SE447477B - BRAND CAPACULTURE DERIVATIVES OF A SUBSTITUTED PROLINE, PROCEDURE FOR PREPARING THIS AND A PHARMACEUTICAL ACTIVE COMPOSITION CONTAINING THE ASSOCIATION - Google Patents

Description

447 477 R 5 represents Cl_ n represents 0, 1 or 2. 7-alkyl, phenyl or phenyl-C 1-4 alkyl and the invention comprises in its broadest aspect ether and thioether mercaptoacyl prolines of formula I above, compositions containing such compounds and methods of use such compounds as antihypertensive agents.

The term C 1-7 alkyl, which is used to define the symbols R1, R1, R2 and R3, is straight or branched chain hydrocarbon having up to 7 carbon atoms, for example methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, isopentyl, etc. The preferred alkyl groups have up to 4 carbon atoms and methyl and ethyl are most preferred.

The term C 2-7 alkenyl used to define the symbol R1 is a monounsaturated straight or branched chain hydrocarbon having 2 to 7 carbon atoms such as ethenyl, propenyl, isopropenyl, butenyl and the like. The C 2-7 alkynyl groups form straight or branched chain hydrocarbon having 2-7 carbon atoms with a triple bond, e.g. propargyl. The preferred alkenyl groups have 2-5 carbon atoms and the preferred alkynyl groups have 3-4 carbon atoms.

The substituted phenyl and phenyl lower alkylene groups used to define the symbol R 1 have one or two, preferably a substituent in the phenyl ring consisting of C 1-4 alkyl, especially methyl, C 1-4 alkoxy, especially methoxy, C 1-4 alkylthio, especially methylthio, halogens, especially chlorine or fluorine, trifluoromethyl, acetyloxy and hydroxy. The hydroxy-substituted phenyl and phenyl-C 1-4 alkyl groups are obtained by hydrolysis of the corresponding acetyloxy-substituted phenyl compound as the final step in the synthesis.

The term halogen includes the four common groups of chlorine, bromine, fluorine and iodine, with chlorine, bromine and fluorine being preferred.

The term phenyl-C 1-4 alkyl used to define the symbols R1 and R5 includes groups such as _ (CH2) fi <š§> 447 477 wherein m is an integer from 1-4. Preferred phenyl-C 1-4 alkyl groups are phenylmethyl and phenylethyl, especially phenylmethyl.

The lower alkanoyl groups illustrated by R5-CO- are those with acyl radicals of lower (C2-C7) fatty acids, for example acetyl, propionyl, butyryl, isobutyryl and the like. The lower alkanoyl groups having up to four carbon atoms are preferred and acetyl is especially preferred. When R 5 in the group R 5 -CO- is phenyl-lower alkyl, benzoyl is preferably correspondingly preferred.

The asterisk in formula I shows an asymmetric center, which is present in the proline ring. Of course, an additional T center of asymmetry may be present in the mercaptoside chain depending on the substituents R2 and R3. Accordingly, the products of formula I exist in stereoisomeric forms or as racemic mixtures thereof. All of these are included within the scope of the invention. The syntheses described below can use the racemate or one of the enantiomers as starting material. When the racemic starting material is used for the synthesis, the stereoisomers obtained in the final product can be separated by conventional chromatographic or fractional crystallization methods. The X-R1 group also gives rise to cis-transisomerism.

Preferably, the asymmetric center of the proline ring is in the L-configuration or if there is an asymmetric center in the mercaptoacyl side chain, this is in the D-configuration. Preferred compounds of formula I are those wherein R represents hydrogen, R 1 represents C 1-3 alkyl or 2 ra 2 represents R 6 wherein p represents 0, 1 or 2 and R 6 represents hydrogen, methyl, methoxy, methylthio, chlorine, fluorine, trifluoromethyl or hydroxy, R 2 represents hydrogen, methyl or trifluoromethyl, R 3 represents hydrogen, n represents 0 or 1 and R 4 represents hydrogen. Also preferred as intermediates are the above-mentioned compounds wherein R represents acetyl or benzoyl, preferably acetyl.

The most preferred of the above compounds are those wherein X represents oxygen, R 1 represents methyl or ethyl, especially methyl, n represents 1, R represents hydrogen or methyl, especially 2 methyl, R represents hydrogen, R 4 represents and -XR 1 - the group 3 is in the 4-position of the proline ring, especially those in which the -XR1- group is cis-configuration.

The ethers and thioethers of formula I are obtained by substituting the ether or thioether proline of formula XR H C 1 2 | II HN c * _- cooR I H is coupled with an acid or its chemical equivalent of the formula R Rs 2 | | III R'4 -S- (cmh- cH-coon wherein R'4 represents hydrogen or R5-CO-, to give a product of the formula 447 477 s / \ xnl. 1: 3 RZ H20 / í II l Iv R This reaction may be effected in the presence of a coupling agent such as dicyclohexylcarbodiimide or the like, or the acid may be activated by the formation of its mixed anhydride, symmetrical anhydride, acid halide , active esters or using Woodward reagent K, N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline or the like Regarding methods of acylation see Methods of Organic Chemistry (Houben-Weyl), Volume XV, Part II, p. Preferably, the acid halide, especially the acid chloride of formula III, is reacted with the acid of formula II.

The ester compounds of formula IV, i.e. R represents alkyl, can be converted to the free acid, i.e.- R represents hydrogen, in a conventional manner. For example, when R represents t-butyl, treatment with trifluoroacetic acid and anisole gives the free acid.

The product of formula IV is preferably isolated and purified by crystallization, e.g. by forming the dicyclohexylamine salt and subsequently transferring the salt to the free acid by treatment with an aqueous solution of an acid such as potassium hydrogen sulphate.

The product of formula IV, bearing the acyl group RS-CO-, can be converted to the products of formula I wherein R 4 represents hydrogen by conventional hydrolysis or by ammonolysis.

The products of formula I in which R4 represents XRI 1 »R3 R2 HZC 3 IIII -s- (cxnrr- cn- co__1q __... <| 2 ,, - COOH H 447 477 are obtained by direct oxidation with iodine of a product of formula I wherein R4 represents hydrogen.

The esters of formula I wherein R represents C 1-7 alkyl can be obtained from the carboxylic acid compounds, i.e. wherein R represents hydrogen, according to conventional esterification procedures, e.g. by esterification with a diazoalkane such as diazomethane, 1-alkyl-3-p-tolyltriazen such as 1-n-butyl-3-p-tolyltriazen or the like.

The proline reactants of formula II can be prepared in various ways. For example, a hydroxy or mercaptoproline of the formula XH HZC V HN --- C; COOH I H is acetylated with an acetylating agent such as acetic anhydride, acetyl chloride, propionic anhydride, butyric anhydride, benzyl chloroformate or the like to protect the nitrogen. The R1 group is then introduced by reacting the N-protected form of the compound of formula V with a halide, R1 hal, wherein hal represents a halogen, preferably iodine, in the presence of silver oxide, sodium hydride, sodium hydroxide or the like to prepare Alkaline hydrolysis of the intermediate of formula VI with a base such as barium hydroxide, sodium hydroxide, potassium hydroxide or the like first gives the free acid (COOH) and then gives hydrolysis with a mineral acid such as a compound of the formula XR1 H2C Protected-N - ~ c * - cooR1 VI 1H sulfuric acid the starting material of formula II.

Another way of preparing the proline reactants of formula II is by treating the N-protected tosyloxy-proline ester, preferably the methyl ester of the formula OTS Hzci: get C; COOa] cooler V1 in protected N with the sodium salt of the formula R -X-Na VIII l to the intermediate of the formula H20 / 7: m1 I in IX protected-N ïik * In formula VII the symbols denote the group ~ S0¿ {Éš> -CH3 and the N-protected group is benzyloxycarbonyl, which is preferred or others usually use acyl protecting groups.

If the tosylate group in this reaction is in the cis configuration, the XR1 group will be in the trans configuration and if the tosyloxy group is in the trans configuration, the XR1 group will be in the cis configuration.

The intermediate of formula IX is then treated to remove the alkyl ester group and then reacted with hydrogen bromide to the HBr salt of the proline reactant of formula II which can then be coupled with the acid, preferably the acid chloride of formula III.

The proline starting materials of formula II wherein X 1 represents sulfur and the XRI group is bonded in the 3-position of the proline can also be obtained by treating a 1,2-dehydroporlin ester, preferably the t-butyl ester of formula 447 477 ¿::;: 1 COCOalkyl X with an acylating agent such as benzyl chloroformate, acetyl chloride, etc., to the 4,5-dehydro compound.

Which is then reacted with the mercaptan R 1 -SH to F The N-protected and alkyl groups are then removed to give the desired starting material.

The proline starting materials of formula II wherein R 1 represents phenyl, substituted phenyl, phenyl-lower alkylene or substituted phenyl-lower alkylene can also be obtained by treating the benzyl ester of the N-protected proline of formula V with the alcohol R 1 carboxylate according to the method of Bittner et al. ., Chemistry and Industry, March 15, 1975, p. 281. The removal of the N-protecting group and the benzyl ester group gives the starting -OH in the presence of triphenylphosphine and the diethyl azodi of formula II.

Reference is also made to the following publications for further illustrative information regarding the preparation of starting materials and intermediates: Ondetti et al., U.S.P. 4,046,889, 4, 105,776 and 4,154,935, Neuberger, J. Chem.

Soc., 1945, p. 429-432, Patchett et al., J. Amer. Chem. Soc. 79, p. 185-192 (1957), Baer et al., Can. J. Biochem. and Phys., 37, p. 583-587 (1959) Sheehan et al., J. Amer. Chem.

Soc. 85, p. 3863-3865 (1963), Magerlein, J. Med, Chem. 10, p. 1161-1163 (1967). The methods illustrated therein can be used as general methods for the synthesis and stereo-transfer of compounds useful in the present invention. 447 477 Additional experimental details are found in the examples, which constitute preferred embodiments of the invention and also serve as a model for the production of other members of the group.

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 metal ions, e.g. aluminum, alkali metal ions such as sodium or potassium, alkaline earth metal ions such as calcium or magnesium or an amine salt ion of which a number are known for this purpose, for example aralkylamines such as dibenzylamine, N, N-dibenzylethylenediamine, lower alkylamines such as methylamine, t-butylamine, procaine , lower alkylpiperidines such as N-ethylpiperidine, cycloalkylamines such as cyclohexylamine or dicyclohexylamine, 1-adamantanamine, benzatin or salts derived from amino acids such as arginine, lycine or the like.

The physiologically acceptable salts such as the sodium or potassium salts may be used medically in the manner set forth below and constitute preferred embodiments of the invention. These and other salts which may not necessarily be physiologically acceptable may be used to isolate or purify a product acceptable for the purposes set forth below which is illustrated by the dicyclohexylamine salt and the cyclohexylamine salt in the examples.

The salts are prepared by reacting the acid form of the compound with one equivalent of the base to give the desired base ion in a medium in which the salt precipitates or in aqueous medium and subsequent lyophilization. The free acid form can be obtained from the salt by conventional neutralization techniques, e.g. with potassium bisulfate, hydrochloric acid etc.

The compounds of the present invention inhibit the transfer of the decapeptide angiotensin I to angiotensin II and can therefore be used to reduce or alleviate hypertension. The compounds of the present invention interfere with renin -r angiotensinogen -r angiotensin I -V angioten- sin TI-Sckverlsäcxl gr-nf fi xn: JH iJillilurg-ra .unginluxmínövrørffširundn _ .. ........- ...__ V ........-. «.«.-... .VV- fl ø-w - ø-M- --- 4-47 477 10 enzyme and reduce or eliminate the formation of the pressor substance angiotensin II. Thus, by administering a hypotensively effective amount of a compound containing one or a combination of the compounds of formula I or physiologically acceptable salts thereof, hypertension can be reduced or alleviated in mammals suffering therefrom.

A single dose, or preferably two to four divided daily doses provided in an amount of about 0.1-10 mg / kg per day is suitable for reducing blood pressure as indicated in the animal model experiments described by S.L. Engel, T.R. Schaeffer, M.H. Waugh and B. Rubin, Prcc. Soc. Exp. Biol. With. volume 143 (1973) page 483. The substance is preferably administered orally but parenteral administration such as subcutaneous, intramuscular, intravenous or intraperitoneal may also be used.

The compounds of the present invention may be used to effect a reduction in blood pressure in compositions such as tablets, capsules or elixirs for oral administration or in sterile solutions or suspensions for parenteral administration. Approximately 10-500 mg of a compound or mixture of compounds of formula I or physiologically acceptable salts thereof is processed with a physiologically acceptable vehicle, carrier, excipient, a binder, a preservative, a stabilizer, a flavoring agent, etc. in a dosage unit form. form of accepted pharmaceutical practice. The amount of active substance in these compositions or preparations is such that a suitable daily dose is obtained within the above range.

Examples of adjuvants that can be incorporated into tablets, capsules and the like are as follows: binders such as gum tragacanth, acacia, corn starch or gelatin; excipients such as dicalcium phosphate or microcrystalline cellulose, disintegrants such as corn starch, potato starch, alginic acid and the like, lubricants such as magnesium stearate, sweeteners such as sucrose, lactose or saccharin, flavoring agents such as peppermint, wintergreen or cherry.

When the dosage unit form is a capsule, it may contain, in addition to the above 447,477 μl of material, a liquid carrier such as a fatty oil. Various other materials may be present as a coating or to otherwise modify the physical form of the dosage unit. For example, tablets may be coated with shellac, sugar or both. A syrup or elixir may contain the active compound, sucrose as a sweetening agent, methyl and propyl parabens as preservatives, a coloring matter and a flavoring agent such as cherry or orange flavor.

Sterile compositions for injection can be prepared according to conventional pharmaceutical practice by dissolving or suspending the active substance in a vehicle such as water for injection, a naturally occurring vegetable oil such as sesame oil, coconut oil, peanut oil, cottonseed oil EIC. The invention is further illustrated by the following examples in which the temperatures refer to degrees Celsius.

Example 1- (1- (3-Acetylthio-1-oxopropyl) -trans-4-methoxy-L-proline α, N-acetyl-trans-4-hydroxy-L-proline A stirred suspension of 26.2 g (0.2 mol) trans-4-hydroxy-L-proline in 400 ml of acetic acid is treated with 26 ml of acetic anhydride. The solid gradually dissolved after stirring for 2 hours at room temperature. The solution is transferred to a 2-liter flask and the solvent is removed on a rotary evaporator at a bath temperature of 450. The syrupy residue (57.5 g) is diluted with 100 ml of ether to give a crystalline solid. After cooling overnight, the solid is filtered, washed with cold ether and dried in a desiccator.

This material (35.7 g) is pulverized and suspended in 100 ml of ether, cooled and filtered to give 33.8 g (98 "%) of N-acetyl-trans--4-hydroxy-L-proline, 128-1310. Recrystallization of 0.5 g of this material from 5 ml of acetonitrile gives 0.45 g of colorless solid, m.p. 130-1320; [a] š5-920 (c, 1% in EtOH) 447 477 12 b) N-acetyl trans-4-methoxy-L-proline, methyl ester A mixture of 30.0 g (0.7 mol) of N-acetyl-trans-4-hydroxy-L-proline and 130 g of silver oxide is pulverized in a mortar and this intimate mixture is added. to a 1-liter flask with 300 ml of acetone. The slurry is stirred, treated portionwise with 130 ml of methyl iodide and the temperature is kept below 400 by cooling with a cold water bath. After stirring for 7 hours, the mixture is allowed to stand overnight. The solid is filtered, washed well with acetone and the filtrate are concentrated on a rotary evaporator to give 38.3 g of a syrupy residue, the latter being redissolved in 350 ml of acetone and treated again with 130 g of silver oxide and 130 ml of methyl iodide to give 41 g. g remained. The latter is distilled to give 32.2 g of distillate; boiling point 130-1400 (0.3 mm).

After digestion in 30 ml of cyclohexane and cooling, the almost colorless solid N-acetyl-trans-4-methoxy-L-proline methyl ester weighs 31.4 g, m.p. 71-750. Recrystallization from 31 ml of ethyl acetate gives 25.1 g (66%) of a colorless solid, m.p. 76-77 °. [α] D 5 -s3 ° (a, 1% i ston). c) trans-4-methoxy-L-proline To a stirred solution of 27.0 g (0.085 mol) of barium hydroxide BH 2 O in 525 ml of water (about 3.3 N) is added 11.0 g (0.05 mol) of N- acetyl-trans-4-methoxy-L-proline methyl ester. The resulting solution is stirred at 18-200 for 3 hours, cooled and treated with dilute sulfuric acid (8.8 g of concentrated H 2 SO 4 in 20 ml of water). The acidified suspension is allowed to stand overnight.

The mixture is filtered through a thick layer of celite to give a "milky" filtrate. The latter is concentrated on a rotary evaporator at 500 using a high vacuum pump to give a milky residue weighing 121 g. This material is mixed with dilute sulfuric acid (19.0 g of concentrated H 2 SO 4 in 75 ml of water) and the resulting mixture is stirred and recycled. boil for 3 hours. After cooling to 300, the mixture is treated portionwise with 48 g of barium hydroxide. The pH of the SHZO and the mixture are then adjusted from 6.0 to 4.0 with dilute sulfuric acid. After standing overnight, the mixture is filtered through a thick layer of celite. The "milky" filtrate is concentrated as above to give 50 g of a colorless dry residue. The latter is treated with 200 ml of hot chloroform and filtered through a pad of celite to remove the barium sulfate. The slightly cloudy filtrate is concentrated on a rotary evaporator to give a gelatinous material (17.7 g), suspended in 100 ml of ether and filtered to give 7.5 g (94%) of an almost colorless solid, m.p. 185-1900 (dec.) . This material is suspended in 30 ml of hot acetonitrile, cooled and filtered to give 4.0 g (50%) of a colorless solid trans-4-methoxy-L-proline, m.p. 209-2110 (dec.); [1] 55-75 ° (C, 1% 1 st). d) 1- (3-Acetylthio-1-oxopropyl) -trans-4-methoxy-L-proline A solution of 3.5 g (0.024 mol) of trans-4-methoxy-L-proline in 50 ml of water is stirred, cooled to 50 and 3 g of sodium carbonate are added. This mixture is treated with a solution of 4.0 g (0.024 mol) of 3-acetylthiopropionyl chloride in 5 ml of ether over 10 minutes with the intermittent addition of 3 g of sodium carbonate to maintain the pH of the mixture at about 8.0. The mixture is stirred on an ice bath for another hour, 25 ml of water are added and then a solution of 5 ml of concentrated hydrochloric acid in 25 ml of water (CO 2 evolution). The strongly acidic solution is moistened with sodium chloride and extracted with 50 ml of ethyl acetate (4 times). The organic phases are combined, dried (MgSO 4), filtered and the solvent evaporated to give 6.0 g (90%) of colorless syrup 1- (3-acetylthio-1-oxopropyl) -trans-4-methoxy-L-proline. This acid is dissolved in 25 ml of ethyl acetate and treated with 4.7 g of dicyclohexylamine to give a solution which rapidly becomes a solid. An additional 15 ml of ethyl acetate is added and the mixture is treated on a steam bath, cooled and filtered to give 8.7 g of dicyclohexylamine salt, m.p. 170-1720. After recrystallization from 60 ml of acetonitrile, the colorless solid weighs 8.3 g (75 [mu] l), m.p. 171-173 °; [α] 25 D -5-35 ° (C,% 1 ston).

The dicyclohexylamine salt is converted to 1- (3-acetylthio-1-oxopropyl) trans-4-methoxy-L-proline by suspending 8.0 g of 60 ml of ethyl acetate cooled on an ice bath and batching with 60 ml of 10% potassium bisulfate. . The clear layers are separated and the aqueous portion is extracted with 60 ml of ethyl acetate (2 times). The organic phases are combined, dried (MgSO 4), filtered and the solvent is evaporated to give 4.6 g (80%) of colorless syrup.

Example 2 1- (3-Mercapto-leoxopropyl) -trans-4-methoxy-L-proline To 1- (3-acetylthio-1-oxopropyl) -trans-4-methoxy-L-proline obtained in Example 1 (4, 6 g, 0.07 mol) is added to a cold solution of 9 ml of concentrated ammonia in 22 ml of water. The base is dissolved for about 30 minutes and the resulting solution (under argon) is allowed to stand for 2 hours at room temperature. This solution is cooled, extracted with 25 ml of ethyl acetate (2 X) and the ethyl acetate extract is discarded. The solution is layered again with 25 ml of ethyl acetate and acidified with 17 ml of 1: 1 hydrochloric acid. The mixture is shaken, separated and the aqueous phase is extracted with 25 ml of ethyl acetate (3 X). The organic phases are combined, dried (MgSO 4), filtered and the solvent is removed on a rotary evaporator to give 2.3 g (59%) of colorless syrup, 1- (3-mercapto-1-oxopropyl) -trans-4- ° (c, i mares), Rf 0.49 (meon on silica gel, visualized with nitroprusside reagent).

Analysis calculated for C 9 H 15 NO 4 S. 1 / 4H 2 O: C 45.46; H 6.57; N 5.87; S 13.48.

Found: C 45.42; H 6.78; N 5.96; S 13.27. -methoxy-L-proline, [d] š5-60 An additional 1.1 g of the product (total 3.4 g, 87%) is obtained by saturating the aqueous phase with sodium chloride and extracting it with 25 ml of ethyl acetate (2 X).

The sodium salt is formed by treating the syrup with aqueous sodium bicarbonate and freeze-drying.

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 is stirred, cooled to 50 and 3 g of sodium carbonate are added. This solution is treated with 5.2 g (0.029 mol) of D-3- (acetylthio) -2-methylpropionyl chloride in 5 ml of ether over 10 minutes with intermittent addition of 3 g of sodium carbonate to maintain the pH of the mixture at about 8.0. This mixture was stirred in an ice bath for 1.5 hours, 25 ml of water were added and then a solution of 6 ml of concentrated hydrochloric acid in 25 ml of water (CO 2 evolution). The strongly acidic solution formed is extracted with 50 ml of ethyl acetate (4 X). The organic phases are combined, dried (MgSO 4), filtered and the solvent is evaporated to give 6.1 g (73%) of (trans) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4 -methoxy-L-proline as a light yellow syrupy residue. This acid is dissolved in 50 ml of ethyl acetate and treated with a solution of 4.0 g of dicyclohexylamine in 20 ml of ethyl acetate. The product begins to crystallize from the solution within about 1 minute. After cooling overnight, the almost colorless solid is filtered and dried to give 6.7 g melting point 175-177 ° [a] 25-55 ° (a, in mares). After crystallization from 60 ml of acetonitrile, the almost colorless solid dicyclohexylamine salt weighs 5.6 g (41%), m.p. 179-1810, [α] D -e2 ° (c, in mares).

The dicyclohexylamine salt is converted to the acid by suspending 5.5 g in 50 ml of ethyl acetate, cooling in an ice bath and treating with 50 ml of 10% potassium bisulfate. The layers are separated and the aqueous portion is extracted with 50 ml of ethyl acetate (2 X).

The organic phases are combined, dried (MgSO 4), filtered and the solvent is evaporated to give 3.4 g (41%) of the almost colorless (trans) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl ] -4-methoxy-L-proline as a syrup.

Example 4 (trans) -4-methoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline Till (trans) -1- [D-3- (acetylthio) -2-methyl -1-oxepropyl] -4-methoxy-L-proline (3.4 g) add a cold solution of 8 ml of concentrated ammonia in 20 ml of water. The base dissolves within about 10 minutes and the resulting solution (under argon) is allowed to stand at room temperature for 2 hours. This solution is cooled, extracted with 44 ml of ethyl acetate (2 X), layered with 20 ml of ethyl acetate and acidified with 15 ml of 1: 1 hydrochloric acid. This mixture is saturated with sodium chloride, the layers are separated and the aqueous phase is extracted with 20 ml of ethyl acetate (3 X). The organic phases are combined, dried (MgSO 4), filtered and the solvent is evaporated to give 2.9 g (100%) of an almost colorless (trans) -4-methoxy-1- (D-3-mercapto-2-methyl-1 -oxopropyl) -L-proline, [α] D -5-800 (c, 1% in EtOH); Rf nitroprusside reagent).

Analysis calculated for CloH17NO4S. 1 / 4H 2 O: C 47.69; H 6.83; X 5.56; S 12.73.

Found: C 47.90; H 6.84; N 5.85; S 12.76. 0.53 (MeOH on silica gel, visualized with Exemgel 5 trans) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-ethoxy-L- -eroline Using the procedure of Example 3 but by replacing the equivalent amount of trans-methoxy-L-proline (J. Med. Chem., Vol. 10, (1967) p. 116), with (trans) -4-ethoxy-L-proline, trans is obtained) - 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-ethoxy-L- -proline. The product is purified as dicyclohexylamine salt, m.p. 170-1720 (crystallized from isopropyl alcohol); [d] δ5-649 (C, 1% in EtOH \.

This salt (7.75 g) is converted to the free acid by treatment with potassium bisulfate solution as described in Example 4 to give 4.85 g of almost colorless (trans) -1- [D-3- (acetylthio) -2-methyl -1-oxopropyl] -4-ethoxy-L-proline as a syrup.

Example gel 6 (trans) -4-ethoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline To the material from Example 5 (4.85 g) is added a cold solution of 9 ml of concentrated ammonia in 25 ml of water (under argon). The mixture is treated in the same manner as in Example 4 to give 4.2 g (100%) of almost colorless (trans) -4-ethoxy-1- (D-3-mercapto-2-methyl-1-oxypropyl) -L- prolín som vn syrup, - 1? -ao ° (u, u. i ston), R 0.64 (neon ps. siiikagei, ia f 447 477 17 visualized with nitroprusside reagent).

Analysis calculated for C 11 H 19 NO 4 S: C 50.55; H 7.33; N 5.36; S 12.27.

Found: C 50.34, H 7.34; N 5.39; S 12.11.

Example 7 (cis) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-Methoxy-L- -proline a) N-carbobenzyloxy-cis-4-hydroxy-L-proline N Carbobenzyloxy-4-keto-L-proline (10 g, 0.038 mol) is dissolved in 300 ml of methanol and reduced with 5.8 g (0.1 mol) of sodium borohydride in 20 ml of water as described in JACS, 79 (1957 ) p. 189 and gives 8.7 g of a foaming product. This material is dissolved in 30 ml of ethanol, treated with 3.5 g of cyclohexylamine in a small amount of ethanol and diluted with 500 ml of ether. By grafting and grating, the crystalline cyclohexylamine salt is rapidly separated to give 10.8 g; melting point 163-1650. This cyclohexylamine salt is then treated with 30 ml of 2N HCl and extracted with ethyl acetate (4 x 50 ml) to give as a glass-like material 8 g of N-carbobenzyloxy-cis-4-hydroxy-L-proline. b) N-Carbobenzyloxy-cis-4-methoxy-L-proline methyl ester N-Carbobenzyloxy-cis-4-hydroxy-L-proline (1.3.9 g, 0.052 mol) is treated with 40 g of silver oxide and 40 ml of methyl iodide (2 X) in acetone (100 ml initially, then 120 ml) as described in Example 1 (b) to give 17.5 g (100%) of N-carbobenzyloxy-cis-4-methoxy-L-proline, methyl ester as a yellow oil. c) N-Carbobenzyloxy-Cis-4-methoxy-L-proline The N-carbobenzyloxy-cis-4-methoxy-L-proline methyl ester (17.5 g, about 0.052 mol) is dissolved in 135 ml of methanol, treated by drug at - 1 ° to 4 ° with 32 ml (0.64 mol) of 2N sodium sodium aroxia, then kept at 0 DEG for one hour and at room temperature overnight. After removing about half of the solvent on a rotary evaporator, the solution is diluted with 300 ml of water, washed with ether (the washing liquid is discarded), acidified 447 477 l8 while cooling with 12.5 ml of 1: 1 hydrochloric acid to pH 2 and extracted with ethyl acetate (4 x 150 ml). The extracts are combined, dried (MgSO 4), filtered and the solvent is evaporated to give 15 g of an orange-yellow syrup. The latter is dissolved in 60 ml of ethanol, treated with 6 g of cyclohexylamine in 10 ml of ethanol and diluted to 900 ml with ether. By grafting and grating, crystalline N-carbobenzyloxy-cis-4-methoxy-L-proline is separated, cyclohexylamine salt: weight after cooling overnight 10.2 g, m.p. 148-150 ° (S. 144 °), After recrystallization from 40 ml of acetonitrile, the almost colorless solid weighs 8.8 g, m.p. 150-1520 (p. 1450), [α] D6-34 ° (C, 1% 1 ethanol). (c,% in ethanol).

The cyclohexylamine salt is treated with hydrochloric acid to give 6.9 g (48%) of N-carbobenzyloxy-cis-4-methoxy-L-proline as light yellow O (c, 1% in ethanol). viscous syrup [a] š6-32 d) cis-4-methoxy-L-proline A mixture of 6.8 g of N-carbobenzyloxy-cis-4-methoxy-L-proline, 210 ml of 2: 1 methanol and water and 2 .3 g of 5% Pd-C are placed on a hydrogenate at 3 atmospheres of hydrogen for 4 hours. The mixture is filtered to remove the catalyst and the filtrate is evaporated to give 3.15 g of a grayish solid; melting point 218-2200 (decomposition). The sample is crystallized from methanol-ether to give colorless cis-4-methoxy-L-proline, m.p. 224-22 ° (dec.), [Α] 25-42 ° Analysis calculated for CH NO 'C 49.64, H 7.64 , N 9.65 6 11 3 'Found: C 49.63; H 7.71; N 9.54. (c, 1% in methanol). e) (cis) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-methoxy-L-proline cis-4-methoxy-L-proline (3 g, 0.02l mol) and 4.2 g (0.023 mol) of D-3-acetylthio-2-methylpropionyl chloride in 5 ml of ether are reacted in 60 ml of water in the presence of sodium bicarbonate as described in Example 3. About 20 ml of 25% sodium carbonate (weight / volume) is required to initially give a pH of 8.5 and to maintain this at 7.5 to 8.4 during the acylation. The resulting crude viscous product (6.4 g) is dissolved in 50 ml -, ~ .._..... f _.- ,,., ._ _. ,. ,. -f _.-_-.-_- f - V. Ethyl acetate and treated with 3.9 g of dicyclohexylamine in 20 ml of ethyl acetate. The product crystallizes out of solution and is filtered and dried to give 6.6 g of dicyclohexylamine salt, m.p. 172-114 ° (S 180 °), [al66-eo ° (C,% 1 ethanol). 6.5 g of this material are recrystallized from 35 ml of acetonitrile to give 6 g of a colorless solid dicyclohexylamine salt, m.p. 173-1750 (S. 180 °), [α] D 6-60 ° Analysis calculated for Cl 2 H 19 NO 5 S.Cl 2 H H 9.00; N 5.95; S 6.81.

Found: C 61.16; H 8.81; N 5.95; S 6.67. (c,% in ethanol).

Using the procedure of Example 3, the dicyclohexylamine salt is converted to the acid by suspending 5.9 g in 60 ml of ethyl acetate, cooling the mixture on an ice bath and treating it with 60 ml of 10% potassium bisulfate. The layers are separated and the aqueous phase is extracted with 50 ml of ethyl acetate (4 X). The organic phases are combined, dried (MgSO 4), filtered and the solvent is evaporated to give 3.5 g (60%) of colorless (cis) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4 -methoxy-L- -proline; mp 90-920 (decomposed with ether), [d] š6-1390 (c,% in ethanol), Rf 0.63 (methanol on silica gel).

Analysis calculated for C 12 H 19 NO 5 S: C 49.81; H 6.62; N 4.84. Found: C, 49.85; H 6.66; N 4.97.

Example gel 8 (cis) -4-methoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline (cis) -1- [D-3- (acetylthio) -2-methyl- 1-Oxopropyl] -4-methoxy-L- -proline (2.9 g, 0.01 mol) is hydrolyzed in 1.5 ml of water containing 6.5 ml of concentrated ammonia as described in Example 4 to give 2.3 g ( 93%) of an extremely viscous (cis) -4- -methoxy-1- (D-3-mercapto-2-methyl-1-okopropyl) -L-proline which becomes waxy when allowed to stand; [alao-88o (c, 1% in ethanol). -w Lxemgel 8a (cis) -4-methoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L- -orolin-1-adamantanamine salt A solution of 0.55 g (0.0022 mol ) cis-4-methoxy-1- (D-3-447 477 -mercapto-2-methyl-1-oxopropyl) -L-proline in 15 ml of ethyl acetate is treated under an argon atmosphere with a hot solution of 0.34 g (0 .0022 mol) of 1-adamantanamine in 10 ml of ethyl acetate to precipitate the salt. After 3 hours in the cold, a colorless solid is filtered under argon (the solvent is kept sticky), washed with cold ethyl acetate and dried in vacuo for 20 hours to give 0.7 g (79%) of (cis) -4-methoxy-1- ( D-3-mercapto-2-methyl-1-oxopropyl) -L-proline-1-adamantanamine salt, m.p. 21s-217 ° (s. 21o °, solar eclipse zzoo), fcqšö-ecP, 1% in methanol).

Example 9 (cis) -4-methoxy-1- (3-mercapto-2-methyl-1-oxonropyl) -L-proline a) (cis) -4-methoxy-1- [3- (benzoylthio) -2- methyl-1-oxopropyl] -L-proline Reaction between 3-benzoylthio-2-methylpropionyl acid chloride (prepared by treating 3-benzoylthio-2-methylpropanoic acid with thionyl chloride) and cis-4-methoxy-L-proline according to the general procedure in Example 3 gives (cis) -4-methoxy-1- [3- (benzoylthio) -2-methyl-1-oxopropyl] -L-proline. b) (cis) -α-methoxy-1- (3-mercapto-2-methyl-1-oxopropyl) -L-proline Hydrolysis of (cis) -2-methoxy-1- [3- (benzoylthio) -2- methyl-1-oxo-propyl] -2-proline with an aqueous ammonia solution according to the general procedure of Example 4 gives (cis) -4-methoxy-1- (3-mercapto-2-methyl-1-oxopropyl) -L -proline.

Example gel 10 (trans) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-propoxy-L-proline a) N-acetyl-trans-4-propoxy-L-proline propyl ester Reaction between 30 g of N-acetyl-trans-4-hydroxy-L-proline from Example 1 (a) and 10 g of silver oxide and 10 ml of propyl iodide in 300 ml of acetone according to the procedure of Example 1 (b) give 19.6 g (41%). light yellow-orange N-acetyl-trans-4-propoxy-L-proline propyl ester, b.p. 155-1650 (0.2 mm). 447 477 21 b) N-acetyl-trans-4-propoxy-L-proline A solution of 6 g (0.5 mol) of sodium hydroxide in 150 ml of water is added to 19.4 g (0.075 mol) of N-acetyl-trans. 4-propoxy-L- -proline propyl ester and gives a bright orange solution.

After standing overnight at room temperature, the solution is extracted with 60 ml of ethyl acetate (the washing liquid is discarded), then acidified with 1: 1 hydrochloric acid, then saturated with sodium chloride and extracted with 50 ml of chloroform (3X). The organic phases are combined, dried (MgSO 4), filtered and the solvent is evaporated to give 12.6 g of a brown oil. The latter is dissolved in 80 ml of ethyl acetate and treated with a solution of 10.7 g of dicyclohexylamine salt in 20 ml of ethyl acetate. The salt crystallizes at room temperature. After standing overnight under cooling, the dicyclohexylamine salt is filtered and washed with cold ethyl acetate to give 17.3 g of an almost colorless solid dicyclohexylamine salt; melting point 148-1530. Recrystallization of this material from 125 ml of ethyl acetate gives 14.5 g of a colorless dicyclohexylamine salt; melting point l57 ~ l59O, [a] š5-300 (c, 1% in ethanol).

Analysis calculated for ClOH17NO4. Cl 2 H 23 N: C 66.63; H 10.17; N 7.07.

Found: C 66.47; H 10.22; N 7.06.

The dicyclohexylamine salt (14.4 g) is transferred to the free acid by pulverization, suspended in 100 ml of ethyl acetate and the slurry is treated portionwise with 100 ml of 10% potassium bisulfate. The organic phase is separated and the aqueous phase is extracted with 100 ml of ethyl acetate (ZX). The organic phases are combined, dried (MgSO 4), filtered and the solvent is evaporated to give 6.7 g (41%) of N-acetyl-trans-4-propoxy-L--proline as a light brown liquid. c) (trans) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-propoxy-L-proline -w N-acetyl-trans-4-propoxy-L-proline ( 6.4 g, 0.03 mol) are treated with a solution of 10 g of concentrated sulfuric acid in 100 ml of water and the resulting solution is stirred and refluxed for 3 hours. The solution is then cooled to 150, treated portionwise with 12 g of sodium carbonate to transfer the pH to 8.0 and then treated with a solution of 5.4 g (0.03 mol) of D-3- acetylthio-2-methylpropionyl chloride in 5 ml of ether for 10 minutes while adding 7 g of sodium carbonate to keep the pH at about 8.0. The mixture is then stirred in an ice bath for 30 minutes and at room temperature for 1 hour. The product is then isolated and purified as dicyclohexylamine salt according to the procedure of Example 3 to give 6.3 g of dicyclohexylamine salt, m.p. 165-1670 (from acetonitrile), [α] D -5-560 (c, 1% in ethanol).

Analysis calculated for C 14 H 23 NO 5 S. Cl 2 H 23 N: C 62.62; H 9.30; N 5.6l; S 6.43. Found: C 62.35; H 9.48; N 5.88; S 6.45.

The dicyclohexylamine salt (6.1 g) is transferred to the free acid by suspending in 60 ml of ethyl acetate, cooling on an ice bath and treating with 60 ml of 10% potassium bisulfate. The layers are separated and the aqueous phase is extracted with 60 ml of ethyl acetate (2X). The organic phases are combined, dried (MgSO 4), filtered and the solvent is evaporated to give 4.0 g (42%) of (trans) -1- [D- 3- (acetylthio) -2-methyl-1-oxopropyl] - 4-propoxy-L-proline as an almost colorless syrup.

Example 11 - 1- (D-3-mercapto-2-methyl-1-oxopropyl) -trans-4-propoxy-L-proline Hydrolysis of 4.0 g (trans) -1- [D-3- (acetylthio) - 2-Methyl-1-oxo-propyl] -4-propoxy-L-proline with 8 ml of concentrated ammonia in 20 ml of water under an argon atmosphere according to the procedure of Example 4 gives 3.42 g (97%) of 1- (D-3- mercapto-2-methyl-1-oxopropyl) -trans-4-propoxy-L-proline as an almost colorless syrup [d] D-720 (c,% in ethanol).

Analysis calculated for C 12 H 2 NO 4 S 1/4 H 2 O: C 51.49; H 7.74; N 5.05; S ll, 46 '' Found: C 51.66; H 7.76; N 5.94; S 10.51.

Example Gel 12 1- (3-Mercapto-1-oxopropyl) -cis-4-methoxy-L-proline 447 477 23 a) 1- (3-Acetylthio-1-oxooropyl) -cis-4-methoxy-L-proline According to the procedure of Example 1 (d) is treated with cis-4-methoxy-L-proline with a solution of 3-acetylthiopropyl chloride in the presence of sodium carbonate to give 1- (3-acetylthio-1-oxopropyl) -cis-4-methoxy-L- proline. b) 1- (3-Mercapto-1-oxooropyl) -cis-4-methoxy-L-proline 1- (3-acetylthio-1-oxopropyl) -cis-4-methoxy-L-proline hydrolyzed with an aqueous solution of ammonia according to the procedure of Example 2 to give 1- (3-mercapto-1-oxopropyl) -Cis-4-methoxy-L-proline.

Example gel 13 (cis) -4-ethoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline a) cis-4-ethoxy-L-Eroline According to the procedure of Example 7, part ( a) to (d) but using ethyl iodide instead of the methyl iodide in part (b), (cis) -4-ethoxy-L-proline is obtained. b) (cis) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-ethoxy-L-proline (cis) -4-ethoxy-L-proline is reacted with a solution of D-3-acetylthio-2-methylpropionyl chloride in the presence of sodium carbonate according to the procedure of Example 7 (e) to give (cis) -1- - [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-ethoxy-L-proline. c) (cis) -4-ethoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L- -proline cis-1- [D-3- (acetylthio) -2-methyl-1 -oxopropyl] -4-ethoxy-L-proline is hydrolyzed with a solution of aqueous ammonia according to the procedure of Example 8 to give (cis) -4-ethoxy-1- (D-3-mercapto--2-methyl-1-oxopropyl ) -L-proline.

Example 14 (trans) -4-allyloxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L--orolin a) (trans) -4-allyloxy-L-proline 4-47 477 24 Using the procedure of Example 1, Part b, but using allyl bromide instead of methyl iodide, the (trans) -N-acetyl-4-allyl-L-proline allyl ester is obtained. The latter is then hydrolyzed in the manner set forth in Example 1, Part C, to (trans) -4-allyloxy-L-proline. b) (trans) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-allyloxy-L-proline Reaction between (trans) -4-allyloxy-L-proline from part ( a) with an equivalent amount of D-3- (acetylthio) -2-methylpropionyl chloride according to the procedure of Example 3 gives (trans) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4- allyloxy-L-proline. c) (trans) -4-allyloxy-1- (D-3-mercapto-2-methyl41-oxopropyl) -L-proline (trans) -1- [D-3- (acetylthio) -2-methyl-1 -oxopropyl] -4-allyloxy-L- -proline is hydrolyzed with an aqueous ammonia solution according to the procedure of Example 4 to give (trans) -4-allyloxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline.

Example 15 1- (D-3-Mercapto-2-methyl-1-oxopropyl) -trans-4-propargyloxy-L--orolin a) (trans) -4-propargyloxy-L-proline Using the procedure of Example 1 , part b, but using propargyl bromide instead of methyl iodide, the (trans) -N-acetyl-4-propargyl-L-proline propargyl ester is obtained. The latter is then hydrolyzed in the manner set forth in Example 1, Part C, to (trans) -4-propargyloxy-L-proline. b) (trans) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4- -propargyloxy-L-proline Reaction between (trans) -4-propargyloxy-L-praline from part ( a) with the equivalent amount of D-3- (acetylthio) -2-methylpropionyl chloride according to the procedure of Example 3 gives (trans) -1- [D-3- (acetylthio) -1-2-methyl-1-oxopropyl] -4- propargyloxy-L-proline. C) 1- (D-3-mercapto-2-methyl-1-oxopropyl) -trans * 4-propargyloxy-L-proline (trans) -1- [D-3- (acetylthio) -2-methyl- 1-oxopropyl] -4-propargyl-L-proline is hydrolyzed with an aqueous ammonia solution according to the procedure of Example 4 to give 1- [D-3-mercapto-2-methyl-1-oxopropyl)] - trans-4-propargyloxy -L-proline.

Example 16 (trans) -4-benzyloxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L- -proline a) (trans) -4-benzyloxy-L-proline Using the procedure in Example 1, part b, but using benzyl chloride instead of methyl iodide, the (trans) -N-acetyl-4-benzyloxy-L-proline benzyl ester is obtained. The latter is then hydrolyzed in the manner described in Example 1, Part C, to (trans) -4-benzyloxy-L-proline. b) (trans) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -1- 4-benzyloxy-L-proline Reaction between (trans) -4-benzyloxy-L-proline from part (a) with the equivalent amount of D-3- (acetylthio) -2-methylpropionyl chloride according to the procedure of Example 3 gives (trans) -1 [[3- (acetylthio) -2-methyl-1-oxopropyl] -4- benzyloxy-L-proline. c) (trans) -4-Benzyloxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline (trans) -1- [D-3- (acetylthio) -2-methyl -1-oxopropyl] -4-benzyloxyl-L-proline is hydrolyzed with aqueous ammonia solution according to the procedure of Example 4 to (trans) -4-benzyloxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline.

Example 17 1- (D-3-mercapto-2-methyl-1-oxopropyl) -trans-4-phenethyloxy-L--proline a) (trans) -4-phenethyloxy-L-proline Using the procedure of Example 1 , part b, but by replacing the methyl iodide with phenethyl bromide, the (trans) -N-acetyl-4-phenethyloxy-L-proline phenethyl ester is obtained. The latter is then hydrolyzed in the manner described in Example 1, Part C, to (trans) -4-phenethyloxy-L-proline. b) (trans) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-phenethyloxy-L-proline Reaction between (trans) -4-phenethyloxy-L-proline from part (a) with the equivalent amount of D-3- (acetylthio) -2-methylpropionyl chloride according to the procedure of Example 3 gives (trans) -1- [D-3 ~ (acetylthio) -2-methyl-1-oxopropyl] -4- phenethyloxy-L-proline. c) 1- (D-3-mercapto-2-methyl-1-oxoepropyl) -trans-4-phenethyloxy-L-proline Trans-1- [D- (acetylthio) -2-methyl-1-oxopropyl] - 4-Phenethyloxy-L- -proline is hydrolyzed with an aqueous ammonia solution according to the procedure of Example 4 to 1- (D-3-merceto-2-methyl-1-oxo-propyl) -trans-4-phenethyloxy-L-proline .

Example 18 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 Using the procedure of Example 7 but using the equivalent amount of (cis) -3-methoxy-L-proline [J. Amer. Chem.

Soc. 85, (1963) p. 3863] instead of -proline there is obtained 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -cis- (cis) -4-methoxy-L--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] - The cis-3-methoxy-L- -proline is hydrolyzed with an aqueous ammonia solution according to the procedure of Example 4 to give 1- (D: 3; mercapto-2-methyl-1-oxopropyl) -cis-3-methoxy-L-proline .

Example Gel 19 1- (D, L-3-mercapto-2-methyl-1-oxopropyl) -trans-3-methoxy-L-groline 447 477 27 a) 1- [D, L-3- (acetylthio) -2 -methyl-1-oxopropyl] -trans-3-methoxy-L-proline Reaction between equivalent amounts of (trans) -3-methoxy-L-proline (J. Amer. Chem. Soc. 85, (1963) p. 3863 and D, L-3- (acetylthio) -2-methylpropionyl chloride according to the procedure of Example 3 gives 1- [D, L-3- (acetylthio) -2-methyl-1-oxopropyl] -trans-3-methoxy-L - -proline b1 1- (D, L-3-mercapto-2-methyl-1-oxopropyl) -trans-3-methoxy-L-proline 1- [D, L-3- (acetyltic) -2- methyl-1-oxopropyl] -trans-3-methoxy-L-proline is hydrolyzed with an aqueous ammonia solution according to the procedure of Example 4 to give 1- (D, L-3-mercapto-2-methyl-1-oxopropyl (-trans) -3-methoxy-L-proline.

Example 20 1- (D-3-Mercapto-2-methyl-1-oxonropyl) -C 1-4-methylthio-L-proline a) 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -cis-4-methylthio- -L-proline Reaction between equivalent amounts of cis-4-methylthio-L-proline. Amer. Chem. Soc., 79, (1957) p. 185] and D-3- (acetylthio) -2-methylpropionyl chloride according to the procedure of Example 3 gives 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -cis-4-methylthio-L- -proline. b) 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4-methylthio-L- -proline 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] - The cis-4-methylthio-L--proline is hydrolyzed with an aqueous ammonium solution according to the procedure of Example 4 to give 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4-methylthio-L-proline .

Example 21 '* 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 447 477 28 Reaction between equivalent amounts of trans-4-methylthio-L-proline [J. Amer. Chem. Soc., 79, (1957) p. 18 fl and D-3- (acetylthio) -2-methylpropionyl chloride according to the procedure of Example 3 gives 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] - trans-4-methylthio-L- -proline. b} 1- (D-3-mercapto-2-methyl-1-oxopropyl) -trans-4-methylthio-L- -proline 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] - The trans-4-methylthio-L- -proline is hydrolyzed with an aqueous ammonia solution according to the procedure of Example 4 to give 1- (D-3-mercapto-2-methyl-1-oxopropyl) -trans-4-methylthio-L-proline .

Example 22 1- (D-3-mercapto-3-methyl-1-oxopropyl) -cis-4- (4-pentenylthio) -L-proline a) (cis) -4- (4-pentenylthio) -L- proline Reaction between (cis) -N-acetyl-4-mercapto-L-proline [Chem.

Pharm. Bull., 20, (1972) p. 543] and 5-bromo-1-pentene in acetone in the presence of silver oxide according to the procedure of Example 1, part b, gives (cis) -N-acetyl-4- (4-pentenylthio -L-proline-4-pentenyl ester The latter is then hydrolyzed in the manner described in Example 1, part c, to give cis-4- (4-pentenylthio) -L-proline b) LID-3 - (acetylthio) -3-methyl-1-oxopropyl] -cis-4- (4-pentenylthio) -L-proline Reaction between cis-4- (4-pentenylthio) -L-proline with equivalent amount of D-3 - (acetylthio) -3-methylpropionyl chloride according to the procedure of Example 3 gives 1- [D-3- (acetylthio) -3-methyl-1-oxopropyl] -cis-4- (4-pentenylthio) -L-proline . c) 1- (D-3-mercapto-3-methyl-1-oxopropyl) -cis-4- (4-pentenylthio) -L-proline _ * 1- [D-3- (acetylthio) -3- methyl-1-oxopropyl] -cis-4- (4-pentenylthio) -L-proline is hydrolyzed with an aqueous ammonia solution according to the procedure of Example 4 to give 1- (D-3-mercapto-3-methyl-1- oxopropyl) -cis-4- (4-pentenylthio) -L-proline. 447 477 29 Example gel 23 (trans) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -4-methoxy-L- -proline methyl ester A solution of the material from Example 3 in ether is treated with a light excess diazomethane. After standing at room temperature, the solvent is evaporated to give (trans) -1- [D- -3- (acetylthio) -2-methyl-1-oxopropyl] -4-methoxy-L-proline methyl ester.

Similarly, using the cis material of Example 7 of this procedure, (cis) -1- [D-3- (acetylthio) -2- -methyl-1-oxopropyl-4-methoxy-L-proline methyl ester is obtained.

Example gel 24 1,1 '- [Dithiodi- (1D-3-mercapto-2-methyl-1-oxopropyl)] - bis- - [(trans) -4-methoxy-L-proline] A solution of the material from Example 4 dissolved in ethanol, stirred and treated with a solution of one equivalent of iodine in ethanol. The pH of the solution is maintained at 6-7 by the addition of N- sodium hydroxide solution. The solvent is evaporated and the residue is extracted with ethyl acetate. After drying over MgSO 4, the solution is filtered and the solvent is removed to give 1,1 '- [dithiodi (1D-3-mercapto-2-methyl-1-oxopropyl)] bis- -X (trans) -4-methoxy-L-proline ].

In the same manner, but using the cis material of Example 8, this procedure gives 1,1 '- [dithiodi- (1--D-3-mercapto-2-methyl-1-oxopropyl)] - bis ~ [(cis ) -4-methoxy-L- -proline].

Example gel The sodium salt of (trans) -4-methoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline A solution of 2.5 g of the material from Example 4 in 25 ml of water was treated with 0.85 g of sodium bicarbonate. The solution is lyophilized to give the sodium salt of (trans) -4-methoxy-1- ({D-3-mercapto-2-methyl-1-oxopropyl) -L-proline. Similarly, using the cis material of Example 8 according to this procedure, the sodium salt of (cis) -4-methoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L is obtained. -proline.

Example 26 1- (4-Mercapto-1-oxobutyl) -cis-4-methoxy-L-proline a) (cis) -1- (4-acetylthio-1-oxobutyl) -4-methoxy-L-proline Reaction between an equivalent amount of (cis) -4-methoxy-L-proline and 4-acetylthiobutyroyl chloride according to the procedure of Example 1 gives (cis) -1- (4-acetylthio-1-oxobutyl) -4-methoxy-L-proline. b) 1- (4-Mercapto-1-oxobutyl) -cis-4-methoxy-L-proline Hydrolysis of (cis) -1- (4-acetylthio-1-oxobutyl) -4-methoxy-L- -proline with an aqueous ammonia solution according to the procedure of Example 2 gives 1- (4-mercapto-1-oxobutyl) -cis-4-methoxy-L- -proline.

Example 27 27 1- (L-3-mercapto-2-ethyl-1-oxopropyl) -trans-4-methoxy-D-proline a) (trans) -1- [L- (3-acetylthio) -2-ethyl- 1-oxopropyl] -4-methoxy-D-D-troline Using the procedure of Example 1 but using (trans) -4-hydroxy-D-proline instead of (trans) -4--hydroxy-L- the proline in part (a) is obtained (trans) -4-methoxy-D- -proline. Reaction of the latter compound with L- (3-acetylthio) -2-ethylpropionyl chloride according to the procedure of Example 3 gives (trans) -1- [L- (3-acetylthio) -2-ethyl-1-oxopropyl] -4-methoxy-D-proline. b) 1- (L-3-mercapto-2-ethyl-1-oxopropyl) -trans-4-methoxy-fi -proline Hydrolysis of (trans) -1- [L- (3-acetylthio) -2-ethylL1 -oxopropyl] -4-methoxy-D-proline with an aqueous ammonia solution according to the procedure of Example 4 gives 1- (L-3-mercapto-2-ethyl-1-oxopropyl) -trans-4-methoxy-D- proline. 447 477 31 Example 28 1- (2-Mercapto-1-oxoethyl) -trans-4-methoxy-L-proline (a) trans) -1- (2-acetylthio-1-oxoethyl) -4-methoxy-L-proline Using the procedure of Example 1 but using 2-acetylthioacetyl chloride instead of the 3-acetylthiopropionyl chloride, (trans) -1- (2-acetylthio-1-oxoethyl) -4-methoxy-L-proline is obtained. b), 1- (2-Mercapto-1-oxoethyl) -trans-4-methoxy-L-proline Hydrolysis of trans-1- (2-acetylthio-1-oxoethyl) -4-methoxy-L-proline with an aqueous ammonia solution according to the procedure of Example 2 gives 1- (2-mercapto-1-oxoethyl) -trans-4-methoxy-L- -proline.

Example 29 1- (2-Mercapto-1-oxoethyl) -cis-4-methoxy-L-proline a) (cis) -1- (2-acetylthio-1-oxoethyl) -4-methoxy-L-proline cis- 4-Methoxy-L-proline is treated according to the procedure of Example 28 with a solution of 2-acetylthioacetyl chloride in the presence of sodium carbonate to (cis) -1- (2-acetylthio-1-oxoethyl) -4-methoxy-L-proline. b) 1- (2-Mercapto-1-oxoethyl) -cis-4-methoxy-L-proline Hydrolysis of (cis) -1- (2-acetylthio-1-oxoethyl) -4-methoxy-L- -proline with an aqueous ammonia solution gives 1- (2-mercapto-1-oxoethyl) -cis-4-methoxy-L-proline.

Example gel 1- (2-mercapto-1-oxoethyl) -cis-4-methylthio-L-proline a) (cis) -1- (2-acetylthio-1-oxoethyl) -4-methylthio-L-proline Reaction between equivalent amounts of (cis) -4-methylthio-L- -proline [J. Amer. Chem. Soc., 79, (1957) p. 185] and 2-acetylthioacotyl chloride according to the procedure of Example 1 gives (cis) -1- (2-acetylthio-1-oxoethyl) -4-methylthio-L-proline. 447 477 32 b) 1- (2-Mercapto-1-oxoethyl) -cis-4-methylthio-L-proline Hydrolysis of (cis) -1- (2-acetylthio-1-oxoethyl) -4-methylthio-L- -proline with an aqueous ammonia solution according to the procedure of Example 2 gives 1- (2-mercapto-1-oxoethyl) -cis-4-methylthio- -L-proline.

Example 31 1- (D-3-Mercapto-3-methyl-1-oxopropyl) -cis-4- (4-pentynylthio] -1-L-proline a) (cis) -1- [D-3- (acetylthio) -3-methyl-1-oxopropyl] -4- (4-pentynylthio) -L-proline Reaction between (cis) -N-acetyl-4-mercapto-L-proline and 5-chloro-1-pentyne in acetone in the presence of silver oxide according to the procedure of Example 1, Part b, gives (cis) -N-acetyl-4- (4-pentynylthio) -L-proline-4-pentynyl ester. The latter is then hydrolyzed in the manner set forth in Example 1, Part C, to give (cis) -N-acetyl-4- (4-pentynylthio) -L-proline. Reaction of this compound with an equivalent amount of D-3- (acetylthio) -3-methylpropionyl chloride according to the procedure of Example 3 gives (cis) -1- [D-3- (acetylthio) -3-methyl-1-oxopropyl] - 4- (4-pentynyl-thio) -L-proline. b) 1- (D-3-mercapto-3-methyl-1-oxopropyl) -cis-4- (4-pentynylthio) -L-proline Hydrolysis of (cis) -1- [D-3- (acetylthio) ) -3-methyl-1-oxopropyl] -4- (4-pentynylthio) -L-proline with an aqueous ammonia solution according to the procedure of Example 4 gives 1- (D-3-mercapto-3-methyl-1 -oxopropyl) -cis-4- (4-pentynylthio) -L-proline.

Example 32 (cis) -4-Benzylthio-1- (D, L, -3-mercapto-3-ethyl-1-oxopropyl) -L--proline a (cis) -1-in, La- (acetyl) - 3-Ethyl-1-oxopropyl] -ph 2 -benzylthio- -L-proline Reaction between (cis) -N-acetyl-4-mercapto-L-proline and benzyl chloride in acetone in the presence of silver oxide according to the procedure of 447 477 33 Example 1, part b gives (cis) -N-acetyl-4-benzylthio-L-proline-benzyl ester. The latter is hydrolyzed as described in Example 1, Part c to give (cis) -N-acetyl-4-benzylthio-L-proline.

Reaction of this compound with an equivalent amount of D, L-3- (acetylthio) valeroyl chloride according to the procedure of Example 3 gives (cis) -1- [D, L-3- (acetylthio) -3-ethyl-1-oxopropyl] - 4- - (benzylthio) -L-proline. b) (cis) -4-Benzylthio-1- (D, L-3-mercapto-3-ethyl-1-oxopropyl) -L-proline Hydrolysis of (cis) -1- [D, L-3- (acetylthio) -3-ethyl-1-oxopropyl] -4- (benzylthio) -L-proline and an aqueous ammonia solution according to the procedure of Example 4 give (cis) -4-benzylthio-1- (D, L-3- -mercapto-3-ethyl-1-oxopropyl) -L-proline.

Example gel 33 1,1 '- [dithiodi- (1,3-D-3-mercapto-2-methyl-1-oxopropyl)] - bis-1- (trans) -4-methylthio-L-nrolin] The product of Example 21 is treated with iodine in ethanol according to the procedure of Example 24 to give 1,1 '- {dithiodi- (1D-3-mercapto--2-methyl-1-oxopropyl)] bis [(trans) -4-methylthio-L-proline] .

Example gel 34 (cis) 41- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4-methylthio-L--proline Reaction between equivalent amounts of (cis) -4-methylthio-L-proline [J . Amer. Chem. Soc., 79, (1957) p. 185] and D-3- (benzoylthio) -2-methyl-propionyl chloride according to the procedure of Example 3 gives (cis) -1- [D-3- (benzoylthio) -2- methyl-1-oxo-propyl] -4-methylthio-L- -proline.

Example Gel 35 (trans) -1- [D-3- (phenylacetyl) -2-methyl-1-oxopropyl] -4-methylthio- -L-proline Reaction between equivalent amounts of (trans) -4-methylthio-L-proline [ J. Amer. Chem. Soc., 79, (1957) p. 185] and D-3- (phenylacetylthio) -2-methylpropionyl chloride according to the procedure of Example 3 gives 447 477 34 (trans) -1- [D-3- (phenylacetyl) - 2-methyl-1-oxopropyl] -4-methylthio-L-proline.

Example then (cis) -4- (4-fluorophenoxy) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-orolin a; (cis) -4- (4-fluorophenoxy) -L-proline To a solution of 8.4 g (0.024 mol) of N-carbobenzoxy-trans--4-hydroxy-L-proline benzyl ester [Baer et al., Can. J. Bioxhem. & Phys., 37, (1959) p. 5831, 4.0 g (0.036 mol) of 4-fluorophenol and 9.27 g (0.036 mol) of triphenylphosphine in 75 ml of dry tetrahydrofuran are added dropwise over 1 hour 6.2 g (0.036 mol) of diethyl azodicarboxylate in 25 ml of tetrahydrofuran. The solution is stirred overnight at room temperature. The mixture is evaporated to dryness and 100 ml of ether are added to the residue. A precipitate of triphenylphosphine and diethyl azodicarboxylate is filtered off.

Column chromatography (silica gel) separates 8.1 g of a CL 'O mixture containing approximately 70 N-carbobenzoxy-cis-4- - (4-fluorophenoxy) -L-proline benzyl ester.

A solution of 7.5 g of a mixture containing the above-mentioned benzyl ester is hydrogenated at an atmosphere (room temperature) with 0.8 g of 10 -g Pd / C. A white precipitate forms during the reaction. When hydrogen uptake has ceased, the mixture is filtered and the filter cake is leached with three 125 ml portions of hot methanol.

The methanol solution is evaporated to dryness to give 3.2 g of cis--4- (4-fluorophenoxy) -L-proline; mp 235-2360. lHl2FNO3. 1/3 H 2 O: C 57.14; H 5.48; % Analysis calculated for Cl N 6.06; F 8.22 Found: C 56.94; H 5.19; N 5.94; F 7.97. b) 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -cis-4- (4-fluoro-phenoxy) -L-proline To a suspension of 2.25 g (0, 1.0 g (0.01 mol / ml) of c-4- (4-fluorophenoxy) -L-proline in 125 ml of dry pyridine at room temperature is added 1.0 g (0.0 ml / ml) of trictylamine and 2 g (0.0 μl of mol) of D-3- ( acetylthio) -2-methylpropionyl chloride. After stirring overnight at room temperature, the mixture is evaporated to dryness. The residue is taken up in water, covered with ether and acidified with 10% hydrochloric acid. The aqueous layer is extracted repeatedly with ether, the ether layers are combined, washed with water, dried (Na 2 SO 4) and evaporated to dryness to give 3.9 g of residue. The residue is chromatographed on 250 ml of silica gel with ether to give a fraction containing the desired product. The column is washed with methanol and the methanol washings are chromatographed on a short silica gel column to give more of the product.

This process is repeated once more to give 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-mercapto-2-methyl-1-oxopropyl) -L-proline 1,2 g 1- [D-3- (acetylthio) - 2-Methyl-1-oxopropyl] -cis-4- (4-fluorophenoxy) -L-proline is dissolved in 25 ml of methanol and treated with 5 ml of concentrated ammonia under an argon atmosphere for 40 minutes. The volatiles are removed and the residue is covered with ethyl acetate. The aqueous layer is acidified with 10% hydrochloric acid. The layers are separated and the acidic layer is washed with ethyl acetate. The combined organic layers are stripped off with water (2 X), saturated sodium chloride solution (2 X) and dried (Na 2 SO 4). The solvent is stripped off to give 1.1 g of a solid foam residue of cis-4- (4-fluorophenoxy) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline.

Analysis calculated for C 15 H 18 FNO 4. 1/3 H 2 O: C 54.05; H 5.70; N 4.20; F 5.70; S 9.60; Found: C 54.04; H 5.71; N 4.05; F 5.40; S 9.61.

Thin layer chromatography showed the product at Rf 0.30 detected by UV light, SH reagent (yellow spot) and vanilla (yellow spot). [α] D -5-800 (c, 1% in chloroform).

Example 37 1- (3-Mercapto-1-oxopropyl) -cis-4-phenoxy-L-proline a) (cis) -4-phenoxy-L-proline 447 477 36 According to the procedure of Example 36 (a) but by using the equivalent amount of phenol instead of 4-fluorophenyl, (cis) -4-phenoxy-L-proline is obtained. b) 1- [3- (acetylthio) -1-oxopropyl] -cis-4-phenoxy-L-proline (cis) -4-phenoxy-L-proline is reacted with a solution of 3--acetylthiopropionyl chloride in the presence of sodium carbonate according to the procedure of Example 1 to give 1- [3- (acetylthio) -1-oxopropyl] -cis-4-phenoxy-L-proline. c) 1- (3-Mercapto-1-oxopropyl) -cis-4-phenoxy-L-proline Hydrolysis of 1- [3- (acetylthio) -1-oxopropyl] -cis-4-phenoxy-L- -proline with an aqueous ammonia solution according to the procedure of Example 2 gives 1- (3-mercapto-1-oxopropyl) -cis-4-phenoxy-L- -proline.

Example 38 1- (D-3-Mercapto-2-methyl-1-oxopropyl) -cis-4- (4-methylbenzyloxy) - -L-proline Following the procedure of Example 36 but using the equivalent amount of 4-methylbenzyl alcohol instead of the 4-fluorophenol in part (a), 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis--4- (4-methylbenzyloxy) -L-proline is obtained.

Example 39 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4-phenethyloxy-L-proline According to the procedure of Example 36 but using an equivalent amount of phenethyl alcohol instead of the 4-fluorophenol in part ( a) there is obtained le (D-3-mercapto-2-methyl-1-oxopropyl) -cis--4-phenethyloxy-L-proline.

Example 40 'a 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4- (3-methylthiophenoxy) -L-proline Following the procedure of Example 36 but using an equivalent amount of 3- methylthiophanol instead of 4-fluorophenol in part (a) gives 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis--4- (3-methylthiophenoxy) -L-proline.

Example 41 (cis) -4- (4-chlorophenoxy) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline According to the procedure of Example 36 but using an equivalent amount of 4- chlorphenol instead of 4-fluorophenylene in part (a), (cis) -4- (4-chlorophenoxy) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline is obtained. Example 42 1- (2-Mercapto-1-oxoethyl) -cis-4- (4-methoxyphenoxy) -L-proline a) (cis) -4- (4-methoxyphenoxy) -L-proline According to the procedure of Example 36 ( a) but by using an equivalent amount of 4-methoxyphenol instead of the 4-fluorophenol, (cis) -4- (4-methoxyphenoxy) -L-proline is obtained. b) 1-2- (acetylthio) -1-oxoethyl] -cis-4- (4-methoxyphenoxy) -L-proline (Cis} -4- (4-methoxyphenoxy) -L-proline is reacted with a solution of 2 acetylthioacetyl chloride according to the procedure of Example 1, part (d) to give 1- [2- (acetylthio) -1-oxoethyl] -cis-4- (4-methoxyphenoxy) -L-proline c) 1- (2 -mercapto-1-oxoethyl) -cis-4- (4-methoxyphenoxy) -L-proline Hydrolysis of 1- [2- (acetylthio) -1-oxoethyl] -cis-4- (4-methoxyphenoxy) -L -pricline with an aqueous ammonia solution according to the procedure of Example 2 gives 1- (2-mercapto-1-oxoethyl) -cis-4- - (4-methoxyphenoxy) -L-proline.

Example 43 - '(cis) -4- (4-fluorophenylthio) -1- (D-3-mercapto-2-methyl-1-oxo-pronyl) -L-proline According to the procedure of Example 36 but using one equivalent amount of 4-fluorophenylmercaptan instead of the 4-fluorophenol in part (a) is obtained (cis) -4- (4-fluorophenylthio) -1- (D--3-mercapto-2-methyl-1-oxopropyl) -L-proline.

Example 44 1- (D-3-Mercapto-2-methyl-1-oxopropyl) -cis-4-phenylthio-L-proline and N-carbobenzyloxy-cis-4-phenylthio-L-proline methyl ester Sodium metal (0.85 g, 0.037 mol) is dissolved in 40 ml of absolute ethanol. To this is added with stirring 3.7 ml (0.036 mol) of thiophenol followed by 7.5 g (0.017 mol) of N-carbobenzyloxytrans-4-tosyloxy-L-proline methyl ester [J. Am. Chem. Soc., 79, (1957) pp. 191]. The latter gradually goes into solution but shortly afterwards a solid product is separated. After stirring for 4 hours and after being allowed to stand overnight at room temperature, the main mass of the ethanol is evaporated on a rotary evaporator. Most of the solid residue is stirred with 120 ml of dichloromethane and 60 ml of water. The layers are separated (a certain amount of methanol is added to facilitate the breakdown of the emulsions) and the aqueous phase is extracted with additional dichloromethane (2 X 60 ml).

The combined organic phases are washed with 100 ml of saturated sodium chloride solution, dried (MgSO 4) and the solvent is evaporated to give 6.5 g (100%) of N-carbobenzyloxy-cis-4-phenylthio-L-proline methyl ester as a light yellow viscous oil. b) N-Carbobenzyloxy-cis-4-phenylthio-L-proline The methyl ester from part (a) (6.5 g, 0.017 mol) is dissolved in 55 ml of methanol, treated portionwise at -10 to 40 with 13 ml (0.026 mol) 2N sodium hydroxide is stirred at 0 ° C for one hour and kept at room temperature for about 16 hours. After removing about half of the solvent on a rotary evaporator, the cooled solution is diluted with 100 ml of water, washed with 60 ml of ether (the washing liquid is discarded), layered over 70 ml of ethyl acetate, stirred, cooled and acidified with 4.8 ml of 1L hydrochloric acid. After separation, the hydrogen phase is extracted with additional ethyl acetate (3 x 40 ml) and the combined organic layers are dried (MgSO 4) and evaporated to give 5.9 g of a light yellow viscous oil. The latter is dissolved in 30 ml of ethanol, treated with 1.9 g of cyclohexylamine in 3 ml of ethanol and diluted with 447,477 39 JS ml of ether. Upon seeding, the crystalline cyclohexylamine salt is separated. The latter weighs 5.3 g after cooling for about 1 hour; melting point 148-151 ° (p. 1350). This material is combined with 1.5 g of identical product from a previous experiment, stirred with 200 ml of boiling acetonitrile and cooled to give 6.3 g of colorless cyclohexylamine salt; melting point l52-1550 rs. 1370) [a1â6 -240 (C,% 1 ethanol).

This cyclohexylamine salt is suspended in 25 ml of ethyl acetate and stirred and treated with 25 ml of N hydrochloric acid. When two clear layers are obtained, these are separated and the aqueous phase is extracted with additional ethyl acetate (3 X 25 ml). The combined layers are dried (MgSO 4) and the solvent is evaporated to give 5.0 g (65%) of N-carbobenzyloxy-cis-4-phenethylthio-L-proline as an almost colorless highly viscous syrup. c) (cis) -4-phenylthio-L-proline hydrobromide N-carbobenzyloxy-cis-4-phenylthio-L-proline (4.9 g, 0.014 mol) is treated with 25 ml of hydrogen bromide in acetic acid (30-32%) and is stirred magnetically. After 1 hour, the orange-yellow solution is diluted to 250 ml with ether to precipitate the product as a heavy oil which gradually crystallizes as it is inoculated, grated and cooled. After stirring in an ice bath for 1 hour, the material is filtered under a nitrogen atmosphere, washed with ether, suspended in fresh ether, cooled for about 16 hours and filtered again to give 3.2 g (77%) of a colorless solid (cis) -4. -phenylthio-L-proline hydrobromide; mp o 7 196-1o9 ° (S. 99 °>, [α156-3- (C, s 1 methanol). d) 1- [D ~ 3 ~ (acetylthio) -2-methyl-1-oxopropyl] ~ cis -4-phenylthio- -L-proline Reaction between 3.0 g (0.0094 mol) (cis) -4-phenylthio-L-proline hydrobromide and 2.0 g (0.0 μl mol) of D-3-acetylthio -2-methyl-tropionyl chloride in 25 ml of water as described in Example 1, part (d) (using about 15 ml of 20% sodium carbonate solution to maintain the pH at 8.0 to 8.4) gives 3.3 g of a light yellow viscous oil. The dicyclohexylamine salt 4-47 477 40 (prepared in 30 ml of ethyl acetate using 1.8 g of dicyclohexylamine) weighs 2.9 g (isolated in two crops); mp 184-188 (p. 1800). After decomposition with 15 ml of acetonitrile, 2.4 g of colorless solid dicyclohexylamine salt are obtained; mp 1254-1860 (p. 180 °), (oqâö-vso, (c, 1% in ethanol).

This diocylohexylamine salt is treated with 30 ml of 10% potassium bisulfate and extracted into ethyl acetate in the manner described in Example 1 to give 2.0 a (59%) glass-like 1- [D-3- - (acetylthio) - 2-methyl-1-oxopropyl] -cis-4-phenylthio-L-proline. e) 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4-phenylthio-L--orolein 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] - cis-4-phenylthio-L-proline (2.0 g, 0.0042 mol) is treated with 3.5 ml of concentrated ammonia in 8.5 ml of water according to the procedure of Example 2. The ammonium salt of the product is separated from the reaction. the mixture does not give 1.35 g (100%) of viscous syrupy 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4-phenylthio-L-proline, [α] 6-430 gc .1% in ethanol).

Example 45 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4- (4-chlorophenylthio) -L-proline Following the procedure of Example 44 but using the equivalent amount of 4-chlorophenyl mercaptan instead of the thiophenol in part (a), 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4- - (4-chlorophenylthio) -L-proline is obtained.

Example 46 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4- (3-trifluoromethyl-phenylthio) -L-proline Following the procedure of Example 44 but using the equivalent amount of 3- trifluoromethylphenylmercaptan instead of the thiophenol in part (a) there is obtained 1- (D-3-mercapto-2-methyl-1-oxo-5-propyl-cis- (3-trifluoromutylphenylthio) -L-proline 447 477 41 Example 44 (cis ) -4- (4-hydroxyphenylthio) -1- (3-mercapto-1-oxopropyl) -L- -nroline a) (cis) -4- (4-acetyloxyphenylthio) -L-proline hydrobromide Following the procedure of Example 44 (a ) to (c) but by using an equivalent amount of 4-acetyloxyphenyl mercaptan instead of the thiophenol in part (a), (cis) -4- (4-acetyloxyphenylthio) -1-proline hydrobromide is obtained. b} (cis) -4- (4-acetyloxyphenylthio) -1- [3- (acetylthio} -1-oxopropyl] -L-nrolin Reaction between (cis) -4- (4-acetyloxyphenylthio) -L-proline hydro- bromide and 3-acetylthiopropionyl chloride according to the procedure of Example 1, part (d) gives (cis) -4- (4-acetyloxyphenylthio) -1- [[3-acetylthio) -1-oxopropyl] -L-proline. c) (cis) -4- (4-hydroxyphenylthio) -1- (3-mercapto-1-oxopropyl) -L-proline Hydrolysis of (cis) -4- (4-acetyloxyphenylthio) -1- [3- ( acetylthio) -1- -oxopropyl] -1-oxopropyl] -L-proline with an aqueous ammonia solution according to the procedure of Example 2 gives (cis) -4- (4-hydroxyphenylthio) -1- (3-mercapto- 1-oxopropyl) -L-proline. cell 48 (cis) -4-benzyloxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L- -proline Following the procedure of Example 44 but using the equivalent amount of benzyl alcohol instead of thiophenol in part (a) gives (cis) -4-benzyloxy-1- (D-3-mercapto-2-ethyl-1-oxopropyl) -L- -proline.

Example 49 - - (trans) -1- (3-mercapto-1-oxopropyl) -3-methylthio-D, L-proline a) 1,2-dehydroproline, t-butyl ester To a stirred solution of 34.2 q ( 0.20 mol) of prinlin-1-bullyl ester in 600 ml of ether at -50 to 0 ° C is added dropwise over 447 477 42 minutes 21.7 g (23.9 ml, 0.20 mol) of freshly prepared t-butyl [Org. Syn., Coll. Vol. V, 184 (lQ73)]. During the addition, the temperature is kept at -50 to 0 ° C. When the addition is complete, the solution is stirred at this temperature for a further 5 minutes.

To the thoroughly stirred solution is rapidly added ('5-3 minutes) a solution of 7.8 g (0.20 mol) of potassium in freshly distilled dry (CaH2) t-butanol. After the addition, the temperature of the reaction mixture is about 180. The reaction vessel is removed from the cooling bath and stirred for 30 minutes. The reaction mixture is filtered through celite (diatomaceous earth) and the filtrate is concentrated in vacuo. The residue is taken up in ether and washed with several portions of water. The ether solution is dried and concentrated in vacuo to 31.6 g of a yellow liquid. Traces of hydroquinone are added and the crude product is distilled to give 22.4 g of 1,2-dehydroproline, t-butyl ester (66%), b.p. 60-620 / 0.1 mm. b) 1-Benzyloxycarbonyl-4,5-dihydro-1H-pyrrole-2-carboxylic acid, t-butyl ester A solution of 16.9 g (0.1 mol) of 1,2-dehydroproline, t-butyl ester in 70 ml of dichloromethane is cooled to -100 under argon atmosphere. A solution of freshly distilled benzyl chloroformate [14.2 ml, 0.1 mol, b.p. 62 DEG-64 DEG (0.4 mm)] in 70 ml of dichloromethane is added dropwise over 30 minutes. After stirring under cooling for a further 30 minutes, 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 over a 20-minute period. minutes period. The cooling bath is then removed and the mixture is stirred at room temperature for 1 hour. After washing twice with cold dilute hydrochloric acid and once with saturated sodium carbonate solution, the solution is dried in vacuo to give 18.2 g (60%) of 1-benzyloxycarbonyl-4,5-dihydro-1H-pyrrole-2-carboxylic acid, t-butyl ester as bright yellow oil. c) (trans) -1-Benzyloxycarbonyl-3-methylthio-D, L-proline, t-butyl ester 'A solution of 18.2 g (0.06 mol) of 1-benzyloxycarbonyl-4,5-dihydro- 1H-Pyrrole-2-carboxylic acid, t-butyl ester in 180 ml of dry methanol is treated with 3.24 g (0.06 mol) of sodium methoxide and cooled in an ice bath. The methanethiol is bubbled slowly into the solution for 30 minutes. The mixture is stirred overnight under an argon atmosphere at room temperature. Diluted aqueous hydrochloric acid is added until the solution is slightly acidic. Argon is bubbled through the solution for 1 hour before being transferred almost to dryness in vacuo. Ethyl acetate is added and the solution is washed twice with saturated sodium carbonate solution, dried and freed from the solvent in vacuo to give 17 g of yellow oil. This oil is chromatographed using 300 g of silica gel and petroleum ether ether (4: 1) to give 11.1 g of (trans) -1-benzyloxycarbonyl-3-methylthio-D, L-proline as a colorless oil. d) (trans) -3-methylthio-D, L-proline 8.4 g (0.024 mol) of (trans) -1-benzyloxycarbonyl-3-methylthio-D, L-proline are treated with 45 ml of 4N hydrobromic acid in acetic acid.

After stirring for 1 hour at room temperature, the solution is dried in vacuo. A small amount of water is added and this is washed twice with ether. The aqueous solution is applied to a column containing 300 ml of ion exchange resin and water is passed through the column until the eluate is no longer strongly acidic. The product is then eluted with pH 6.5 (aqueous pyridine acetate) buffer. Fractions, positive for ninhydrin, are combined and lyophilized to give 3.4 g (88%) of white fluff. A small sample of this material is crystallized from methanol to give (trans) -3-methylthio-D, L-proline; melting point 196-2000 (decomposition) <3. 192 °).

Analysis calculated for C 6 H 11 O 2 NS: C 44.70; H 6.88; N 8.96; S 19.89.

Found: C 44.53; H 7.10; N 8.61; S 19.95. e) (trans) -1- [3- (acetylthio) -1-oxopropyl] -3-methylthio-D, L-proline 3.05 g (0.019 mol) (trans) -3-methylthio-D, L The protein is dissolved in 19 ml of 1N sodium carbonate and diluted with 100 ml of water. The solution is cooled in an ice bath and with rapid stirring a solution of 3-acetylthiopropionyl chloride in 20 ml of ether is added. The pH is maintained at 8 by the addition of 1N sodium carbonate. 447 477 44 Towards the end of a 30 minute period the pH is kept constant and 45 ml of sodium carbonate solution are added. The layers are separated and the aqueous layer is washed with 10% potassium bisulfate solution and once with ether. The aqueous layer is then acidified with the product extracted into ethyl acetate, dried and freed from the solvent in vacuo to give 5.2 g of oil. The material is chromatographed on 150 g of silica gel using ethyl acetate for elution. 3.85 g of a slightly crude (trans) -1- [3- - (acetylthio) -1-oxopropyl] -3-methylthio-D, L-proline are obtained.

A small sample is dissolved in ether and converted to the dicyclohexylamine salt which is recrystallized from ethyl acetate to give (trans) -1- [3- (acetylthio) -1-oxopropyl] -3-methylthio-D, L-proline, dicyclohexylamine salt; melting point 153-1570.

H O NS: (C 6 H 11) 2 NH: 11 17 4 c 58.44; H 8.53; Analysis calculated for C N 5.83; S 13.57.

Found: C 58.77; H 8.57; N 5.68; S 13.74. f) (trans) -1- (3-mercapto-1-oxopropyl) -3-methylthio-D, L-proline 2.05 g (0.007 mol) (trans) -1- [3- (acetylthio) -1- oxopropyl] -3-methylthio-D, L-proline is cooled in an ice bath under an argon atom and treated with a cold argon saturated mixture of 7 ml of water and 7 ml of concentrated ammonia. After stirring for 30 minutes at 0 DEG C., the solution is acidified with hydrochloric acid. The product is extracted into ethyl acetate, dried and freed from solvent in vacuo to give 1.85 g of material which becomes partially crystalline when allowed to stand. Decomposition with ether gives 1.0 g (57%) of white crystalline product. Recrystallization from ethyl acetate (5 ml) gives 0.85 g of (trans) -1- (3-mercapto-1-oxopropyl) -3-methylthio-D, L-proline; mp 89-930.

Analysis calculated for C 9 H 15 O 3 NS 2: C 43.35; H 6.06; N 5.62; S 25.72.

Found: C 43.35; H 6.27; N 5.54; S 25.91.

Example 50 (trans) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -3-ethylthio- D, L-proline 447 477 45 a) (trans) -3-ethylthio-D, L -proline According to the general procedure of Examples 49 (a) to (d) but by replacing the methanethiol with the equivalent amount of ethyl mercaptan, (trans) -3-ethyl-D, L-proline is obtained. b) (trans) -1- [D-3- (acetylthio) -2-methyl-1-oxoprocyl) -3-ethylthio-D, L-proline Reaction between (trans) -2-ethylthio-D, L -proline and D-3-acetylthio-2-methylpropionyl chloride according to the procedure of Example 3 give (trans) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -3-ethylthio- -D , L-proline. c) (trans) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -3-ethylthio- -D, L-proline Hydrolysis of (trans) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -3-ethylthio-D, L-proline with an aqueous ammonia solution according to the procedure of Example 4 gives (trans) -1- (D-3-mercapto--2-methyl-1- oxopropyl) -3-ethylthio-D, L-proline.

Example gel 51 (trans) -1- (3-mercanto-1-oxopropyl) -3-phenylthio-D, L-proline According to the general procedure of Example 49 but substituting the methanethiol for equivalent thiophenol (trans) -1- (3-mercapto-1-oxopropyl) -3-phenylthio-D, L-proline.

Example Gel 52 (cis) -4-Methoxy-1- (D-3-mercapto-2-trifluoromethyl-1-oxopropyl) -L-proline a) 3- (4-methoxybenzyl) thio-2-trifluoromethylpropionyl chloride A pure mixture of 1-Trifluoromethylacrylic acid (3.9 g) and 4-methoxybenzylthio (4.3 g) are stirred at 100-1100 for one hour.

The mixture is cooled to room temperature and the solid is recrystallized from cyclohexane to give 3- (4-methoxybenzyl) thio--2-trifluoromethylpropanoic acid, m.p. 72-740.

Treatment of this acid with thionyl chloride gives 3- (4-methoxybunic acid thio-2-trifluoromethylpropionyl chloride. B) (cis) -4-methoxy * 1- {D-3- (4-methoxybenzyl) thio-2-trifluoro methyl-1-oxopropyl] -L-proline 3- (4-methoxybenzyl) thio-2-trifluoromethylpropionyl chloride is reacted with (cis) -4-methoxy-L-proline to give (cis) -4-methoxy-1- [D-3- (4-methoxybenzyl) thio-2-trifluoromethyl-1-cyclopropyl] -L- -proline. c) (cis) -4-methoxy-1- (D-3-mercapto-2-trifluoromethyl-1-oxopropyl) -L-proline (cis) -4-methoxy-1- [D-3- (4-methoxybenzyl) The thio-2-trifluoromethyl-1-oxopropyl] -L-protein is mixed with trifluoroacetic acid and anisole and stirred under nitrogen. The solvent is removed in vacuo to give the remaining (cis) -4-methoxy-1- (D-3- mercapto-2-trifluoromethyl-1-oxopropyl) -L-proline Example 53 '(trans) -4-methoxy-1- (D-3-mercapto-2-trifluoromethyl-1-oxopropyl) -L-proline According to the procedure in Example 52 but by replacing the cis isomer with the (trans) -4-methoxy-L-proline the (trans) -4-methoxy-1- (D-3-mercapto-2-trifluoromethyl-1-oxopropyl) is obtained. L-proline.

Example Gel 54 (trans) -4-Ethoxy-1- (D-3-mercapto) -2-trifluoromethyl-1-oxopropyl) -L-proline a) 3-Acetylthio-2-trifluoromethylpropionyl chloride A mixture of thiol acetic acid and 2- ( trifluoromethyl) acrylic acid is heated on a steam bath for 1 hour and then stored at room temperature for 18 hours. The reaction mixture is distilled off in vacuo to give 3-acetylthio-2-trifluoromethylpropanoic acid.

Treatment of this acid with thionyl chloride gives 3-acetylthio-2-trifluoromethylpropionyl chloride. 447 477 47 b) (trans) -4-ethoxy-1- [D-3- (acetylthio) -2-trifluoromethyl-1-oxopropyl] -L-proline Reaction between 3-acetylthio-2-trifluoromethylpropionyl chloride and trans-4 -ethoxy-L-proline according to the procedure of Example 3 gives (trans) -4-ethoxy-1- [D-3- (acetylthio) -2-trifluoromethyl-1-oxopropyl] -L-proline. c) (trans) -4-ethoxy-1- (D-3-mercapto-2-trifluoromethyl-1-oxo-propyl) -L-proline Treatment of (trans) -4-ethoxy-1- [D-3- (acetylthio) -2-trifluoromethyl-1-oxopropyl] -L-proline with an aqueous ammonia solution according to the procedure of Example 4 gives (trans) -4-ethoxy-1- (D-3-mercapto-2 -trifluoromethyl-1-oxopropyl) -L-proline. 447 477 48 Example 55 (cis) -4- (1,1-dimethylethoxy) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline (a) N-carbobenzyloxy-cis -4- (1,1-dimethylethoxy) -L-proline, methyl ester A solution of 6.0 g (0.02l mol) of N-carbobenzyloxy-cis-4-hydroxy-L-proline, methyl ester in 60 ml of methylene chloride is placed in a Parr bomb, is magnetically stirred, cooled in a dry ice-propanol bath and treated with about 40 ml of condensed isobutylene followed by 0.75 ml of concentrated sulfuric acid. The bomb is sealed and the reaction mixture is allowed to warm to room temperature with continued stirring. No measurable pressure increase is registered. After stirring at room temperature for 4 days, the bomb is opened and the solution (80 ml) is diluted with 120 ml of methylene chloride and washed with 5 g of sodium bicarbonate in 100 ml of water. The aqueous phase is re-extracted with 50 ml of methylene chloride, the organic layers are combined and dried (MgSO 4) and the solvent is evaporated to give 7.5 g of N-carbobenzyloxy-cis-4- (1,1-dimethylethoxy) -L-proline, methyl ester as a bright yellow oil; [α] D 25 -460 (c, 1% in chloroform). TLC (on silica gel): Rf 0.62 (ethyl acetate), Rf 0.43 (7: 1 benzene: acetic acid); visualized: U.V. I2 steam. (b) N-Carbobenzyloxy-cis-4- (1,1-dimethylethoxy) -L-proline A stirred solution of the methyl ester from part (a) (7.2 g, 0.02 mol) in 15 ml of ether is cooled in ice water. and treated portionwise with 42 ml (0.042 mol) of ice-cold 1N sodium hydroxide. After stirring and cooling for a total of 6 hours, the cooling bath is removed and stirring is continued overnight at room temperature. The clear solution is washed with 40 ml of ether (the washing liquid is discarded), layered with 40 ml of ethyl acetate, stirred, cooled and acidified with 8 ml of 6N hydrochloric acid. After separation, the aqueous phase is extracted with additional ethyl acetate (3 x 40 ml), the organic layers are combined and dried (MgSO 4) and the solvent is evaporated to give 6.8 g of a light yellow viscous oil. This oil is dissolved in 50 ml of acetonitrile and treated with a hot solution of 3.2 g of 1-adamantanamine in 20 ml of acetonitrile. The solid adamantanamine salt is rapidly separated. After cooling overnight, the colorless salt is filtered under nitrogen, washed with cold acetonitrile and ether and dried in vacuo to give 8.8 g of N-carbobenzyloxy-cis-4- (1,1-dimethylethoxy) -L-proline, adamantanamine salt ; mp 228 ° -23 ° (dec.), p. 21s °, [α2nzs -280 (c, 1% in methanol).

Analysis. Calculated for C 17 H 23 NO 5.ClOH 17 N.O, 25 H 2 O: C 67.96; H 8.56; N 5.87. Found: C 67.77; H 8.54; N 5.93.

Treatment of the above adamantanamine salt (8.5 g) with acid gives 5.5 g of N-carbobenzyloxy-cis-4- (1,1-dimethylethoxy) -L-proline as an almost colorless viscous syrup. Thin layer chromatography: Rf 0.20 (85: 15 toluene: acetic acid on silica gel; visualized Iz steam or PMA plus heat). (c) cis-4- (1,1-dimethoxyethoxy) -L-proline The N-carbobenzyloxy product from part (b) (5.5 g, 0.017 mol) is hydrogenated in 165 ml of 2: 1 methanol: water under 3 atmospheres of hydrogen in presence of 1.7 g of 5% palladium / carbon catalyst to give 3.2 g of a sticky, partially solid product. This material is suspended in 30 ml of acetonitrile, rubbed and cooled overnight to give 1.35 g of cis-4- (1,1-dimethylethoxy) -L-proline as a colorless solid; mp 2400-2420 (dec.); the occurrence of gradual darkening and "sintering"; [d] D25 -360 (c, 0.5% in methanol).

Analysis. Calculated for C H NO .0.25 H O: C 56.37; H 9.20; 9 17 3 2 N 7.31. Found: C 56.26; H 9.27; N 7.26. (d) 1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -cis-4- (1,1-dimethylethoxy) -L-proline cis-4- (1,1-dimethylethoxy) - The L-proline from part (c) (1.3 g, 0.0069 mol) is reacted with 1.4 g (0.0078 mol) of D-3-acetylthio-2-methylpropionyl chloride in 20 ml of water in the presence of sodium bicarbonate according to the procedure of Example 3 to give 2.2 g of an almost colorless viscous oil. The crude product obtained is dissolved in 50 ml of ethyl acetate and treated with 1.3 g of dicyclohexylamine 447 in 50 ml of ethyl acetate. The product crystallizes from solution and is filtered and dried to give 2.65 g of dicyclohexylamine salt; melting point 181 ° -ls3 °, e. l7o °, [o] Dzs -ez ° (0.1% 1 ethanol).

Decomposition with 15 ml of hot acetonitrile followed by cooling gives 2.4 g of colorless solid dicyclohexylamine salt; melting point 1830-1850, e. l75 ° [o1D2s -e5 ° (o,% 1 ethanol).

Analysis. Calculated for C 15 H 25 NO 5 S.Cl 2 H 23 N: C 63.24; H 9.44; N 5.46; S 6.25. Found: C 63.22; H 9.61; N 5.41; S 6.02.

Using the procedure of Example 3, 2.4 g of the dicyclohexylamine salt is converted to the acid by suspending ethyl acetate, cooling in an ice bath and treating with 30 ml of 10% potassium bisulfate. The layers are separated and the aqueous phase is extracted with 25 ml of ethyl acetate (4x). After the solvent was removed, the material which had become partially crystalline after being subjected to 10 ml of ether was triturated for complete crystallization, diluted with 20 ml of hexane, rubbed and cooled to give 1.3 g of ~ [D-3- (acetylthio) - 2-Methyl-oxopropyl] -cis-4- (1,1-dimethylethoxy) -L-proline as a colorless solid; mp 960-980 (p. 93o), [d] D25 -109 ° (o, in ethanol).

Analysis. Calculated for C 15 H 25 NO 5 S: C 54.36; H 7.60; N 4.23; S 9.68. Found: C 53.92; H 7.73; N 4.30; S 9.29. (e) cis-4- (1,1-dimethylethoxy) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline 1- [D-3- (acetylthio) -2-methyl] -1-oxopropyl] -cis-4- (1,1-dimethylethoxy) -L-proline from part (d) (1.3 g, 0.0039 mol) is hydrolyzed with 2.6 ml of concentrated ammonium hydroxide in 6 ml of water to give 1.1 g of a glass-like residue. Inoculum crystals appear in the product when it is allowed to stand. The material is covered with 8 ml of ether, inoculated and torn. When the glassy product goes into solution, a crystalline solid gradually separates. After 2 hours at room temperature, 20 ml of hexane are added and the mixture is cooled overnight under an argon atmosphere. The solvent is removed to give 1.0 g of colorless solid cis-4- (1,1-dimethyloxy) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline; melting point lo6 ° -los ° (a. lo3 °) [o1D25 -7a ° (o, lt 1 ethanol). 447 477 51 Analysis. Calculated for C 13 H 23 NO 4 S.0.25 H 2 O: C 53.12; H 8.06; N 4.77; S 10.91. Found: C 53.30; H 8.28; N 4.76; S 10.70.

Example 56 (cis) -4 - [(4-fluorophenyl) thio] -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline, L-arginine (1: 1) salt (a) (trans) -1- [D-3- (benzoethyl) -2-methyl-1-oxopropyl] -4-hydroxy-L-proline, methyl ester (D) -3- (benzoyl) -2-methylpropanoic acid ( 56.05 g, 0.25 mol) is suspended in 62.5 ml of toluene. The temperature drops to 15 ° and then 0.386 ml of dimethylformamide is added. Then 32.7 g (0.25 mol + 10% excess) of thionyl chloride are added all at once with stirring. The temperature of the reaction mixture drops to 120 and the container used to measure the thionyl chloride is rinsed with 21.2 ml of toluene, which is then added to the reaction mixture. The temperature is gradually increased to 350 and is kept there for 1 hour. The reaction mixture is stirred at room temperature overnight. The solvent and excess thionyl chloride are removed and the residue is treated twice with 100 ml of toluene, after which the toluene is removed to give 63.4 g of (D) -3- (benzoylthio) -2-methylpropanoic acid chloride.

L-4-hydroxyproline (32.7 g, 0.25 mol) is dissolved in 250 ml of water at pH 5.8. About 60 ml of 10% sodium carbonate is added to adjust the pH to 9.3. The solution is heated to 30 ° and a toluene solution (75 ml) containing 63 g of (D) -3- (benzoylthio) -2-methylpropanoic acid chloride is added simultaneously with 10% aqueous sodium bicarbonate for 1 hour at 300 while maintaining the pH at 9.0. The solution is stirred at pH 9.0 for 1.5 hours and the toluene layer is separated. The aqueous layer is made strongly acidic with concentrated HCl and the crystalline solid is filtered, washed with water and air dried to give 71.4 g of (trans) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 -hydroxy-L-proline; melting point 1950-1960. Recrystallization from alcohol gives a melting point of 1960-1970; [α] D 25 -1390 (c = 1, methanol). 447 477 52 Analysis. Calculated for C 16 H 19 NO 5 S: N 4.15; C 56.95; H 5.67; S 9.50. Found: N 3.96; C 56.56; H 5.77; S 9.50.

A solution of 33.7 g (0.1 mol) of (trans) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] 4-hydroxy-L-proline and 500 mg of p-toluenesulfonic acid in 1 liter of methanol is refluxed gently for about 18 hours. The methanol is removed to give 37 g of a viscous residue which is dissolved in 1400 ml of ether. The ether solution is washed twice with 250 ml of water, twice with 250 ml of 5% sodium bicarbonate and once with 250 ml of brine and dried over MgSO 4.

The ether is removed to give 27.3 g of crystalline product (after decomposition with petroleum ether); mp 640-650. Recrystallization from ether gives (trans) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4-hydroxy-L-proline, methyl ester; mp 65.50-670; [Α] D 25 -580 (c = 1, methanol).

Analysis. Calculated for C 17 H 21 NO 5 S: N 3.99; C 58.10; H 6.02; S 9.12. Found: N 3.96; C 57.96; H 6.09; S 9.11. (b) N- (p-fluorophenylthio) succinimide According to the procedure of Y. Abe et al., Bull. Chem. Soc.

Japan, Volume 46, page 1898 (1973), a suspension of 1,2 g (90.8 mmol) of N-chlorosuccinimide in 500 ml of benzene under nitrogen is treated with a solution of 9.7 g (75.7 mmol) of p-fluorothiophenol. dissolved in 90 ml of benzene. A modest increase in temperature is observed and the reaction mixture turns yellow-orange. After 75 minutes, the solution is cooled to 15 ° C and treated with 9.19 g (90.8 mmol) of triethylamine in 90 ml of benzene added over a period of 25 minutes. The cooling bath is removed and the reaction mixture is stirred for 45 minutes, then filtered and the organic solution is rinsed with three 150 ml portions of water, brine and dried (MgSO 4). When the solvents are removed in vacuo, 15.8 g of crude product are obtained. Recrystallization from chloroform / hexane gives 1.6 g of N- (p-fluorophenylthio) -succinimide, m.p. 130 DEG-130 DEG. 447 477 53 (c) (cis) -1-ID-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(4-fluorophenyl) thio] -L-proline, methyl ester A solution of II, 0 g (48.8 mmol) of N- (p-fluorophenylthio) succinimide in 200 ml of benzene are treated under a nitrogen atmosphere with 9.87 g (48.8 mmol) of tri-n-butylphosphine in 25 ml of benzene. The resulting dark solution is stirred for 10 minutes at room temperature and then 15.6 g (44.4 mmol) of (trans) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 are added. -hydroxy-L-proline, methyl ester. After stirring overnight at room temperature, the reaction mixture is diluted with 200 ml of ether and rinsed with four 75 ml portions of water, brine and dried (MgSO 4). The solvent is removed in vacuo to give 32.6 g of crude product, which is absorbed on approximately 70 g of silica gel and chromatographed on 450 g of Baker silica gel, packed and eluted with 2 liters of 2 L Et 2 O: hexane, then diluted with 2 liters of 2: 1 Et 2 O : hexane and finally with 100% ether. The fractions containing the best product are collected to give 16.7 g of (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(4-fluorophenyl) thio] -L -proline, methyl ester as an oil; [α] D 25 -80.2 (c = 1, chloroform). (d) (cis) -4 - [(4-fluorophenyl) thio] -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline, L-arginine (1: 1) salt En solution of 15.7 g (34.0 mmol) of (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(4-fluorophenyl) thio} L-proline, methyl ester in a mixture of 50 ml of methanol and 150 ml of tetrahydrofuran is cooled in an ice bath under a nitrogen atmosphere. The cold solution is treated with 71.4 ml of 1N aqueous sodium hydroxide added over a period of 10 minutes. The cold bath is removed and the reaction is stirred at room temperature for 5.5 hours, then diluted with 300 ml of water and washed with three 200 ml portions of ether.

The aqueous layer is cooled under nitrogen on an ice bath and acidified to pH 1-2 with concentrated aqueous HCl, then extracted with three 200 ml portions of ether. The combined organic extracts are rinsed with 200 ml of water, brine and dried (MgSO 4).

The solvents are removed in vacuo to give 1.1 g of crude product.

This material is dissolved in ether and treated with a solution of 5.66 g (37.4 mmol) of 1-adamantanamine in methanol. Dilution with 447,477,54 ether gives 15.2 g of adamantanamine salt which is recrystallized by dissolving in (1zl) chloroform-methanol and diluted with ether. This procedure gives 13.3 g of the adamantanamine salt; melting point 2380-2400 (decomposition). Two further recrystallizations from chloroform-methanol-ether give 10.6 g of (cis) -4 - [(4-fluorophenyl) -thio] -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L- proline, adamantanamine salt; mp 242 ° ~ z43 ° (decomposition), [α] D 25 -s1, s ° (c = 0.5, methanol).

A sample of this adamantanamine salt is extracted with ethyl acetate from 1N aqueous HCl to give (cis) -4 - [(4-fluorophenyl) thio] -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline ; [α] D 25 -42.50 (c = 1, absolute ethanol).

A rapidly stirred mixture of 20 ml of 1N HCl, 40 ml of water and 60 ml of ethyl acetate is treated with 8.0 g (16.2 mmol) of (cis) -4 - [(4-fluorophenyl) thio] -1- (D-3 -mercapto-2-methyl-1-oxopropyl) -L-proline, adamantanamine salt which is added portionwise. The above procedure is carried out under nitrogen with ice bath cooling. The aqueous layer is extracted with two additional 60 ml portions of ethyl acetate and the combined organic extracts are rinsed with dilute aqueous HCl, water and brine. After drying (MgSO 4), the solvents are removed in vacuo to give 5.78 g of the liberated acid as a crude oil. The oil is dissolved in a mixture of 40 ml of ethyl acetate and 10 ml of ether. This solution is shaken in a separatory funnel with 2.68 g (1.54 mmol) of L-arginine dissolved in 50 ml of water. The aqueous layer is rinsed again with ether, placed on a rotary evaporator for 15 minutes at low vacuum and finally lyophilized overnight to give 7.97 g of (cis) -4 [(4-fluorophenyl) thio] -1- (D) -3- mercapto-2-methyl-1-oxopropyl) -L-proline, L-arginine salt (1: 1); [d] D 25 -42.7 (c = 1, water). Analysis.

Calculated for C 15 H 18 FNO 3 S 2 .C 6 H 14 N 4 O 2 C 47.08; H 6.40; N 13.08; S ll, 97; F 3.55; SH 6.16. Found: C, 47.21; H 6.74; N 13.28; S ll, 7l; F 3.38; SH 5.98. 447 477 55 Example 57 (cis) -4 - [(4-chlorophenyl) thio] -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline, L-arginine salt (1: l) (a) N- (p-chlorophenylthio) succinimide According to the procedure of Y. Abe et al., supra, 4.3 g (33.2 mmol) of N-chlorosuccinimide and 1800 ml of benzene are treated with 40.0 g (27 g). .7 mmol) p-chlorothiophenol dissolved in 360 ml of benzene. After 1 hour, the resulting orange solution is cooled to 150 and 33.6 g (33.2 mmol) of triethylamine in 360 ml of benzene are added over a period of 15 minutes. The cooling bath is removed and the reaction mixture is stirred at room temperature for a further 45 minutes. The reaction mixture is then filtered and the organic solution is rinsed with three 500 ml portions of water, 500 ml of brine and dried (MgSO 4). The solvents are removed in vacuo to give 55.1 g of crude product. Decomposition with 900 ml of petroleum ether gives 42.0 g of N- (p-chlorophenylthio) succinimide; melting point 1359-1529. (b) (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] - [(4-chlorophenyl) thio] -L-proline, methyl ester 12.6 g (62, 3 mmol) of tri-n-butylphosphine dissolved in 25 ml of benzene are added to a solution of 15.1 g (62.3 mmol) of N- (p-chlorophenylthio) succinimide in 250 ml of benzene at room temperature under a nitrogen atmosphere. After 10 minutes, add 9 (56.9 mmol) (trans) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4-hydroxy-L-proline, methyl ester and keep the reaction mixture at room temperature. temperature under a nitrogen atmosphere for 2 days. At the end of this time, the reaction mixture is diluted with 300 ml of ether and rinsed with four 100 ml portions of water, brine and dried (MgSO 4). The solvents are removed in vacuo to give 46 g of crude material which is absorbed onto approximately 75 g of silica gel and chromatographed on a 450 g Baker silica gel column. The column is packed and eluted with ether and the fractions containing the best product are collected to give 27.2 g of product. A small amount (0.48 g) of the above product was flash flash chromatographed on 25 g of EM9385 silica gel packed and eluted first with methylene chloride and then with 18: 1 methylene chloride zethyl acetate to give 0.28 g (cis). -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(4-chlorophenyl) thio] -L-proline, methyl ester; [d] D 25 -86.6o (c = 1, chloroform). (c) (cis) -4 - [(4-chlorophenyl) thio] -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline, L-arginine salt (lzl) A solution of 24 , 3 g (50.8 mmol) (cis) - [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(4-chlorophenyl) thio] -L-proline, methyl ester i a mixture of 80 ml of methanol and 220 ml of tetrahydrofuran is cooled in an ice bath under a nitrogen atmosphere and treated with 106 ml of 1N aqueous sodium hydroxide added for 10 minutes. The cooling bath is removed and the reaction mixture is stirred at room temperature for 5.5 hours, then diluted with 500 ml of water and rinsed with three 300 ml portions of ether. The aqueous solution is cooled in an ice bath under nitrogen and acidified to pH 1-2 with concentrated HCl and extracted three times with 500 ml portions of ether. The combined ether extracts are rinsed with 400 ml of water and brine, then dried (MgSO 4) and concentrated in vacuo to 18.2 g of crude product. This material is dissolved in ether and treated with a solution of 8.5 g (55.9 mmol) of 1-adamantanamine in methanol. The mixture is diluted to about 1 liter with ether, refrigerated for 1.5 hours and filtered to give 20.1 g of adamantanamine salt, m.p. 2390-2420. This material is dissolved in 1Z1 chloroform: methanol and diluted with ether to give 1.5.3 g of (cis) -4 - [(4-chlorophenyl) thio] -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline, l-adamantanamine salt; melting point 240 ° -241 ° (decomposition flfl qnzs -5s, 4 ° (c = o, s, methanol).

A small sample of this adamantanamine salt (0.5 g, 0.98 mmol) is partitioned between aqueous HCl and ethyl acetate to give the corresponding free acid; [α] D 25 -38.10 (c = 1, absolute ethanol).

To a rapidly stirred mixture of 18.8 ml of 1N aqueous HCl, 30 ml of water and 50 ml of ethyl acetate is added portionwise 8 g (1.56 mmol) of the adamantanamine salt. The solution is kept cold in an ice bath and stored under a nitrogen atmosphere. When all solids have dissolved, the aqueous layer is extracted with two additional 447 477 57 50 ml portions of ethyl acetate. The organic extracts are combined and rinsed with 30 ml of 0.5N aqueous HCl, 30 ml of water and finally brine. The solution is dried (MgSO 4) and concentrated in vacuo to give 5.6 g of liberated acid. The acid is dissolved in a mixture of 50 ml of ethyl acetate and 15 ml of ether and shaken with a solution of 2.57 g (14.8 mmol) of L-arginine dissolved in 65 ml of water. The aqueous layer is rinsed with 50 ml of ether and lyophilized overnight to give 8.0 g of (cis) -4 - [(4-chlorophenyl) thio] -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L -proline, L-arginine salt (1: 1); [α] 25 D -44.3 (c = 1, water).

Analysis. Calculated for: C 15 H 18 ClNO 3 S 2 .C 6 H 14 N 4 O 2 C 45.09; H 6.27; N 12.52; S 11.46; Cl 6.34; SH 5.91. Found: C 45.34; H 6.34; N 12.57; S 11.48; Cl 6.12; SH 5.44.

Example 58 (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -4 - [(4-methylphenyl) -thio] -L-proline, L-arginine salt (1: 1) a) (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(4-methylphenyl) thio] -L-proline, methyl ester A solution of 12.6 g ( 62.5 mmol) of tri-n-butylphosphine in 20 ml of benzene are added over a five minute period to a solution of 20 g (56.8 mmol) of (trans) -1- [D-3- (benzoylthio) -2-methyl- 1-oxopropyl] -4-hydroxy-L-proline, methyl ester and 1.5.4 g (62.5 mmol) of p-tolyl disulfide in 120 ml of benzene at room temperature under an atmosphere of nitrogen. After standing overnight, the reaction mixture is diluted with 300 ml of Et 2 O and the organic solution is rinsed with three times 100 ml portions of water, brine and dried (MgSO 4). Concentration in vacuo gives 49 g of crude product mixture. This material is absorbed on 75 g of Baker silica gel and applied to a 450 g Baker silica gel column packed with 1: 1 hexane ether. This column is eluted with 3 liters of 1: 1 followed by 2 liters of 2: 1 of ether: hexane and finally with 100% of ether. Combination of the best product-containing fractions gave 14.6 g of (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(4-methylphenyl) thio] L-proline, methyl ester. A small sample is purified by evaporative chromatography on EM9385 silica gel using methylene chloride: ethyl acetate; [α] D 25 -70.80 (c = 1, chloroform). 447 477 58 (b) (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -4 - [(4-methylphenyl) thio] -L-proline, L-arginine salt (1 : l) An ice-cold solution of 13.0 g (28.4 mmol) of (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(4-methylphenyl) ) thio] -L-proline, methyl ester in a mixture of 40 ml of methanol and 130 ml of tetrahydrofuran is continuously purified with nitrogen while adding 59.6 ml of 1N aqueous sodium hydroxide for 10 minutes.

At the end of this time, the cooling bath is removed and the reaction mixture is stirred under nitrogen at room temperature for 5.5 hours.

The reaction mixture is then diluted with 250 ml of water and rinsed twice with 200 ml portions of ether. The aqueous layer is then cooled in an ice bath under nitrogen and acidified to pH 1-2 with concentrated HCl and extracted with three 200 ml portions of ether. The combined organic extract is rinsed with 200 ml of water and brine, dried (MgSO 4) and concentrated in vacuo to 10.6 g of a colorless oil which is almost homogeneous by thin layer chromatography. The product is dissolved in ether and treated with 4.72 g (3l, 2 mmol) of 1-adamantanamine dissolved in 20 ml of methanol.

The precipitate is rapid and the reading is diluted with ether to about 700 ml of the total volume and the salt is collected. Re-pulverization with hot methanol-ether gives 12.4 g of adamantanamine salt, melting point 2370-2400 (decomposition). This salt is recrystallized by dissolving in a minimal amount of 1: 1 chloroform: methanol and diluting with ether. After 10 minutes at room temperature, the solid is collected and dried to give 8.2 g of adamantanamine salt; melting point 24 ° -241 ° (sonar formation); [α] D 25 -5s, 0 ° (c = 0.5, methanol).

A small sample of this adamantanamine salt is partitioned between aqueous HCl and ethyl acetate to give (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -4 - [(4-methylphenyl) thio] -L -proline as an oil; [α] D 25 -45.1 ° (c = 1, absolute ethanol).

To a mixture of 17.1 ml of aqueous 1N HCl, 30 ml of water and 50 ml of ethyl acetate is added 7.0 g (14.3 mmol) of the above-mentioned adamantanamine salt in several portions. During the addition, the solution is cooled in an ice bath and kept covered with argon. When all the salt 447 477 59 is dissolved, the layers are separated and the ethyl acetate layer is combined with two additional 50 ml extracts of the aqueous solution. The combined ethyl acetate extract is rinsed with dilute HCl, water and brine, dried (MgSO 4) and concentrated in vacuo to give the free acid. The acid is dissolved in a mixture of 40 ml of ethyl acetate and 10 ml of ether and shaken with a solution of 2.37 g (1.3.6 mmol) of L-arginine in 50 ml of water. The aqueous layer is rinsed with 50 ml of ether and then lyophilized to give (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -4 - [(4-methylphenyl) thio] -L-proline, L- arginine salt (1: 1); [α] D 25 -45.30 (c = 1, water).

Analysis. Calculated for: C 16 H 21 NO 3 S 2 .C 6 H 14 N 4 O 2 C 49.69; H 7.01; N 13.17; S 12.06; SH 6.22. Found: C 49.55; H 7.04; N 13.28; S 11.73; SH 5.97. Example 59 (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -4 - [(4-methoxyphenyl) thio] -L-proline, L-arginine salt (1: 1) ( a) N- (p-methoxyphenylthio) succinimide A mixture of 17.1 g (128 mmol) of N-chlorosuccinimide and 700 ml of benzene is treated with 15 g (107 mmol) of p-methoxythiophenol dissolved in 125 ml of benzene. After 75 minutes, the resulting orange solution is cooled to 150 and 13.0 g (128 mmol) of triethylamine in 125 ml of benzene are added over a period of 25 minutes. The cooling bath is removed and the reaction mixture is stirred at room temperature for a further 45 minutes. The reaction mixture is then filtered and the organic solution is rinsed with three 200th portions of water, 200 ml of brine and dried (MgSO 4). The solvents are removed in vacuo to give 27.0 g of crude product. Recrystallization from chloroform / hexane gives 21.2 g of N- (p-methoxyphenylthio) succinimide; melting point 1000-1060. (b) (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(4-methoxy) phenylthio] -L-proline, methyl ester To a solution of 14.0 g (59.1 mmol) of N- (p-methoxyphenylthio) succinimide in 250 ml of benzene at room temperature under nitrogen was added 12.0 g (59.1 mmol) of tri-n-butylphosphine dissolved in 25 ml of benzene 447 477 60 sen. After 10 minutes, 18.9 g (53.7 mmol) of (trans) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4-hydroxy-L-proline, methyl ester are added and the reaction is stand at room temperature under nitrogen for 25 hours. At the end of this time, the reaction mixture is diluted with 300 ml of ether and rinsed with three 100 ml portions of water, brine and dried (MgSO 4). The solvents are removed in vacuo to give 40 g of onam material which is absorbed on about 80 g of silica gel and chromatographed on a 450 Baker silica gel column. The column is packed and eluted with a 4: 1 mixture of hexane ether, followed by 2: 1 hexane ether and finally 1: 1 hexane: ether. The best product-containing fractions are collected to give 20.6 g of product. A small sample (0.5 g) of the product is further purified by evaporative chromatography on 50 g of EM9385 silica gel packed and eluted with ether. The best product-containing fractions are collected to give 480 mg of (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(4-methoxyphenyl) thio] -L-proline, methyl- ester; [α] D 31 66.9 ° (c = 1, kiomform). (c) (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -4 - [(4-methoxyphenyl) thio] -L-proline, L-arginine salt (1: 1) A solution of 20.1 g (42.4 mmol) of (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4 - [(4-methoxyphenyl) thio] -L- proline, methyl ester in a mixture of 70 ml of methanol and 200 ml of tetrahydrofuran are cooled in an ice bath under nitrogen and treated with 89 ml of 1N aqueous sodium hydroxide for 10 minutes. The cooling bath is removed and the reaction mixture is stirred at room temperature for 5.5 hours, then diluted with 500 ml of water and rinsed with three 300 ml portions of ether. The aqueous solution is cooled in an ice bath under nitrogen and acidified to pH 1 with concentrated HCl and saturated with three 500 ml portions of ether. The combined ether extracts are rinsed with 400 ml of water and brine, dried (MgSO 4) and concentrated in vacuo to give 14.8 g of crude product.

This material is dissolved in ether and treated with a solution of 6.34 g (42 mmol) of 1-adamantanamine in methanol. The mixture is diluted to about 1 liter with ether, left at room temperature for 10 minutes and filtered to give 12.8 g of adamantanamine salt; melting point 2350-2360 (decomposition). This material is dissolved in 1: 1, chloroform-methanol under gentle heating and diluted with ether.

This recrystallization is repeated two more times to give 12.2 g of (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -4 - [(4-methoxyphenyl) thio] -L-proline, 1 -adamantanamine salt; mp 23v ° -z39 ° (decomposition [oqDzs -s2, a °; A small sample of this 1-adamantanamine salt (500 mg, 0.99 mmol) is partitioned between aqueous HCl and ethyl acetate and gives the corresponding free acid; [d] D25 -36.80 (C = 1, absolute ethanol).

To a rapidly stirred mixture of 27.2 ml of 1N aqueous HCl, 55 ml of water and 75 ml of ethyl acetate is added portionwise 11.5 g (22.7 mmol) of the above-mentioned 1-adamantanamine salt. The solution is kept cold in an ice bath and covered with nitrogen. When all the solid has dissolved, the aqueous layer is extracted with two additional 75 ml portions of ethyl acetate. The organic extracts are combined and rinsed with 50 ml of 0.5N aqueous HCl, 50 ml of water and finally brine. The solution is dried (MgSO 4) and concentrated in vacuo to 8.2 g of free acid. The acid is dissolved in a mixture of 75 ml of ethyl acetate and 20 ml of ether and shaken with a solution of 3.76 g (2l, 6 mmol) of L-arginine dissolved in 100 ml of water. The aqueous layer is rinsed with 75 ml of ether and lyophilized overnight to give 1.1 g (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -4 - [(4-methoxyphenyl) thio] -L-proline, L-arginine salt (1: 1); [d] D25 -46.00 (c = 1, water).

Analysis. Calculated for C 16 H 21 NO 4 S 2 .C 6 H 14 N 4 O 2 C 47.93; H 6.84; N 12.70; S ll, 63; SH 6.00. Found: C 47.99; H 6.61; N 12.66; S ll, 62; SH 6.00.

Example 60 (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -4- (phenylthio) -L-proline, L-arginine salt (1: 1) A solution of 1- (D- 3-Mercapto-2-methyl-1-oxopropyl) -cis-4-phenylthio-L-proline (5.0 g, 0.0536 mol) dissolved in 286 ml of absolute ethanol is treated with a solution of L-arginine ( 98%) (2.70 g, 0,052 mol) in 28.6 ml of water to give a clear solution. The solution is concentrated in vacuo to a clear viscous 7 ___..___..........._.-...-- uw-_. 447 477 62 oil. The oil is dissolved in 286 ml of absolute ethanol and concentrated again in vacuo to a viscous oil. The oil is triturated under 280 ml of ether to give an amorphous solid. The solid is stirred for 30 minutes and allowed to settle. The supernatant is removed and the treatment is repeated. Removal of the supernatant gives 7.7 g of amorphous solid (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -4- (phenylthio) -L-proline, L-arginine salt, which becomes a free-flowing powder for drying in vacuo; melting point 1260-12s °; [α] D 25 -43.5 ° (c = 1.0, methanol).

Analysis. Calculated for C 15 H 19 NO 3 S 2 .C 6 H 14 N 4 O 2 .H 2 O C 50.03; H 6.70; N 13.89; S 12.72. Found: C 49.89; H 6.66; N 14.24; S 12.67.

Example 61 (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -4- (phenylthio) -L-proline, ethyl ester A stirred solution of 3.9 g (0.012 mol) l - (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4-phenylthio-L-proline in 40 ml of ethanol is treated under argon with 0.3 ml of concentrated sulfuric acid, sealed and kept at room temperature . After 24 hours, the solution is treated with an additional 0.3 ml of concentrated sulfuric acid and after standing for 3 days, thin layer chromatography shows that the reaction is complete. The majority of the ethanol is removed on a rotary evaporator and the oil residue is taken up in 100 ml of ethyl acetate, stirred, cooled and treated under argon with 25 ml of 5% sodium bicarbonate. The layers are separated, the organic phase is washed with 15 ml of 5% sodium bicarbonate, followed by water (2 x 5 ml), dried (MgSO 4) and the solvent is evaporated. The oily residue is taken up in ether and the evaporation is repeated, finally at 0.2 mm, to give 3.8 g of an almost colorless viscous oily (cis) -1- (D-3-mercapto-2-methyl-1-oxo propyl) -4- (phenylthio) -L-proline, ethyl ester; [d] D25 -490 (c = 1.0, ethanol).

Analysis. Calculated for C 17 H 23 NO 3 S 2 C 57.76; H 6.56; N 3.96; S 18.14. Found: C 57.66; H 6.53; N 3.96; S 18.15. 447 477 63 Bxemoel 62 (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline, L-arginine salt (1: 1) 2,3 g (0.0054 mol) (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline dissolved in 100 ml of methanol is treated with 0.941 g (0.0054 mol) of L-arginine. A clear solution is formed after stirring for about 10 minutes. The reaction mixture is stirred at room temperature for about 5 hours, the solvent is removed and the resulting solid is decomposed with ether and filtered to give 2.5 g of (cis) -1- [D-3- (benzoylthio) -2-methylfluoxopropyl] -4- (phenylthio) -L-proline, L-arginine salt (1: 1); soft at 100 °, melting point 110 ° -112 ° (decomposition), [α] 25 D -2780 (c = 1, methanol).

Analysis. Calculated for C 22 H 23 NO 4 S 2 .C 6 H 14 N 4 O 2 C 54.88; H 6.25; N 11.43; S 10.47. Found: C 54.44; H 6.21; N 11.60; S 10.40.

Example gel 63 (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline, sodium salt (1: 1) A solution of 4.29 g ( 0.01 mol) (cis) - [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline in 25 ml of methanol and a solution of 0.540 g (0.0l mol) sodium methoxide in 25 ml of methanol is combined. About 50 ml of ether are added and after stirring for about 10 minutes a precipitate begins to form. The mixture is allowed to stand overnight in a cold room. The gelatinous solid is filtered, washed with ether and desiccator dried to give 2.5 g of (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L- proline, sodium salt (1: 1); melting point 2180-2200 (decomposition); [α] D 25 -105.2 (c = 1, water).

Analysis. Calculated for C 22 H 22 NO 4 S 2 .Na C 57.36; H 5.03; N 3.04; Na 4.99. Found: C 57.62; H 5.08; N 3.01; Na 4.68. 447 477 64 Example 64 (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline, 2-amino-2- (hydroxymethyl) -1 , 3-propanediol salt (1: 1) A solution of 121.14 mg (0.00l mol) of tris (hydroxymethyl) aminoethane in 5 ml of n-butanol and a solution of 429.5 mg (cis) -1- [ D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline in 5 ml of n-butanol are combined. The resulting clear solution is allowed to stand for 48 hours. The solution is inoculated and the whole mass is crystallized. It is allowed to stand for 3 hours, filtered, washed well with ether and dried to give 400 mg of (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxo6ropyl] -4- (phenylthio) -L -proline, 2-amino-2-hydroxymethyl-1,3-propaniol salt (1 = 1); mp 13s ° -136 °; [@ 1D2s -20.6 (c = 1, water).

Analysis. Calculated for C 22 H 23 NO 4 S 2 .C 4 H 11 NO 3 C 56.70; H 6.22; N 5.09. Found: C 56.66; H 6.36; N 5.00.

Example gel 65 (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) - L-proline, potassium salt (1: 1) A solution of 21.5 g ( 0.05 mol) (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline in 100 ml ethanol and 50 ml 1N alcoholic potassium hydroxide are combined and a crystalline solid begins to form almost immediately. The mixture is allowed to stand overnight in a cold room. The solid is filtered, washed with 60 ml of cold ethanol, washed twice with 100 ml portions of ether, dried in vacuo overnight to give 16.5 g of product containing ethanol. 14.4 g of this material are allowed to dry at room temperature for 60 hours to give 14.2 g [no alcohol present] (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline, potassium salt (1: 1); melting point 19s ° -2os °; [α] D 25 -114 ° (c = 1, water).

Analysis. Calculated for C H NO S K.1; H C 53.41; H 5.09; 22 22 4 2 2 2 N 2.83; S 12.96; K 7.88. Found: C 53.55; H 4.89; N 2.90; S 12.88; K 8.03. 5447 477 65 Example 65a (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline potassium salt (1: 1) The product of Example 65 can also prepared by the following procedure: (a) N-benzoyl-cis-4-phenylthio-L-proline N-benzoyl-trans-4-tosyloxy-L-proline, methyl ester (prepared according to the procedure of Portoghese et al., Tetrahedron, volume 27, pages 961-967) (750 g, 1.86 mol) is added to 2.5 liters of methanol and the mixture is heated and stirred at 350. 200 ml (1.95 mol) of thiophenyl are added followed by a solution of 78 g of sodium hydroxide (1.95 mol) in 500 ml of methanol. The mixture is heated to reflux until thin layer chromatography shows that the reaction is complete. The mixture is allowed to cool to room temperature and a solution of 80 g of sodium hydroxide in 500 ml of water is added with continuous stirring for 1 hour. The solvent is evaporated in vacuo and the oily concentrate is diluted with 2.5 liters of water and extracted with 0.7 liters of isobutyl alcohol. The pH of the aqueous phase is adjusted to below 2 with 0.2 liters of concentrated HCl. The precipitated oil is extracted with 2 liters of isobutyl acetate in three portions. The organic layer is filtered and vacuum concentrated to 650 g of N-benzoyl-cis-4-phenylthio-L-proline as a thick syrup. (b) cis-4-phenylthio-L-proline N-benzoyl-cis-3-phenylthio-L-proline is heated on a steam bath and 0.5 liters of glacial acetic acid are added. The mixture is shaken and 0.5 liters of water followed by 100 ml of concentrated sulfuric acid are added. The cloudy mixture is heated to reflux at an oil bath temperature of about 1250 and kept at reflux until the reaction is complete. The reaction liquid is cooled to room temperature and 0.75 liters of isobutyl acetate and 3 kg of crushed ice are added with vigorous stirring. 50 g of concentrated aqueous sodium hydroxide solution are added and the product is collected and washed with methanol. The product is further purified by dissolving in aqueous sodium hydroxide, treatment with activated carbon, filtration and thorough crystallization with HCl. The crystals are collected, washed with water and dried to give cis-4-phenyl-thio-L-proline as a white crystalline powder; melting point 2400 (decomposition); [α] D 25 -1180 (C = 1.1 N sodium hydroxide).

Analysis. Calculated for C 11 H 13 NO 2 S: C 59.17; H 5.87; N 6.27; S 14.36. Found: C 58.58; H 5.63; N 6.28; S l4.07. (c) (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline, potassium salt (1: 1). cis-4-phenylthio-L-proline is acylated in water at pH 8.3 with an equimolar amount of (D) -3- (benzoylthio) -2-methylpropanoyl chloride. The pH is maintained at 8-8.5 by the addition of SN sodium hydroxide solution.

The reaction mixture is acidified with hydrochloric acid and the product is extracted into isobutyl acetate. Concentration of the brine-washed extract gives crude (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline as a tacky resin.

This resinous material is dissolved in isopropanol and a solution of potassium 2-ethylhexanoate in isopropanol is slowly added at elevated temperature. The isopropyl adduct of the desired potassium salt crystallizes.

The adduct is collected, washed with isopropanol and vacuum dried.

Exposure of the dried adduct to moist air causes the isopropanol to be exchanged for water to give (cis) -1- [D-3-benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline , potassium salt (lzl).

Example Gel 66 (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) - L-proline, magnesium salt (2: 1) Mixtures of 429.5 mg (0 .01 mol) cis-1- [D-3-benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline in 30 ml ethanol and 29.1 mg (0.005 mol) magnesium hydroxide in 30 ml ml of water is combined and gives a clear solution. The solution is stirred at room temperature overnight. The pH is 5.9. The ethanol is removed and a cloudy mixture is formed. The aqueous layer is extracted with ether and then liberated from residual ether by evaporation of evaporation and lyophilized to give 150 mg of (cis) -1- [D-3-benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline, magnesium salt (2 = 1); soft at so °, melting point 11o ° -1zo °.

Analysis. Calculated for C 22 H 22 NO 4 S 2 .0.5 Mg.2 H 2 O C 55.42; H 5.49; N 3.05. Found: C 55.39; H 4.93; N 2.94.

Example 67 (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline, calcium salt (2: 1) Mixtures of 859 mg (0.002 mol) (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline in 50 ml of ethanol and 56 mg (0.00l mol) of calcium oxide suspended in 50 ml of water is combined and a clear solution is formed. The solution becomes cloudy and is stirred at room temperature overnight. A solid is present. The ethanol is removed by evaporation evaporation and the suspension is extracted with ether and traces of ether are then removed from the aqueous suspension by evaporation evaporation. The suspension is lyophilized to give 400 mg of (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline, calcium salt (2 = 1); melting point z35 ° -237 ° (solar eclipse).

Analysis. Calculated for C 22 H 22 NO 4 S 2 .0.5 Ca.0.5 H 2 O C 55.74; H 5.06; N 3.06. Found: C 57.07; H 5.02; N 2.84.

This product can also be obtained according to the following procedure. (cis) -1- [D-3- (benzoylthio) -2-methyl-1-oxopropyl] -4- (phenylthio) -L-proline, potassium salt is dissolved in water to a 5% solution.

A moderate excess of 2N aqueous calcium chloride is added very slowly during inoculation. The desired calcium salt is crystallized in the form of very small plates. These are collected on a filter and washed with copious amounts of water. Vacuum drying at slightly elevated temperature gives the desired calcium salt as a fine anhydrous powder; melting point about 2500; [α] D 23 -67.60 (c = 1, methanol / HCl). 447 477 68 Examples §§ 1,1 '- [dithiodi- (1D-3-mercapto-2-methyl-1-oxopropyl)] bis [(cis) - 4- (phenylthio) -L-proline] A mixture of 2 9 g (0.089 mol) of (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -4- (phenylthio) -L-proline and 9 ml of 1N sodium hydroxide in 70 ml of water are stirred and treated dropwise with a solution of 1.2 g (0.047 mol) of iodine in 10 ml of 95% ethanol while maintaining the pH of the solution at 5.5 to 6.5 with 1N sodium hydroxide. After about 15 minutes, remove a slight excess of iodine dye with dilute sodium thiosulphate and acidify the reaction mixture with 6N HCl and extract with ethyl acetate (3 x 70 ml). The organic phases are combined, dried (MgSO 4), filtered and the solvent is evaporated to give 2.4 g of a yellow foam-like solid, m.p. 750-850 (p. 470). This material is dissolved in 40 ml of ethyl acetate and treated with a solution of 1,4 g of dicyclohexylamine in 5 ml of ethyl acetate. The product is rapidly separated from a gelatinous material. After standing overnight at room temperature, the solid is filtered to give 4.2 g of a light yellow solid; melting point 2050-2070. This material is crystallized from 40 ml of ethanol to give 2.8 g of a colorless solid 1,1 '- [dithiodi- (1D-3-mercapto-2-methyl-1-oxopropyl)] bis [(cis) -4- (phenylthio ) -L-proline], dicyclohexyamine salt, mp 20 ° -2o9 °. ' Analysis. Calculated for C 30 H 36 N 2 O 6 S 4.2 (Cl 2 H 23) C 64.12; H 8.17; N 5.54; S 12.68. Found: C 63.87; H 8.30; N 5.45; S 12.46.

The above dicyclohexylamine salt is decomposed in a mortar, suspended in 30 ml of ethyl acetate, treated with 30 ml of 10% potassium bisulfate and shaken to give two layers. The organic phase is separated and the aqueous phase is extracted with ethyl acetate (3 x 30 ml). The organic phases are combined, washed twice with 10 ml of water, dried (MgSO 4), filtered and the solvent is evaporated to give a foam-like colorless solid. The latter is treated with 25 ml of ether (the solid gives an oil) and the solvent is evaporated on a rotary evaporator to give 1.8 g of colorless granular 1,1 '- [dithiodi- (1D-3-mercapto-2-methyl-1-oxopropyl)] bis [(cis) -4 - (phenylthio) -L-proline]; mp 75 ° -90 ° (s. 65%; foqDzs -4z ° (c = 1, ethanol).

Analysis. Calculated for C 30 H 36 N 2 O 6 S 4.% H 2 O C 54.77; H 5.67; N 4.26; S 19.50. Found: C 54.79; H 5.95; N 4.01; S 19.52.

Example gel 69 1,1'-Indithiodi- (1D-3-mercapto-2-methyl-1-oxopropyl)] bis [(cis) -4- (phenylthio) -L-proline, dipotassium salt A stirred solution of 7.0 g (0,0106 mol) 1,1 '- [dithiodi- (1D-3-mercanto-2-methyl-1-oxopropyl)] bis [(cis) -4- (phenylthio) -L-proline] in 200 ml ethanol treated with 21.3 ml of 1N potassium hydroxide (two equivalents) in ethanol. The resulting solution is inoculated, allowed to crystallize at room temperature for several hours and placed in a cold room overnight. The solid is filtered, washed with ethanol and ether to give 5.2 g of a colorless solid; melting point 2750 (decomposition). The material is then air dried overnight to give 5.3 g, 1 '- [dithiodi- (1D-3-mercapto-2-methyl-1-oxopropyl)] bis [(cis) -4- (phenylthio) -L proline], dipotassium salt; melting point 2750 (decomposition); [α] D 25 -2270 (c = 1, water).

Analysis. Calculated for C 30 H 34 N 2 O 6 S 4.2Cl 3 H 2 O C 46.24; H 5.17; N 3.59; S 16.46; K 10.04. Found: C 45.98; H 5.11; N 3.36; S 16, 10; K 10.03, Exemgel 70 (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -3-phenoxy-D, L-proline (a) 3-phenoxy-1,2-dehydroproline , t-butyl ester A mixture of 9.25 g (50 mmol) of 1,2-dehydroprolin-1-butyl ester in 70 ml of toluene with 8.9 g (50 mmol) of n-bromosuccinimide heated at reflux while exposed to a solar lamp (distance 5.1 cm) for an hour. During this time succinimide is formed and the reaction is cooled to room temperature. The succinimide is removed by filtration and the filtrate is evaporated to dryness. The residue is distilled at 800 to give 3.5 g of crude bromo-1,2-dehydroproline, t-butyl ester.

A mixture of this crude 3-bromo-1,2-dehydroproline, t-butyl chloride and thallium phenoxide (3.9 g, 13 mmol) in 30 ml of dry dimethylformamide is stirred at room temperature under an argon atmosphere for 24 hours. The solvent is removed in vacuo and the residue is diluted with ether to precipitate thallium bromide, which is removed by filtration. The filtrate is concentrated to give an oil which is purified by distillation. After 2 hours at 0.005 mm and 800, 1.48 g of 3-phenoxy-1,2-dehydroproline, t-butyl ester remain in the distillation flask. (b) (cis) -3-phenoxy-D, L-proline A mixture of 1.48 g of 3-phenoxy-1,2-dehydroproline, t-butyl ester, 5 ml of 1N sodium hydroxide and 20 ml of 80% dioxane / water is stirred at room temperature for 4 hours. The solvent is removed in vacuo and the residue is dissolved in 25 ml of water and treated with 168 mg of sodium borohydride for 1 hour at room temperature.

The mixture is acidified to pH 6 by the addition of 2N HCl and the solution is kept at 0 DEG for 16 hours after which crystals of (trans) -3-phenoxy-D, L-proline precipitate (about 25 mg). These are removed by filtration and the filtrate is desalted by passing through a Dowex 50 WX8 column (1 "x12") using 1N ammonium hydroxide as eluent. The UV-active fractions are combined and concentrated to give 616 mg of solid (cis) -3-phenoxy-D, L-proline. (c) (cis) -1- [D-3- (acetylthio) -2-methyl-1-oxopropyl] -3-phenoxy-D, L-proline 616 mg (cis) -3-phenoxy-D, L- proline is suspended in 20 ml of water at 50 and the pH is adjusted to 8.0 with solid sodium carbonate. A solution of 550 mg (2.5 mmol) of D-3-acetylthio-2-methylpropanoyl acid chloride in 1 ml of ether is added and the pH of the reaction mixture is kept between 7.3 and 8.2 for the following 1.5 hours by adding sodium carbonate. The mixture is washed with ethyl acetate (2 x 20 ml), acidified to pH 2 by the addition of 10% HCl and extracted with ethyl acetate (3 x 50 ml). The extracts are combined, dried (MgSO 4) and concentrated to give 810 mg of an oil. This oil is purified by evaporative chromatography on silica gel (LP-1, 300 ml) using 10-20% acetic acid-toluene mixtures as eluent to give 530 mg (cis) -1- [D-3- (acetylthio) - 2-methyl-1-oxopropyl] -3-phenoxy-D, L-proline. (d) (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -3-phenoxy-D, LfBrolin 530 mg (cis) -1- [D-3- (acetylthio) -2 -methyl-1-oxopropyl] -3-phenoxy-D, L-proline is dissolved in 50/50 concentrated ammonia hydroxide / water (degassed by bubbling argon through the solution for 15 minutes) under an argon atmosphere and stirred at room temperature for 1.5 hours. The slightly cloudy solution is adjusted to pH 6.5 with concentrated HCl (some heating takes place) and extracted with methylene chloride (2 x 25 ml). The pH is then adjusted to 1 and the solution is re-extracted with methylene chloride (3 x 50 ml). The extracts are combined, dried (MgSO 4) and concentrated to give 410 mg of a glassy compound. Decomposition with chloroform gives crystallization. The solid is recrystallized from ethyl acetate / hexane to give 261 mg of (cis) -1- (D-3-mercapto-2-methyl-1-oxopropyl% 3-phenoxy-D, L-proline; mp 1340-1550).

Analysis. Calculated for clsnlguoéls c 58.23; H 6.19; N 4.53; S 10.36. Found: C 58.07; H 6.18; N 4.45; S 10.16.

Example 71 71 tablets each containing 100 mg of 1- (D-3-mercapto-1-oxopropyl) -trans-4-methoxy-L-proline, sodium salt is prepared from the following ingredients: 1- (3-mercapto-1-oxopropyl) -trans-4-methoxy-L-proline, sodium salt 100 g Maize starch 50 g Gelatin 7.5 g Avicel (microcrystalline cellulose) 25 g Magnesium stearate 2.5 g 447 477 72 l- (D-3-mercapto-1-oxopropyl The trans-4-methoxy-L-proline salt and the corn starch are mixed with an aqueous solution of the gelatin. The mixture is dried and ground to a fine powder.

Breeding cell and then magnesium stearate are mixed with the granulate.

This is then compressed in a tablet press into 1000 tablets each containing 100 mg of the active ingredient.

Example 72 Tablets each containing 200 mg of 1- (D-3-mercapto-2-methyl-1-oxopropyl) -trans-4-methoxy-L-proline are prepared as in Example 71.

Example 73 1000 tablets each containing 200 mg of 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4-methoxy-L-proline, sodium salt was 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 38 g Maize starch 15 g Magnesium stearate 2 g 1- (D-3-mercapto-2-methyl- 1-oxopropyl) -cis-4-methoxy-L-proline, sodium salt, lactose and Avicel are mixed, after which the corn starch is mixed. Magnesium stearate is added. The dry mixture is compressed in a tablet press into 1000 tablets weighing 130 mg each containing 50 mg of active ingredient. The tablets are coated with a solution of Methocel E (methylcellulose) comprising as a dye a substrate pigment containing yellow no. 6.

Example 74 Two pieces no. 1 gelatin capsules each containing 100 mg of 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4-methoxy-L-proline, sodium salt is filled with a mixture of the following ingredients: 447 477 73 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis--4-methoxy-L-proline, sodium salt 100 mg Magnesium stearate 7 mg USP lactose 193 mg Example 75 An injectable solution is prepared as follows: (trans) -4-methoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -L-proline 500 mg Methylparaben 5 mg Propylparaben 1 mg Sodium chloride 25 mg Water for injections qs. 5 mg The active substance, preservatives and sodium chloride are dissolved in 3 l of water for injection and then the volume is made up to 5 l. The solution is filtered through a sterile filter and aseptically filled into pre-sterilized bottles which are then closed with pre-sterilized rubber devices. Each vial contains 5 ml of solution with a concentration of 100 mg of active ingredient per ml of solution for injection.

The products in each example can be prepared in the same manner as in Examples 71-75.

Claims (5)

M 447 477 CLAIMS 1. Compound of the formula X-R 1/1 1: 1 ïz H 2? a Rlf-S- (CIUX-I-CH-CO - N -_.- C; - CQQR 1 H and basic salts thereof, wherein the group X-R1 is located in the 3- or 4-position of the proline ring, X represents oxygen or sulfur, R represents hydrogen or C 1-7 alkyl, R 1 represents C 1-7 alkyl, C 2-7 alkenyl, C 2-7 alkynyl, one optionally with C 1-4 alkyl-, C 1-4 alkoxy-, C 1-4 alkylthio-, halogen-, trifluoromethyl-, acetyloxy or hydroxy-substituted phenyl or phenyl-C 1-4 alkyl group, R and R independently represent hydrogen, C 1-7 alkyl or trifluoromethyl, O R 4 represents hydrogen, R 5 -E or XR 1 // 1 RB 112 Hzc 5% II I -s- (cm-cn- co- N-ff -COOR H R 5 represents C 1-7 alkyl, phenyl or phenyl-C 1-4 alkyl and n represents 0, 1 or 2. A compound according to claim 1, characterized in that A compound according to claim 1, characterized in that X represents sulfur 4. A compound according to claim 1, characterized in that 444 477 wherein R4 represents hydrogen. l, k ä n n e t e c k n a d d a r a v, that the proline ring is in L ~ configuration. A compound according to claim 1 having the formula -R R R H C / 1 1 I3 l2 2 '3 _ _ ___ _. __. - C - COOR R 4 S (CH) n CH CO NI * H and basic salts thereof wherein the group X-R 1 is located in the 3- or 4-position of the proline ring, X represents oxygen or sulfur, R represents hydrogen, R1 represents lower alkyl having 1 to 3 carbon atoms or (1x) 6 R 2 represents hydrogen, methyl or trifluoromethyl, R 3 represents hydrogen, R 4 represents hydrogen, acetyl or benzoyl, R 6 represents hydrogen, methyl, methoxy, methylthio, chlorine, fluorine, trifluoromethyl or hydroxy, n represents 0 or 1, and p represents 0, 1 or 2. A compound according to claim 6, characterized in that V represents X. A compound according to claim 7, characterized in that R 4 represents hydrogen, R 2 represents hydrogen or methyl and n represents 1. A compound according to claim 8, characterized in that R 1 represents lower alkyl having 1-3 carbon atoms. A compound according to claim 9, wherein the proline radical is in the L-configuration: and when R 2 is other than hydrogen is the asymmetric carbon atom to which R 2 is attached in the D-configuration; and the -O-R 1 group is in the 4-position of the proline ring and in the cis configuration. ll. A compound according to claim 10, characterized in that R 1 is methyl. 12. A compound according to claim 11, characterized in that it constitutes (ciaf4-methoxy-1- (D-3-mercapto-2-methyl- 1. 1-oxopropyl) -L-proline. A compound according to claim 11, characterized in that it is (ciaP4-methoxy-1- (3-mercapto-1-oxopropyl) -L-proline. A compound according to claim 9, characterized in: that the proline ring is in the L-configuration, and when R 2 is other than hydrogen is the asymmetric carbon atom to which R 2 is attached in the D-configuration, and the -O-R A compound according to claim 14, characterized in that R 1 is methyl 16. A compound according to claim 15, characterized in that it constitutes (trans) -4-methoxy-1- (D- 3-Mercapto-2-methyl-1-oxopropyl) -L-proline A compound according to claim 15, characterized in that it is trans-4-methoxy-1- (3-mercapto-1- oxopropyl) -L-proline 18. A compound according to claim 14, characterized in that R1 is ethyl. A compound according to claim 18, characterized in that it is ethyl. , that it constitutes (trans) -4-ethoxy-1- (D-3-mercapto-2-methyl-1-oxopropyl) -1-proline. A compound according to claim 14, characterized in that R1 is n-propyl. A compound according to claim 20, characterized in that it constitutes (trans) -4-propoxy-1- (D-3-mer- Rapto-2-methyl-10-oxopropyl) -1-proline. A compound according to claim 8, characterized in that R1 is - (CH2) É- <šêâ> 3 R6 represents hydrogen, R methyl, methoxy, methylthio, chlorine, fluorine trifluoromethyl or hydroxy; and p represents O, 1 or 2. 23. A compound according to claim 22, characterized in that the proline ring is in the L-configuration and when R 1 has a meaning other than hydrogen is the asymmetric carbon atom to which R 2 is attached in The D-configuration and the -O-R 1 group are in the 4-position of the proline ring. A compound according to claim 23, characterized in that it is (cis) -4- (4-fluorophenoxyl) -1- (D-3-mercapto-2-methyl-1-oxopropyl) -L- proline. A compound according to claim 6, characterized in that X is sulfur. A compound according to claim 25, characterized in that R 4 is hydrogen, R 2 is hydrogen or methyl and n is 1. A compound according to claim 26, characterized in that R 1 is lower alkyl having 1 to 3 carbon atoms. 28. A compound according to claim 27, characterized in that R1 is methyl. 318 447 477 29. A compound according to claim 28, characterized in that it is (trans) -1- (3-mercapto-1-oxo-propyl) -3-methylthio-D, L-proline. A compound according to claim 26, characterized in that R 1 is _ (CH) -, R 6 represents hydrogen, R 6 represents methyl, methoxy, methylthio, chloro, fluorine, trifluoromethyl or hydroxy and p represents 0 A compound according to claim 30, characterized in that it is 1- (D-3-mercapto-2-methyl-1-oxopropyl) -cis-4-phenylthio-L-proline. A compound according to claim 7, characterized in that R 4 represents acetyl, R 2 represents hydrogen or methyl and n is 1. 33. A compound according to claim 32, characterized in that R 1 represents lower alkyl having 1 - 3 carbon atoms. A compound according to claim 33, characterized in that the proline ring is in the L-configuration and when R 2 has a meaning other than hydrogen is the asymmetric carbon atom to which R is attached in the D-configuration and the -O-R 1 group is in 4- 2. Position of the proline ring and in cis configuration. A compound according to claim 34, characterized in that R1 is methyl. A compound according to claim 35, characterized in that it is (cis) -4-methoxy-1- [D ~ (% cetylthio) -2-methyl-1-oxopropyl] -L-proline. 37. A compound according to claim 33, characterized in that the proline ring is in the L-configuration and when R 2 is other than hydrogen is the asymmetric carbon atom to which R 2 is attached in the D-configuration and -O-R 1 the group is in the 4v H 447 477 position of the proline ring and in the trans configuration. A compound according to claim 37, characterized in that R1 is methyl. A compound according to claim 37, characterized in that R1 is ethyl. A compound according to claim 37, characterized in that R1 is n-propyl. A compound according to claim 32, characterized in that R 1 is (CH 2) p C), R 6 represents hydrogen, methyl, R 1 -methoxy, methylthio, chloro, fluoro, trifluoromethyl or hydroxy and p represents 0.1 or 2. 42. A compound according to claim 25, characterized in that R 4 represents acetyl, R 2 represents hydrogen or methyl and n represents 1. 43. A compound according to claim 42, characterized in that R 1 represents lower alkyl of 1 to 3 carbon atoms. A compound according to claim 42, characterized in that R represents - (CH), R 6 represents hydrogen, 29 R 6 represents methyl, methoxy, methylthio, chlorine, fluorine, trifluoromethyl or hydroxy and p represents 0.1. or 2. 45. A process for the preparation of a compound of formula XR 1 / u 1.321, Tz H 2? ß N --- * _- COOR _80 447 477 and basic salts thereof, wherein the group X-R1 is located in the 3- or 4-position of the proline ring, X represents oxygen or sulfur, R represents hydrogen or C1-7 alkyl, R1 represents C 1-7 alkyl, C 2-7 optionally with C 1-4 alkyl, C 1-4 alkoxy, C 1-4 alkylthio-, alkenyl, C 2-7 alkynyl, halogen, trifluoromethyl, acetyloxy- or hydroxy-substituted phenyl or phenyl-C 1-4 alkyl group, H and R 6 independently of one another denote hydrogen, C 1-7 alkyl or trilluoromethyl, R 4 represents hydrogen, R 5 -a- or X 1. 'RRH a * R 1 1' 3 2 2 3 I 1 I -s- (cm H-R 5 represents C 1-7 alkyl, phenyl or phenyl-C 1-4 alkyl and n represents 0, 1 or 2, characterized in that a proline compound of the formula XR1 Haïs COOR H is coupled with an acid or its chemical equivalent of the formula vt __ __- --coon R 11 -s (CPUn CH _. wherein R 4 'represents hydrogen or R 5 -CO- to form a product wherein R 4 represents hydrogen or R 5 CO, and that if desired said product wherein R4 represents R5CO is hydrolyzed to form a product wherein R4 represents hydrogen and that if desired a product wherein R4 represents hydrogen is oxidized with iodine to form a product wherein R4 represents 81 XR 1 H3 RZ h | I H2? 3 -s - (CH) n- ~ CH - CO - N-- | ¿-COOR H 46. A process according to claim 45, characterized in that a compound of the formula -RHC H coon is allowed to react with an acid or its chemical equivalent of the formula Ta TZ 4 to form a product wherein R 4 represents hydrogen or R 5 -CO- R '- s - (cH) n - cñ - aoon 47. Process according to claim 45, characterized in ~ natd ä rav, that a compound of the formula xa 3 2 | H2 R5co - s - (cH) n - CH - co - N COOR H is hydrolyzed to give a product wherein R4 represents hydrogen. 48. Pharmaceutically active composition containing a compound of the formula X-R / 4 1:31 * "z" is R -5- (CH) - CH - CO - N-- C; * - COOR 4 X1 IH 1 and basic salts thereof, wherein the group X ~ R1 is located in 3. - or Position of the proline ring, 447 477 X represents oxygen or sulfur, R represents hydrogen or C 1-7 alkyl, R 1 represents C 1-7 alkyl, C 2-7 alkenyl, C 2-7 alkynyl, optionally with C 1-4 alkyl-, C 1-4 alkoxy-, C 1-4 alkylthio-, halogen-, trifluoromethyl-, acetyloxy- or hydroxy-substituted phenyl or phenyl-C 1-4 -alkyl group, R 2 and R 3 independently represent hydrogen, C 1-7 alkyl or trifluoromethyl, R 4 represents hydrogen, R 5. -ë- or XR 1 / G R3 az Hzc 5% Ia -II as- (öfn-CH- co- N-J1-COOR n H R5 represents C1-7-alkyl, phenyl or phenyl-C1-4-alkyl and n represents 0, 1 or 2 and a pharmaceutically acceptable carrier thereof.