CS204002B2 - Process for preparing mercaptoacylaminoacids - Google Patents

Description

The invention relates to a process for the preparation of a pseptide useful for reducing angiatensin-induced hyper Terraceo.

Angiotensin II is a potent vascular contracting agent that has been found to be the major agent involved in the development of renovascular hypertension.

Angiotensin II is formed from angiotensin I by the action of an angiotensin converting enzyme. Angiotensin I is a biologically inert decapeptide cleaved from the blood protein of angiophensinogen by the action of the renin enzyme [Opařil et al. New England J. of Med., 291, 389-457 (1974)]. Augiotensinogen and renin are also biologically inert.

Angiotensin-converting enzyme is also responsible for the inactivation of bradykinin, a vasodilating agent effective in regulating renal functions (Erdos, Circulation Research 36,247 (1957)).

Thus, angiotensin converting enzyme inhibiting agents can counteract the pressure effect of angiotensin I, since this effect is only due to the conversion to angiotensin II. These agents can be used therapeutically in the treatment of forms of renovascular and malignant hypertension as well as other forms of angiotensin-dependent hypertension [Gavras et al., New England J. of Med. 291, 817 (1974)].

In scaled et al above, angiotensin II has a major role in maintaining circulating DC stability in animals with depleted sodium, but also normal animals with normal angiotensin II salt intake are not required for acute blood pressure maintenance. In various conditions that depress the renin-angOtensin system, acute administration of an angiotensin-converting enzyme inhibitor or angiotensin II blocker reduces blood pressure and causes an increase in plasma renin activity.

Certain mercaptoacylamino acids have already been reported in the literature. U.S. Patent 3,246,025, issued April 12, 1966, claims mercaptopropionylglycine derivatives useful for enhancing liver function and as antidotes for poisons such as mercury and organoarsenite compounds. See also DOS number

U.S. Patent No. 3,897,480, issued July 29, 1957, discloses the utility of N- (α-mercaptoacyl) amino acids for prophylaxis and therapy in the treatment of metabolic irregularities, diabetes and hepatitis. US Patent Number

No. 857,951, dated December 31, 1974, discloses the use of 2-methoxycapropionylglycine and its alkali metal salts in the treatment of respiratory-tract diseases.

It has been reported that 2-mercaptoproipionylglycine, used as a liver protective agent, lowers blood pressure by intravenous injection to anesthetized rats with normal blood pressure [Schulze, Arzneim. Forseh. 22, 1433 (1972)], an unreliable model [Schwarts, Methods in Phairmacology, Vol. 1, 1215 (1971), Berger, Selected Pharmacologieal Testing Methods, Vol. 3, 171,194 (1968)]; whereas in other works the effect on blood pressure was not reported [Fujimura et al., Nippon Yakurigaku Zasshi 60, 278-92 (1964)]. See also Ripa, Why. Int. Symp. Thiola, Osaika, Apan 1970, pp. 226-202, which reported that in rats, β normal blood pressure increases anglo'tensinogen levels and decreases renin levels.

It has now been found that certain mercaptoacylamino acids are inhibitors of the angioteinsin converting enzyme and reduce or eliminate angio-induced hypertension when administered to mammals with high blood pressure. tenšinjem.

The invention relates to certain compounds useful for reducing or eliminating hypertension in mammals. A method of lowering blood pressure in hypertensive mammals comprises administering an angiotensin-converting enzyme inhibitor selected from the group of compounds of Formula I,

R4 Ri Ra Ri

R 5 -S- (CH) _n -OH-CO-N-CH-COOH (I) wherein

R1, R2, R1, R4 and R5 are as defined below, or a salt thereof.

The present invention provides a process for the preparation of mercaptoacylamino acids of Formula I,

R4 R3 Ra R1

R 5 —S — 1 (CH) _n —CH — CO — N — CH — COOH (I) wherein

R 1 is aminoalkyl of 1 to 7 carbon atoms, gulanidinoalkyl of β 1 to 7 carbon atoms in alkyl, and when n is 1, alkyl of 1 to 7 carbon atoms or phenylalkyl of 1 to 7 carbon atoms in alkyl,

R 2, R 3 and R 4 are the same or different, namely hydrogen, alkyl of 1 to 7 carbon atoms or benzyl and (R 5 is hydrogen, alkanoyl β 1 to 7 carbon atoms or * benzoyl, n is 0, 1 or 2, or a salt thereof, characterized in that the compound of formula II,

R4 R3 Ra R1

X - (CH) n - CH - CO - N - CH - COOH (H) wherein

R1, R2, R3, R4 and n are as defined above and wherein

X is a halogen atom, reacted with the aroion of the thioacid of formula III,

Re — COSH (III) where

R 6 is alkyl of 1 to 6 carbon atoms or phenyl, to give the product of formula I wherein R 5 is alkanoyl of 2 to 7 carbon atoms or benzoyl, which is then optionally converted to the product of formula I wherein R 5 is hydrogen, ammonolysis and optionally converting a compound of formula I into a salt.

Compounds of formula I and salts thereof, wherein n is 0, R 1 is aminoalkyl, guanidinoalkyl, Ra, R 3, R 1 and R 5 are as defined above, compounds of formula I and salts thereof, wherein n is 1, R 1 alkyl, benzyl, aminoalkyl, guanidinoalkyl , R 2 and R 3 are hydrogen, alkyl or benzyl, R 4 is hydrogen, and R 5 is as defined above, and compounds of formula and salts thereof, wherein n is 2 and R 1, R 2, R 3, R 4 and R 5 are as defined above , the compounds are new. Other compounds are known compounds.

The invention encompasses a method of preparing compounds for reducing or ameliorating renin-angiotensin-induced hypertension in mammals, such as rats, dogs, and the like. These types of renin-angiotensin-induced hypertension include, for example, renovascular hypertension and malignant hypertension. Accordingly, the invention relates to novel compounds described above and to a method of removing or ameliorating reinertin-angiotensin-induced hypertension by administering a compound or compounds of Formula I above. The method comprises administering to a mammal with renin-angiotensin-induced hypertension an effective amount of an angiotensin-converting enzyme inhibitor selected from the group consisting of compounds of formula I.

The term alkyl refers to a straight or branched chain hydrocarbon radical containing up to seven carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, ipentyl, isopentyl, hexyl, beptyl and the like. kinds. C 1 -C 4 alkyls and alkylenes are preferred, and C 1 -C 4 alkyls are particularly preferred. Alkanoyl groups are acyl residues of lower fatty acids such as acetyl, propionyl, butyryl and the like. Acyls having 2 to 4 carbon atoms are preferred.

WITH

Compounds of formula I are amino acid-derived or include amino acid structures of alanine, leucine, phenylalanine, arginine, sarcosine, serine, asparagine, lysine, glutamine, histidine, tryptophan, cysteine, methionine, threonine, lysine, tyrosine ·, leucine, valine or aspartic acids, and arginine, alanine, phenylalanine and leucine are particularly preferred. Preferably R5 is hydrogen.

Experimental evidence suggests that N '- (3-mercapto-2-methylpropanoyl) -L-arginine,

N '- 1 (3-mercaptopropanoyl) -L-arginine, N- (3-mercaptopropanoyl) -L-phenylalanine and N- (3-mercaptopropanoyl-L-leucine) are the most effective preferred group and constitute a particularly preferred feature of the invention.

The compounds of formula I also form salts with various inorganic and organic bases, which are also within the scope of the invention. These salts include ammonium salts, alkali metal salts such as sodium and potassium, alkaline earth metal salts such as calcium and magnesium, salts with organic bases such as dicyclohexylamine, benzathine, hydrabamine and N-methyl-D-glucamine .

The compounds of the invention have one, two or three asymmetric carbon atoms when R 1, R 5 and R 4 are other than hydrogen. These carbon atoms are indicated by the asterisks of formula I. Thus, the compounds exist in diastereoisomeric forms or in racemic mixtures. All of these compounds are within the scope of the invention.

It has been found that to achieve a significant degree of biological activity, the asymmetric carbon bearing R 1 should have an L-configuration and this stereospecificity has not been reported in previous patents disclosing mercaptoacylamino acids. Compounds with L-configuration are preferred.

Inhibition of angiotensin-converting enzyme by compounds of formula I was measured in vitro with rabbit angiotensin-converting enzyme isolated from rabbit lung as described by Cushman and Cheung [Biochem. Pharmacol., 20, 1637 (1971)] and the smooth muscle cut test [Ε. O ¹ Keefe aj ,, Federation Proc. 31, 511 (1972)].

In these assays, the compounds are potent inhibitors of the contraction effect of angiotensin I and potentiators of the contraction effect of bradykinin.

By administering a composition comprising one or more angiotensin-converting enzyme inhibitors or corresponding physiologically acceptable salts to a hypertensive mammal, wherein the hypertension is caused by angiotensin, the sequence renin -> angiotensin I -> angiotensin II is affected and the hypertension is reduced or alleviated.

A single dose or preferably two to four divided doses per day in an amount of 1 to 1000 milligrams per kg per day, preferably 10 to 50 milligrams per kg per day, and in particular 30 to 300 milligrams per kg per day, are suitable for lowering blood pressure. caused by angiotensin. The animal model experiments described by S. L. Engel, T. R. Schaeier, Μ. H. Waugh and R. Ruby, Proc. Soc. Exp. Biol. Copper. 143, 483 (1973) provide valuable information. Preferably, the composition is administered orally, but a parenteral route may also be used, such as subcutaneously, intramuecularly, intravenously, or intraperitoneally.

The compounds of formula I are used to alleviate angiotensin-induced hyper-tension and can be formulated as tablets, capsules or infusions for oral administration. Sterile solutions or suspensions may be used for parenteral administration. About 10 to 500 milligrams of a compound or mixture of compounds of Formula I or a physiologically acceptable salt is mixed with a physiologically acceptable carrier, excipient, binder, preservative, stabilizer, flavoring and the like, and a unit dosage form suitable for pharmaceutical practice is prepared. The amount of active compound in the composition of such dosage form is within the dosage ranges set forth above.

Examples of ingredients that can be added to tablets, capsules and the like are: binders such as tragacanth, acacia, corn starch or gelatin, ingredients such as calcium phosphate, disintegrating agents 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 oil, oil of wintergreen, cherry essence. When capsules are used as the unit dosage form, these may contain, in addition to substances of the above type, liquid carriers such as oils. Various materials can be used to coat or otherwise enhance the pharmaceutical elegance of these preparations. For example, tablets may be coated with cream, sugar, and the like. Syrups or infusions may contain the active compound, sucrose as sweeteners, methyl and propylparabens as preservatives and colorings and flavors such as cherry or orange.

Sterile injectable compositions may be prepared by a method commonly used in pharmaceutical practice by dissolving or suspending the active compound in a conventional carrier, such as water for injection, in a natural vegetable oil such as sesame, coconut, peanut oil, cottonseed oil seeds or the like, or in synthetic fat carriers such as ethyl oleate and the like. Alternatively, they may also be used (buffers, preservatives, antioxidants and the like).

The invention is illustrated by the following examples. Temperatures are given in degrees Celsius.

Example 1

N- (3-benzoylthi-propanoyl) -L-alanine

L-alanine (4.45 g) was dissolved in aqueous 1 N sodium hydroxide (50 mL) and the solution was cooled in an ice bath with stirring. 2N sodium hydroxide (27 ml) and 3-bromopropionyl chloride (8.5 g) were added sequentially, the mixture was removed from the ice bath and stirred for three and a half hours at room temperature. A mixture of ithiobenzoic acid (7.5 g) and potassium carbonate (4.8 g) in water (50 mL) was added and the mixture was stirred at room temperature overnight. After acidification with concentrated hydrochloric acid, the aqueous solution is extracted with ethyl acetate and the organic phase is washed with water, dried and concentrated to dryness. The residue (14.9 g) was crystallized from ether to give 7.1 g of N- (3-benzoylthiopropanoyl) -L-alanine, m.p. 99—100 °.

Example 2

N- (3-mercap topropanoyl) -L-alanine

Dissolve N- (3-benzoylthiopropanoyl) -L-alanine (4.2 g in a mixture of water (7.5 ml) and concentrated ammonium hydroxide (8 ml). After one hour, dilute with water, filter and extract the filtrate. The aqueous phase was acidified with concentrated hydrochloric acid and extracted with ethyl acetate, the organic phase was washed with water, dried and concentrated in vacuo to dryness, and the residue was crystallized from ethyl acetate / hexane to give 1.87 g of N- (3-mercaptopropanoyl). -L-alanine, mp 79-81 °.

Example 3

N- (3-benzoylthiopyranoyl) -L-leucine

Substitution of L-leucine (6.55 g) with L-alanine in Example 1 gave 16.7 g of crude N- (3-benzoylthiopropanoyl) -L-leucine. This material was dissolved in a mixture of ethyl acetate (209 mL) and dicyclohexylamine. The crystalline salt was filtered and dried. Yield 19.5 g, mp 178-180 °. The dicyclohexylammonium salt was treated with a mixture of ethyl acetate (200 mL) and 10% aqueous potassium sulfite (50 mL). The organic phase was dried over magnesium sulfate, concentrated to dryness in vacuo, and the residue was recrystallized from ethyl acetate-hexane to give 8. 8 g of pure N- (3-benzoylthioipropanoyl) -L-leucine, mp 99-101 °.

Example 4

N- (3-mercaptopropanoyl) -L-leucine

The substitution of N- (3-beuzoylthiopropanoyl) -L-leucine (6.40 g for N- (3-benzoylthiopropanoyl) -L-alanine in Example 2 gives 2.75 g of N- (3-mercaptopropanoyl) -L-leucine, m.p. 132 DEG C. This material was recrystallized from acetonitrile.

Example 1 a d 5

N- (3-benzoylithipropanoyl) -L-phenylalanine

Substitution of L-phenylalanine (8.25 g) with L-alanine in the procedure of Example 1 affords 18.8 g. Of crude N- (3-ibenzoylthiopropanoyl) -L-phenylalanine. This material was crystallized from acetonitrile to give 11.1 g of the product, mp 123-124 °.

Example

N- (3-mercaptopropanoyl) -L-phenylalanine

Nm (3-benzoylthiopropanoyl) -L-phenylalanine (1.78 g) was dissolved in a mixture of water (70 ml) and 1 N sodium hydroxide solution (5.5 ml). To this solution was added concentrated ammonium hydroxide (20 mL and then water (20 mL). After three hours, the reaction mixture was extracted with ethyl acetate, acidified with concentrated hydrochloric acid and extracted again with ethyl acetate. The second ethyl acetate extract was washed with water, dried with magnesium sulfate and concentrated. The residue is chromatographed on a silica gel column with a mixture of benzene and acetic acid to give 0.47 g of N- (3-mercaptopropanoyl) -L-phenylalanine, mp 106-107 °.

Example 1 a d 7

N '- [(3-benzoylthiopropanoyl) -L-arginine]

L-arginine (8.7 g) was dissolved in 1N aqueous sodium hydroxide solution (50 ml) and the solution was cooled with stirring in an ice bath. 2N sodium hydroxide solution (25 ml) was added and 3-bromopropionyl chloride (8 ml) was added. 5 g), after which the mixture was removed from the ice bath and stirred at room temperature for two hours, a mixture of thiobenzoic acid (7.5 g) and potassium carbonate (2.4 g) in water (10 ml) was added and the mixture was stirred over Ion exchange resin (Dowex 50 ipolystyrene sulfone resin (Mikeš, Laboratory Handbook of Chromatographic Methods, Van Nostrand, 1961, p. 256)) was then added (100 mL) and the suspension was applied to an icolone of the same resin (300 mL). After washing the acidic materials with water, N - (3-benzoylthiopropanoyl) -L-arginine is eluted with pyridine-acetic acid-water buffer, pH 6.5 The fractions containing the desired material are combined, concentrated to dryness in vacuo and the residue triturated with ether to give 7 g of product m.p. 345 ° (stamp.

Example 8

N '- (3-mercaptopropanoyl) -L-arginine

N - (3-benzoylthi-propanoyl) -L-arginine (1 gram) was dissolved with vigorous stirring in a mixture of water (5 ml) and concentrated ammonia (5 ml). After one hour, the solution was extracted with ethyl acetate and concentrated to dryness in vacuo. The residue is chromatographed on a DEAE Sephadex column (dextran-derived ion exchange ion exchange resin (Mikeš, supra, p. 328)) (85 ml) with 0.005M ammonium bicarbonate buffer. Fractions containing N '-> (3-mercaptopropanoyl) -L-arginine ( as shown by a positive thiol and Sakaguchi reaction) were combined and aroonic acid carbonate was removed by lyophilization. Yield 200 mg, m.p. 230 ° (decomposition start 200 °).

Example 9

N- (3-benzoylthiproppanoyl) sarcosine

Substitution of sarcosine (4.45 g) with L-alanine in Example 1 gives 7.9 g of N- (3-benzoylthiopropanoyl) sarcosine, m.p. 139-140 °.

Example 10

N- (3-mercaptopropanoyl) sarcosine

By substituting N- (3-benzoylthiopropanoyl) sarcosine (2.8 g) for N- (3-benzoylthiopropanoyl) -L-alanine in the procedure of Example 2, 1.65 g of crude N- (3-mercaptopropanoyl) sarcosine is obtained. This material was converted to the dicyclohexylammonium salt (2.7 g), m.p. 157-158 °, and the purified salt was converted to the free acid by shaking between ethyl acetate and 10% potassium sulfite.

Example 11

N- (3-mercaptopropanoyl) -L-serine

Substitution of L-serine with L-alanine in Example 1 followed by reaction of the product of Example 2 gives N- (3-benzoylthiopropanoyl) -L-serine and N - (3-mercaptopropanoyl) -L-serine.

Example 12

N- (3-mercaptopropanoyl) -L-aspartin

Substitution of L-asparagine with L-alanine in Example 1 followed by reaction of the product according to Example 2 affords N- (3-benzoyl (thiO-propanoyl) -L-asparagine) and

N- (3-mercaptopropanoyl) -L-asparagine. Example 13

N ° - (3-mercaptopropanoyl) -L-lysine

By substitution of N ^with -tert-butyloxycarbonyl-L-lysine [R. Schwyzer and W. Rittel, Helv. Chim. Acta 44, 159 (1961)] for L-alanine in the procedure of Example 1 and then reacting the product according to Example 2 yields N ^K - (3-benzoylthiopropanoyl) -Neteře, 1 they butyloxycarbonyl-L-lysine and N '- ( 3-mercaptopropanoyl) -N-tert-butyloxycarbonyl-L-lysine. Reaction of this material with trifluoroacetic acid at room temperature for 15 minutes to give N '- (3-benzoylthiopropanoyl) -L-lysine and N ^Affairs - (3-merkaptopr opanoy 1) -L-lysine.

Example 14

N '- (3-mercapto (propanoyl) -L-histidine)

Substitution of L-histidine with L-alanine in Example 1 followed by reaction of the product according to Example 2 gives N - (3-benzoylthioprcpanoyl) -L-histidine and N - (3-neraptopropanoyl) -L-histidine.

Example 15

N- (3-mercaptopropanoyl) glycine

Substitution of glycine with L-alanine in Example 1 followed by reaction of the product of Example 2 yields (3-benzoylthiopropanoyl) glycine and N- (3-mercaptopropanoyl) glycine.

Example 16

N- (3-mercaptopropanoyl) -L-tryptophan

Substitution of L-tryptophan with L-alanine in Example 1 followed by reaction of the product of Example 2 affords N- (3-benzoylthiopropanoyl) -L-tryptophan and N- (3-mercaptopropanoyl) -Ldryptophan.

Example 17

N- (3-mercaptopropanoyl) -L-cyano

Substitution of L-cysteine with L-alanine in Example 1 followed by reaction of the product of Example 2 gives N- (3-benzoylthiopropanoyl) -L-cysteine and N- (3-mercaptopropanoyl) -L-cysteine.

Example 18

N- (3-mercaptopropanoyl) -L-methionine

Substitution of L-methionine for L-alanine in Example 1 followed by reaction of the product of Example 2 gives N- (3-banzoylthiopropanoyl) -L-methionine and N- (3-mercaptopropanoyl) -L-methionine.

Example 19

N- (3-mercaptopropanoyl) -N-methyl-L-leucine

Substitution of N-methyl-L-leucine with L-alanine in Example 1 followed by reaction of the prodrug to Example 2 affords N- (3-benzoylthiopropanoyl) -N-methyl-L-leucine and N- (3- mercaptopropanoyl) -N-methyl-L-leucine.

Examples 20—33

L-alanine and chloroacetyl chloride followed by 3-bromopropionyl chloride according to Example 1 and then reaction of the product according to Example 2 gave the compounds in column II.

Replacing the amino acid in column I with

example AND II 20 May glycine N-2-mercaptoacetylglycine 21 L-alanine N-2-mercaptoacetyl-L-alanine 22nd L-valine N-2-mercaptoaceityl-L-valine 23 L-leucln N-2-mercaptoacetyl-L-leucine 24 L-serine N-2-mercaptoacetyl-L-serine 25 L-asparagine N-2-mercaptoacetyl-L-asparagine 26 N-Boc-L-lysine N '-2-mercapitoacetyl-N ^E -Boc-L-lysine 27 Mar: L-histidine N-2-mercaptoacetyl-L-histidine 28 L-phenylalanine N-2-mercaptoacetyl-L-phenylalanine 29 L-itryptothane N-2-mercapitoacetyl-L-tryptophan 30 L-cysteine N-2-mercaptoacetyl-L-cysteine 31 L-methionine N-2-mercaptoacetyl-L-methionine 32 sarcosine N-2-mercaptoacetyl sarcosine 33 N-methyl-L-leucine N-2-mercaptoacetyl-N-methyl-L-leucine Example 34 propionyl chloride according to the procedure of

du 7 and reaction of the product according to the procedure of N-2-mercaptoacetyl-L-lysine of Example 8 gave N 2 -2-benzoylthioacetyl-L-arginine and N ^K -2-mercaptoacetyl-L-arginine.

Reaction of N ^K -2-meercaptoacetyl-N ⁶ -Boc-L-lysi-

with trifluoroacetic acid at temperature Examples 3 6—49 room for 15 minutes gets N “-2- -mercaptoacetyl-L-lysine. By substituting the amino acids listed in column I after L-alanine and 2-bromoproplonyl- Example 35 chloride with 3-bromopropionyl chloride of the process according to Example 1 and then by reaction of N '-2-mercaptoacetyl-L-arginine The product of Example 2 is obtained the compounds listed in column II. Confused chloracetyl chloride for 3-bromo- example AND II 36 glycine N-2-mercaptopropanoylglycine 37 L-alanine N-2-mercaptopropanoyl-L-alanine 38 L-valine N-2-mercaptopropanoyl-L-valine 39 L-leucln N-2-mercaptopropanoyl-L-leucine 40 L-serine N-2-mercaptoprO'panOyl-L-serine 41 L-glutamine N-2-mercaptopropanoyl-L-glutamine 42 N ^E -Boc-L-lysine N-mercaptopropanoyl-N ^with -Boc-lysine 43 L-histidine N-2-mercaptopropanoyl-L-hlididine 44 L-phenylalanine N-2-mercaptopropanoyl-L-phenylalanine 45 L-tryptophan N-2-mercaptopropanoyl-L-tryptophan 46 L-cysteine N-2-mercaptopropanoyl-L-cysteine 47 L-methionine N-2-mercaptopropanoyl-L-m-thionine 48 sarcosine N-2-mercaptopropanoylsarcosine 49 N-methyl-L-phenylalanine N-2-mercaptopropanoyl-L-methyl-L- -phenylalanine

Example 50

N 1 -mercaptopropane LL L-lysine.n

Reaction of N ^and -2-mercaptopropanoyl-N ^with -Boc-L-lysine with trifluoroacetic acid at room temperature for 15 minutes gives N-2-mercaptopropanoyl-L-lysine.

Example 51

N '-2-mercury (ptopropanoyl-L-arginine

Substitution of 2-bromopropionyl chloride with 3-bromopropionyl chloride in Example 7 and then reaction of the product according to Example 8 with N-2-benzoylthiopropanoyl-L-arginine and N-2-mercaptopropanoyl-L-arginine.

Example 52

N ^and -4-mercapitobutanoyl-L-arginine

Confused. 4-chlorobutyryl chloride to 3-bromopropionyl chloride according to the procedure of Example 7 and then reaction of the product according to the procedure of Example 8, gives N '-4-benzoylthlobutanoyl-L-arginine and N' -4-mercaptobutanoyl-L-arginine.

The racemic forms of the end products in each of the preceding examples are formed using DL forms of the starting amino acids instead of the L-forms.

Similarly, the D-forms of the end products in each of the preceding examples are formed using the D-forms of the starting amino acids instead of the L-forms.

Example 53

N- (3-mercaptopropanoyl) -N-benzylglycine

By substituting N-benzylglycine for L-alanine in the procedure of Example 1, and then reacting the product as in the example. 2, N- [3-benzoylthiopropanoyl) -N-benzylglycine and N- (3-mercaptopropanoyl) -N-benzylglycine are obtained.

Example 54

N- (3-mercaptopropanoyl) -N-benzyl-L-leucine

Substitution of N-benzyl-L-leucine with L-alanine in Example 1 and then reaction of the product according to Example 2 gives N- (3-benzoylthioprotpanoyl) -N-benzyl-L-leucine and N- (3-mercaptoprcpanoyl) -N-benzyl-L-leucine.

Example 55

N- (3-mercaptopropanoyl) -L-aspartic acid

Substitution of L-aspartic acid with L-alanine in Example 1 followed by reaction of the product of Example 2 gives N- (3-benzoylthiopropanoyl) -L-aspartic acid and N- (3-mercaptopropanoyl) -L-aspartic acid.

Example '56

1000 tablets containing 100 mg of N- (3-mercaptopropanoyl) -L-phenylalanine are prepared from the following ingredients:

N- (3-mercaptopropanoyl) -L-phenylalanine 100 g corn starch 50 g gelatin 7.5 g avicel (microcrystalline cellulose) 25 g magnesium stearate 2.5 'g

N- [3-mercapitopropanoyl] -L-phenyl-alanine and corn starch are mixed with an aqueous gelatin solution. The mixture is dried and ground to a fine powder. Avicel and then magnesium stearate are admixed and granulation is performed. The granulate is compressed into tablets to give 1000 tablets containing 100 mg of active ingredient each.

Example 57

1000 tablets, each containing 200 mg of N-2-mercaptopropanoylglycine, are prepared from the following ingredients:

N-2-mercapto * propoanoylglycine 200 g lafetose 100 g avicel 150 g corn starch 50 g magnesium stearate 5 g

The N-2-mercaptopropanoylglycine, lactose and avicel are mixed, and then corn starch and then magnesium stearate are added. The dry mixture is compressed into tablets to give 1000 tablets each having a weight of 505 mg and containing 200 mg of active ingredient each. The tablets were coated with a solution of Meithocel E15 (methylcellulose) and a colored lacquer containing yellow # 6.

Example 58

The injectable solution is prepared from the following ingredients:

N- (3-mercaptopropanoyl) -L-phenylalanine 500 g methylparaben 5 g propylparaben 1 g sodium chloride 25 g water for injections, qs. 5 1

The active ingredient, preservatives and sodium chloride are dissolved in 3 liters of water for injection and then the total volume is adjusted to 5 liters. The solution is filtered through a sterile filter and asep204002 filled into sterile vials which are sealed with pre-sterilized rubber stoppers. Each vial contains 5 ml of solution containing 100 mg of active ingredient per ml of solution for injection.

Example 59

Although the angiotensin I to anglotensin II iconveirse angiotensin converting enzyme is probably the most important in hypertension pathology, the activity of the isolated enzyme is preferably more accurately measured by the rate of cleavage of the simpler peptide substrate hippuryl-L-histidyl-L-leucine. To determine the Iso values (concentration of compound expressed in rpm programs / im, 1 causing 50% inhibition of angiotensin-converting enzyme) of different concentrations of each compound, the following components are added to 13 X 100 mm tubes such that said final concentration is in a final volume of 0.25 ml: 100 mM potassium phosphate buffer pH 8.3, 300 mM sodium chloride, 5 mM hippuryl-L-histidyl-L-leucine and 5-milliliter units of angiotensin-converting enzyme prepared from rabbit lung Controls not containing inhibitor (100% effect) All enzymatic reactions are initiated by the addition of the enzyme, incubated for 30 minutes at 37 DEG C. and quenched by the addition of 0.25 ml of 1N hydrochloric acid. enzyme converting angiotensin to hippuryl-L-histidyl-L-leucine, is extracted into ethyl acetate, The amount of inhibition at each concentration of compound is calculated by comparison and control activities at 0 and 100%. The concentrations of representative compounds of the invention that inhibit the effect of the angiotensin converting enzyme by 50% are shown in the following table:

compound dose count according to e.g. ing / kg animals

15 Dec 10 100 ALIGN! 2 2 36 10 2 30 2 100 ALIGN! 2

IR compound according to Ex.

150 (/ tg / ml)

2 1.2 4 1.8 6 0.86 8 0.17 10 1,8 15 Dec 2,0 36 2.6

Example 00

The procedure for determining inhibition of angiotensin I-converting enzyme in excised guinea pig ileum is performed as follows: Different concentrations of compound are added to the excised ileum in the Krebs solution bath, aerated with 95% Oa and 5% CO 2. After two minutes, angiotensin I (25 µg / ml) is added and the isotonic contraction is measured. The concentrations of representative compounds of the invention (in micrograms per ml) that inhibit the effect of angiotensin I by 50% (IC 50) are shown in the following table:

the compound of Example. IC 50 (tg / ml) 2 0.94 4 2,0 6 0.52 8 0.9 10 0.94 15 Dec 4,5 36 2,0

Example 61

Representative compounds of the invention are administered orally to non-anesthetized male Sprague-Dawley rats weighing about 200 g and then injected with 0.31 µg / kg angiotensin I. The degree of inhibition obtained is shown in the following table.

% maximum inhibition of angiotensin I pressure + SE

34.2 ± 6.7%

61.5 ± 1.2%

29.9 + 3.1%

52.9 + 15.8%

64.0 +12.3%

Example 62

Male CF Nelson rats are anesthetized with ether and each of the left renal arteries is partially contracted with a silver clamp (0.22 mm). The right kidney and renal artery are left intact. This model is commonly referred to as the "2-kidney Goldblatt renal hypertensive rat" and is considered to be typical of hyper, tensile, dependent on the renin-angiotensin response [(Gavras et al., Science 188, (1975) j. One week after the connection, the mean blood pressure and heart rate are monitored directly for 4 and 8 hours, during which time 300 mg of the compound according to the invention is dosed every 24 hours for two consecutive days. Example 36. The following table shows the blood pressure reduction in two different rats on the second dosing day.

mean blood pressure kPa rat ΦΦ 9 rat ΦΦ 10

before application 29.6 27.5 after application 1 h 27.5 27.1 2 h 23.1 25.3 3 h 20.1 25.2 4 h 24.5 26.5 5 h 27.5 26.0 6 h 26.5 26.3

When the same dose was administered orally to rats with normal blood pressure, no effect on blood pressure was observed.

Claims (5)

OBJECT OF THE INVENTION A process for the preparation of a mercaptoacylamino-R6-COSH selin of the general formula I, R4 R3 R2 R2 R1 R 5 -S- (CH) n-CH-CO-N-CH-COOH (I) wherein R 1 is aminoalkyl of 1 to 7 carbon atoms, guanidinoalkyl of 1 to 7 carbon atoms in alkyl, and when n is 1, alkyl of 1 to 7 carbon atoms or phenylalkyl of 1 to 7 carbon atoms in alkyl, R 2, R 3 and R 1 are the same or different, hydrogen, alkyl of 1 to 7 carbon atoms or benzyl, and R 5 is hydrogen, C 1 -C 7 alkanoyl or benzoyl, n is 0, 1 or 2, or a salt thereof, characterized in that the compound of formula (II), R1 R1 R2 R2 R1 X - (CH) n - CH - CO - N - CH - COOH (II) wherein R1, R2, R3, R1 and n are as defined above and wherein X is a halogen atom, reacts with the thioacid anion of formula III, (III) wherein R 6 is alkyl of 1 to 6 carbon atoms or phenyl, to give the product of formula I wherein R 5 is alkanoyl of 2 to 7 carbon atoms or benzoyl, which is then optionally converted to the product of formula I where R 5 is hydrogen by ammonolysis and optionally converting a compound of Formula I to a salt. 2. A process according to claim 1, wherein R1 is guanidinopropyl, aminopropyl, aminobutyl, phenylmethyl or isobutyl and R2, R3, R1 are as defined in item 1. 3. The process of claim 1, wherein R1 is phenylmethyl and R3 is hydrogen and R2 and R1 are as defined in 1. 4. The process of claim 1, wherein R1 is isobutyl and R3 is hydrogen and R2 and R1 are as defined in 1. 5. The process of claim 1, wherein R1 is guanidinopropyl and R3 is hydrogen and R2 and R1 are as defined in 1.