EP0083612A1

EP0083612A1 - New derivatives of dipeptides, method for the preparation thereof and utilization thereof as drugs

Info

Publication number: EP0083612A1
Application number: EP82902071A
Authority: EP
Inventors: Michel Flork
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-07-09
Filing date: 1982-07-08
Publication date: 1983-07-20
Also published as: ES513829A0; EP0069674B1; ES8306106A1; WO1983000146A1; CH665645A5; GR78088B; ATE12768T1; JPS5865214A; CA1190243A; EP0069674A1; DE3263121D1

Abstract

Dipeptide derivatives represented by the general formula Ac - A - X - Y, wherein Ac represents the acyl rest of an organic carboxylic acid. A is an amino acid carrying a carboxylic function at alpha . X is an amino acid rest and Y is hydrogen or the rest of a mono- or disubstituted amine. They are prepared by acetylation of the amino acid A and then by dihydration of the N-acetyl amino acid into anhydride, coupling with an X amino acid, new dihydration of the dipeptide N-acetyl A-X into anhydride-amide and condensation with a Y amine to form the dipeptide Ac - A - X - Y.

Description

NOVEL DIPEPTIDE DERIVATIVES, THEIR PREPARATION PROCESS AND THEIR USE AS MEDICS.

The present invention relates to new dipepti derivatives, their preparation process and their use as a medicament, in particular in the area of the central nervous system.

The present invention relates more specifically to N-acyl dipeptides in which the acyl group is a residue of carboxylic acid, aliphatic or aromatic, with or without pharmacodynamic properties.

The present invention relates specifically to N-acyl di peptides of general formula I

Ac - A - X - Y (I)

in which,

Ac represents the acyl residue of an aliphatic, aromatic or hydroaromatic organic carboxylic acid,

A is the residue of an amino acid carrying another carboxylic function substituted at α,

X is the residue of an amino acid, and Y is hydrogen or the remainder of a mono or disubstituted amine, preferably physiologically active, linear or cyclic.

Among the compounds of general formula I, a more specific distinction will be made: the N-acyl dipeptides corresponding to the general formula I '

in which Ac is an acetyl radical

Z is hydrogen or forms with Z 'a lower alkylene radical optionally substituted by a hydroxyl or optionally inte broken by a heteroatαrne.

Z 'is hydrogen, a linear or branched lower alkyl radical, optionally substituted by a hydroxyl radical, a carbamoyl radical, a ureido radical, a guanidino radical, or a sulphonic group; a lower phenylalkyl or indolyl lower alkyl radical, or else Z ′ forms with Z a lower alkyl radical, optionally substituted by a hydroxyl or optionally interrupted by a heteroatom.

Y 'and Y ", distinct from each other, represent hydrogen, an alkyl, aryl, hetero aryl, aralkyl radical, these radicals being able to be substituted by 1 to 3 substituents, with the limitation that Y and Y 'cannot represent hydrogen simultaneously and n is an integer varying from 1 to 3.

. N-acyl dipeptides referring to the general formula I "

wherein the substituents Z, Z 'and n are defined as above.

Y and Y 'are hydrogen and Ac represents the acyl residue of a organic carboxylic acid in which the hydrocarbon residue is an alkyl radical having from 2 to 18 carbon atoms in a straight or branched chain, a mono, bi- or tricyclic aryl radical having from 5 to 15 carbon atoms, an aralkyl radical in which the alkyl residue has from 1 to 8 carbon atones and where the aryl residue is mono, bi- or tricyclic and has from 5 to 15 carbon atones, a heteroaryl radical mono, bi- or tricyclic, lin hydroaromatic radical having from 3 to 15 atoms of mono, bi- or tricyclic carbon or a (hydroaryl) alkyl radical in which the hydroaryl residue is defined as above and the alkyl residue has from 1 to 8 carbon atoms optionally substituted by a hydroxyl or an oxo radical, or interrupted by an amino group.

In this formula, the group Ac is preferably the acyl residue of a low molecular weight organic carboxylic acid, such as an acetyl, propionyl, butyryl, succinoyl, fumaroyl, glutaroyl, or the acyl residue of an arαnatic acid such that a benzoyl radical, 2,6 dichloro benzoyl, β-trifluorobenzoyl, veratroyle, syringoyl, toloyl, durene carbonyle, naphtoyl, indenecarbonyle, fluorenecarbonyle, pramoyl, ni cotinoyl, isonicotinoyl, thiophenecarbonyle (2 or 3), thiaz 2-roethylthiazole 5-oarbonyl ... or a hydro aromatic acid like a dibenzocycloheptene carboxylic acid.

The group Ac can also be the acylated residue of a therapeutically usable organic carboxylic acid such as n-propyl acetic acid, acetylsalicylic acid, gentisigue acid, N-phenylanthranilic acids. It is also possible to use as acyl radical the remainder of an aromatic or hydroaromatic acid of mono, bi or tricyclic structure carrying a carboxylic substituent or an alkyl-carboxylic chain such as tricyclic acids carrying an aminepentanoic, aminohexanoic or aminoheptanoic, bicyclic or tricyclic aromatic acids carrying an acetic or α-methylacetic, oxobutanoxque or hydroxybutanoic chain; N-acylated 3-acetic indolyl acids. The radical A is a carboxylic residue of an α-amino polycarboxylic acid capable of giving rise to an α-ismeria in β. Among the amino acids which meet this definition, there may be mentioned more particularly aspartic acid, glutamic acid, β-hydroxyaspartic acid or N ₁ methyl lanthionine.

Group X can be any amino acid, and in particular a natural amino acid such as lysine, valine, leucine, isoleucine, alloisoleucine, glycine, serine, proline, 4-hydroxyproline, cysteine, taurine, carτiitine, citrulline, ornithine, histidine or tryptopbane.

Group X can also be an artificial amino acid like β-alanine, the acid -aminobutyric acid -amino β-hydroxybutyric, N-acylcarnitines.

Functional derivatives of natural amino acids can also be used by blocking the terminal carboxylic function in the form of a friend of, for example, prolinamide or glutamine, or in the form of an alcohol such as mathioninol. It is also possible to use, in the case of sulfur-containing amino acids, derivatives whose thiol function is protected in the form of sulfoxide (methionine sulfoxide for example) or sulfone (methionine sulfone for example).

The group Y is hydrogen when the terminal carboxylic function of X is blocked or transformed into another functional group which is not reactive under the experimental conditions.

The group Y is also, when the carboxylic group is capable of reacting, the radical of an aliphatic or arylaliphatic primary or secondary amine, optionally substituted.

The radical Y can be the residue of an amino heterocyclic base such as adenosine, guanine, inosine, N-alkyl glucosamines, tryptamine or tryptamines substituted by one or more substituents selected from the group of halogens, alkoxy, lower alkyl, or trifluoromethyl; phenylalkoylamines such as adrenaline, isopre naline, noradrenaline, dopamine, dihydroxyphenylalamine (DOPA), α -methyl DOPA, amphetamine, substituted amphetamines such as α-methylamphetamine, methoxy amphetamine, terbutylphenylamine, (m.trifluorophenyl) α-methyl ethyl amino, non-substituted or substituted quinolines or iso-quinolines such as 6,7-dimethoxy tetra hydroisoquinoline, 6,7-dimethoxy 1-methyl tetrahydroisoquinoline (Salsolinol), papaverine tetrahydropapaverinol, ethaverine; amino derivatives of bicyclic or tricyclic compounds such as benzodiazepines, quinoxalines, benzotriazines or tricyclic compounds such as phenothiazines which are not substituted for nitrogen or substituted for nitrogen such as demethylpromethazine, demethylchlor promazine, demethyltrifluoroperazine, trimepramine, derivatives substituted by an alkyl or alkylene amino chain of dibenzo azepines, dibenzothiazepines, dibenzo oxazepines, azadibenzo azepines or azadibenzodiazepines, thienobenzo azepines.

This list is not exhaustive. It only aims to give information on the generality of the radicals Y which it is possible to attach to the substituent X.

The principle of this structure is to attach to a dipeptide vector Ac-AX, an amino molecule that the dipeptide will be able to convey to the central nervous system, where it will produce a different or improved physiological effect. It is therefore possible to increase or modify the physiological properties, the metabolic fate or the pharmacokinetics of a very large number of medicinal substances whose properties are limited or insufficient to produce an interesting effect or too fleeting to be used as drug. It is also possible to attach very unstable amino molecules to the vector peptide. The resulting product is itself stable and can therefore find a therapeutic use as is the case for example of S-adenosylmethionine which is easily broken down while the dipeptide according to the invention Acyl-A-methionyl-adenosine e is perfectly resistant to hydrolysis. This is also the case for dyhidroxyphenylalnine (DOPA), dopamine or serotonin which are intense but very fleeting chemical mediators. By coupling with the vector, compounds according to the invention are obtained Ac-AX-dihydrαxvphenylalanine or Ac-AX-dopamine or Ac-AX-serotonin, the duration of action of which makes them usable as a medicament for Parkinson's disease or the states of depression.

The principle of this therapeutic use stems from the experimental fact observed by administration of N-acetyl α-aspartyl glutamic acid (NAAGA). This acid is excreted via the urine in the form of α-aspartyl glutamic acid. The brain in which it binds, as has been shown by autoradiography, is therefore capable of using this N-acyl dipeptide by hydrolyzing the N-acetyl group and of using this compound for metabolic purposes by isomerizing the radical α -aspartyle in β-aspartyle. The excreted product is completely inactive.

On the basis of this principle, it has been found that by replacing the acetyl radical with any other acyl residue and in particular the acyl residue of a therapeutically active carboxylic acid and / or by condensing glutamic acid with an active or non-active amino derivative physiologically, it is possible to have a dipeptide derivative capable of binding to a cerebral center and of producing more selective, improved or different effects compared to those produced by the physiologically active molecule fixed to the vector dipeptide.

Among the peptide compounds according to the invention, there may be mentioned more particularly as currently preferred compounds: N-acetyl α -aspartyl glutamyl taurine N-butyryl α -aspartyl glutamyl dopamine N-butyryl α -aspartyl glutam yl (dihydroxyphenyl) alanine N-butyryl α -aspartyl histidyl salsolinol N-bu tyryl α -aspartyl glycyl N-acetyloarnitine N-butyryl α- aspartyl glycyl glutamine N-acetyl α-glutamyl -m ethicnyl-S-adenosine N-acetyl α -glutam yl-glycyl α -methyl DOPA N- (dibenzocycloheptenyl-5) aminoheptanoyl α - aspartyl-glycine l- [(dibenzocycloheptenyl-5) amino] 3-methyl 3- (N-acetyl α- aspartyl) glycyl propane N (3, 4, 5, 6-tetrahydro 2-oxacyclohexyl) pyroglutamyl aspartyl glutamic acid N- (5-methoxy 2-methyl N (p.chlorobenzoyl indolyl 3-acetyl) α- aspartyl glycine N-prppionyl α-glutamyl glycyl (4-amino 5-chloro 2 methoxy)

N 'N'-diethylamino ethyl benzamide la l- (N-benzoyl α -aspartyl glycyl) 7-chloro 2,3-dihydro 5-phenyl

[1H] benzodiazepine-1, 42-one.

The invention also relates to a process for obtaining the compounds of general formula I

Ac - A - X - Y (I)

in which the radicals Ac, A, X and Y have the meanings provided previously, characterized in that an amino acid A - OH is subjected to the action of an acid of formula Ac - OH in which Ac is defined as before or of one of its functional derivatives in the presence of a basic agent to form an acylated derivative of general fotmule II

Ac - A - OH (II)

in which the residues Ac and A are defined above, submits the latter to the action of a dehydrating agent to form an anhydride of general formula III

in which,

Ac is defined as above n is equal to 1, 2 or 3 or one of its structural analogues substituted by a methylamino, hydroxy or thio radical, can react this ring in an aqueous medium with an amino acid of formula H - X - CH ( in which X is defined as above), to obtain the N-acyl dipeptide of general formula TV

(N) Ac - A - X - OH (IV)

in which, Ac, A and X are defined above, subjects it to the action of a dehydrating agent at low temperature to form the corresponding anhudride which, by reaction with a primary or secondary amine of general formula XH , makes it possible to obtain the N-acyl dipeptide of general formula I

N - Ac - A - X - Y (I)

In a preferred mode of action of the method according to the invention, this can be characterized by the following points:

- the acylation of the amino acid AH is carried out at pH 9 and at 20 °

- the acylation is carried out in an aqueous medium

the acylation is carried out in the presence of an alkali metal hydroxide which is not earthy and in particular in the presence of lime

the dehydrating agent is a carboxylic or sulfonic acid anhydride and in particular acetic anhydride

- the reaction between the anhydride of formula III and the amino acid XH takes place in an aqueous medium

- the reaction between the anhydride of formula III and the amino acid XH takes place at a temperature close to 0 °

- the reaction between the anhydride of formula III and the amino acid XH takes place at a pH between 8 and 9

the formation of anhydride from the N-acyl dipeptide of general formula IV is carried out by the action of a carboxylic or sulfonic acid anhydride at a temperature below 10 °

- The anhydride is opened with the amine YH in water in the presence of a mineral acid.

The invention also relates to another process for obtaining the compounds of general formula I which consists in subjecting the dipeptide of general formula III

(N) Ac - A - X - OH (IV)

in which,

Ac, A and X have the meanings previously provided. to the action of a hot dehydrating agent to form the imi-anhydride of general formula V

in which Ac, n and X have the same meanings as above, treats the latter with a primary or secondary amine in an acid medium to form an imide of general formula VI

which, by the action of an acid agent, provides a compound of general formula I Ac - A - X - Y (I)

in which the meaning of the radicals Ac, A, X and Y remains unchanged.

The invention also relates to another process for obtaining the compounds of general formula I, characterized in that the amino function of amino acid A is blocked by the action of formic acid or one of its functional derivatives, form the anhydride of the formylated derivative which is condensed with an amino acid to obtain an N-formyl dipeptide then deformylated it in an acid medium to obtain a dipeptide of formula H - A - X - OH in which A and X are defined like before,

which is reacted with a functional derivative, Ac OH acid (Ac having the meanings provided previously) and isolates the corresponding N-acylated derivative of formula (N) Ac - A - X - OH (IV) that l 'is converted into the corresponding anhydride, then condensed with a primary or secondary amine to obtain the N-acyl dipeptide of general formula I.

EXAMPLE I

N-acetyl α -aspartyl α -glutamyl (3, 4-dihydroxyphenyl) alanine

Stage A: N-acetylaspartic acid.

133 g of aspartic acid (Imol) are dissolved in 500 ml of water previously brought to pH 9 by gentle addition of 10 N sodium hydroxide solution. It is poured into the solution while maintaining the temperature below 20 ° and the pH at 9, 113 g of acetic anhydride

(i.e., 1.1 mol) with stirring in one hour. The reaction mixture is then percolated on a sulfonic resin capable of fixing the sodium ions (Duolity C-20 resin sold by the company DIA PROSM G, previously treated with clH 2N or 2N sulfuric acid at the rate of 1.2 vol. by resin volure).

The percolate is concentrated in vacuo at ordinary temperature (20 - 25 °). A pale yellow limpid oil is collected which crystal reads slowly. The crystals are separated by filtration, drained and then dried under vacuum, first at ordinary temperature, then ending at 45 ° at the end of drying.

The yield of acetylated product is 99%. The crystallization yield is 75% of first jet product and 15% of second jet product.

Determination of nitrogen by protometry (C10 ₄ H): O% Determination of the acid function by sodium methylate: 99% of theory (2 eq / faole).

STAGE B: N-acetylaspartic anhydride

175 g of N-acetyl L aspartic acid (1 mol) obtained in stage A are loaded into a flask with three tubes. 255 g of acetic anhydride are added. It forms a very fine and fluid porridge. This suspension is heated to 60 ° for 45 min and then allowed to cool with stirring. The reaction mixture is then left 6 hours in a cooler to complete crystallization. The crystals formed are then separated by vacuum filtration or by spin drying. They are washed with trichloro 1,1,1-ettane added in small portions to remove the excess reagent or the acetic acid which may have formed.

The yield of crystallized product is 95%. Acidimetric titer (Me ONa) 100%.

N-acetylaspartic anhydride is in the form of very large pancake crystals. This anhydride is stable but must be kept away from humidity.

STAGE C: N-acetyl α -asnartyl α -qlutamioue acid.

154.35 g (ie, 1 mol 05) of glutamic acid are dissolved in a liter of water previously adjusted to pH 8.5 and at a temperature in the region of 0 °. The dissolution is rapid at this pH. The temperature of the solution is maintained at 0 ° by immersion in an ice bath, then with very vigorous stirring and while regulating the pH very exactly at pH 8.5 by addition of sodium hydroxide solution ION, the anhydride is added N-acetyl α - L - aspartic in solid form (1 mole).

Once the addition is complete, stirring is continued for a few more minutes, then percolation is carried out on Duolite C 20 resin previously treated with 2N hydrochloric acid. The percolation liquid is then concentrated under vacuum at 20 - 25 °. This gives a thick, syrupy yellow, clear solution which does not crystallize.

Analysis shows that it contains 75 X of N-acetyl α -aspartyl α -glutamic acid / and 25% of N-acetyl β -aspartyl glutamic acid. Coupling yield relative to the anhydride = 99%. Coupling yield relative to the glutamic acid used: 94%.

STAGE D: Activation of N-acetyl α (or β) aspartyl glutamic acid. 1 mol of N-acetyl L-aspartyl glutamic acid (mixture of α-aspartyl and β-aspartyl isomers) is dissolved in 500 ml of water. A concentrated solution is obtained which is mixed while cooling approximately 750 g of acetic anhydride ( 7 to 8 mol) then the mixture is heated to 60-70 ° for 6 hours. Then allowed to cool. The crystals of N-acetyl aspartimide glutamic anhydride which have formed are allowed to settle. They are filtered, washed with 1,1,1-trichloroethane, then dried under vacuum. The glutamic N-acetylaspartimido anhydride thus obtained is used as it is for the next stage of the synthesis.

STAGE E: N-acetyl α -aspartyl α -alutamyl (3,4-dihydroxyphenyl) alanine.

198 g of dihydroxy phenyl ala nine are dissolved under a nitrogen atmosphere in a liter of water, the pH of which has been basified to 8.5 with stirring and at a temperature of 0 °. 240 g of N-acetyl aspartimido glutamic anhydride in solid form are added to this solution in small portions over approximately one hour, strictly keeping the temperature at 0 ° and the pH at 8.5 (by addition of 5N sodium hydroxide). After the addition is complete, the reaction mixture is passed through a column loaded with Duolite C 20 resin and the percolating liquid is collected. The percolate is acidified by addition of hydrochloric acid (1 mole) then diluted by addition of water until a total volume of 10 liters is obtained.

This solution is then heated for one hour at 45 °, which causes the opening of the aspartimide to the α-aspartic derivative. It is then concentrated under vacuum and the crystallization of the tripeptide from the medium is obtained.

The crystallization is made more complete by taking up the residue of the mother liquors with acetone. The crystals are separated, washed and spun under vacuum. N-acetyl α -aspartyl α -glutamyl (3,4 - dihydroxyphenyl) alanine is in the form of colorless crystals soluble in water, giving the colored reactions of phenols and browning in alkaline solution. The product does not have of net melting point. The infrared spectrum shows a strong absorption at 1720 cm ^-1 (carbonyl of the amide) at 1735 cm ^-1 (carbonyl of the carboxyl) and at 3200 cm ^-1 (NH band). The infrared spectrum conforms to the structure announced.

EXEMEI-E II:

N-butyryl α aspartyl α -glutamyl (3, 4-dihydroxyphenyl) alanine.

STAGE A: N-formyl aspartic acid Eh operating according to the procedure of Stage A of Exerple I, starting from 133 g of aspartic acid and a mixture of 113 g. acetic anhydrid and 59.8 g of anhydrous formic acid, prepared in advance, N-formyl aspartic acid is obtained with a yield of 87%.

STAGE B: N-formylaspartic anhydrous

By operating according to the procedure of Stage B of Exercple I, starting from N-formyl aspartic acid, the N-formylaspartic anhydride is obtained in quantitative yield.

STAGE C: N-formyl α-aspartyl α dutamioue acid By operating as in Stage C of Experple I, starting from 154.35 g of glutamic acid and 143 g of N-formyl aspartic anhydride, a concentrated solution containing 71% of N-formyl aspartic glutamic acid (mixture of α and isomers) which is used as it is for the next step.

STAGE D:

The concentrated solution containing the mixture of isomers of N-formyl α and β-aspartyl α -glutamic acids is treated with acetic anhydride according to the procedure of Stage D of Example I. The anhydride is thus obtained N-formyl aspartimido α - glutamic acid which is used as it is for the further synthesis.

STAGE E: α -aspartyl α-alutamyl (3,4 - dihydroxypbényl) alanine The procedure is carried out according to the procedure of Stage E of Example I starting from 198 g of dihydroxyphenylalanine and 226 g of N-formylaspartimido glutamic anhydride.

The deformylated derivative is obtained after hydrochloric hydrolysis, which is precipitated by adding dioxane to the peroolate. The tripeptide crystals are dried under vacuum at ordinary temperature.

STAGE F: N-butyryl α-aspartyl α-alutamyl (3,4-dihydroxyphenyl) alanine. 44.3 g of α -aspartyl α-glutamyl (3,4-dihydroxyphenyl) alanine are dissolved in 450 ml of water previously brought to pH 9 by addition of sodium hydroxide solution. It is poured into this solution while maintaining the temperature in the vicinity of 0 ° and the pH at 9.16.1 g of butyric anhydride with vigorous stirring within 45 minutes. After the addition is complete, stirring is continued at 0 ° for one hour, then the reaction mixture is percolated on a chromatography column loaded with Duolite C 20 resin previously washed with hydrochloric acid. By usual treatment of perco lat, the N-tutytylated derivative is obtained with a yield of 67%.

Determination of nitrogen by protometry: 0% Determination of the acid function: 98 - 99%

Likewise, nitrogen can be acylated with propionyl chloride to form an N-propionyl derivative, with benzoyl chloride to form an N-benzoyl derivative or with acid chloride (dibenzocycloheptene 5-yl) heptanoic amino to form the derivative (diberizocyclohepten - 5 yl) corresponding heptanoylated amino.

EXAMPLE III:

N-butyryl α -aspartyl α -qlutamyl dopamine.

By operating as in Example II, stage E, starting from 154 g of

(3,4-dihydroxyphenyl) ethylamine and 226 g of N-formyl aspartimido glutamic anhydride, after hydrochloric hydrolysis, 321 g of α -aspartyl α -glutairyl dopamine.

Butyrylation of 321 g of α-aspartyl α-giutaιrryl dopamine is carried out with butyric anhydride according to the procedure of Experple II, Stage F and 284 g of N-butyryl α -aspartyl α are collected after the usual purifications. -glutamyl dopamine.

Determination of amino nitrogen by protometry: 0% Determination of arid functions: 98%

EXEMPTA IV:

N-acetyl α -glutamyl glycyl α -methyl (3, 4-dihydroxyphenyl) alani ne.

STAGE A: N-acetyl glutamic acid By operating as in Stage A of Example I, starting from 147.5 g of L-glutamic acid and purification by percolation on an ion exchange resin in acid form, we obtain with an 87% yield of the N-acetylated product.

STAGE B: N-acetyl clutamic anhydride By operating as in Stage B of Example I, starting from 189 g of N-acetylated derivative, obtained therewith a N-acetyl glutamic anhydride with a yield of 90%.

STAGE C: N-acetyl α -glutamyl glycine By operating as in Stage C of Example I, starting from the N-acetyl glutamic anhydride and 75 g of glycine, a concentrated solution containing approximately 70% of N is obtained. -acetyl α -glutamyl glycine and 30% of N-acetyl β -glutarryl glycine which is used for the next stage of the synthesis without additional separation.

STAGE D: N -acetyl glutarimido glycine anhydride. Εn operating as in Stage D of Example I, starting from 251 g of N-acetyl glutam yl glycine (mixture of α and β isomers in concentrated aqueous solution) and 750 g of acetic anhydride, forms N-acetyl glutarimido glycine anhydride.

STAGE E: N-acetyl α qlutamyl glycyl α -methyl (3,4-dihvdroxy phenyl) alanine. 21.5 g of L-3- (3,4-dihydroxy phenyl) 2-methyl alanine are dissolved in 750 ml of water brought to pH 8.5 under a nitrogen atmosphere. The solution is cooled to 0 ° and with vigorous stirring, about 25.5 g of N-acetyl glutarimido glycine anhydride is added in small portions over an hour.

After percolation of the reaction medium on Duolite C 20 resin and hydrochloric hydrolysis of the percolate, 33.4 g of N-acetyl α -glutarryl glycyl α -methyl (3,4-dihydroxyphenyl) alanine are obtained, which is precipitated by addition of 'acetone.

Protometric titration: 97 - 97.5%

EXAMPLE V:

N- (5-methoxy 2-methyl N-p. Chlorobenzoyl indolyl-3 acetyl) α -aspartyl α -glutamic acid.

18 g of indomethacin are dissolved in 150 ml of dioxane and 4.5 ml of triethylamine. 22 g of dicyclohexyl carbodiimide are added to this solution and the solution is stirred for

45 mins. The precipitate of closed dicyclohexyl urea is separated by filtration and the dioxane solution of mixed anhydride is gradually added to a solution of 27 g of α-aspartyl α-glutamic acid in 125 ml of dimethylformamide. After one hour of contact at ordinary temperature, the precipitate is separated by filtration, then the peptide solution is concentrated in vacuo. It is then diluted with two volumes of ice water and the crystallization is started by scraping. The indole derivative gradually precipitates. It is separated by filtration, washed with water until the washings are neutral and dried under vacuum.

N- (5-methoxy 2-methyl N '- (p.chlorobenzoyl) indolyl-3 acetyl- α -aspartyl α-glutamic acid is present in the form of a ocher cream powder slightly soluble in water, soluble in pyridine, dimethylforma mide and alkaline solutions. The α -aspartyl α -glutamic acid is obtained by hydrochloric hydrolysis of the N-formyl aspartimido α-glutamic anhydride obtained in Example II, Stage D.

EXAMPLE VI:

N-acetyl α -glutamyl glycyl (4-amino 5-chloro 2-methoxy) N'N - diethylamino benzamide. By operating as in Stage E of Example IV, starting from 30 g of metoclopramide (dihydrochloride) in 250 ml of water, then adjusting the pH to 8.5 and 25 g of N-acetyl glutarimido glycine anhydride, after percolation on Duolite C 20 resin and hydrochloric hydrolysis at 60 °, 26 g of N-acetyl α -glutamyl glycyl (4-amino 5-chloro 2-methoxy) N'N'-dierythylamino benzamide are obtained which are recrystallized from acetonitri.

The product is in the form of crystals with pink reflections which are not very soluble in water and the hydroxylated solvents but which are soluble in alkaline solutions.

EXAMPLE VII:

N-acetyl α -aspartyl histidyl α -methyl N '- (3-trifluoromethyl phenyl) ethyl N'-ethyl amino. STAGE A:

N-acetyl α -aspartyl histidine.

Starting from 156 g of L-histidine in solution in water at pH 8.5, 1 mole of N-acetyl α-L-aspartic anhydride is added according to the procedure of Example I, Stage C in solid form. After purification on Duolite C 20 resin and concentration of the aqueous solution, a syrupy tooth mass is obtained, the analysis shows that it contains 80% of N-acetyl α-aspartyl histidine and

20% N-acetyl β-aspartyl histidine.

Coupling yield with respect to the anhydride = 81%. STAGE B: (N-acetyl aspartimido) histidine anhydride. By operating according to the procedure of Example I, Stage D, starting from the concentrated solution of N-acetyl α (and β) aspartyl histidine and 750 g of acetic anhydride, the N-acetyl anhydride is formed. aspartimido histidine which is used as is for the next step of the synthesis.

STAGE C: N-acetyl α-aspartyl histidyl α-methyl N '- (3-trifluorome thylphenyl ethyl) N'-ethyl amino. 269 g of 2- (3-trifluoromethyl phenyl propyl) N-ethyl amino hydrochloride are dissolved in 1000 ml of water, the pH of which has been brought to 8.5 and the temperature of which is lowered to 0 °. 240 g of N-acetyl α-aspartyl histidine anhydride in solid form are added to this solution with very vigorous stirring, in small fractions, in about one hour. The temperature of the reaction mixture is kept close to 0 ° for the entire duration of the addition and the pH of the medium is 8.5.

After completion of the addition, the reaction mixture is passed through a column chromatography loaded with Duolite C 20 resin previously treated with hydrochloric acid. The percolation liquid is collected and then acidified frankly by the addition of hydrochloric acid. The solution is then diluted by adding water and the solution is brought to 45 ° for 2 hours. Then allowed to cool and the solution is concentrated under reduced pressure without exceeding 40 °. The solid mass is taken up in acetone and the crystallization is started by scraping. The mixture is then left to stand by resting in a cooler for 12 hours.

the crystals are then separated, washed with acetone, wrung out, then dried in vacuo. N-acetyl α -aspartyl histidyl α -methyl N'- (3-trifiuoromethyl phenyl ethyl) N'-ethyl amino occurs in the form of yellowish white crystals, not very soluble in water, soluble in acidic or alkaline medium , poorly soluble in organic solvents. The product shows a decomposition point rather than a specific melting point.

Claims

The object of the invention is:

1. The new N - acyl dipeptides of general formula

Ac - A - X - Y in which Ac represents the acyl residue of an organic carboxylic, aliphatic, aromatic or hydroaroraatic acid. A is the remainder of an amino acid carrying another carboxylic function, substituted at α X is the remainder of an amino acid and

Y is hydrogen or the remainder of a mono or disubstituted, linear or cyclic amine.

2. The N-acyl dipeptides according to claim 1, corresponding to the general formula I '

in which Ac is an acetyl radical

Z is hydrogen or forms with Z 'a lower alkylene radical optionally substituted by a hydroxyl or optionally interrupted by a heteroatom.

Z 'is hydrogen, a linear or branched lower alkyl radical optionally substituted by a hydroxyl radical, a carbamoyl radical, a ureido radical, a guanidino redical, or a sulphonic group; a lower phenylalkyl or indolyl lower alkyl redical, or else Z1 forms with Z a lower alkyl radical, optionally substituted by a hydroxyl or optionally interrupted by a heteroatom. Y 'and Y ", distinctly from each other, represent hydrogen, an alkyl, aryl, hetero aryl or aralkyl radical, these radicals being able to be substituted by 1 to 3 substituents, with the limitation that Y and Y 'cannot simultaneously represent hydrogen and n is an integer varying from 1 to 3.

3. The N - acyl dipeptides according to claim 1, corresponding to the general formula I ".

wherein the substituents Z, Z 'and n are defined as above. Y and Y 'are hydrogen and Ac represents the acyl residue of an organic carboxylic acid, the hydrocarbon residue of which is an alkyl radical having from 2 to 18 carbon atoms in straight or branched chain, a mono, bi- or tricyclic having 5 to 15 carbon atoms, an aralkyl radical in which the alkyl residue has from 1 to 8 carbon atoms and where the aryl residue is mono, bi- or tricyclic and has from 5 to 15 carbon atoms, a radical heteroaryl mono, bi- or tricyclic, a hydro aromatic radical having 3 to 15 carbon atoms mono, bi- or tricyclic or a (hydroaryl) alkyl radical in which the hydroaryl residue is defined above and the alkyl residue has 1 to 8 carbon atoms optionally substituted by a hydroxyl or an oxo radical, or interrupted by an amino group.

4. The new N-acyl dipeptides according to claim 1 in which the residue A is an α-aspartyl or α-glutamyl residue.

5. The new N-acyl dipeptides according to claim 1 in which X is a natural amino acid residue of configuration L.

6. The new N-acyl dipeptides according to claim 1 in which the residue Y is a nitrogenous base having a phenylalkylamine or an indolylalkylamine.

7. A process for obtaining the compounds of general formula I

Ac - A - X - Y (I) in which the radicals Ac, A, X and Y have the meanings previously supplied, characterized in that an amino acid A - C is subjected to the action of an acid of formula Ac - CH in which Ac is defined as above, or one of its functional derivatives, in the presence of a basic agent to form an N - acylated derivative, of general formula II Ac - A - OH (II) in which the residues Ac and A are defined as above, subjects it to the action of a dehydrating agent to form an anhydride of general formula III

in which Ac is defined as above, n is equal to 1, 2, or 3, or one of its structural analogs, substituted by a methylamino, hydroxy or thio radical, reacts the latter in an aqueous medium with an amino acid of formula

H - X - OH in which X is defined as above, to obtain the N-acyl dipeptide of general formula IV

Ac - A - X - OH (IV) in which Ac, A and X are defined as above, subjects it to the action of a dehydration agent at temperature breaks to form the corresponding anhydriαe, which by reaction with a primary or secondary amine of general formula YH makes it possible to obtain the N-acyl dipeptide of general formula I

Ac - A - X - Y (I)

8. Another process for obtaining the compounds of general formula I according to claim 1 which consists in subjecting the dipeptide of formula σeneral IV

Ac - A - X - CH (IV) in which Ac, A and X have the same meanings as those supplied previously, to the action of an agent for this dehydration, when hot to form the imideanhydride of general formula V