NL8104048A - METHOD FOR PREPARING A THERAPEUTIC PREPARATION, AND METHOD FOR PREPARING SUITABLE COMPOUNDS. - Google Patents

Description

«.

- 1 - ί

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

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

Such a method in which a proline 5 is brought into a form suitable for therapeutic use 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 able to inhibit the enzyme, which converts angiotensin I, which substance is produced in the body, into angiotensin II, which substance has an antihypertensive effect.

According to the invention, a compound of the formula I of the formula sheet, wherein R is a hydroxy or amino group or a lower alkoxy group, and R 1 is each separately introduced a hydrogen atom, an optionally substituted lower alkyl group with a phenyl group or a phenyl group, R 1 a lower alkyl, phenyl, substituted phenyl group, wherein the phenyl substituent is a halogen atom, lower alkyl or lower alkoxy group, a phenyl-lower alkyl, diphenyl-lower alkyl, triphenyl-lower alkyl, lower alkyl

thiomethyl, phenyl bearing: alkylmethyl, lower alkanoylamidomethyl group, Μ M

It 11 represents R - M-C-, R-NH-C-, R, -S- or R_, R is a hydrogen, 5 5 6 7 3 hydroxy or lower alkyl group, R 1. lower alkyl, phenyl or phenyl-25 lower alkyl, R. represents a lower alkyl, phenyl, substituted

O

phenyl-, wherein the phenyl substituent is halogen, lower alkyl or lower alkoxy, hydroxy-lower alkyl or amino (carboxy) lower alkyl and R_ is a group of formula 29, M 0 or S, m = 1 and n and p is each 0, 1 or 2, or brings a salt thereof into a form suitable for therapeutic use.

Namely, it has been found that these much simpler prolines, which are not peptides, are also suitable according to 8104048 for the same mechanism to effectively combat high blood pressure. It is also important that they also exert this action 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, 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-15 radicals of the lower (C 2 -C 4) 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 term "halogen" includes the four usual halogens, but chlorine and bromine are preferred. The substituted phenyl groups preferably contain the substituent in the 4-position of the ring. The hydroxy lower alkyl groups contain a hydroxy group on an alkyl chain in the same manner as those described above, preferably on the terminal carbon atom, for example hydroxymethyl, 2-hydroxyethyl, etc. The 25 amino (carboxy) lower alkyl groups contain one amino group and one carboxy group on a lower alkyl group, such as those described above, preferably both on one carbon atom, for example on the terminal carbon atom, such as in the preferred 2-amino-2-carboxyethyl group.

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

In general, the compounds of the invention are prepared by acylating a compound of the formula III with an acid of the formula III or a chemical equivalent thereof.

8104048 - 3 -%

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 tosyloxyalkanoic acid, that is, an acid of the formula 5, wherein X is tosyloxy (ch3 - <2> - SO ^ 0-}, or (c) a substituted acrylic acid of the formula 6. The product of this acylation is then subjected to rearrangement or addition with the anion of a thiol or thioic acid of the formula 7.

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 dicyclohexylcarbodiimide or the like, or the acid can be activated by forming its mixed anhydride, symmetrical anhydride, acid-15. chloride, acid ester or use of the Woodward reagent K, N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline, or the like. In connection with the acylation methods, reference is made to Methods of Organic Chemistry (Houben-Weyl), Vol. XV, Part II, p. 1 et seq. (1974).

According to a preferred method of preparing compounds of the formula 1, an acid or ester of the formula 3 is coupled with a haloalkanoic acid of the formula 5, wherein X represents halogen, preferably chlorine or bromine. This can be accomplished by using any of the known procedures, wherein the acid 4 is activated for the reaction with the acid 3 by forming a mixed anhydride, symmetrical anhydride, acid chloride or active ester or by using Woodward reagent K, EEDQ (N-ethoxycarbonyl-2-ethoxy-1,2-dihydroxyquinoline) or the like. The product of this reaction is a compound of the formula 10. 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. When R is an ester group (ie R represents a lower alkoxy group), the ester group can be removed from an ester of the formula 11 8104048 V 'Si - 4 - by treatment with trifluoroacetic acid and insulin, whereby the corresponding free acid is obtained. The corresponding acid can also be obtained by alkaline hydrolysis.

A variation on this procedure involves the use of an acrylic acid of the formula 6 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 10 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 acylation agent 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 of the formula III, further following the procedure described above.

The acid or ester of the formula III can also be acylated with a "protected" form of a merc-mercap-toalkanoic 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.

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

In a particularly preferred modification of the process, the acid or ester of 8104048-5 - 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. When an acid of the formula III is used as starting material, the end product obtained as the free carboxylic acid can then be converted into its ester, for example by esterification with a diazoalkane, such as diazomethane, an 1-alkyl-3-p-tolyl- triazene, such as 1-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, i.e. in a product in which R represents NH2 · 20. In another method, an ester, preferably the t-butyl ester of the formula 3 in an anhydrous medium, such as dichloromethane, tetrahydrofuran, dioxane or the like, treated with a thioalkanoic acid of the formula 18 in the presence of dicyclohexylcarbodiimide, N.N'-carbonyl bisimidazole, ethoxy-acetylene, diphenylphosphorylazide or analog coupling agents at a temperature of about 0-10 ° C. The ester group (R) can then be removed, for example, by treatment with trifluoroacetic acid and anisole at room temperature. Products of the formula I in which R 'represents the group M are prepared

^ II

R5-MC- by reaction of a compound of formula 12 with a halogenated compound of formula 19 or by reaction of a compound of formula 10 with an alkali metal salt or alkaline earth metal salt of a compound of formula 20, wherein Imagine an alkali metal or alkaline earth metal.

8104048 * ^ - 6 -

A product of the formula I in which the group represents M is prepared by reaction of a compound »

R5-NH-C

of formula 12 with an appropriately substituted isocyanate 5 or isothiocyanate of formula 21. On the other hand, the same products can be obtained by coupling an acid of formula 22 with an amino acid of formula 3.

Compounds of the formula 1, wherein lower alkyl, phenyl, substituted phenyl, phenyl-lower alkyl, triphenyl-lower alkyl, lower alkylthiomethyl or phenyl-lower alkyl-thiomethyl, are obtained by reacting a compound of the formula 12 with the corresponding halide R 1 X or by reaction of a compound of the formula 10 with the corresponding thiol R 2 SH in the same manner as described above.

A compound of the formula 1, wherein R 2 represents a lower alkanoylaminomethyl group, can be prepared by condensing a compound of the formula 12 with a corresponding hydroxymethyl-lower alkanoylamide of the formula 23 in the presence of an acidic catalyst, such as trifluoroacetic acid. A compound of the formula 1, wherein R 1 represents the group R 2 -S, can be prepared by known methods for the synthesis of mixed disulfides, for example, by reacting a compound of the formula 12 with a thiosulphate with the formula 24, thiosulfonate of the formula 25, sulfenyl-25 halide of the formula 26, thiosulfate of the formula 27 or sulfenyl thiocyanate of the formula 28.

In the special case where R 7 represents a group of formula 29 and R 1, R 1, and R 2 have the same meanings as <fe corresponding substituents in formula 1 and p 30 is the symmetrical disulfides can be obtained by direct oxidation of a compound of the formula 12 with iodine. When p is 1 or 2, such products can be obtained by stepwise oxidation of the corresponding compound, wherein p is 0. Mixed disulfides are obtained using the modification described in the Examples.

8104048 - 7 -

Products of the formula I have one or more asymmetric carbon atoms. When R ^, R ^ or R ^ 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 that carries it).

The compounds of the invention form basic salts with different inorganic and organic bases, which salts are also within the scope of the invention. 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, for example the dicyclohexylamine salt, benzathi-25-ne, 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.

8104048

W.

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By neutralizing the salt with an insoluble acid such as a hydrogen form cation exchange resin (e.g. polystyrene sulfonic acid resin such as Dowex 50) or with an aqueous acid and extraction with an organic solvent such as ethyl acetate, dichloro-5 methane or the like, the free acid form and, if desired, an end salt is 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 the conversion of the decapeptide angiotensin I to angiotensin II and are therefore useful for lowering angiotensin-related hypertension. Angiotensin I is formed by the action of the enzyme renin 15 on angiotensinogen, a pseudoglobulin in blood plasma. Angiotensin I is converted by angiotensin converting enzyme (ACE) into angiotensin II. The latter is an active blood pressure raising agent, which is considered to be the cause of different forms of hypertension in different mammalian species, for example rats and dogs. The compounds of the invention block the conversion of angiotensin (renin) - angiotensin I -> angiotensin II by inhibiting the angiotensin converting enzyme and reducing or eliminating the formation of the blood pressure-increasing angiotensin II. By administration of a preparation containing one or more compounds of the formula 1 and / or physiologically acceptable salts thereof, the 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 in 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, may 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. About 10-500 mg of a compound or mixture of compounds of the formula 1 or physiologically acceptable salts thereof are mixed with physiologically acceptable vehicles, carriers, excipients, binders, preservatives, stabilizers, flavors, etc. to form a unitary Dosage form as required in pharmaceutical practice. The amount of active substance in these preparations is such that an appropriate dose is obtained within the above range.

Examples of additives that can be included in tablets, capsules and the like are 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 sweetener, such as sucrose, lactose or saccharin, and a flavoring agent such as peppermint, wintergreen or cherry oil. When the unit dosage form is a capsule, it may additionally contain, in addition to the materials of the above type, a liquid carrier, such as a fatty oil. Various other materials may 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 may contain the active compound, sucrose as a sweetener, methyl or propyl parabens as preservatives, a colorant and a flavoring agent such as cherry or orange flavor.

Sterile preparations for injection can be prepared by conventional pharmaceutical procedures by dissolving or suspending the active substance in a vehicle, such as water for injections, 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, buffer, preservatives, antioxidants and the like can be included.

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

Example I

1 - 3 -> (Ethoxy) thiocarbonyl / thio / propanoyl / - L-azetidine-2-carboxylic acid.

Aqueous 2N sodium hydroxide (25ml) and 3-bromo-10-propionyl chloride (8.5g) are added to a solution of L-azetidine-2-carboxylic acid (6.45g) in N. sodium hydroxide (50ml), cooled and stirred in an ice bath. After 5 min. The ice bath is removed and stirring is continued at room temperature. After 3 hours, ethylxanthogenic acid potassium salt (9.6 g) is added and the mixture is stirred at room temperature overnight. The solution is acidified with concentrated hydrochloric acid and extracted with ethyl acetate. The organic layer is evaporated to dryness and the residue is chromatographed on a column of silica gel with a mixture of benzene acetic acid (7: 1) as a solvent to give the title compound.

Example_II

1- (3-Methylthiopropanoyl) -L-azetidine-2-carboxylic acid.

Methyl 3-methylthiopropionate (51 g) is saponified with an IQ% sodium hydroxide solution (150 ml, 30 min at 100 ° C). The cooled solution is extracted with ether and then acidified. The crude acid thus obtained is distilled and converted into the acid chloride with thionyl chloride.

A solution of L-azetidine-2-carboxylic acid (10.1 30 g) in sodium hydroxide (100 ml) is cooled in an ice bath and 3-methylthiopropanoic acid chloride (6.9 g) is added dropwise with vigorous stirring over a period of 10 min. added. After 5 hours, the reaction mixture is acidified and extracted with ethyl ether to yield the title compound. The dicyclo-35 hexyl ammonium salt is prepared by adding dicyclohexyl-8104048-11

amine to a solution of the free acid in ethyl acetate. Example III

1- / 3- (Ethyldithio) propanoyl / L-azetidine-2-carboxylic acid.

5-Mercaptopropanoyl-L-azetidin-2-carboxylic acid (9.3 g) is added to a solution of ethyl thiosulfinate (8.4 g) in methanol (100 ml) and the reaction mixture is stirred vigorously at room temperature for 4 hours. The methanol is removed in vacuo to give 1- (3-ethyldithiopropanoyl) -L-azetidine-2-carboxylic acid.

A solution of ethyl thiosulfinate (8.4 g) in ethanol (50 ml) is added to an aqueous solution of 3-mercaptopropanoyl-L-azetidine-2-carboxylic acid (9.3 g), which is at a pH of 6-7 is held by cautious addition of sodium hydroxide. The mixture is stirred vigorously at room temperature until the reaction to thiol is negative. The mixture is diluted with water, adjusted to pH 8 and extracted with ethyl acetate, the aqueous phase acidified to pH 3 and extracted again with ethyl 20 acetate. The latter extract is washed with water, dried and evaporated to dryness to yield 1- / 3- (ethyldithio) propanoyl_y-L-azetidine-2-carboxylic acid.

Example IV

1.1 (Dithiobisacetyl) bis-L-azetidine-2-carboxylic acid.

1- (2-Mercaptoacetyl) -L-azetidin-2-carboxylic acid (0.87 g) is dissolved in water (20 ml) and the pH is adjusted to 6.5 with N. sodium hydroxide. An ethanolic solution of iodine is added dropwise while maintaining the pH 30 at 6.5 by cautious addition of N. sodium hydroxide. When a permanent yellow color is obtained, the addition of iodine is stopped and the color is removed with a small amount of sodium thiosulfate. The reaction mixture is acidified with concentrated hydrochloric acid and extracted with ethyl acetate. The organic phase is washed with water, dried and evaporated to dryness, yielding 8104048 5-12-1.1 (dithiobisacetyl) bis-L-azetidine-2-carboxylic acid. The dicyclohexylammonium salt is prepared by adding dicyclohexylamine to a solution of the free acid in acetonitrile.

8104048

Claims (4)

A process for the preparation of a therapeutic composition having an antihypertensive effect, characterized in that a compound of the formula 1, wherein R is a hydroxy or amino group or a lower alkoxy group, and R 1 is each a hydrogen atom, optionally with a phenyl group substituted lower alkyl group, R2 a lower alkyl, phenyl, substituted phenyl group, wherein the phenyl substituent is a halogen, lower alkyl or lower alkoxy group, a phenyl-lower alkyl, diphenyl-10 lower alkyl, triphenyl-lower alkyl , lower alkylthiomethyl, phenyl-lower alkylmethyl, lower alkanoylamidomethyl group, Μ M If II R ^ -MC-, R5-NH-C-, Rg-S- or R ^, R ^ represents a hydrogen, hydroxy or lower alkyl group, Rg represents lower alkyl, phenyl or phenyl-15 lower alkyl, Rg represents a lower alkyl, phenyl, substituted phenyl, wherein the phenyl substituent is halogen, lower alkyl or lower alkoxy, hydroxy-lower alkyl or amino (carboxy ) -lower alkyl and a group of the formula II 9, MO or S, m-1 and n and p are each 0, 1 or 2, or bring a salt thereof into a form suitable for therapeutic use. 2. Process for preparing a compound suitable for use in the process according to claim 1, characterized in that a compound of the formula 1, wherein R, R 1, R 2, R 3, R 4, m and n have the same meaning as in claim 1, prepared in a manner conventional for such compounds. 30 8104048 V '*. . Reg.nr .: 115 »773 RJl Ri, i. 1.1 l, Rg — S— (CHI - CH — COOH X - (CM) ,, - CH — COX 16 17 R, Μ MI il II R2-S- (CHi) M — CH-COOH 18 Rr-MC -Xg Rr-MCS-Me ^ g M RL Rf Rt — N = C = M III 9 21 Rf NH - CS (CH) m CH COOH R J_S_R ^ 24. Lower alkyl— CO - NHCHgOH 0 0 * 5 I1 • Ri-SS-Rt RiS —X ¢ 5 25 26 Rt — S —SojH (¾— S - SCN 27 * 28 R, (HC) -CH2 Rt Ri ι «II r R-OC - HC- N-CO - CH - (CH \ —SioL * * J * K lF 29 E, R, Squibb 4 Son» , Inc. of Fiinceton, New Jersey, United States of America 8104048 Rj Reg Reg .: 115,778 R * R * * - - (crt 1, III * 1 R2-S-fCH) - CH - CO— N— CH - C0R V '^' Y) ^? * "Ϊ́ ~ ('H) * 3 HN - = - CH - COR p Rt /» 1 4 R * —S— (chJ ^ - CH — COOH * RA Rt. R4 Rt X— (Ch) ^ - CH — COOH 5 CHs-C —COOH g Ri - SH - R \ 5 Rj ", c- (C« J "] 0 X— (CH) * CH — CO N- CH-COR R5 RA Ri HjC- (CH) ^ Ri— (ch) „- CH - CO — N —CH — COR ψ 11 r, H * c- (a}„ HS— ( CHJ - - CH - CO - N — CH — COR R 12 | * 'Row Rf H2c (ch) -wi CH - C— CO— N- CH — COR 13 f A Ri ™ 3- ^ y-S0! ° - (CH \ —CH-C00H R R- 14 I 1 15 - S - CH - CH - COOH E.R. Squibb & Sonsj Ine. 8 1 0 4 0 '4 S in Princeton, New Jersey, USA St. America