) in ethanol (10 mL) was added and diluted with diethyl ether (900 mL). Crystalline N-benzyloxycarbonylcis-4-methoxy-L-proline-cyclohexylamine salt precipitates from the solution after inoculation and rubbing; weight of product precipitated after cooling overnight

10.2 g. Mp 148-150 ° (shrinks at 144 °); [α] D = -35 ° (c = 1% in ethanol). Recrystallization from 40 ml of acetonitrile gave 8.8 g of an almost colorless crystal. Mp 150-152 ° (shrinks at 145 °); = - 34 ° (c = 1% in ethanol).

Reaction of the cyclohexylamine salt with hydrochloric acid afforded 6.9 g (48%) of N-benzyloxycarbonyl-cis-4-methoxy-L-proline as a pale yellow, dense syrup. -32 ° (c = 1% in ethanol).

Recrystallization of 6.5 g of this product from 35 ml of acetonitrile gives 6 g of the dicyclohexylamine salt as a colorless solid. Mp 173-175 ° (shrinks at 170 °); [α] D = -60 ° (c = 1% in ethanol).

In the same manner as in Example 3, the dicyclohexylamine salt was acidified by dissolving 5.9 g of the salt in 60 ml of ethyl acetate, cooling in an ice-water bath and adding 60 ml of a 10% potassium hydrogen sulfate solution. The layers were separated and the aqueous layer was extracted with ethyl acetate (4 x 50 mL). The combined organic extracts were dried over magnesium sulfate, filtered and the filtrate was evaporated to give colorless cis-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-methoxy (3.5 g, 60%). -L-proline is obtained. M.p. 90-92 ° with trituration with diethyl ether; [.alpha.] D @ 20 = -139 DEG (c = 1% in ethanol). Rf = 0.63 (on methanol, silica gel).

Example 8 Cis-4-Methoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline

Following the procedure of Example 4, 2.9 g (0.01 mol) of cis-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-methoxy-L-proline

Hydrolyzed in 6.5 ml of concentrated ammonia in 6.5 ml of water to give 2.3 g (93%) of the title compound as an extremely viscous but waxy product, [α] D 20 = -88 ° (c = 1% in ethanol). .

d) cis -4-Methoxy-L-proline

6.8 g of N-benzyloxycarbonyl-cis-4-methoxy-L-proline 210 ml 2; A mixture of 1% methanol / water and 2.3 g of 5% palladium on carbon was hydrogenated in an autoclave at 3 atmospheric pressure for 4 hours. The catalyst was removed by filtration, and the filtrate was evaporated to give 3.15 g of a gray solid. 218-220 ° (dec.). A small sample was recrystallized from a mixture of methanol and diethyl ether to give colorless cis-4-methoxy-L-proline. 224-226 ° (dec.); [.alpha.] D @ 20 = - 42 DEG (c = 1% in methanol).

e) cis-1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -4-methoxy-L-proline (0.021 mol) cis-4-methoxy-L-proline and 5 ml D-3-acetylthio-2-methylpropionyl chloride (4.2 g, 0.023 mol) in diethyl ether was reacted in 60 ml of water in the presence of sodium bicarbonate as described in Example 3. Approximately 20 ml of 25% w / v sodium carbonate solution is required to initially adjust the pH to 8.5 and maintain the acylation at 7.5-8.4. The resulting thick flow 6.4 g of crude product was dissolved in 50 ml of ethyl acetate and dissolved in 20 ml of ethyl acetate.

Reaction with 3.9 g of dicyclohexylamine. The product crystallized from the solution was filtered off and dried, yielding 6.6 g of dicyclohexylamine salt. Melting point 172-174 ° (shrinks at 170 °). [α] D = -60 ° (c = 1% in ethanol).

Example 8a Cis-4-Methoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline-1-adamantanamine salt

To a solution of 0.55 g (0.0022 mole) of cis-4-methoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline in 15 ml of ethyl acetate was added 0.34 g of argon. A solution of 1-adamantanamine (g, 0.0022 mol) in ethyl acetate (10 mL) was used to separate the salt. The reaction mixture was allowed to stand for 3 hours in the cold, then the colorless crystals precipitated were collected by filtration (difficult to remove solvent), washed with a little cold ethyl acetate and dried in vacuo for 20 hours to give 0.7 g (79%) of the title compound. Mp 215-217 ° (shrinks at 210 °), decomposes at 220 °; [.alpha.] D @ 20 = -60 DEG (c = 1% in methanol).

Example 9 Cis-4-Methoxy-1- (3-mercapto-2-methyl-1-oxopropyl) -L-proline

a) Cis-4-Methoxy-1- [3- (benzoylthio) -2-methyl-1-oxopropyl] -L-proline

Following the procedure of Example 3, 3-benzoylthio-2-methylpropionic acid chloride prepared by reaction of 3-benzoylthio-2-methylpropionic acid with cis-4-methoxy-L-proline was reacted with cis-4-methoxy-1- [3- (benzoylthio) -2-methyl-1-oxopropyl] -L-proline is obtained.

-6179782 bJ cis-4-Methoxy-1- (3-mercapto-2-methyl-1-oxopropyl) -L-proline

Following the procedure of Example 4, cis-4-methoxy-1- [3- (benzoylthio) -2-methyl-1-oxopropyl] -L-proline was hydrolyzed with aqueous ammonia to give cis-4-methoxy-1-. (3-Mercapto-2-methyl-1-oxopropyl) -L-proline is obtained.

Example 10 Trans-1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -4-propoxy-L-proline

a) N-Acetyl-trans-4-propoxy-L-proline-propyl ester

30 g of N-acetyl-trans-4-hydroxy-L-proline prepared according to Example 1 (a) were treated with 110 g of silver oxide and 10 ml of propyl iodide in 300 ml of acetone according to Example 1 (b). % pale yellow N-acetyl-trans-4-propoxy-L-pro-propyl ester. Boiling point 155-165 ° at 0.2 Torr.

bj To a solution of N-Acetyl-trans-4-propoxy-L-proline in g (0.15 mol) in 150 ml of water was 19.4 g (0.075 mol) of N-acetyl-trans-4-propoxy-L-proline-propyl ester. giving a pale orange solution. The solution was allowed to stand overnight at room temperature, then extracted with ethyl acetate (60 mL) (poured wash) and acidified with 1: 1 hydrochloric acid / water, saturated with sodium chloride and extracted with chloroform (3 x 3 mL). The organic extracts were combined, dried over magnesium sulfate, filtered and the filtrate evaporated to give 12.6 g of a brown oil. This oil was dissolved in ethyl acetate (80 mL) and a solution of dicyclohexylamine (10.7 g) in ethyl acetate (20 mL) was added. The salt crystallizes at room temperature. After cooling overnight, the dicyclohexylamine salt was separated by filtration and washed with cold ethyl acetate to give 17.3 g of an almost colorless crystalline dicyclohexylamine salt. 148-153 °. Recrystallization from 125 ml of ethyl acetate gives 14.5 g of the colorless dicyclohexylamine salt. 157-159 °. [.alpha.] D @ 20 = -30 DEG (c = 1% in ethanol).

14.4 g of dicyclohexylamine salt were converted to the free acid by powdering, slurried in 100 ml of ethyl acetate, and 100 ml of 10% potassium hydrogen sulfate solution added. Separate the organic layer, extract the aqueous layer with ethyl acetate (2 x 100 mL), combine the organic extracts, dry over magnesium sulfate, filter, and evaporate the filtrate to give 6.7 g (41%) of N-acetyl-trans-4-propoxy-L as a pale brown liquid. -proline.

c) Trans-1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -4-propoxy-L-proline

To a solution of 6.4 g (0.03 mol) of N-acetyl trans-4-propoxy-L-pro-1 is added a solution of 10 g of concentrated sulfuric acid in 100 ml of water and the resulting solution is refluxed for 3 hours. The solution was then cooled to 15 °, 12 g of sodium carbonate was added in portions to adjust the pH to 8.0, and 5.4 g (0.03 mol) of D-3-acetylthio- was added over 10 minutes. 214

methylpropionyl chloride in diethyl ether (5 mL) while adding 7 g of sodium carbonate to maintain a pH of 8.0. The reaction mixture was then stirred in an ice water bath for 30 minutes and then at room temperature for one hour. The product obtained is then purified as the dicyclohexylamine salt according to Example 3 and isolated to give 6.3 g of the dicyclohexylamine salt. M.p. 165-167 ° C, recrystallized from acetonitrile. [α] D = -56 ° (c = 1% in ethanol).

The dicyclohexylamine salt (6.1 g) was converted to the free acid by slurrying in ethyl acetate (60 ml), cooling in an ice-water bath and reacting with 60 ml of 10% potassium hydrogen sulfate solution. Separate the layers, extract the aqueous layer twice with ethyl acetate (60 mL), combine the organic layers, dry over magnesium sulfate, filter, and evaporate the filtrate to give 4.0 g (42%) of trans-1- [D-3- (acetylthio) as an almost colorless syrup. ) -2-methyl-1-oxopropyl] -4-propoxy-L-prolm is obtained.

Example 11 1- (D-3-Mercapto-2-methyl-1-oxo-propyl) -trans-4-propoxy-L-proline

In the same manner as in Example 4, 4.0 g of trans-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-propoxy-L-proline were dissolved in 8 ml of concentrated ammonia in 20 ml of water. hydrolysis under argon to give 3.42 g (97%) of the title compound as an almost colorless syrup. [.alpha.] D @ 20 = -72 DEG (c = 1% in ethanol).

Example 12 1- (3-Mercapto-1-oxo-propyl) -cis-4-methoxy-L-proline and 1- (3-Acetylthio-1-oxo-propyl) -cis-4-methoxy. L-proline

In the same manner as in Example 1 (d), cis-4-methoxy-L-proline was reacted with 3-acetylthiopropyl chloride in the presence of sodium carbonate to give 1- (3-acetylthio-1-oxopropyl) cis-4-methoxy. L-proline is obtained.

b) 1- (3-Mercapto-1-oxopropyl) -cis-4-methoxy-L-proline

In the same manner as in Example 2, hydrolyzed with 1- (3-acetylthio-1-oxopropyl) -cis-4-methoxy-L-proline in an aqueous solution of ammonia, 1- (3-mercapto-1-oxopropyl) cis-4- methoxy-L-proline is obtained.

Example 13 Cis-4-Ethoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline

a) cis-4-Ethoxy-L-proline

Example 7 a) -d) but using bis ethyl iodide in step b) gives cis-4-ethoxy-L-proline.

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b) cis-1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -4-ethoxy-L-proline

The cis-4-ethoxy-L-proline was reacted with a solution of D-3-acetylthio-2-methylpropionyl chloride in the presence of sodium carbonate according to Example 7 (e) in the presence of cis-1- [D-3- (acetylthio) -2-methyl -1-oxopropyl] -4-ethoxy-L-proline is obtained.

c) cis-4-Ethoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline

The cis-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-ethoxy-L-proline was hydrolyzed with an aqueous solution of ammonia as in Example 8 to give cis-4-ethoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline is obtained.

Example 14 1- (D-3-Mercapto-2-methyl-1-oxopropyl) cis-3-methoxy-L-proline

a) 1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] cis-3-methoxy-L-proline

Proceeding as in Example 7, but replacing cis-4-methoxy-L-proline with an equivalent amount of cis-3-methoxy-L-proline [J. 85, 3863 (1963)], 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] cis-3-methoxy-L-proline.

b) 1- (D-3-Mercapto-2-methyl-1-oxopropyl) cis-3-methoxy-L-proline

1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] cis-3-methoxy-L-proline was hydrolyzed with aqueous ammonia according to Example 4 to give 1- (D-3-mercapto) -2-methyl-1-oxopropyl) -cis-3-methoxy-L-proline is obtained.

Example 15 1- (D, L-3-Mercapto-2-methyl-1-oxopropyl) -trans-3-methoxy-L-proline

a) 1- [D, L-3- (Acetylthio) -2-methyl-1-oxopropyl] -trans-3-methoxy-L-proline

Following the procedure of Example 3, an equivalent amount of trans-3-methoxy-L-proline [J. Amer. Chem. Soc., 85, 3863 (1963)] with D, L-3- (acetylthio) -2-methylpropionyl chloride to give 1- [D, L-3- (acetylthio) -2-methyl-1]. -oxopropyl] -trans-3-methoxy-L-proline is obtained.

b) 1- (D, L-3-Mercapto-2-methyl-1-oxopropyl) -trans-3-methoxy-L-proline

1- [D, L-3- (acetylthio) -2-methyl-1-oxopropyl] -trans-3-methoxy-L-proline was hydrolyzed with aqueous ammonia according to Example 4 to give 1- (D, L -3-mercapto-2-methyl-1-oxopropyl) -trans-3-methoxy-L-proline is obtained.

Example 16 1- [D-3-Mercapto-2-methyl-1-oxopropyl] cis-4-methylthio-L-proline

a) 1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -cis-4-methylthio-L-proline

In the same manner as in Example 3, an equivalent amount of cis-4-methylthio-L-proline [J. Amer. Chem. Soc. 79, 185 (1957)] with D-3- (acetylthio) -2-methylpropionyl chloride to give 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] cis -4-methylthio-L-proline is obtained.

b) 1- (D-3-Mercapto-2-methyl-1-oxopropyl) -cis-4-methylthio-L-proline

1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -cis-4-methylthio-L-proline was hydrolyzed with aqueous ammonia according to Example 4 to give 1- (D-3-mercapto) -2-methyl-1-oxopropyl) -cis-4-methylthio-L-proline is obtained.

Example 17 1- (D-3-Mercapto-2-methyl-1-oxopropyl) -trans-4-methylthio-L-proline

a) 1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -trans-4-methylthio-L-proline trans-4-Methylthio-L-proline [J. Amer. Chem. Soc., 79, 185 (1957)] and D-3- (acetylthio) -2-methylpropionyl chloride were reacted as in Example 3 to give 1- [D-3- (acetylthio) -2-methyl- 1-oxopropyl] -trans-4-methylthio-L-proline is obtained.

bj 1- (D-3-Mercapto-2-methyl-1-oxopropyl) -tra-4-methylthio-L-proline

Following the procedure of Example 4, hydrolyzing 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -trans-4-methylthio-L-proline with aqueous ammonia, 1- (D-3-mercapto) -2-methyl-1-oxopropyl) -trans-4-methylthio-L-proline is obtained.

Example 18 Trans-1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -4-methoxy-L-proline methyl ester

A solution of the product prepared in Example 3 in diethyl ether was reacted with a slight excess of diazomethane. After standing at room temperature, the solvent was distilled off to give trans-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-methoxy-L-proline methyl ester.

Similarly, when the cis compound prepared in Example 7 is used in this procedure, cis-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-methoxy-L-proline methyl ester is obtained. .

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Example 19 Trans-4-Methoxy-1- (D-3-mercapto-2-diethyl-1-oxopropyl) -L-proline sodium salt

The product (2.5 g) obtained in Example 4 was dissolved in water (25 ml) and treated with sodium hydrogencarbonate (0.84 g). The solution was freeze-dried to give the sodium salt of trans-4-methoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline.

Similarly, using the cis compound prepared in Example 8 in this procedure gives the cis -4-methoxy-1- (D-3-mercapto-2-methyl-oxopropyl) -L-proline sodium salt.

Example 20 1- (L-3-Mercapto-2-ethyl-1-oxo-propyl) -trans-4-methoxy-D-proline

a) Trans-1- [L- (3-Acetylthio) -2-ethyl-1-oxopropyl] -4-methoxy-D-proline

Following the procedure of Example 1, but using trans-4-hydroxy-D-proline instead of trans-4-hydroxy-L-proline used in step a), trans-4-methoxy-D-proline is obtained. The compound thus obtained was reacted with L- (3-acetylthio) -2-ethylpropionyl chloride as in Example 3 to give trans-1- [L- (3-acetylthio) -2-ethyl-1-oxopropyl] -4-. methoxy-D-proline is obtained.

b) 1- (L-3-Mercapto-2-yl-1-oxopropyl) -trans-4-methoxy-D-proline

The trans-1- [L- (3-acetylthio) -2-ethyl-1-oxopropyl] -4-methoxy-D-proline was hydrolyzed with aqueous ammonia according to Example 4 to give 1- (L-3-mercapto) -2-ethyl-1-oxopropyl) -trans-4-methoxy-D-proline is obtained.

Example 21. i _{c c} .4- (4-Fluoro-phenoxy) -1 - (D-3-mercapto-2-methyl -1-oxopropyl) -L-proline

a) cis-4- (4-Fluorophenoxy) -L-proline

8.4 g (0.024 mol) of N-benzyloxycarbonyl trans-4-hydroxy-L-proline benzyl ester (Baer et al., Can. J. Biochem. and Phys. 37, 583 (1959)] A solution of 4.0 g (0.036 mol) of 4-fluorophenol and 9.27 g (0.036 mol) of triphenylphosphine in 75 ml of anhydrous tetrahydrofuran is added dropwise over one hour to 6.2 g (0.036 mol) of diethylazo- dicarboxylate in 25 ml of tetrahydrofuran. After stirring overnight at room temperature, the reaction mixture was evaporated to dryness and diethyl ether (100 mL) was added to the residue. The precipitate of triphenylphosphine and diethyl azodicarboxylate was removed by filtration. Chromatography on a silica gel column yielded 8.1 g of a mixture containing 70% of N-benzyloxycarbonylcis-4- (4-fluorophenoxy) -L-proline benzyl ester.

A solution of the mixture containing 7.5 g of benzyl ester was hydrogenated at atmospheric pressure, at room temperature, in the presence of 0.8 g of 10% palladium on carbon. A white precipitate formed during the reaction.

After uptake of hydrogen, the reaction mixture was separated by filtration and the cake was washed three times with 125 mL each of 125 mL of hot methanol. The methanolic filtrate was evaporated to dryness to give 3.2 g of cis-4- (4-fluorophenoxy) -L-proline. 235-236 °.

b) 1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -cis-4- (4-fluorophenoxy) -L-proline

To a suspension of cis-4- (4-fluorophenoxy) -L-proline (2.25 g, 0.01 mol) in anhydrous pyridine (125 ml) was added triethylamine (1.0 g, 0.01 mol) and 2 g (0.011 mol) at room temperature. ) D-3- (acetylthio) -2-methylpropionyl chloride. The reaction mixture was stirred at room temperature overnight and then concentrated. The resulting residue was suspended in water, diethyl ether layered and acidified with 10% hydrochloric acid. The aqueous layer was repeatedly extracted with diethyl ether, the diethyl ether extracts were combined, washed with water, dried over anhydrous sodium sulfate and evaporated to give 3.9 g of a residue. This product was chromatographed on 250 ml of silica gel with diethyl ether to give a fraction containing the desired product. The column was washed with methanol and the methanolic wash was rechromatographed on a short silica gel column to yield additional product. Repeat this procedure to obtain a total of 1.2 g of pure 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -cis-4- (4-fluorophenoxy) -L-proline. .

c) cis-4- (4-Fluorophenoxy) -1-D-3-mercapto-2-methyl-1-oxopropyl) -L-proline

1.2 g of 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] cis-4- (4-fluorophenoxy) -L-proline are dissolved in 25 ml of methanol and under argon Reaction with 5 ml of concentrated ammonia for 40 minutes. The volatiles were distilled off and ethyl acetate was added to the residue. The aqueous layer was acidified with 10% hydrochloric acid and the layers were separated and the acidic layer was washed with ethyl acetate. The combined organic extracts were evaporated twice with water, saturated twice with sodium chloride and dried over sodium sulfate. Evaporation of the solvent gave 1.1 g of cis-4- (4-fluorophenoxy) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline as a solid foam. TLC Rf = 0.30 for ultraviolet light [SH (yellow spot) and vanillin (yellow spot)] [α] = -80 ° (c = 1%, in chloroform).

Example 22 1- (3-Mercapto-1-oxo-propyl) -cis-4-phenoxy-L-proline a) cis-4-Phenoxy-L-proline

Following the procedure of Example 21, section a, but using an equivalent amount of phenol instead of 4-fluorophenol, cis-4-phenoxy-L-prooline is obtained.

b) 1- [3- (Acetylthio) -1-oxopropyl] -cis-4-phenoxy-L-proline

The cis-4-phenoxy-L-proline was reacted with a solution of 3-acetylthiopropionyl chloride in the presence of sodium carbonate as in Example 1 to give 1- [3- (acetylthio) -1-oxopropyl] cis-4-phenoxy-L-proline. we get.

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c.) 1- (3-Mercapto-1-oxopropyl) -cis-4-phenoxy-L-proline

1- [3- (Acetylthio) -1-oxopropyl] cis-4-phenoxy-L-proline is hydrolyzed with aqueous solution of ammonia as in Example 2 to give 1- (3-mercapto-1-oxopropyl). ) -cis-4-phenoxy-L-proline is obtained.

Example 23 Cis-4- (4-Chlorophenoxy) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline

Following the procedure of Example 21, but employing an equivalent amount of 4-chlorophenol in step a) instead of 4-fluorophenol, the title compound is obtained.

Example 24 Cis-4- (4-Fluorophenylthio) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline

Following the procedure of Example 21 but substituting an equivalent amount of 4-fluorophenyl mercaptan in step a) for the title compound, the title compound is obtained.

let stand. Then half of the solvent was removed on a rotary distillation, the cooled solution was diluted with 100 mL of water, washed with 60 mL of diethyl ether (the wash was discarded), layered with 70 mL of ethyl acetate, stirred, cooled and acidified with 4.8 mL of 1: 1 dilute hydrochloric acid. After separating the layers, the aqueous phase was extracted with three additional portions of ethyl acetate (40 mL) and the combined organic extracts were dried (MgSO4) and evaporated to give 5.9 g of a light yellow oil. This oil was dissolved in ethanol (30 mL) and added to the solution

A solution of 1.9 g of cyclohexylamine in 3 ml of ethanol was diluted with diethyl ether to 330 ml. Crystalline cyclohexylamine salt is precipitated upon inoculation. After cooling for 16 hours, the product weighed 5.3 g; mp 148-151 ° (shrinks at 135 °). This product was combined with 1.5 g of the same product obtained in the previous step, stirred in 200 ml of hot acetonitrile and cooled to give 6.3 g of the colorless cyclohexylamine salt. 152-155 ° (shrinks at 137 °). [α] D = -24 ° (c = 1% in ethanol).

This cyclohexylamine salt is suspended in 25 ml of ethyl acetate, stirred and reacted with 25 ml of n hydrochloric acid. When the reaction mixture separates into two clear layers, the layers are separated and the aqueous phase is extracted three times with additional 25-25 mL of ethyl acetate. The combined organic extracts were dried over magnesium sulfate and evaporated to give 5.0 g (65%) of N-benzyloxycarbonyl-cis-4-phenylthio-L-proline as an almost colorless, very viscous syrup.

Example 25 1- (D-3-Mercapto-2-methyl-1-oxo-propyl) -cis-4-phenylthio-L-proline and N-Benzyloxycarbonyl-cis-4-phenylthio-L-propoline methyl ester

0.85 g (0.037 mol) of sodium metal are dissolved in 40 ml of anhydrous ethanol and 3.7 ml (0.036 mol) of thiophenol are added, followed by 7.5 g (0.017 mol) of N-benzyloxycarbonyl-trans-4-tosyloxy- L-proline methyl ester [J. Chem. Soc., 79, 191 (1957)]. This latter compound gradually dissolves but then rapidly solidifies. The reaction mixture was stirred for 4 hours and then allowed to stand at room temperature overnight. Subsequently, most of the ethanol was removed on a rotary evaporator and most of the solid residue was mixed with 120 mL of dichloromethane and 60 mL of water. The layers were separated (little methanol was added to facilitate separation of the emulsion) and the aqueous layer was extracted twice with additional 60-60 mL dichloromethane. The combined organic extracts were washed with 100 mL of saturated sodium chloride solution, dried over magnesium sulfate and evaporated to give 6.5 g (100%) of N-benzyloxycarbonylcis-4-phenylthio-L-proline methyl ester as a pale yellow viscous oil.

bJ N-Benzyloxycarbonyl-cis-4-phenylthio-L-proline

6.5 g (0.017 mol) of the methyl ester obtained in step a) are dissolved in 55 ml of methanol and 13 ml (0.026 mol) of 2N sodium hydroxide solution are added portionwise at -0 ° C and stirred at 0 ° for one hour. then cis-4-phenylthio-L-proline hydrobromide at room temperature for 16 hours

N-Benzyloxycarbonyl-cis-4-phenylthio-L-proline (4.9 g, 0.014 mol) was reacted in a loosely-flask-flask equipped with a magnetic stirrer with 25 ml of hydrogen bromide in 30-32% acetic acid. The orange solution was diluted with 250 mL of diethyl ether and, after inoculation, rubbing and cooling, the product as a thick oil slowly became crystalline. After stirring the reaction mixture for one hour in an ice-water bath, the product was filtered off under nitrogen, washed with diethyl ether and suspended in fresh diethyl ether. The suspension was cooled for about 16 hours and re-separated by filtration to give 3.2 g (77%) of cis-4-phenylthio-L-proline hydrobromide as a colorless solid. Melting point 106-109 ° (99 °). [.Alpha.] D @ 20 = -3 DEG (c = 1% in methanol).

d) 1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -cis-4-phenylthio-L-proline

In the same manner as in Example 1 (d), 3.0 g (0.0094 mol) of cis-4-phenylthio-L-proline hydrobromide were treated with 2.0 g (0.011 mol) of D-3-acetylthio-2-methylpropionyl chloride. Reaction is carried out in 25 ml of water (pH 8.0 and

15 ml of 20% sodium carbonate solution). The product (3.8 g) was obtained as a pale yellow dense oil by reaction with 1.8 g of dicyclohexylamine in 30 ml of ethyl acetate to give 2.9 g of dicyclohexylamine salt. Mp 184-188 ° (shrinks at 180 °). Trituration with 15 ml of acetonitrile gives 2.4 g of a colorless clear product. 184-186 ° (shrinks at 180 °). [α] D = -75 ° (c = 1% in ethanol).

-1017978:

To the dicyclohexylamine salt was added 30 ml of a 10% potassium bisulfate solution and extracted with ethyl acetate as in Example 1, 2.0 g (59%) of 1- (D-3- (acetylthio) -2-methyl-1-oxo-propyl) powder. Cis-4-phenylthio-L-proline is obtained.

e) 1- (D-3-Mercapto-2-methyl-1-oxopropyl) cis-4-phenylthio-L-proline

1- (D-3- (acetylthio) -2-methyl-1-oxo-propyl) -cis-4-phenylthio-L-proline (2.0 g, 0.0042 mol) obtained in the previous step was prepared as described in Example 2. By reaction with a solution of 3.5 ml of concentrated ammonia in 8.5 ml of water (the solid ammonium salt of the product is precipitated), 1.35 g (100%) of 1- (D-mercapto-2-methyl-1-oxor) -propyl) -cis-4-phenylthio-L-proline is obtained. [Α] D = -43 ° (c = 1% in ethanol).

Example 26 1- (D-3-Mercapto-2-methyl-1-oxopropyl) -cis-4- (4-chlorophenylthio) -L-proline

Following the procedure of Example 25, but using an equivalent amount of 4-chlorophenylmercaptan in step a) instead of thiophenol, the title compound is obtained.

Example 27 Trans-1- (3-Mercapto-1-oxopropyl) -3-methylthio-D, L-proine

a) 1,2-Dehydroproline tert-butyl ester

To a solution of proline tert-butyl ester (34.2 g, 0.20 mol) in diethyl ether (600 ml) was added dropwise a solution of 21.7 g (23.9 ml, 0.20 mol) freshly with stirring at 5 ° to 0 ° for 10 minutes. prepared tert-butyl hypochlorite [Org. Syn. Coll., Vol. V, 184 (1973)]. The temperature is maintained between -5 ° and 0 ° during the addition. After the addition was complete, the solution was stirred at this temperature for an additional 5 minutes.

To the vigorously stirred solution is added rapidly (3-5 minutes) a solution of potassium hydride (7.8 g, 0.20 mol) in freshly distilled anhydrous t-butanol. Upon completion of the addition, the temperature of the reaction mixture is about 18 °. At this time, the reaction vessel was removed from the cooling bath and stirring continued for 30 minutes. The reaction mixture was filtered over diatomaceous earth (Celite) and the filtrate was concentrated in vacuo. The residue was taken up in diethyl ether and washed several times with water. The diethyl ether solution was dried and concentrated in vacuo to give 31.6 g of a yellow liquid. By adding traces of hydroquinone to the crude product and distilling,

22.4 g (66%) of 1,2-dehydroproline tert-butyl ester are obtained. It boils at 60-62 ° at 0.1 Torr.

b) 1-Benzyloxycarbonyl-4,5-dihydro-1H-pyrrole-2-carboxylic acid tert-butyl ester

A solution of 16.9 g (0.1 mol) of 1,2-dehydroproline tert-butyl ester in 70 ml of dichloromethane was cooled to -10 ° under argon and added dropwise over 30 minutes.

14.2 ml (0.1 mol) of freshly distilled benzyl ester of chloroformate (boiling point 62-64 ° C at 0.4 Torr) in dichloromethane (ml). After stirring for a further 30 minutes under cooling, a solution of 15.22 g (0.1 mol) of 1,5-diazabicyclo [5.4.0] undec-5-ene in 70 ml of dichloromethane is added dropwise over 20 minutes. The cooling bath was then removed and the reaction mixture was stirred at room temperature for 1 hour. The solution was washed twice with cold dilute hydrochloric acid and once with saturated sodium carbonate solution and dried in vacuo to give 1-benzyloxycarbonyl-4,5-dihydro-1H-pyrrole-2-carboxylic acid tert-butyl ester (18.2 g, 60%).

c) Trans-1-Benzyloxycarbonyl-3-methylthio-D, L-proline tert-butyl ester

To a solution of 18.2 g (0.06 mol) of 1-benzyloxycarbonyl-4,5-dihydro-1H-pyrrole-2-carboxylic acid tert-butyl ester in 180 ml of anhydrous methanol is added 3.24 g (0.06 mol) of sodium methoxide, and cooling the reaction mixture in an ice-water bath. Methanethiol is bubbled through the solution slowly for 30 minutes and then stirred at room temperature overnight under argon. Subsequently, dilute acetic acid was added until the solution became acidic, and argon gas was bubbled through it for one hour and then concentrated to near dryness in vacuo. Ethyl acetate was added to the residue, washed twice with saturated sodium carbonate solution, dried and the solvent was evaporated in vacuo to give 17 g of a yellow oil. This oil was chromatographed on 300 g of silica gel with 4: 1 petroleum ether / diethyl ether to give 11.1 g of trans-1-benzyloxycarbonyl-3-methylthio-D, L-proline as a colorless oil.

dj trans-3-Methylthio-D, L-pioline

Trans-1-benzyloxycarbonyl-3-methylthio-D, L-proline (8.4 g, 0.024 mol) was treated with a solution of 4N hydrobromic acid in acetic acid (45 ml), stirred at room temperature for one hour, dried in vacuo and a little water was added. washed twice with diethyl ether. The aqueous solution is applied to a column containing 300 ml of ion exchange resin and passed through water until the eluate is no longer strongly acidic. Then the product

Elute with pH 6.5 buffer (aqueous pyridine acetate). Fractions giving a positive reaction with ninhydrin were combined and lyophilized to give 3.4 g (88%) of a white fluffy product. Recrystallization of a small sample from methanol gave the resulting trans-3-methylthio-D, L-proline having a melting point of 196-200 [deg.] (Dec., 192 [deg.]).

e) Trans-1- [3- (Acetylthio) -1-oxopropyl] -3-methylthio-D, L-proline

Trans-3-methylthio-D, L-proline (3.05 g, 0.019 mol) was dissolved in n-carbonate solution (19 ml) and diluted with water (10 ml), and 3-acetylthio-propionyl chloride was added under cooling with ice-water. ml of diethyl ether while maintaining the pH at 8 by addition of n sodium carbonate solution. After 30 minutes, the pH remains constant and 45 ml of sodium carbonate solution are added. The layers were separated and the aqueous layer was washed once with diethyl ether. The aqueous layer was acidified with 10% potassium hydrogen sulfate solution, the product was extracted with ethyl acetate, the organic extract dried and the solvent was removed by filtration.

Evaporation ⁷ -11179 kuum 82, 5.2 g of an oil. The product was chromatographed on 150 g of silica gel using ethyl acetate as eluent. 3.85 g of slightly crude trans-1- [3- (acetylthio) -1-oxopropyl] -3-methylthio-D, L-proline are obtained.

A small sample was dissolved in diethyl ether, converted to the dicyclohexylamine salt and then recrystallized from ethyl acetate to give the trans-1- [3- (acetylthio) -1-oxopropyl] -3-methylthio-D, L-proline-dicyclohexylamine salt. 153-157 °.

f) trans-1- (3-Mercapto-1-oxopropyl) -3-methylthio-D, L-proline

Trans-1- [3- (acetylthio) -1-oxopropyl] -3-methylthio-D, L-proline (2.05 g, 0.007 mol) was cooled in an ice bath under argon, 7 mL of water and 7 mL of concentrated ammonia saturated with argon reaction mixture. After stirring for 30 minutes at 0 °, the solution is acidified with hydrochloric acid. The product was extracted with ethyl acetate, dried and the solvent was evaporated in vacuo to give 1.85 g of product which partially crystallized on standing. Trituration with diethyl ether gave 1.0 g (57%) of a white crystalline product. Recrystallization from 5 ml of ethyl acetate gave 0.85 g of trans-1- (3-mercapto-1-oxopropyl) -3-methylthio-D, L-proline. 89-93 °.

Example 28 Trans-1- (D-3-Mercapto-2-methyl-1-oxopropyl) -3-ethylthio-D, L-proline

a) Trans-3-Ethylthio-D, L-proline

Following the general procedure of Example 27 (a) to (d), but using an equivalent amount of ethyl mercaptan instead of methanethiol, trans-3-methyl-D, L-proline is obtained.

b) Trans-1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -3-ethylthio-D, L-proline

Trans-2-ethylthio-D, L-proline was reacted with D-3-acetylthio-2-methylpropionyl chloride according to Example 3 to give trans-1- [D-3- (acetylthio) -2-methyl-1-oxo]. -propyl] -3-ethylthio-D, L-proline is obtained.

c) Trans-1- (D-3-Mercapto-2-methyl-1-oxopropyl) -3-ethylthio-D, L-proline

Trans-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -3-ethylthio-D, L-proline was hydrolyzed with an aqueous solution of ammonia according to Example 4 to give trans-1- (D- 3-mercapto-2-methyl-1-oxopropyl) -3-ethylthio-D, L-proline is obtained.

Example 29 Trans-1- (3-Mercapto-1-oxopropyl) -3-phenylthio-D, L-proline

Following the general procedure of Example 27, but using an equivalent amount of thiophenol instead of methanethiol, the title compound was obtained.

Example 30 Cis-4- (1,1-Dimethylethoxy) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline

a) N-Benzyloxycarbonylcis-4- (1,1-dimethylethoxy) -L-proline methyl ester

A solution of 6.0 g (0.021 mol) of N-benzyloxycarbonyl-cis-4-hydroxy-L-proline methyl ester in 60 ml of methylene chloride was placed in a Parr apparatus, stirred with a magnet, cooled in anhydrous ice and isopropanol bath, Concentrated sulfuric acid (0.75 mL) was added. The apparatus was then sealed and the reaction mixture allowed to warm to room temperature with stirring. There is no significant increase in pressure. After stirring for 4 days at room temperature, the apparatus was opened and the 80 ml solution was diluted with 120 ml of methylene chloride and washed with a solution of 5 g of sodium bicarbonate in 100 ml of water. The aqueous phase was re-extracted with methylene chloride (50 mL), the organic layers were combined and dried over magnesium sulfate, and the solvent was evaporated to give 7.5 g of the title compound as a pale yellow oil. [.alpha.] D @ 20 = - 46 DEG (c = 1, in chloroform). Silica gel TLC: _Rf = 0.62 (ethyl acetate) _Rf = 0.43 (7: 1 mixture of benzene and acetic acid gel); called by ultraviolet light in iodine vapor.

b) N-Benzyloxycarbonylcis-4- (1,1-dimethylethoxy) -L-proline

A solution of 7.2 g (0.02 mol) of the methyl ester obtained in the preceding point in 15 ml of ether is cooled in ice-water with stirring, and 42 ml (0.042 mol) of ice-cold sodium hydroxide solution are added. After stirring for 6 hours and cooling, the cooling bath was removed and stirred overnight at room temperature. The clear solution was washed with 40 mL of ether, 40 mL of ethyl acetate was layered, stirred, cooled and acidified with 8 mL of 6N hydrochloric acid. After separation, the aqueous phase was extracted with ethyl acetate (40 mL x 3), the organic layers were combined and dried over magnesium sulfate, and the solvent was evaporated to give 6.8 g of a pale yellow viscous oil. This oil was dissolved in 50 mL of acetonitrile and a warm solution of 3.2 g of 1-adamantanamine in 20 mL of acetonitrile was added. The solid adamantanamine salt precipitates rapidly. After cooling overnight, the colorless salt was filtered under nitrogen, washed with cold acetonitrile and ether and dried in vacuo to give 8.8 g of N-benzyloxycarbonylcis-4- (1,1-dimethylethoxy) -L-proline adamantanamine salt; melting point 228-230 ° C dec., 215 ° C; M ² D ⁵ = -28 ° (c = 1 in methanol).

Treatment of the above salt with 8.5 g of the acid gave 5.5 g of the title compound as an almost colorless, dense syrup. _Rf 0.25 (85: 15 toluene: acetic acid on silica gel, visualized with iodine vapor or with PMA and heating).

c) cis-4- (1,1-Dimethoxyethoxy) -L-proline

The product (5.5 g, 0.017 mol) obtained in the previous point was treated with hydrogen (3.2 g) in dichloromethane (3.2 g) in 165 ml of 2: 1 methanol / water (hydrogen) in the presence of 1.7 g of 5% palladium on carbon.

-1 225

17S782. This product was suspended in 30 ml of acetonitrile, triturated and cooled overnight to give 1.35 g of the title compound as a colorless solid. Melting point 240-242 ° C with decomposition, slowly darkens and shrinks; [Α] D = -36 ° (c = 0.5 in methanol).

d) 1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -cis-4- (1,1-dimethylethoxy) -L-proline

The product (1.3 g, 0.0069 mol) obtained in the previous point is treated with D-3-acetylthio-2-methylpropionyl chloride (1.4 g, 0.0078 mol) in water (20 ml) in the presence of sodium bicarbonate. according to example; 2.2 g of an almost colorless, thick oil are obtained. This crude product was dissolved in ethyl acetate (50 mL) and reacted with a solution of dicyclohexylamine (1.3 g) in ethyl acetate (20 mL). The product crystallized from the solution, filtered and dried. 2.65 g of dicyclohexylamine salt are obtained; mp 181-183 ° C, shrinks from 170 ° C; trituration with hot acetonitrile (15 mL) and cooling gave 2.4 g of a colorless solid dicyclohexylamine salt, m.p. 183-185 ° C, mp 175 ° C; = -65 ° (c = 1, in ethanol).

In the same manner as in Example 3, 2.4 g of dicyclohexylamine salt were acidified by slurrying in ethyl acetate, cooling in an ice bath and adding 30 ml of 10% potassium hydrogen sulfate solution. The layers were separated and the aqueous layer was extracted with ethyl acetate (25 mL x 4). After removal of the solvent, the semi-crystalline solid, which was standing, was triturated with ether (10 mL), diluted with hexane (20 mL), triturated again and cooled to give 1.3 g of the title compound as a colorless product; 96-98 ° C, shrinks from 93 ° C; [α] D = -109 ° (c = 1, in ethanol).

e) cis-4- (1,1-Dimethyl-ethoxy) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline

The product (1.3 g, 0.0039 mol) obtained in the previous point was hydrolyzed in 6 ml of water with 2.6 ml of concentrated ammonium hydroxide to give 1.1 g of a glassy residue. While standing, crystal germs appear on the product. 8 ml of ether were layered, inoculated and triturated. As the glassy material dissolves, a crystalline solid precipitates. After standing for 2 hours at room temperature, hexane (20 mL) was added and the mixture was cooled overnight under argon. Removal of the solvent afforded 1.0 g of the title compound as a colorless solid. 106-108 ° C, shrinks from 103 ° C; [α] D = -78 ° (c = 1, in ethanol).

Example 31 Cis-4 - [(4-Fluorophenyl) thio] -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline-L-arginine salt

As described in the preceding examples, from the appropriate starting compounds, cis-1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(- 4-fluorophenyl) thio] - L-proline methyl ester is prepared; oily product [g -80.2 (c = 1, in chloroform).

A solution of methyl ester (15.7 g, 34.0 mmol) in methanol (50 mL) and tetrahydrofuran (150 mL) was cooled in an ice bath under nitrogen. To the cold solution was added 71.4 ml of aqueous sodium hydroxide solution over 10 minutes. The reflux bath was removed and the mixture was stirred at room temperature for 5.5 hours, water (300 ml) was added and the mixture was washed with ether (200-200 ml). The aqueous layer was cooled in an ice bath under nitrogen, acidified to pH 1-2 with concentrated aqueous hydrochloric acid, and extracted with 3 * 200 ml of ether. The combined organic extracts were washed with water (200 mL), brine and dried over magnesium sulfate. Removal of the solvent in vacuo gave 11.7 g of crude product. This material was dissolved in ether and reacted with a solution of 1-adamantanamine in methanol (5.66 g, 37.4 mmol). Dilution with ether gives 15.2 g of the adamantanamine salt, which is dissolved in 1: 1 chloroform-methanol and diluted with ether. 13.3 g of salt are obtained, m.p. 238-240 ° C with decomposition. Recrystallization twice from chloroform / methanol / ether gives 10.6 g of the adamantanamine salt; mp 242-243 ° C with decomposition; [AF ^s _D = -51.8 ° (c = 0.5, methanol).

The salt gives aqueous cis 4 - [(4-fluorophenyl) thio] -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline in aqueous acetate with n-hydrochloric acid; [α] D = -42.5 ° (c = 1, in anhydrous ethanol).

To a vigorously stirred mixture of 1 ml of n hydrochloric acid, 40 ml of water and 60 ml of ethyl acetate under ice-cooling under ice-cooling was added 8.0 g (16.2 mmol) of cis -4 - [(4-fluorophenyl) thio] -1 - (D). -3-mercapto-2-methyl-1-oxopropyl) -L-proline adamantanamine salt is added. The aqueous layer was extracted twice with ethyl acetate (60 mL), and the combined organic extracts were washed with dilute hydrochloric acid, water, and brine. After drying over magnesium sulfate, removing the solvent in vacuo, 5.78 g of the free acid is obtained as a crude oil. The oil was dissolved in a mixture of ethyl acetate (40 mL) and ether (10 mL). This solution was shaken in a separatory funnel with a solution of 2.68 g (15.4 mmol) of L-arginine in 50 mL of water. The aqueous layer was again washed with ether, dried under mild vacuum for 15 minutes, and lyophilized overnight to give the title L-arginine salt (7.97 g). [Α] D = - 42.7 ° (c = 1, in water).

Example 32 Cis -4 - [(4-Chlorophenyl) thio] -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline-L-arginine salt

From the appropriate starting materials, cis-1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(4-chlorophenyl) thio] -L, as described in the previous examples. preparing a proline methyl ester; [α] D = -86.6 ° (c = 1, from chloroform).

A solution of the above methyl ester (24.3 g, 50.8 mmol) in methanol (80 ml) and tetrahydrofuran (220 ml) was cooled in an ice bath under nitrogen and 106 ml of aqueous sodium hydroxide solution were added over 10 minutes. The cooling bath was removed and the reaction mixture was stirred at room temperature for 5.5 hours, then diluted with 500 mL of water and extracted three times with 300-300 mL of ether. The aqueous solution was cooled in an ice bath under nitrogen, acidified to pH 1-2 with concentrated hydrochloric acid and extracted three times with 500 ml of ether. The combined ether extracts were washed with water (400 mL) and brine, dried over magnesium sulfate and evaporated in vacuo.

18.2 g of crude product are obtained. This material was dissolved in ether and reacted with a solution of 8.5 g (55.9 mmol) of 1-adamantanamine in methanol. The mixture was about 1 L13

The mixture was diluted with -13179782 square ether, cooled for 1.5 hours, and then filtered

20.1 years of ananthanamine salt are obtained; m.p. 239-242 ° C. The product was dissolved in a 1: 1 mixture of chloroform and methanol and diluted with ether 15.3 g of cis-4 - [(4-chlorophenyl) thio] -1- (D-3-mercapto-2-methyl-1 oxopropyl) -L-proline-1-adamantanamine salt is obtained; mp 240-241 ° with decomposition; [Α] D = -55.4 ° (c = 0.5 in methanol).

0.5 g (0.98 mmol) of the above salt is treated with aqueous hydrochloric acid and ethyl acetate to give the corresponding free acid; [α] D = -38.1 ° (c = 1, in anhydrous ethanol).

The adamantane amine salt was reacted with L-arginine as in Example 31 to give 8.0 g of the title compound; [.alpha.] D @ 20 = 44.3 DEG (c = 1 in water).

Example 33 Cis-1- (D-Mercapto-2-methyl-1-oxopropyl) -4 - [(4-methylphenyl) thio] -L-proline-L-arginine salt

From the appropriate starting materials, as described in the previous examples, cis-1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(4-methylphenyl) thio] - L-proline methyl ester is prepared. A sample of silica gel purified with a mixture of methylene chloride and ethyl acetate had a [α] θ value of -70.8 ° (c = 1, in chloroform).

The ice-cold solution of methyl ester (13.0 g, 28.4 mmol) in methanol (40 mL) and tetrahydrofuran (130 mL) was continuously purged with nitrogen while adding 59.6 mL of aqueous sodium hydroxide solution over 10 minutes. The cooling bath was then removed and the reaction mixture was stirred under nitrogen at room temperature for 5.5 hours. It is then diluted with 250 ml of water and extracted twice with 200-200 ml of ether. The aqueous layer was cooled in an ice bath under nitrogen, acidified to pH 1-2 with concentrated hydrochloric acid and extracted with ether (200-200 ml). The combined organic extracts were washed with water (200 mL) and brine, dried over magnesium sulfate and evaporated in vacuo to give 10.6 g of a colorless oil which was essentially homogeneous by TLC. The product was dissolved in ether and reacted with a solution of 4.72 g (31.2 mmol) of 1-adamantanamine in 200 mL of methanol. Precipitation was rapid, the solution was diluted to about 700 mL with ether and the salt was separated. Trituration with hot methanol / ether gave 12.4 g of the adamantanamine salt; mp 237-240 ° C with decomposition. This salt was recrystallized from chloroform: methanol (1: 1) and diluted with ether. After 10 minutes at room temperature, the solid was collected and dried to give 8.2 g of adamantanamine salt; 240-241 ° C (dec.); [α] D = -58.0 ° (c = 0.5 in methanol).

A smaller sample of the salt was treated with aqueous hydrochloric acid and ethyl acetate to give cis-1- (D-3-mercapto-2-methyl-1-oxopropyl) -4 - [(4-methylphenyl) thio] -L-proline. in the form of an oil; [?] D = -45.1 ° (c = 1, in anhydrous ethanol).

To a mixture of aqueous hydrochloric acid (17.1 mL), water (30 mL) and ethyl acetate (50 mL) was added 7.0 g (14.3 mmol) of the above adamantanamine salt. During the addition, the solution was cooled in an ice bath and kept under nitrogen. After the salt has dissolved, the layers are separated and the ethyl acetate layer is combined with two extracts of 50 ml each obtained by extraction of the aqueous layer. The combined ethyl acetate extracts were washed with dilute hydrochloric acid, water and brine, dried over magnesium sulfate and evaporated in vacuo to give the free acid. The acid was dissolved in a mixture of ethyl acetate (40 mL) and ether (10 mL) and shaken with a solution of L-arginine (2.37 g, 13.6 mmol) in water (50 mL). The aqueous layer was washed with ether (50 mL) and lyophilized to give the title L-arginine salt: [.alpha.] D @ 20 = -45.2 DEG (c = 1 in water).

Example 34 Cis-1- (D-3-Mercapto-2-methyl-1-oxopropyl) -4 - [(methoxyphenyl) thio] -L-proline-L-arginine salt

From the appropriate starting materials, cis-1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(4-methoxyphenyl) thio] -L-, as described in the previous examples. preparing a proline methyl ester; [α] D = -66.9 ° (c = 1, in chloroform).

A solution of methyl ester (20.1 g, 42.4 mmol) in methanol (70 ml) and tetrahydrofuran (200 ml) was cooled in an ice bath under nitrogen and 89 ml of aqueous sodium hydroxide solution were added over 10 minutes. The cooling bath was removed and the reaction mixture was stirred at room temperature

After stirring for 5.5 hours, 500 ml of water are added and the mixture is extracted three times with 300 to 300 ml of ether. The aqueous solution was cooled in an ice bath under nitrogen and acidified to pH 1 with concentrated hydrochloric acid and extracted three times with 500 ml of ether. The combined ethereal extracts were washed with water (400 mL) and brine, dried over magnesium sulfate and concentrated in vacuo to give 14.8 g of crude product. This material was dissolved in ether and reacted with a solution of 6.34 g (42 mmol) of 1-adamantanamine in methanol. The mixture was diluted with about 1 liter of ether, kept at room temperature for 10 minutes, and then filtered to give 17.8 g of the adamantanamine salt; mp 235-236 ° C with decomposition. This salt was dissolved in chloroform / methanol (1: 1) with gentle heating and diluted with ether. The recrystallization step was repeated 2 times with 12.2 g of cis-1- (D-3-mercapto-2-methyl-1-oxopropyl) -4 - [(4-methoxyphenyl) thio] -L-proline. l-adamantane amine salt is obtained; mp 237-239 ° C with decomposition; [α] D = -52.8 ° (c = 0.5 in methanol).

From this salt, the corresponding free acid is treated with aqueous hydrochloric acid and ethyl acetate; [α] D = -36.8 ° (c = 1, in anhydrous ethanol).

To a vigorously stirred mixture of 27.2 ml of n aqueous hydrochloric acid, 45 ml of water and 75 ml of ethyl acetate are added

11.5 g (22.7 mmol) of 1-adamanthanamine salt. The solution was kept under nitrogen while cooling with ice. After the solid has dissolved, the aqueous layer is extracted twice with 75 ml of ethyl acetate. The organic extracts were combined and washed with aqueous 0.5N hydrochloric acid (50 mL), water (50 mL), and finally brine. The solution was dried over magnesium sulfate and evaporated in vacuo to give 8.2 g of the free acid. The acid was dissolved in a mixture of ethyl acetate (75 mL) and ether (20 mL) and shaken with a solution of L-arginine (3.76 g, 21.6 mmol) in water (10 mL). The aqueous layer was partitioned between ether (75 mL) and lyophilized overnight

11.2 g of the title L-arginine salt are obtained; [α] D = -46.0 ° (c = 1 in water).

-14179782

Example 35 Cis-1- (D-3-Mercapto-2-methyl-1-oxopropyl) -4- (phenylthio) -L-proline ethyl ester

Of a solution of 3.9 g (0.012 mol) of 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4-phenylthio-L-proline in 40 ml of ethanol with stirring under nitrogen, Concentrated sulfuric acid (3 mL) was added and allowed to warm to room temperature. After 24 hours, an additional 0.3 mL of concentrated sulfuric acid was added and after 3 days, the reaction was confirmed to be complete by TLC. Most of the ethanol was removed on a rotary evaporator and ethyl acetate (100 mL) was added to the oily residue, stirred, cooled and treated with 25 mL of 5% sodium bicarbonate solution under argon. The layers were separated, and the organic layer was washed with 5% sodium bicarbonate solution (15 mL), water (5 x 5 mL), dried over magnesium sulfate and the solvent was evaporated. The oily residue was taken up in ether and re-evaporated, partially at 0.2 mmHg, in vacuo to give 3.8 g of the title ethyl ester as a nearly colorless viscous oil; [Α] D = -49 ° (c = 1, in ethanol).

Example 36 Cis-1- (D-3-Mercapto-2-methyl-1-oxopropyl) -3-phenoxy-D, L-proline

a) 3-Phenoxy-1,2-dehydroproline tert-butyl ester

9.25 g (50 mmol) of 1,2-dehydroproline tert-butyl ester in 70 mL of toluene was heated under reflux with 8.9 g (50 mmol) of N-bromosuccinimide while illuminated for 6 hours under sunlight. The reaction mixture was cooled to room temperature and the succinimide was filtered off and the filtrate was evaporated to dryness. The residue was distilled at 80 ° C

3.5 g of crude 3-bromo-1,2-dehydroproline tert-butyl ester are obtained.

A mixture of the crude 3-bromo-1,2-dehydroproline tert-butyl ester obtained and 3.9 g (13 mmol) of thallium phenoxide in 30 ml of anhydrous dimethylformamide was stirred at room temperature for 24 hours under argon. The solvent was removed in vacuo and the residue diluted with ether to remove the thallium bromide and filter. The filtrate is evaporated to give an oil which is purified by distillation. After 2 hours at 0.005 Torr and 80 DEG C., 1.48 g of 3-phenoxy-1,2-dehydroproline tert-butyl ester are obtained and stored in a vessel.

b) cis-3-Phenoxy-D, L-proline

A mixture of 1.48 g of 3-phenoxy-1,2-dehydroproline tert-butyl ester, 5 ml of n-hydroxide and 20 ml of 80% aqueous dioxane is stirred for 4 hours at room temperature. The solvent was removed in vacuo and the residue was dissolved in water (25 mL) and treated with sodium borohydride (168 mg) at room temperature for 1 hour. The mixture was acidified to pH 6 with 2N hydrochloric acid and after 16 hours at 0 ° C, a crystalline precipitate containing about 25 mg of trans-3-phenoxy-D, L-proline was obtained.

The precipitate was filtered off and the filtrate was passed through a column packed with Dowex 50W x 8 resin and eluted with a solution of nammonium hydroxide. The UV-active fractions were combined and evaporated to give cis-3-phenoxy-D, L-proline (616 mg).

c) cis-1- [D-3- (Acetylthio) -2-methyl-1-oxopropyl] -3-phenoxy-D, L-proline

Cis-3-phenoxy-D, L-proline (616 mg) was suspended in water (20 ml) and adjusted to pH 8.0 with solid sodium carbonate at 5 ° C. A solution of 550 mg (2.5 mmol) of D-3-acetylthio-2-methylpropanoyl chloride in 1 ml of ether was added and the pH of the reaction mixture was maintained between 7.3 and 8.2 by addition of sodium carbonate, 5 hours. The mixture was washed with ethyl acetate (20 x 20 mL), acidified to pH 2 with 10% hydrochloric acid and extracted with ethyl acetate (50 x 50 mL). The extracts were combined, dried over magnesium sulfate and evaporated to give 810 mg of an oil. The oil was chromatographed on 300 ml of silica gel with toluene containing 10-20% acetic acid to give 530 mg of the title compound.

d) cis-1- (D-3-Mercapto-2-methyl-1-oxopropyl) -3-phenoxy-D, L-proline

530 mg of cis-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -3-phenoxy-D, L-proline are dissolved in a 50:50 mixture of concentrated ammonium hydroxide and water ( degassed by passing argon for 15 minutes) under argon and at room temperature for 1.5 hours. The slightly cloudy solution is acidified to pH 6.5 with concentrated hydrochloric acid, slightly warmed, then extracted twice with 25 ml of methylene chloride. The pH is then adjusted to 1 and the solution is extracted again with 50 ml of methylene chloride 3 times. The extracts were combined, dried over magnesium sulfate and evaporated to give 410 mg of a glass. Trituration with chloroform crystallizes. Recrystallization from ethyl acetate-hexane gave 261 mg of the title compound; 134-155 °.

Example 37

1000 tablets each containing 100 mg of the sodium salt of 1- (D-3-mercapto-1-oxopropyl) -trans-4-methoxy-L-proline are prepared from the following ingredients;

- (3-mercapto-1-oxo-propyl) -trans-4-methoxy-L-

proline, sodium salt 100 g kukorccakeményítő 50g gelatine 7.5 g Avicel (microcrystalline cellulose) 25g magnesium stearate 2.5 g

The 1- (D-3-mercapto-1-oxopropyl) -trans-4-methoxy-L-proline salt and the corn starch are mixed with an aqueous solution of gelatin, dried and ground to a fine powder. Avicel is added to the granulate followed by magnesium stearate. The mass is compressed into tablets to give 1000 tablets of 100 mg of active ingredient each.

-15179782

Example 38

Each tablet containing 200 mg of 1- (D-3-mercapto-2-methyl-1-oxo-propyl) -trans-4-methoxy-L-proline was prepared as described in Example 37.

Example 39

Each 1000 tablet containing 200 mg of sodium salt of 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4-methoxy-L-proline is prepared from the following ingredients: 1- (D-3- mercapto-2-methyl-1-oxopropyl) -cis-4-methoxy-L-proline sodium salt 50 g lactose 25 g

Avicel (microcrystalline cellulose) 38 g corn starch 15 g magnesium stearate 2 g

The sodium salt of 1- (D-3-mercapto-2-methyl-1-oxo-propyl) -cis-4-methoxy-L-proline is mixed with milk sugar and Avicel, then corn starch and finally magnesium stearate are added. The dry mixture was compressed on a tabletting machine to give 1000 tablets weighing 130 mg and containing 50 mg of active ingredient. The tablets are coated with Methocel E 15 (methylcellulose) solution containing a yellow lacquer 6.

Example 40

100 mg of sodium salt of 1- (D-3-mercapto-2-methyl-1-oxopropyl) cis-4-methoxy-L-proline each,

No. 1 two-part gelatin capsules are filled with a mixture of the following ingredients: 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4-methoxy-L-proline sodium salt 100 mg magnesium stearate 7 mg lactose 193 mg

Example 41

An injection solution was prepared as follows: trans-4-methoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline 500 g methylparaben 5 g propylparaben 1 g sodium chloride in water for injection 25 g supplemented with 5 liters.

The active ingredient, preservatives and sodium chloride are dissolved in 3 liters of water for injections and made up to 5 liters. The solution was filtered through a sterile filter and aseptically filled into pre-sterilized vials and pre-sterilized with a rubber seal. Each vial of solution for injection contains 5 ml of solution containing 100 mg of active substance per ml.

In each example, the product obtained is shown in Figures 35-41. Examples may be formulated into a pharmaceutical composition.

Claims (13)

Patent claims A process for preparing the ether or thioether derivatives of mercaptoacyl-proline of formula I and their base salts and stereoisomers thereof, wherein the group -X-R in formula I is in the 3- or 4-position of the proline ring, X is oxygen or sulfur; R is hydrogen or lower alkyl; R j is lower alkyl or phenyl optionally substituted with halo, lower alkyl or lower alkoxy; R _{2 is} hydrogen or lower alkyl and R _{3 is a} hydrogen atom, a lower alkanoyl or benzoyl group containing a proline or thioether or an acid addition salt thereof with a proline of formula II, optionally in the form of one of its stereoisomers, wherein X, R and R are as defined above; with an acid of the formula wherein R _{2 is} as defined above and R _{3 is} lower alkanoyl or benzo 20 benzoyl, in the presence or in the presence of a reactive derivative, preferably an acid halide thereof, optionally in the form of one of its stereoisomers; optionally hydrolyzing the resulting compound of formula I wherein R _{3 is} lower C 2 alkanoyl or benzoyl to a compound of formula I wherein R _{3 is} hydrogen; optionally, a lower acid alkyl ester or a base thereof, a free lower alkyl ester or a salt thereof 30 to the acid or its other salt. (Priority: August 10, 1979) 2. A process for preparing the ether or thioether derivatives of mercaptoacyl-proline of formula I and their base salts, as well as their stereoisomers, wherein -X-R in the formula I is in the 3- or 4-position of the proline ring, X is oxygen or sulfur, R is hydrogen or lower alkyl; Rj is a lower alkyl group, R _{2 is} hydrogen or lower alkyl; and R _{3 is} hydrogen, lower alkanoyl or C ₃ -C 4 alkanoyl 4f represents a benzoyl group, wherein a proline ether or thioether of formula II or an acid addition salt thereof is optionally in the form of one of its stereoisomers, wherein X, R and Rj have the meanings given above 5C acid formula: - wherein R ₂ is as defined above, and R is a lower alkanoyl or benzoyl group - a condensing agent or a reactive derivative thereof, preferably an acid halide optionally in the form of a stereoisomer 55; optionally hydrolyzing the resulting compound of formula I wherein R _{3 is} lower alkanoyl or benzoyl to a compound of formula I wherein R _{3 is} hydrogen; optionally converting a resulting sa6C watt into its lower alkyl ester or its base with a base, a resulting lower carbon alkyl ester or salt into its free acid, or another salt. (Priority: August 11, 1978) 3. The process of claim 1 wherein the acid is of formula III -16179782 in the form of its chloride. (Priority: August 10, 1979) The process of claim 2 for the preparation of 1- (3-mercapto-1-oxopropyl) -trans-4-methoxy-L-proline, characterized in that trans-4-methoxy-L-proline and 3- 1- (3-acetylthio-1-oxo-propyl) -trans-4-methoxy-L-proline obtained by reaction of acetylthiopropionyl chloride. (Priority: August 11, 1978) 5. A process for the preparation of trans-4-methoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline according to claim 2, characterized in that trans-4-methoxy-1- Trans-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-methoxy-L-proline obtained by reaction of L-proline with D-3- (acetylthio) -2-methylpropionyl chloride hydrolyzing. (Priority: August 11, 1978) 6. A process according to claim 2 for the preparation of trans-4-ethoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline, characterized in that trans-4-ethoxy- Trans-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-ethoxy-L-proline obtained by reaction of L-proline with D-3- (acetylthio) -2-methylpropionyl chloride hydrolyzing. (Priority: August 11, 1978) 7. A process according to claim 2 for the preparation of cis-4-methoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline, characterized in that cis-4-methoxy- Cis-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-methoxy-L-proline obtained by reaction of L-proline with D-3- (acetylthio) -2-methylpropionyl chloride hydrolyzing. (Priority: August 11, 1978) 8. The process of claim 1 for the preparation of cis-4- (4-fluorophenoxy) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline, characterized in that: 1- [D-3- (acetylthio) -2-methyl-1-oxo] obtained by reaction of cis-4- (4-fluorophenoxy) -L-proline with D-3- (acetylthio) -2-methylpropionyl chloride. propyl] -cis-4- (4-fluorophenoxy) -L-proline is hydrolyzed. (Priority: August 1979 10.) The process of claim 1 for the preparation of 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4-phenyl35-thio-L-proline, characterized in that cis-4-phenylthio 1- (D-3-mercapto-2-methyl-1-oxopropyl) cis-4-phenylthio-L- obtained by reaction of -L-proline hydrobromide with D-3-acetylthio-2-methylpropionyl chloride. proline is hydrolyzed. (Priority: August 10, 1979) 10. A process for the preparation of trans-1- (3-mercapto-1-oxopropyl) -3-methylthio-D, L-proline according to claim 2, characterized in that trans-3-methylthio-D, L- trans-1- [3- (acetylthio) -1-oxopropyl] -3-methylthio-D, L-proline obtained by reaction of proline with 3-acetylthiopropionyl chloride is hydrolyzed. (Priority: August 11, 1978) 11. A process according to claim 2 for the preparation of cis-4- (1,1-dimethylethoxy) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline. characterized in that cis-1- [D-3- (acetylthio) -2-methyl is obtained by reaction of cis-4- (1,1-dimethylethoxy) -L-proline with D-3-acetylthio-2-methylpropionyl chloride. - 1-oxopropyl] -4- (1,1-dimethylethoxy) -L-proline is hydrolyzed. (Priority: August 1978 11.) 12. The process of claim 1 for the preparation of cis-1- (D-3-mercapto-2-methyl-1-oxopropyl) -3-phenoxy-D, L-proline, characterized in that cis-3- cis-1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -3-phenoxy obtained by reaction of phenoxy-D, L-proline and D-3-acetylthio-2-methylpropanoyl chloride. -D, L-proline is hydrolyzed. (Priority: August 10, 1979) 13. A process for the preparation of a pharmaceutical composition comprising an ether or thioether derivative of the formula I or a pharmacologically acceptable salt thereof as an active ingredient, as defined in claim 1, wherein X, R, R 1, R ₂ and R _{3 are} mercaptoacylproline. characterized in that the active ingredient produced by the process of claim 1 is formulated with a carrier, diluent, excipient, and / or other excipients customary in the pharmaceutical formulation. (Priority: August 10, 1979) 3 sheets with formulas Responsible for publishing: Director of Economic and Legal Publishing House 844.593.66-4 Alföldi Nyomda, Debrecen - Chief Executive Officer: István Benkő Director -17X —Rj R 1 -S-CH _a R ₂ CH-CO-N COOR International Classification; C 07 D 207/12 COOR II R. S— CH ^ —CH · -COOH xr ₄ R. h ₂ c CH _£ —CH — CO N C-COOR I * COOH International classification: