JPS6131119B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel and useful 1-(3-mercapto-2-methylpropanoyl)prolyl amino acids having antihypertensive effects.

Recently, Cushman et al. synthesized various mercaptoalkanoyl amino acids and examined their angiotensin-converting enzyme inhibitory effects in vitro. It has been reported that proline (SQ-14225) has particularly excellent effects [Biochemistry, 16 , 5484 (1977)]. Furthermore, SQ−
It has been reported that 14225 exhibits an excellent angiotensin-converting enzyme inhibitory effect in vivo, and also exhibits antihypertensive effects based on this inhibitory effect in experimental hypertensive animals [Science, 196 , 441
(1977)]. Also, in Japanese Patent Application Laid-open No. 52-116457, SQ
-14225 and related compounds are disclosed.

As a result of intensive research to find SQ-14225-related compounds with better pharmacological properties, the present inventors discovered that the carboxyl group of the proline moiety of SQ-14225 and its derivatives was converted into an amide bond with an amino acid. The present invention was completed based on the discovery that the antihypertensive effect is milder and lasts longer.

The present invention is based on the general formula () [In the formula, R means a hydrogen atom, a lower alkyl group or a phenyl (lower) alkyl group, R ₁ means a hydrogen atom, R ₄ CO- or R ₅ S-, and R ₂ means a hydrogen atom. , R ₃ is a hydrogen atom, lower alkyl group, phenyl (lower) alkoxy (lower) alkyl group,
N-nitroguanidino (lower) alkyl group, phenyl (lower) alkoxycarbonyl group (lower) alkyl group or indolyl (lower) alkyl group, or R ₂ , R ₃ together with adjacent nitrogen and carbon atoms represent pyrrolidine It may form a ring. However, R ₄ means a lower alkyl group, means. ] 1-(3-Mercapto-2-methylpropanoyl)prolyl amino acids and salts thereof, and methods for producing the same are provided.

Compounds of formula () have two or more asymmetric carbon atoms. That is, when the carbon atom at the 2-position in the 3-mercapto-2-methylpropanoyl group, the carbon atom at the 2-position of proline, and R ₃ are groups other than hydrogen atoms, the carbon atom to which they are bonded is an unsaturated carbon atom. It is Sai. The compounds of the invention therefore exist as stereoisomers or mixtures thereof. All of these are included in the present invention.

The compound () and its salts of the present invention are mainly based on angiotensin converting enzyme inhibitory action,
It has excellent antihypertensive effects and is useful as an antihypertensive agent. By alleviating this, a stable drop in blood pressure can be expected due to its long-lasting antihypertensive effect, and it is considered to be extremely useful in clinical applications. In other words, it is expected to eliminate the clinical inconvenience of rapidly lowering blood pressure and to reduce the number of times the drug is taken.

Among the compounds of the present invention, preferred ones are of the formula ()
In , R ₂ is a hydrogen atom and R ₃ has 1 carbon atom.
-4 lower alkyl group or 3-indolylmethyl group.

More preferred are compounds in which R ₂ and R ₃ are as described above, and R is a hydrogen atom or a lower alkyl group (particularly a methyl group or an ethyl group).

As mentioned above, the compound of formula () has two or more asymmetric carbon atoms. The configuration of these asymmetric carbon atoms can be any of the D type, L type, and DL type, but the configuration of the carbon atom at the 2-position in the 3-mercapto-2-methylpropanoyl group is preferably D-type, and the steric configuration of the carbon atom at the 2-position of proline and the carbon atom to which R ₃ is bonded is preferably L-type.

Among the compounds of the present invention, particularly preferred are:
Examples include:

1-(D-3-acetylthio-2-methylpropanoyl)-L-prolyl-L-tryptophan ethyl ester (compound of Example 12) The compound () of the present invention has the formula () (In the formula, R ₁ means the same as defined above.) A compound represented by the formula or a reactive derivative thereof in the carboxyl group, and a compound represented by the formula () (In the formula, R, R ₂ and R ₃ have the same meanings as above.)

This reaction can be carried out according to methods known in the peptide field. For example, when compound () is used, it is advantageously carried out in the presence of a condensing agent such as dicyclohexylcarbodiimide. In addition, as the reactive derivative in the carboxyl group of the compound (), acid halides, acid amide, mixed acid anhydrides, active esters, active amides, etc. are preferably used. This reaction is usually carried out in a solvent, -
It is carried out at 40° to 40°C. The solvent used should be appropriately selected according to the type of raw material compound, etc., and examples include terahydrofuran, dioxane, chloroform, dichloromethane, ethyl acetate, acetone, acetonitrile, dimethylformamide,
Examples include hexamethylphosphoramide and water.
These solvents can be used alone or in a mixture of two or more. Further, when an acid is produced as a reaction by-product, it is preferable to carry out the reaction in the presence of a base as an acid acceptor. Examples of the base include alkali bicarbonates such as sodium bicarbonate and potassium bicarbonate, alkali carbonates such as sodium carbonate and potassium carbonate, and organic bases such as triethylamine, N-methylmorpholine, and N.N-dimethylaniline. Compound () can also be used in the form of an acid addition salt.

The compound of the present invention in which R ₁ is a hydrogen atom in formula () can be suitably obtained, for example, by treating a compound in which R ₁ is an acetyl group produced according to the above method with an alkali hydroxide. . Also R
The compound of the present invention in which R is a hydrogen atom can also be obtained, for example, by treating a compound in which R is a tert-butyl group produced according to the above method with trifluoroacetic acid.

Compounds () in which R ₁ is a hydrogen atom can be converted into various derivatives by the following methods. That is, R ₄ COOH [wherein R ₄ has the same meaning as above. ] By reacting with a compound represented by or a reactive derivative thereof according to a conventional method,
This can lead to a compound () in which R ₁ is R ₄ CO- (in the formula, R ₁ has the same meaning as above). Furthermore, the compound (I) in which R ₁ is a hydrogen atom can be oxidized in a conventional manner to give a disulfide ( ).

Compounds of the invention () also have the formula () (In the formula, R, R ₂ and R ₃ have the same meanings as above.) A compound represented by the formula () (In the formula, R ₁ means the same as defined above.) It can also be obtained by reacting a compound represented by the following or a reactive derivative thereof according to a conventional method.

The compound () of the present invention produced by each of the above reactions can be isolated and purified by conventional methods such as extraction, chromatography, and recrystallization.

The raw material compound in the above production method, ie, the compound of formula (), (), () or (), may be a racemate or a stereoisomer. However, in order to obtain the desired stereoisomer, the configuration of the carbon atom to which the proline moiety and R ₃ in the starting compounds (), (), and () are
It is desirable to match that of the target object.

A compound in which R is a hydrogen atom in formula () forms salts with various inorganic bases or organic bases. These physiologically acceptable salts are also included in the present invention.

The compound () of the present invention and its salts are SQ-
It has a milder and longer lasting antihypertensive effect than 14225 or its derivatives.

As described above, the compound () of the present invention and its salts exhibit excellent antihypertensive effects, and therefore can be used as antihypertensive agents for the treatment of hypertension.
In particular, it is useful for treating hypertension caused by enhancement of the renin-angiotensin system. The mode of administration may be oral, parenteral, or rectal, but oral administration is preferred. The dosage of the compound of the present invention or its salts depends on the type of compound,
Varies depending on administration method, symptoms, age, etc., but usually
0.2-200mg/Kg/day, preferably 1-50mg/Kg/
It is day.

The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to these Examples. Note that the solvent in the box after the melting point represents the recrystallization solvent.

Example 1 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolylglycine ethyl ester: 1.0 g of 1-(D-3-acetylthio-2-methylpropanoyl)-L-proline Dissolve in 20 ml of anhydrous tetrahydrofuran and then add 0.39 g of N-methylmorpholine. While stirring this solution, 0.61 g of phenyl chlorocarbonate was added at -20° to -15°C, and after 5 minutes, glycine ethyl ester hydrochloride was added.
A mixed solution of 20 ml of anhydrous tetrahydrofuran containing 0.54 g and 0.39 g of N-methylmorpholine is added. After stirring this for 1 hour while keeping it at -20° to -15°C,
Further stir overnight at room temperature.

After filtering off insoluble materials and concentrating the filtrate under reduced pressure, the residue is dissolved in dichloromethane. This solution
After sequentially washing with 1N sodium hydroxide, water, 1N hydrochloric acid and water, drying with anhydrous sodium sulfate. Dichloromethane was distilled off under reduced pressure, and the residue was subjected to silica gel column chromatography and eluted with chloroform to obtain 0.8 g of the target compound.

IR ν _nax cm ^-1 : 3270, 1740, 1680, 1630, 1620. Example 2 1-(3-acetylthio-2-methylpropanoyl)-L-prolylglycine ethyl ester: 1 in Example 1 -Reaction and treatment in the same manner as in Example 1 using 1-(3-acetylthio-2-methylpropanoyl)-L-proline instead of (D-3-acetylthio-2-methylpropanoyl)-L-proline. to obtain the target compound.

Example 3 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolyl-L-alanine ethyl ester: L-alanine ethyl instead of glycine ethyl ester hydrochloride in Example 1 Using the ester hydrochloride, the reaction and treatment are carried out in the same manner as in Example 1 to obtain the target compound.

IR ν _nax cm ^-1 : 3250, 1725, 1675, 1610. Example 4 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolyl-L-proline benzyl ester In Example 1 Using L-proline benzyl ester hydrochloride instead of glycine ethyl ester hydrochloride, the reaction and treatment are carried out in the same manner as in Example 1 to obtain the target compound.

IR ν _nax cm ^-1 : 1730, 1680, 1650 (sh), 1630. Example 5 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolyl-L-aspartic acid α, β- Dibenzyl ester: React and treat in the same manner as in Example 1, using L-aspartic acid α,β-dibenzyl ester p-toluenesulfonate instead of glycine ethyl ester hydrochloride in Example 1. to obtain the target compound.

IR ν _nax cm ^-1 : 3250, 1725, 1685, 1630. Example 6 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolyl-L-leucine.
tert-Butyl ester: 2.65 g of 1-(D-3-acetylthio-2-methylpropanoyl)-L-proline are dissolved in 50 ml of anhydrous tetrahydrofuran, and then 1.03 g of N-methylmorpholine is added. Add 1.61 g of phenyl chlorocarbonate to this solution while stirring at -20° to -15°C. After 5 minutes, 2.28 g of L-leucine tert-butyl ester hydrochloride and 1.03 g of N-methylmorpholine
Add a mixed solution of G and g in anhydrous tetrahydrofuran (30 ml) with shaking, and heat at -20° to -15°C for 1 hour.
Further stir overnight at room temperature.

After filtering off insoluble materials and concentrating the filtrate under reduced pressure, the residue is dissolved in chloroform. Add this solution to 1N
After sequentially washing with sodium hydroxide, water, 10% citric acid and water and drying over anhydrous sodium sulfate, the solvent is distilled off under reduced pressure. The residue was subjected to silica gel column chromatography and eluted with chloroform-methanol (99:1) to obtain 2.7 g of the target compound. Melting point 113-115℃ (diethyl ether-n-hexane) IR ν ^KBr _nax cm ^-1 : 3230, 1725, 1685, 1660, 16
10. Example 7 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolyl-L-leucine: 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolyl-L -Leucine tert
- 2.0 g of butyl ester is dissolved in a mixed solution of 18 ml of anisole and 37 ml of trifluoroacetic acid, left at room temperature for 1 hour, and then concentrated to dryness under reduced pressure.

The residue was subjected to silica gel column chromatography and eluted with chloroform-methanol (95:5). The eluate was concentrated under reduced pressure, and the residue was crystallized from diethyl ether-n-hexane to obtain 1.1 g of the target compound. Melting point 59-62°C IR ν ^KBr _nax cm ^-1 : 1680, 1640, 1610 (sh). Example 8 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolylglycine tert-butyl ester: Glycine in place of L-leucine tert-butyl ester hydrochloride in Example 6 - Using tert-butyl ester hydrochloride, react and treat in the same manner as in Example 6 to obtain the target compound. Melting point 119-120.5
°C (diethyl ether-n-hexane) IR ν ^KBr _nax cm ^-1 : 3230, 1715, 1675, 1620. Example 9 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolylglycine: Using 3.5 g of 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolylglycine tert-butyl ester, the reaction and treatment are carried out in the same manner as in the first paragraph of Example 7. The residue was subjected to silica gel column chromatography and eluted with chloroform-methanol (98:2). The eluate was concentrated under reduced pressure, and the residue was recrystallized from a mixed solvent of dichloromethane-diethyl ether-n-hexane to obtain 2.15 g of the target compound. Melting point 132-133℃ IR ν ^KBr _nax cm ^-1 : 3240, 1710, 1680, 1670 (sh
),
1590. Example 10 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolyl-O-benzyl-L
-Threonine benzyl ester: O-benzyl-L-threonine was used instead of glycine ethyl ester hydrochloride in Example 1.
Example 1 using benzyl ester oxalate
React and treat in the same manner as above to obtain the target compound.

IR ν _nax cm ^-1 : 3270, 1735, 1680, 1620. Example 11 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolyl- ^{N G} -nitro-L-
Arginine benzyl ester: 1.0 g of 1-(D-3-acetylthio-2-methylpropanoyl)-L-proline is dissolved in 20 ml of anhydrous tetrahydrofuran, and then 0.39 g of N-methylmorpholine is added. While stirring this solution, 0.61 g of phenyl chlorocarbonate was added at -20° to -15°C, and after 5 minutes, N ^G -nitro-L-arginine benzyl ester dip-toluenesulfonate was added.
A mixed solution of 2.54 g of N-methylmorpholine and 0.78 g of anhydrous tetrahydrofuran (20 ml) was added to -20
Stir for 1 hour at ~-15°C and then overnight at room temperature.
After filtering off insoluble materials and concentrating the filtrate under reduced pressure, the residue is dissolved in chloroform and washed with 1N sodium hydroxide and then with water. After drying the chloroform solution over anhydrous sodium sulfate, the solvent is distilled off under reduced pressure, and the residue is subjected to silica gel column chromatography. Elution with chloroform-methanol (98:2) yields 1.2 g of the target compound.

IR ν _nax cm ^-1 : 3250, 1725, 1675, 1605. Example 12 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolyl-L-tryptophan ethyl ester: 1-(D- The reaction is carried out in the same manner as in the first paragraph of Example 1 using 1.0 g of 3-acetylthio-2-methylpropanoyl)-L-proline and 1.03 g of L-tryptophan ethyl ester hydrochloride. After filtering off insoluble materials and concentrating the filtrate under reduced pressure, the residue is dissolved in chloroform. This solution is washed with 1N sodium hydroxide, then water, and then dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the residue was subjected to silica gel column chromatography and eluted with chloroform to obtain 1.32 g of the target compound.

IR ν _nax cm ^-1 : 3260, 1730, 1675, 1615. Example 13 1-(D-3-mercapto-2-methylpropanoyl)-L-prolylglycine: 1-(D-3-acetylthio-2 -Methylpropanoyl)-L-prolylglycine (1.0 g) is dissolved in 20 ml of water in a nitrogen stream, and the pH of this solution is maintained at 13 for 1.5 hours using 5N sodium hydroxide. Adjust the pH of the solution to 2 with concentrated sulfuric acid, saturate the solution with sodium chloride, and then extract with ethyl acetate. After drying the organic layer over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure to obtain the target compound.
Obtain 0.75g.

0.50 g of the compound obtained here is dissolved in 50 ml of water, 68 mg of calcium hydroxide is added, and this solution is freeze-dried to obtain the calcium salt of the target compound.

IR ν ^KBr _nax cm ^-1 : 3370, 1600, 1430. Example 14 1.1'-[3.3'-dithiobis(D-2-methylpropanoyl)]-bis(L-prolylglycine): 1 -(D-3-mercapto-2-methylpropanoyl)-L-prolylglycine 0.15g in water 20ml
and adjust the pH to 6.5 with 1N sodium hydroxide. While adjusting the pH of this solution to 6.5, add a solution of iodine in ethanol dropwise until it exhibits an icy yellow color. A small piece of sodium thiosulfate is then added to eliminate the color.

The reaction solution is made acidic with concentrated hydrochloric acid, saturated with sodium chloride, and extracted with ethyl acetate. The organic layer is washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated to dryness under reduced pressure to obtain the target compound.

IR ν _nax cm ^-1 : 3250, 1720, 1600.

Claims (1)

[Claims] 1. General formula [In the formula, R means a hydrogen atom, a lower alkyl group or a phenyl (lower) alkyl group, R ₁ means a hydrogen atom, R ₄ CO- or R ₅ S-, and R ₂ means a hydrogen atom. , R ₃ is a hydrogen atom, lower alkyl group, phenyl (lower) alkoxy (lower) alkyl group,
N-nitroguanidino (lower) alkyl group, phenyl (lower) alkoxycarbonyl (lower) alkyl group or indolyl (lower) alkyl group, or R ₂ , R ₃ together with adjacent nitrogen and carbon atoms represent a pyrrolidine ring may be formed. However, R ₄ means a lower alkyl group, and R ₅ means. ] A compound represented by these and its salts. 2 R ₂ is a hydrogen atom, and R ₃ has 1 to 1 carbon atoms.
The compound according to claim 1, which is a lower alkyl group of No. 4, and salts thereof. 3. The compound and its salts according to claim 1, wherein R ₂ is a hydrogen atom and R ₃ is a 3-indolylmethyl group. 4. The compound and its salts according to claim 2 or 3, wherein R is a hydrogen atom, a methyl group, or an ethyl group. 5 The configuration of the carbon atom at position 2 in the 3-mercapto-2-methylpropanoyl group is D type, and the configuration of the carbon atom at position 2 of proline and the carbon atom to which R ₃ is bonded is L type. The compound according to any one of claims 1 to 4 and salts thereof.