NL8104049A - METHOD FOR PREPARING A THERAPEUTIC PREPARATION, AND METHOD FOR PREPARING SUITABLE COMPOUNDS. - Google Patents

Description

- 1 -%

A process for the preparation of a therapeutic preparation, as well as a process for the preparation of suitable compounds.

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The invention relates to a method for preparing a therapeutic preparation with antihypertensive effect.

Such a method, in which a proline is brought into a form suitable for therapeutic application, can be considered to be known from the German "Offenlegungsschriften" 2,108,043 and 2,124,451. According to these "Offenlegungsschriften" one can use certain peptides with terminal proline groups to combat blood pressure increase. Namely, it has been found that these peptides are capable of inhibiting the enzyme that converts angiotensin I, which is produced in the body, into angiotensin II, which has a blood pressure-increasing effect.

According to the invention, a compound of the formula I of the formula sheet is introduced, in which R is a hydroxy or amino group or a lower alkoxy group, and R4 is each separately a hydrogen atom, an optionally substituted lower alkyl group or a phenyl group, R2 is a hydrogen atom or a group is COR5, where R 1. a phenyl, lower alkylphenyl or phenyl-lower alkyl group and R 1 represents a hydrogen atom or a hydroxy or lower alkyl group, n = 0, 1 or 2 and m = 3, or a basic salt thereof in a form suitable for therapeutic use .

Namely, it has been found that these much simpler compounds, which are not peptides, are also suitable to effectively combat high blood pressure by the same mechanism. It is further important that they also exert this effect when administered orally.

The lower alkyl groups represented by the above symbols include straight and branched chain hydrocarbon radicals from methyl to heptyl, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, isopentyl, and the like. The lower alkoxy groups are of the same type with 1-7 carbon atoms attached to the oxygen atom, for example, methoxy, 8104049-2-ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, t-butoxy and the like. The groups with 1-4 carbon atoms and in particular with 1 or 2 carbon atoms are preferred. Phenylmethyl is the preferred phenyl-lower alkyl group.

The lower alkanoyl groups are those with the acyl residues of the lower (C2-Cy) fatty acids, for example acetyl, propionyl, Butyryl, isoButyryl and the like. The lower alkanoyl groups with up to 4 carbon atoms, especially acetyl, are preferred.

The new compounds of the general formula 1 can be prepared in a manner known per se.

The compounds of formula I and the preferred subgroups can be prepared according to the invention using varying methods.

Generally, the compounds of the invention are prepared by acylating a compound of Formula 3 with an acid of Formula 4 or a chemical equivalent thereof.

Thus, the final product can be obtained not only by direct acylation with an acid of the formula IV but also via intermediates such as (a) ω-haloalkanoic acids of the formula 5, wherein X is bromine, chlorine or iodine, or (b) a tosyl-oxyalkanoic acid, ie an acid of the formula V, wherein X is tosyloxy (CH 2 - -SO 2 O-), or (c) a substituted acrylic acid of the formula 6. The product of this acylation is then subjected to a rearrangement or addition with the anion of a thiol or thioic acid of the formula 7.

The acylation can also be accomplished with a thiolactone of the formula 8 wherein η is 1 or 2, or a mercaptoalkanoic acid of the formula 9 wherein Y represents R2, while, if a product of the formula 3 wherein R2 represents hydrogen, desirably Y may also represent a protecting group, such as (a) CH3O- © -CH2, (b5 Cf ^ X> Cc) CH3CONHCK2, R, R, 11 14 (d] ROC-CH- - (CHI -S- or another sulfur protecting group.

The removal of the protecting group can be accomplished using conventional methods, such as by treatment 8104049

S

-2a - 'r' 4 with hot trifluoroacetic acid, cold trifluoromethanesulfonic acid, mercuric acetate, sodium in liquid ammonia, zinc and hydrochloric acid or the like. In connection with these methods, reference is made to Methods of Organic Chemistry (Houben-Weyl), Vol. XV, Part I, 5 p. 736 et seq. (1974).

When the acid of the formula IV is used as an acylating agent, the acylation can be effected in the presence of a coupling agent, such as dicylohexylcarbo-diimide or the like, or the acid can be activated by formation of its mixed anhydride, symmetrical anhydride, acid chloride. ride, acid ester or use of the Woodward reagent, K, N-ethoxy-carbonyl-2-ethoxy-1,2-dihydroquinoline, or the like. In connection with the acylation methods, reference is made to Methodes der Organischen Chemie (HouBen-Weyl), Vol. XV, Part II, p. 1 ff.

15 (1974}.

Compounds of the formula 3 include azetidine-2-carboxylic acid and its lower alkyl esters. The acylation of such compounds is described in more detail below.

According to a preferred method of preparing compounds of the formula I, especially of compounds, wherein R 1 represents -CO-, an acid or ester of the formula 3 is coupled with a haloalkanoic acid of the formula 5, wherein X is halogen, preferably chlorine or bromine. This can be accomplished by using one of the Known procedures, wherein the acid 4 is activated for the reaction with the acid 3 by formation of a mixed anhydride, symmetrical anhydride, acid chloride or active ester or by using Woodward reagent K, EEDQ (N-ethaxycarbonyl-2-ethoxy-1,2-dihydroxyquinoline) or the like.

The product of this reaction is a compound of the formula IQ. The product of the formula 10 is subjected to a displacement reaction with the anion of a thioic acid of the formula 7 to form a product of the formula 11, wherein R 2 represents R 1 CO, which product can then be converted by ammonolysis into the product of formula 12. When a protecting group is, the compound of formula 12 can be obtained by removing the protecting group on the above described manner. When R is an ester group (i.e. 5 R represents lower alkoxy), the ester group may be removed, for example when R represents tert-butoxy or tert-amyloxy, by treating the ester of formula 11 or 12 with trifluoroacetic acid and anisole, whereby the corresponding acid is obtained. When other alkoxy groups are present, the corresponding acid will be obtained by alkaline hydrolysis.

A variation of this procedure involves the use of an acrylic acid of the formula VI as starting material. This acrylic acid is first converted to the acid halide form and then reacted with a compound of the formula 3 to form a compound of the formula 13 and this intermediate is subjected to the addition reaction with the thiol or thioic acid 7 as described above .

A tosyloxyalkanoic acid of the formula 14 can also be used as the agent for the acylation of the acid of the formula 3, after which the acylation product is subjected to the displacement reaction, etc., as described above.

On the other hand, the acrylic acid of the formula 6 can first be reacted with the thioic acid of the formula 7 to form a product of the formula 15, which is converted into its acid halide, for example with thionyl chloride, and then coupled with the compound with formula 3, after which the procedure described above is further followed.

The acid or ester of the formula III can also be acylated with a "protected" form of an ra-raercapto-alkanoic acid of the formula 16, wherein Rg is the "protecting" group. Such "protecting" groups can be in the form described above.

After acylation, the protecting group can be removed from the product by any of the known methods described above.

8104049 «- 4 -

Yet another acylating agent is a thiolactone, for example, β-propiothiolactone, α-methyl-g-propiothiolactone or the like.

Further details regarding the preferred methods of preparing the compounds of the invention are set forth in the specific examples below.

According to a particularly preferred modification of the process #, the acid or ester of the formula 3 is acylated with a haloalkanoyl halide of the formula 17, wherein each X independently represents a halogen, preferably chlorine or bromine, R represents hydrogen, lower alkyl or phenyl-lower alkyl and n is 0, 1 or 2. This reaction is effected in an alkaline medium, for example a dilute alkali metal hydroxide solution, alkali metal hydrogen carbonate or alkali metal carbonate solution, at a reduced temperature, for example about 0-15 ° C. The reaction product is subjected to a displacement reaction with the anion of the thiol or thioic acid of the formula 7, also in an alkaline medium, preferably an alkali metal carbonate solution, and then worked up in the usual manner. The product of this reaction, wherein R 2 in formula 1, represents R 1 -CO, is converted to the product, in which R 2 represents hydrogen, by ammonolysis, for example with alcoholic ammonia or concentrated ammonium hydroxide solution, or by alkaline hydrolysis, for example with an aqueous metal-25 hydroxide. When an acid of the formula III is used as the starting material, the final product obtained as the free carboxylic acid can then be converted into its ester, for example by esterification with a diazoalkane, such as diazomethane, a 1-alkyl-3-p-tolyltriazene, such as ln- butyl-3-p-tolyltriazene or the like. The treatment of an ester, preferably the methyl ester, with an alcoholic ammonia solution converts the free acid into the amide, ie a product in which R represents NH 2.

According to another variation of the process, an ester, preferably the t-butyl ester, of the formula III in an anhydrous medium, such as dichloromethane, tetrahydrofuran, 8104049 * β-5-dioxane or the like, is treated with a thioalkanoic acid with the formula 18 in the presence of dicyclohexylcarbodiimide, N.N'-carbonyl bisimidazole, ethoxyacetylene, diphenylphosphorylazide or analogous coupling agents at a temperature of about 0-10 ° C. 5 The ester group (R) can then be removed, for example, by treatment with trifluoroacetic acid and anisole at room temperature.

When an ester of the formula 3 (eg R is lower alkoxy, especially t-butoxy) is acylated with a thiolactone, eg S-propiothiolactone, α-methyl - $ - propiothio-lactone or the like, the reaction can be carried out in a anhydrous solvent, such as tetrahydrofuran, dioxane, methylene chloride or the like, at about 0 ° C to about room temperature.

The ester group can then be removed with anisole and tri-fluoroacetic acid in the manner described above.

Products of the formula I have one or more asymmetric carbon atoms. When R 4, R 4, or R 4 have a meaning other than hydrogen, the carbon atom to which this substituent is attached is asymmetric. These carbon atoms are indicated in the formula 1 by an asterisk. The compounds therefore exist in stereoisomeric forms or in racemic mixtures thereof. All these forms and mixtures are within the scope of the invention. In the syntheses described above, the starting materials may be the racemate or one of the enantiomers. When the racemic starting material is used in the synthesis, the stereoisomers obtained in the product can be separated using conventional chromatographic or fractional crystallization methods. Generally, with respect to the carbon atom of the amino acid, the L isomer is the preferred isomeric form. Also preferred is the D isomer with respect to the α-carbon atom in the acyl side chain (i.e., the carbon atom carrying Ej).

The compounds of the invention form basic salts with various inorganic and organic bases, which are also within the scope of the invention.

8104049 4 - 6 -

Such salts include ammonium salts, alkali metal salts such as sodium and potassium salts (which are preferred), alkaline earth metal salts such as the calcium and magnesium salts, salts with organic bases such as the dicyclohexylamine, ben-5 zathine, N-methyl -D-glucamine, hydrabamine salts, salts with amino acids, such as arginine, lysine and the like. The non-toxic, physiologically acceptable salts are preferred, although other salts are also useful, for example in the isolation or purification of the product, as illustrated in the examples for the case of the dicyclohexylamine salt.

The salts are conventionally formed by reacting the free acid form of the product with one or more equivalents of the appropriate base, which provides the desired cation, in a solvent or medium in which the salt is insoluble, or in water and removal of the water by freeze drying.

By neutralizing the salt with an insoluble acid, such as a cation exchanger hard in the hydrogen form (for example, polystyrene sulfonic resin such as Dowex 50) or with an aqueous acid and extracting with an organic solvent, for example ethyl acetate, dichloromethane or the like, the free acid form can be obtained and, if desired, another salt are formed.

Further experimental details are indicated in the examples, which describe preferred embodiments and also serve as a model for the preparation of other members of the group.

The compounds of the invention inhibit conversion of the decapeptide angiotensin X to angiotensin II and are therefore useful for lowering angiotensin-related hypertension. Angiotensin I is formed by the action of the enzyme renin 30 on angiotensinogen, a pseudoglobulin in blood plasma. Angiotensin I is converted into angiotensin II by angiotensin converting enzyme (ACE). The latter is an active blood pressure-raising agent, which is considered to be the cause of various forms of hypertension in different mammalian species, for example rats and dogs. The connections according to 8104049 - 7 - «·% .--. * invention block the conversion of angiotensin (renin)> angiotensin I -> angiotensin II by inhibiting the angiotensin converting enzyme and reducing or eliminating the formation of blood pressure-increasing angiotensin II. By administration of a composition containing one or more compounds of the formula 1 and / or physiologically acceptable salts thereof, angiotensin-induced hypertension in suffering mammals can be reduced. A single dose or preferably 2-4 daily divided doses based on about 0.1-100 mg per kg per day and preferably about 1-50 mg per kg per day is suitable for lowering blood pressure, as shown by the animal experiments described by SL Engel, T.R. Schaeffer, M.H. Waugh and B. Rubin, Proc. Soc. Exp. Biol. Med. 143, 483 (1973). The substance is preferably administered orally, but parenteral administration, such as subcutaneous, intramuscular, intravenous or intraperitoneal administration, can also be used.

The compounds of the invention can be used for lowering blood pressure in the form of preparations such as tablets, capsules or elixirs for oral administration or in sterile solution or suspensions for parenteral administration. About 10-500 mg of a compound or mixture of compounds of the formula 1 or physiologically acceptable bolts thereof are mixed with physiologically acceptable vehicles, carriers, excipients, binders, preservatives, stabilizers, flavors, etc. to form a unit dosage form as required in pharmaceutical practice. The amount of the active ingredient in these preparations is such that an appropriate dose is obtained within the above range.

Examples of additives, which can be incorporated into tablets, capsules and the like, fine the following: a binder, such as gum tragacanth, gum acacia, corn starch or gelatin, an excipient such as dicalcium phosphate, a disintegrant such as corn starch, potato starch, alginic acid and the like , a lubricant, such as magnesium stearate, a STET-35 agent, such as sucrose, lactose or saccharin, and a flavoring agent 8104049 4 • 4 - 8 - such as peppermint, wintergreen or cherry oil, When the unit dosage form is a capsule in addition to the materials of the above type, it may additionally contain a liquid carrier, such as a fatty oil. Various other materials can be present as coatings or to further modify the physical form of the unit dose. For example, tablets can be coated with shellac, sugar or both. A syrup or elixir can contain the active compound, sucrose as a sweetener, methyl and propyl parabens as preservatives, a colorant and a flavoring agent, such as cherry or orange flavor.

Sterile preparations for injection can be prepared according to conventional pharmaceutical procedures 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, etc., or a synthetic fat vehicle, such as ethyl oleate, or the like.

If necessary, buffers, preservatives, anti-oxidants and the like can be included,

The invention is further illustrated but not limited by the following examples.

Example I

1- (2-Ben2-ethylthioacetyl) -L-pipecolic acid.

L-pipecolic acid (6.15 g) is dissolved in 25 N sodium hydroxide (50 ml) and the solution is cooled in an ice-water bath. Sodium hydroxide 2 M (26 ml) and chloroacetyl chloride (5 * 65 g) are added and the mixture is stirred vigorously at room temperature for 3 hours. A suspension of thiobenzoic acid (7 * 5 g) and potassium carbonate (1.8 g) in water (50 ml) is added. After stirring at room temperature for 18 hours, the reaction mixture is acidified and extracted with ethyl acetate. The ethyl acetate layer is washed with water, dried over magnesium sulfate and evaporated to dryness in vacuo. The residue (11.6 g) is dissolved in ethyl acetate (150 ml) and dicyclohexylamine (11 ml) is added. The crystals are filtered and recrystallized from ethyl acetate; 8104049 - 9 -

In order to convert the salt to the acid, the crystals are dissolved in a mixture of 5% aqueous potassium hydrogen sulfate (100 ml) and ethyl acetate (300 ml). The organic phase is washed once with water, dried over magnesium sulfate and evaporated to dryness in vacuo.

Example II

1- (2-Mercaptoacetyl) -L-pipecolic acid

1- (2-Benzoylthioacetyl) -L-pipecolic acid (3.2 g) 10 is dissolved in a mixture of water (10.5 ml) and concentrated ammonia (6.1+ ml). After 1 hour, the reaction mixture is diluted with water and filtered. The filtrate is extracted with ethyl acetate and then acidified with concentrated hydrochloric acid, saturated with sodium chloride and extracted 2 times with ethyl acetate. The ethyl acetate extracts are washed with saturated sodium chloride and evaporated to dryness. The product, 1- (2-mercapto-acetyl) -L-pipecolic acid, is crystallized from ethyl acetate. Example III

a) Tert-butyl ester of L-pipecolic acid.

20 L-pipecolic acid (258 g) is dissolved in a mixture of water (1 L) and 5 N. sodium hydroxide (* K) 0 ml). The solution is cooled in an ice bath and with vigorous stirring 5N sodium hydroxide (h60ml) and benzyloxycarbonyl chloride (3U0ml) are added in five equal portions over a period of 30 min. After stirring at room temperature for 1 hour, the mixture becomes 2 extracted times with ether and acidified with concentrated hydrochloric acid. The precipitate is filtered off and dried.

The benzyloxycarbonyl-L-pipeco-30-line acid thus obtained is dissolved in a mixture of dichloromethane (300 ml), liquid isobutene (800 ml) and concentrated sulfuric acid (7.2 ml). The solution is shaken in a pressure bottle for 72 hours. The pressure is released and the isobutene is allowed to evaporate and the solution is washed with sodium carbonate, water, dried over magnesium sulfate and evaporated to dryness in vacuo, giving 8104049-10 benzyloxycarbonyl-L-pipecolinic acid tert-butyl ester. is acquired.

The benzyloxycarbonyl-L-pipecolinic tert.-butyl ester is dissolved in absolute ethanol (1.2 l) and hydrogenated at normal pressure with 10% Pd on carbon (10 g) until only a trace of carbon dioxide is observed in the leaving hydrogen gas. {2b hours). The catalyst is filtered off and the filtrate concentrated in vacuo at 30 mm Hg. The residue is distilled in vacuo to yield L-pipecolic acid tert-butyl ester.

B) 1- (3-Acetylthiopropanoyl) -L-pipecolinic tert-butyl ester.

L-pipecolinic tert.-butyl ester (5 * 55 g) is dissolved in dichloromethane (ho ml) and the solution is cooled in an ice-water bath. A solution of dicyclohexylcarbodiimide 15 (6.18 g) in dichloromethane (20 ml) is added, immediately followed by 3-acetylthiopropionic acid (h, b5 g). After stirring for 15 minutes in the ice-water bath and 16 hours at room temperature, the precipitate is filtered off and the filtrate is evaporated in vacuo.

The residue is dissolved in ethyl acetate and washed until neutral reaction. The organic layer is dried over magnesium sulfate

and evaporated to dryness in vacuo to give the title compound. Example IV

1- (3-Mereaptopropanoyl) -L-pipecolinic tert.-butyl ester (2.5 g) is dissolved in a mixture of anisole (20 ml) and trifluoroacetic acid (U5 ml). After a 1 hour stay in an argon atmosphere at room temperature, the reaction mixture is evaporated in vacuo and the residue is precipitated several times from ethyl acetate-hexane. The residue (1.9 g) is dissolved in ethyl acetate (30 ml) and dicyclohexylamine (1.85 ml) is added. The crystalline salt is filtered off and recrystallized from isopropanol.

The salt is converted into the acid as described in Example 1. The product is crystallized from ethyl acetate-hexane.

35 Example_V

8104049 t - 11 - 1- (3-Benzoylthiopropanoyl) -5-hydroxy-L-pipecolic acid.

5-Hydroxy-L-pipecolic acid (7.25 g) is dissolved in normal sodium hydroxide (50 ml) and the solution is cooled in an ice bath. 3-Bromopropionyl chloride (8.5 g) and 2 N. sodium hydroxide (27 ml) are added and the mixture is stirred in the ice shad for 10 min and at room temperature for 3 h. A suspension of thiobenzoic acid (7.5 g) and potassium carbonate (H, 5 g) in water (50 ml) is added and the mixture is stirred at room temperature for 18 hours. After acidification with concentrated sodium chloride, the aqueous phase is extracted twice with ethyl acetate. The organic layers are dried, magnesium sulfate top and evaporated in vacuo to give the title compound.

Example VI

1 - (3-Mercaptopropanoyl) -5-hydroxy-L-pipecoline ACID.

1- (3-Ben2oylthiopropanoyl) -5-hydroxy-L-pipecolinic acid (5.1 g) are dissolved in a mixture of water (8 ml) and concentrated ammonium hydroxide (5.6 ml) and the solution is stirred kept in an argon atmosphere for 1 hour. The reaction mixture is diluted with water, filtered and the filtrate extracted with ethyl acetate. The aqueous phase is acidified with concentrated hydrochloric acid, saturated with sodium chloride and extracted with ethyl acetate. The organic layers are washed with saturated sodium chloride, dried over magnesium sulfate and evaporated to dryness in vacuo. The residue, the title compound, is crystallized from ethyl acetate-hexane.

Example VII

1- (3-Acetylthio-2-methylpropanoyl) -L-pipecolinic acid tert-butyl ester.

L-pipecolinZre tert-butyl ester (5.5 g) is dissolved in dichloromethane (bo ml) and the solution is stirred and cooled in an ice bath. Dicyclohexylcarbodiimide (6.2 g), dissolved in dichloromethane (15 ml), is added, immediately 810404¾ - 12 - followed by a solution of 3-acetylthio-2-methylpropanoic acid (U, 9 g) in dichloromethane (5 ml) ). After stirring for 15 minutes in the ice bath and 16 hours at room temperature, the precipitate is filtered off and the filtrate is evaporated to dryness in vacuo. The residue is dissolved in ethyl acetate and washed until neutral reaction. The organic phase is dried over magnesium sulfate and evaporated to dryness in vacuo. The residue, 1- (3-acetylthio-2-methylpropanoyl) -L-pipecolinic acid t-butyl ester, is purified by column chromatography (silica gel chloroform).

Example VIII

1 - (3-Acetylthio-2-methylpropanoyl) -L-pipecoline fire,

The 1- (3-acetylthio-2-methylpropanoyl) -L-pipeline linear tert-butyl ester of Example VII (7.9 g) is dissolved in a mixture of anisole (55 ml) and trifluoroacetic acid (110 ml).

After storage for 1 hour at room temperature, the solvent is removed in vacuo and the residue is precipitated several times from ether-hexane. The residue (6.1 g) is dissolved in acetonitrile (100 ml) and dicyclohexylamine 5 ml) is added. The crystalline salt is boiled with fresh acetonitrile (100 ml), cooled to room temperature and filtered,

This material is crystallized from isopropanol. The crystalline dicyclohexylamine salt is suspended in a mixture of 5 #'s aqueous potassium hydrogen sulfate and ethyl acetate. The organic phase is washed with water and evaporated to dryness. The residue is crystallized from ethyl acetate-hexane to give 1- (3-acetylthio-2-D-methylpropanoyl) -L-pipecolic acid.

Example IX

30 1 - (3-Mercapto-2-D-with hylpropanoyl-) -L-pipecoline Hour.

The thioester (0.85 g) of Example VIII is dissolved in 5.5 N methanolic ammonia and the solution is kept at room temperature for 2 hours. The solvent 35 is removed in vacuo and the residue dissolved in water, 8104049

* V

<- 13 -

applied to an ion exchange column in the H + cycle (Dowex 50 »analytical grade) and eluted with water. The fractions giving a positive thiol reaction are combined and frozen. The residue is crystallized from ethyl acetate-hexane; and 5 yields pure 1 - (3-mercapto-2-D-methylpropanoyl) -L-pipecolic acid. Example X.

1 - (^ - Benzylthiobutanoyl) -L-pipecolic acid.

To a solution of L-pipecolic acid (3.0 g) in normal sodium hydroxide (25 ml), cooled in an ice bath, 2 N. sodium hydroxide (12.5 ml) and U-chlorobutyryl chloride (3.5 g) are added . The reaction mixture is stirred at room temperature for 3.5 hours and a suspension of thiobentphbic acid (3.75 g) and potassium carbonate (2.1). g) in water (25 ml) is added. After stirring overnight at room temperature, the reaction mixture is acidified with concentrated hydrochloric acid and extracted with ethyl acetate. The organic layer is dried over magnesium sulfate and evaporated to dryness in vacuo. The residue is chromatographed on a column of silica gel with benzrene-20 acetic acid (7: 1). . The fractions containing the desired material are combined and evaporated to dryness. A small sample of this material is dissolved in ethyl acetate and dicyclohexylamine is added to a pH of 8-10 (determined with a wet pH paper). The dicyclohexylamine salt crystallizes immediately.

Example XI

1 - (I) —More aptobutanoyl) —L — pipe colinic acid.

1- (1) -Benzylthiobutanoyl) -L-pipecolinic Acid (1.15 g) is dissolved in a mixture of water (U ml) and concentrated ammonia (2.7 ml). After stirring at room temperature for 1 hour, the mixture is diluted with water, filtered off, extracted with ethyl acetate and the aqueous phase concentrated in vacuo. The resulting ammonium salt of 1- (U-mercaptobutanoyl) -L-pipecolic acid is purified by ion exchange chromatography on a column of diethylaminoethyl-Sephadex (cross-linked dextran) with a gradient of ammonium hydrogen carbonate. The ammonium salt is dissolved in 8104049 - 1¼ - - - - * water (2 ml) and applied to a column of Dowex 50 sulfonic acid resin (analytical grade) in the hydrogen form and the free acid is eluted with water. desired material (positive reaction with sulfhydryl reagent and carboxyl reagent) 5 are combined and lyophilized to give 1- (U-mer captobutanoyl) -L-pipecolic acid. The dicyclohexyl ammonium salt is prepared according to the procedure of Example X.

Example XII

1 -J_ 3- (Acetylthio) -DL-propanoyl / pipecolic acid.

10

Pipecolic acid (6.5 g) is suspended in 200 ml of dimethylacetamide. 3-Acetylthiopropanoyl chloride (8.3 g) is added dropwise to the suspension at 23 ° C. A clear solution is formed and the temperature rises to 28 ° C.

N-methylmorpholine (10.1 g) is added to this clear solution. A precipitate is immediately formed and the temperature rises to 3 ° C. The mixture is heated on a steam bath for 1 hour to form a clear solution.

After cooling, the precipitated solid is filtered off, yielding 5.1 g of the title compound; m.p. 190 DEG-200 DEG C. The solvent is removed and the viscous residue triturated with isopropyl ether to yield 7.8 g of product; m.p. = 90-101 ° C. Recrystallization from acetone-hexane gives a solid with a constant melting point; m.p. = 102-10-10 ° C; 0.72 / silica gel, benzene, acetic acid (7: 2) /.

Example XIII

DL-1- (3-Mercaptopropanoyl) pipecolic acid.

12 ml of concentrated ammonium hydroxide is stirred in a nitrogen atmosphere at 10 ° C for about 15 min and then solid 3- (acetylthio) -DL-propanoyl / - pipecolic acid (6.1 g) is added at 5-10 ° C. A clear solution is formed after 2-3 min. The ice bath is removed and the solution is stirred at room temperature in a nitrogen atmosphere for 35.5 min. The solution is made strongly acidic with 20 # 's 8104049 - 15 - φ HCl (cooling) and the precipitated oil is extracted with 3 x 150 ml ethyl acetate. The ethyl acetate extracts are dried over magnesium sulfate and the solvent is removed to yield 6.0 g of the title compound; 0.77 /. silica gel, benzene, acetic acid (7: 1).

Example XIV

1- (3-Mercaptopropanoyl) -L-pipecolic acid.

By using L-pipecolic acid instead of DL-pipecolin-10 acid in the procedure of Example XII and then subjecting the product to the procedure of Example XIII, 1-J-3- (acetylthio) propanoyl-7-L-pipecolic acid and 1- (3-mercapopropropanoyl) -L-pipecolic acid, Rf 0.80 (silica gel, benzene, acetic acid (7: 1) / / $ $ _ 7 ^ -51> 5 ° (c 1.0, absolute ethanol), obtained .

Example XV

1- /. 3- (Acetylthio) -2-methylpropanoyl / DL-pipecolic acid.

6.5 g (0.05 mol) of pipecolic acid are suspended in dimethylacetamide (200 ml), after which 9.0 g (0.05 mol) of 3-20 acetylthio-2-methylpropanoyl chloride are added dropwise. The temperature rises to 29 ° C and a clear solution is formed. Then 10.1 g of R-methylmorpholine are added in one go, the temperature rising to 3 ° C. The mixture is heated on a steam bath for 1 hour to form a clear solution. This solution is allowed to stand at room temperature overnight, after which the precipitated solid is filtered off; 6.1 g; m.p. 203 DEG-20 DEG C. The solvent is removed and the viscous residue triturated with water and 20% HCl. The yellow oil is extracted with 3 x 150 ml of ethyl acetate. The ethyl acetate extracts are dried over magnesium sulfate and removed to give g of the title compound as a viscous oil.

Example XVI

1- (3-Mercapto-2-methylpropanoyl) -DL-pipecolin2hr.

35 8104049 - 16 -

Aqueous 1H 2 OH (30 ml water and 20 ml concentrated M 2 OH) is stirred in a nitrogen atmosphere at 10 ° C for 15 min. This is added to 13 * 0 g (0.05 mol) 1- / 3- (acetyl-thio) -2-methyipropanoyl / DL-pipecolic acid and the resulting solution is stirred in a nitrogen atmosphere for 10 min; then stirred for 50 min, at room temperature, The solution is then treated with water and 20% HCl and the yellow oil is extracted with 3 x 150 ml of ethyl acetate The ethyl acetate extract is dried over magnesium sulfate and evaporated to give 11.1 g of the title compound as a viscous oil; silica gel, benzene, acetic acid (7: 2) /, 15 8104049

Claims (5)

1. A process for the preparation of a therapeutic composition having an antihypertensive effect, in which a proline is brought into a form suitable for therapeutic use, characterized in that a compound of the formula 1 in which R is a hydroxy or amino group or a lower alkoxy group, R 1 and R 2 each separately a hydrogen atom, an optionally substituted phenyl group with a lower alkyl group or a phenyl group, R 9 is a hydrogen atom or a group COR 2, wherein R 1 is a phenyl, lower alkyl phenyl or phenyl lower alkyl group, and R 1 represents a hydrogen atom or a hydroxy or lower alkyl group and n * 0, 1 or 2 and m = 3, or use a basic Zrout thereof. 2. Process for the preparation of a compound suitable for use in the process according to claim 1, characterized in that a compound of the formula 1, in which R, R ^ Rg, R ^, R ^, m and n have the same meaning as in claim 1, prepared in a manner customary for such compounds. 20 8104049 V ''. Reg.nr .: 115.779 R4Ri "/" i 1. I v r4 — s— (chJ ^ - ch — COOH X - (CH) * CH — cox 16 17 R / MMI II! | R2-S- (CHj) m — CH- COOH 18 Rr-MCX g Rr-M -CS-Me ^ g M Rii R * Rj — N = C = Μ Γ | \ I 9 21 Rf-NH-C-S- (CH) -CH-COOH R 1 -S_R 22 R <> ss R 24 phage alkyl— CO - NHCH ^ OH [O I1 "Ri-SSR ^ RtS— X o 25 26 R4— S —SojH Rg .— S - SCN 27 ^ 28 (HC) -CH2 Rt Ri ^ I *! I Γ R - OC - HC- N-CO - CH - (CH \ —S (0) o * * J * v ip 29 El Squibb & Sons, Ine .. in Princeton. New Jersey Ver. S for America 8104049 rs /. Reg.nr .: 115.779 «3 '« 4 J * 1 - (CH) ^. R, —s (CH) -CH - CO— N— CH — COR? * "f -ffl- 3 HN - CH— COR ^ Ri R $ i — S— (CHj ^ —CH— COOH HW * Ji R4 Ri II 'lx ~ (CHk ~ cH — C00H 5 r4 r CH-C— COOH g φ ) ν. — f 8 A ~ SH s_c 7. Nn R4 R | O || • ii YS-fCH) —CH —COR „/ 1, 1 lyi 9 R4 R, H2C - (CH] W 1Q X— (CHU-CH — CO-N - CH-COR r ^ R, M, C- (CH) * R i — S— / ch) * - CH - CO - N —CH — COR ψ 11 .. ^ 1¾. Η ^ ~ ^ Η)% HS— (CH) ^ - CH —CO— N - CH — COR R 12! 4. JU R | H ^ C (CH) w CH · = C— CO— N - CH — COR 13 y * 4 Ri C '^ ~ C ^ S ^ 0 ~ ^ H ^ ~ CH ~ m0H Ri RUII' 15 R2— S - CH - CH - COOH ER Squibb & Sons, Inc. 8 1 0 4 0 4 9:. ^ SitrJers% «·.