IE68060B1 - Nitratoalkanecarboxylic acid derivatives a process for their preparation use thereof and medicaments containing them - Google Patents

Abstract

Nitratoalkanoic acid derivatives of the general formula (I), in particular containing N-acylamino acids or N-acylpeptides, of the general formula (I) <IMAGE> in which the symbols have the meanings mentioned in the claims. They are distinguished by advantageous physicochemical properties and good physiological tolerability for active substances already preventing known nitrate tolerance or weakening a tolerance which has already set in. The compounds are used in medicaments for the treatment of circulatory disorders, high blood pressure, cardiac insufficiency and for dilating the peripheral vessels.

Description

Nitrafcoalkanecarboxylic acid derivatives, a process for their preparation, use thereof and medicaments containing then® The invention relates to nitratoalkanecarboxylic acid derivatives, to a process for their preparation, to the use thereof and to xaedicaments containing them.

Organic nitrates (nitric acid esters) have proved reliable in th© therapy of cardiac disorders.

They exhibit their action both through a relief of the strain on the heart via a lowering of preload and afterload and by an improvement in the oxygen supply to the heart by a dilatation of the coronary vasculature.

However, in past years it has been established that the organic nitrates hitherto employed in therapy, such as glycerol trinitrate (GTH), isosorbide 5-mononitrate or isosorbide dinitrate show a clear decrease in the action - nitrate tolerance - within, a relatively short time with high and continuous supply to the organism. Numerous experiments indicate that the presence of sulphydryl groups can prevent the formation of a nitrate tolerance and reduce a tolerance which has already set in.

The mechanism of the production of tolerance is nowadays interpreted as follows: According to the present state of knowledge, the pharmacological action of the organic nitro compounds is dependent on the presence of cysteine. The organic nitrate forms a common precursor with this, from the decomposition of which, inter alia, NO radicals are released, which activate the target enzyme, the soluble guanylate cyclase of the smooth muscle cell. Other subsequent reactions caused by the formation of cGMP then lead to relaxation or vascular dilatation.

The reactive and short-lived, hitherto still hypothetical intermediate product could be the thioester of nitric acid or a thionitrate. By means of intramolecular rearrangement and other subsequent reactions which have still not been elucidated, the formation, finally, of a nitrosothiol is postulated, from which nitric oxide or nitrite ions are released. The enzymedependent degradation with the aid of GSH reductase could on the other hand, since it leads exclusively to the formation of nitrite ions, be insignificant for the pharmacological action. The non-enzymatic degradation thus requires, as described, cysteine and is thus exhaustible in a dose-dependent manner (exhaustion of the SH group pool) so that in the long term sufficient NO can no longer be formed as an intrinsic activator of the guanyl cyclase and, clinically, a decrease in action occurs .

In EP 89 115 700.9, specifically synthesized compounds which are composed of nitrato fatty acids (nitratoalkanecarboxylic acids) and sulphur-containing amino acids or peptides are mentioned. The presence of sulphydryl groups should prevent a nitrate tolerance or 02N—0reduce a tolerance which has already set in.

Inter alia, compounds are mentioned which contain sulphur-containing amino acids such as cysteine or methionine in the form of their methyl, ethyl or propyl esters. Finally, the SH group of cysteine can he esterified with lower alkanecarboxylic acid having 2 to 8 carbon atoms.

Although these compounds already have useful pharmacological properties with respect to avoidance of a nitrate tolerance or abolishment or reduction of tolerance which has already set in, they are afflicted with disadvantages. They possess low melting points, have a low water solubility and are difficult to prepare in pure form.

The object of the present invention is therefore to prepare new organic compounds which avoid the abovementioned disadvantages and to make them available to the person skilled in the art.

This object has been achieved in that the compounds according to the invention are nitratoslkanecarboxylic acid derivatives of the general formula (I) R3 R4 0 II I I (CH2 C—-N-—(CH2 )n—C—(CH2 )o—C—R (I) I c R‘ -ck2—c— in which <3 ~ 4 ~ R represents hydroxy, amino or ethoxy; R1 represents hydrogen or alkyl with 1 to 6 carbon atoms; R2 represents hydrogen or alkyl with 1 to 6 carbon atoms; R3 represents hydrogen; R4 represents hydrogen, phenyl or methoxyphenyl; R5 represents S-acyi derivatives of mercaptomethyl, chosen from amino-acid thio esters, N-acyl-amino thio esters, peptide thio esters or N-acylpeptide thio esters with 2-5 peptide bonded amino acid groups; groups in, which R and R4 are bonded together in the form of an ester or an amide, groups in which R3 and R4 are bonded together in the form of an alkylene bridge with 2 to 4 carbon atoms, an alkylene bridge with 2 to 3 carbon atoms and a sulfur atom, an alkylene bridge .with 3 to 4 carbon atoms, which contains a double bond or an alkylene bridge as mentioned above which can be substituted with a member of the group consisting of hydroxy; m, n and o are whole numbers from 0 to 10, and pharmacologically acceptable salts thereof.

According to a development of the invention, the nitrato fatty acid constituents have a chain length of C2"C3; they can he straight-chain, branched, racemic or optically isomeric.

Th® nitratoalkanscarboxylic acid derivatives of the general formula (I) according to the invention preferably contain th® amino acids cysteine, methionine or homocysteine from the series comprising sulphurcontaining amino acids.

According to a further embodiment of the invention, the amino acids are present in the stereochemical L-form.

The sulphur-containing amino acids can be esterified at th© C-terminal end.

According to an advantageous development according to the invention, the amino acids cysteine and/or methionine are present as methyl, ethyl or propyl esters.

N-nitratopivaloyl-S- (N-acetylglycyl) -L-cysteine ethyl ester, N-nitratopivaloyl~S-(N-acetylalanyl)~L~ cysteine ethyl ester and N-nitratopivaloyl-S~(N-acetylleucyl)-L-cysteine ethyl ester - 6 are in particular preferred in the sense of the invention .

The compounds of the general formula (I) according to the invention can be prepared in a manner known per se if a compound of the general formula (II) R1 0 R3 R4 0 I ί I I ϊ (II) 02S—c—ck2—C—( ch2 —c—K—(ch2 )( ch2 )O—c—H r2 16 in which R is hydroxy, amino or ethoxy; R is hydrogen or alkyl having 1 to 6 carbon atoms; R is hydrogen or alkyl having 1 to 6 carbon atoms; R is hydrogen; R is hydrogen, phenyl or methoxyphenyl; R and R4 can be connected with one another with the formation of an ester or amide, R3 and R^ can be connected with one another with the formation of an alkylene bridge containing 2 to 4 carbon atoms, an alkylene bridge containing 2 to 3 carbon atoms and a sulphur atom, an alkylene bridge containing 3 to 4 carbon atoms, which contains a double bond, or an alkylene bridge as above, substituted by hydroxy; g R denotes mercaptomethyl; is subjected to a thioester formation reaction known per se using amino acids, N'-acylamino acids, peptides or Nacylpeptides having 2-5 peptide-linked amino acid radicals, preferably N-acetylglycine, W-acetylalanine or N-acetylleucine. The preparation of a compound of the general formula (II) can be carried out in the manner described in EP 89 116 700.9.

Nitrato alkanoic acids of the general formula (A) R1 0 I „ „ ,M 2 i’’-—’—O-=«=Cxi ί—-..0-, (C«s ) C—1 On ( a ) >2 0 in which R1, R2 and m have the abovementioned meanings, can then be employed in the form of their free acids, reactive acid halides, acid azides, esters and acid r R, R' HN—(CH2) n—C-(CH) o—c—R R« in the meaning of R, R3, R4, above, containinc amino acids anhydrides and reacted with a compound of the general formula (B) (B) R6, n and o as mentioned and/or peptides with the formation of compounds of the general formula (II).

To convert the compounds of the general formula (I) into their pharmacologically acceptable salts, the former are preferably reacted with the equivalent amount of an optionally inorganic or organic acid in an organic or aqueous organic solvent. Possible acids are hydrochloric acid, hydrobromic acid, nitric acid, phosphoric acid, sulphuric acid, formic acid, acetic acid, propionic acid, oxalic acid, fumarlc acid, maleic acid, succinic acid, adipic acid, benzoic acid, salicylic acid, Oacetoxybenzoic acid, cinnamic acid, naphthoic acid, mandelic acid, citric acid, malic acid, tartaric acid, aspartic acid, glutamic acid, methanesulphonie acid or ptoluenesulphonie acid.

The new compounds of the general formula (I) according to the invention and their salts can be administered enterally or parenterally in liquid or solid form.

The injection medium used is preferably water, which contains the additives customary in injection solutions such as stabilisers, solubilisers or buffers. Additives of this type are, for example, tartrate and citrate buffers, ethanol, complexing agents (such as ethylenediaminetetraacetic acid and its non-toxic salts) and high molecular weight polymers (such as liquid polyethylene oxide) for viscosity regulation. Solid excipients are, for example, starch, lactose, mannitol, methylcellulose, talc, highly disperse silicic acids, higher molecular weight fatty acids (such as stearic acid), gelatine, agar-agar, calcium phosphate, magnesium stearate, animal and vegetable fats and solid high molecular weight polymers (such as, for example, polyethylene glycols); preparations suitable for oral administration may, if desired, contain flavourings and sweeteners.

According to a further embodiment of the invention, medicaments contain one compound and/or a mixture of the compounds according to the invention.

These medicaments can be employed for the treatment of circulatory disorders, for example as coronary dilators, as agents for the treatment of high blood pressure, cardiac insufficiency and for dilating the peripheral vasculature, including the cerebral and. renal vasculature.

Pharmaceutical preparations containing a previously calculated amount of one or more of the compounds according to the invention can be administered once daily in the form of sustained release preparations or several times daily at regular intervals (2-3 times daily). The Γ amounts of active compound customarily administered per day are 20 - 300 mg per day, relative to a body weight of 75 kg. The compounds according to the invention can be given in the form of injections 1-8 times per day or by continuous infusion. Amounts of 5 - 200 mg/day are normally sufficient.

A typical tablet may have the following composition:' 1) N-nitratopivaloyl-8-(N-acetylglycyl)- L-cysteine ethyl ester 25 mg 2) Starch, U.S.P. 57 mg 3) Lactose, U.S.P. 73 mg 4) Talc, U.S.P. 9 mg 5) Stearic acid 6 mg The substances 1, 2 and 3 are sieved», granulated», mixed homogeneously with 4 and 5 and then tabletted.

The exemplary embodiments illustrate the invention without being restricted thereto.

Example 1 Preparation of N-nitratopivaloyl-S-(N-acetylglycyl)-Lcysteine ethyl ester g (0.41 mol) of N~ ace tyl glycine were suspended in 300 ml of methylene chloride (CH2G12) with stirring at room temperature and the suspension was cooled to 10eC„ A solution of 109.8 g (0.373 mol) of N-nitratopivaloylL-eysteins ethyl ester in 300 ml of CH2Cl2 was added in a weakly exothermic reaction with stirring. The reaction mixture was cooled to 5°C with stirring and a solution of 84.β g (0.41 mol) of dicyclohexylcarbodiimide (DCC) in 200 ml of CH2C12 was slowly added dropwise with stirring such that the temperature was in the range between 5 °C and 10°C. After warming to room temperature, the mixture was stirred at RT for four days. Dicyclohexylurea was filtered off with suction ana washed twice using 100 ml of CH2C12 each time.

The combined CH2C12 phases were successively washed once each with 200 ml of 9% strength NaHC03 solution, 300 ml of 1 N HCl and 300 ml of distilled water. The methylene chloride phase was finally dried over anhydrous sodium sulphate and concentrated on a rotary evaporator (Rotavapor11, Buchi) to constant weight.

The yield was 162.9 g (theoretical 145.74 g) of N-nitratopivaloyl-S-(N-acetylglycyl)-L-cysteine ethyl ester as a pale yellow oil. 162.9 g of N-nitratopivaloyl-S-(N-acetylglycyl)L-cysteine ethyl ester were dissolved in 470 ml of ethyl acetate at room temperature. After stirring at RT for 15 minutes, the undissolved white precipitate was filtered off. The clear pale yellow filtrate was slowly treated with 390 ml of n-hexane at RT with stirring.

Seed crystals were added to this solution and it was stirred at room temperature overnight. The deposited crystals were filtered off with suction and washed at room temperature twice with 100 ml of a mixture of 20 ml of ethyl acetate and 80 ml of n-hexane each time.

The crystals were dried to constant weight in a vacuum drying oven at room temperature and a vacuum of TOrr. r The yield was 85.4 g (theoretical 146.74 g) of Nnitratopivaloyl-S"(Nacetylglycyl)-L-cysteine ethyl ester.

M.p.: 71.8°C Example 2 Preparation of N-nitratopivaloy1-8-(N-acetylalanyl)-Lcysteine ethyl ester 53.8 g (0.41 mol) of N-acetylalanine were suspended in 300 ml of methylene chloride (CH2C12) with stirring at room temperature and the suspension was cooled to 10eC. A solution of 109,8 g (0.373 mol) of N-nitratopivaloyl-L-cysteine ethyl ester in 300 ml of CH2C12 was added in a weakly exothermic reaction with stirring. The reaction xaixture was cooled to 5 °C with stirring and a solution of 84.6 g (0.41 mol) of dicyclohexylcarbodiimide (DCC) in 200 xal of CH2C12 was slowly added dropwise with stirring such that th© temperature was in the range between 5°C and 10°C. After warming to room temperature, the mixture was stirred at RT for four days. Dieyclohexylurea was filtered off with suction and washed twice with 100 ml of CH2C12 each time.

The combined methylene chloride phases were successively washed once each with 200 ml of 9% strength NaHCO3 solution, 300 ml of 1 N HC1 and 300 ml of distilled water. The methylene chloride phase was finally dried over anhydrous sodium sulphate and concentrated to constant weight on a rotary evaporator (Rotavapor11, Biichi) .

The yield was 160.5 g (theoretical 151.84 g) of N-nitratopivaloyl-S- (N-acetylalanyl) -L-cysteine ethyl ester as a pale yellow oil.

IS0.5 c of N-nitratopivaloyl-S-(N-acetylalanyl)~ L-cysteine ethyl ester were dissolved in 345 ml of ethyl acetate at room temperature. After stirring at RT for 15 minutes, the undissolved white precipitate was filtered off. The clear pale yellow filtrate was slowly treated with 345 ml of n-hexane at RT with stirring.

Seed crystals were added to this solution and it was stirred overnight at room temperature. The deposited crystals were filtered off with suction and washed twice at room temperature with 100 ml of a mixture of 20 ml of ethyl acetate and 80 ml of n-hexane each time.

The crystals were dried to constant weight in a vacuum drying oven at room temperature and a vacuum of Torr.

The yield was 78.2 g (theoretical 151.84 g) of Nnitratopivaloyl-S-(N-acetylalanyl)-L-cysteine ethyl ester. Μ.ρ.ϊ 76.6°C Example 3 Preparation of N-nitratopivaloyl-S-(N-acetylleucyl)~L~ cysteine ethyl ester 0.02 mol = 6 g of nitratopivaloylcysteine ethyl ester are dissolved in 100 ml of dichloromethane. 0.03 mol = 5.19 g of N-acetylleucine and 0.1 g of dimethyl aminopyridine (DMAP) are slowly added at 10 °C and with introduction of nitrogen. 0.03 mol = 6.15 g of dicyelohexvlcarbodiimide (DCC), dissolved in 80 ml of Γ dichloromethane, are then added dropwise. The mixture is stirred overnight at RT.

Working ups The mixture is filtered with suction. The solu5 tion is successively extracted with equivalent amounts of 0.1 N HC1 solution, saturated NaHC03 solution and distd. H20. The solvent is then stripped off in a rotary evaporator (Rotavapor®, Biichi) . 10 g of oily residue remain. Recrvstallisations g of oily substance are dissolved in 45 ml of ethanol and 40 ml of distd. H20 with slight warming. The substance is allowed to crystallise out overnight in a refrigerator. The crystals are filtered off with suction and dried in a vacuum drying oven.

The mass spectrum confirms the structure.

Melting point ; 91.4 "C HPLC analysis; 98.7% g ~ 0.012 mol = 57.4% of theory.

Claims (16)

1. Claims : j

1. Nitrato formula (I) alkanoic acid derivatives of the general o 2 n—0—ch 2 R“ 0R J R* 0 SI I s -(C H 2) m —C—N— ( CH 2) n —C— (C h 2) o -^—R (I) R 5 5 wherein R represents hydroxy, amino or ethoxy; R 1 represents hydrogen or alkyl with l to 6 carbon atoms; R 2 represents hydrogen or alkyl with l to 6 carbon atoms; R 3 represents hydrogen; 10 R 4 represents hydrogen, phenyl or methoxyphenyl; R 5 represents S-acyl derivatives of mercaptomethyl, chosen from amino-acid thio esters, N-acyl-amino thio esters, peptide thio esters or N-acylpeptide thio esters with 2-5 peptide bonded amino acid groups; 15 groups in which R and R 4 are bonded together in the form of an ester or an amide, groups in which R 3 and R 4 are bonded together in the form of an alkylene bridge with 2 to 4 carbon atoms, an alkylene bridge with 2 to 3 carbon atoms and a sulfur 20 atom, an alkylene bridge .with 3 to 4 carbon atoms, which contains a double bond or an alkylene bridge as mentioned above which can be substituted with a member of the group consisting of hydroxy; m, η and ο are whole numbers from 0 co 10, and pharmacologically acceptable sales thereof.

2. . Compounds according to Claim 1, characterised in that their nitrato fatty acid constituents have a chain length of C 2 -C e , and are straight-chain,, branched, racemic or optically isomeric.

3.' Compounds according to Claims 1 and 2, characterised in that the sulphur-containing amino acids are preferably cysteine, methionine or homocysteine.

Compounds according to Claims 1 - 3, characterised in that the amino acids are present in the stereochemical L-form.

5. Compounds according to Claims 1 - 4, characterised in that the sulphur-containing amino acids are esterified at th© C-terminal end.

6. Compounds according to claims 1 - 5, characterised in that the amino acids cysteine and/or methionine are present as methyl, ethyl or propyl esters.

7. Compounds according to Claims 1 - 6, characterised in that they are a) N-nitratopivaloyl-S- (N-acetylglycyl) -L-cysteine ethyl ester b) N-nitratopivaloyl-S-(N-acetylalsnyl) -L-cysteine ethyl ester c) N-nitratopivaloyl-S- (N-acetylleucvl) -L-cystexne ethyl ester.

8. Process for the manufacturing of nitratoalkanoic acid derivatives according to claim 1 characterized in that in a known manner a) a compound of the general formula (A) R 1 0 in the form of its free acid, a reactive acylhalide an acid, azide, an ester or an acid anhydride is reacted with an amino group of a compound of the general formula (B) R J RI I HN— (CH 2 ) n —C•(CH), R (B) 10 wherein respectively R, R 1 , R 2 , R 3 and R 4 have the meaning previously set forth in claim l and RP stands for the group -0¾ - SH thereby forming compounds, of the general formula (II) : R OR I Ϊ 1 o 2 n-o—ch 2 —C—( ch 2 ) m —C N— (CH 2 ) n —£—(CH 2 ) q —C_R(II ) 6 R' and b) the compounds (II) subsequently are reacted with N- acetylglycine, N-acetylalanine, N-acetylleucine or M-acetylpeptides with 2 to 5 peptide bonded amino acid residues and, if desired, in form as pharmacologically acceptable salts thereof.

9. Medicaments containing one or more compound(s) according to Claims 1-7 and customary excipients and auxiliaries.

10. Use of compounds according to Claims 1-7 for the production of medicaments for the prophylaxis of cardiac and circulatory disorders.

11. Compounds according to Claims 1-7 for the production of medicaments for the prophylaxis of cardiac and circulatory disorders.

12. a compound of the general formula (I) given and defined in claim 1, or a physiologically tolerable salt thereof, substantially as hereinbefore described and exemplified.

13. A process for the preparation of a compound of the general formula (I) given and defined in claim 1, or a physiologically tolerable salt thereof, substantially as hereinbefore described and exemplified.

14. A compound of the general formula (I) given and defined in claim 1, or a physiologically tolerable salt thereof, whenever prepared by a process claimed In a preceding claim.

15. A medicament according to claim 9, substantially as hereinbefore described.

16. Use according to claim 10, substantially as hereinbefore described.