IE913361A1 - New peptide and pseudopeptide compounds that are¹therapeutically active in the blood coagulation cascade,¹process for the preparation thereof, and pharmaceutical¹compositions containing them - Google Patents

Abstract

Derivatives of formula (I): X-A1-A2-A3-A4-A5-A6-A7-A8-A9-A10-Y (I> in which X, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10 and Y are as defined in the description. Medications.

Description

The present invention relates to new peptide and pseudopeptide compounds that are therapeutically active in the blood coagulation cascade, to a process for the preparation thereof, and to pharmaceutical compositions containing them.

It is now widely known that when the equilibrium between procoagulant and anticoagulant factors in the blood is disturbed, a thrombus or blood clot may form. The development of a thrombosis is furthered essentially by three principal pathogenic factors, which are stasis or diminution of the blood flow, conditions of hypercoagulability, and lesions of the endothelium of the vascular wall.

Anticoagulants are therapeutic agents that can be used in the treatment of acute venous thromboses, pulmonary embolism, arterial embolism of the extremities, arterial thromboses, such as myocardial infarction, and all other symptoms of t h romboemboli sm.

Of the known anticoagulant agents, hirudin, which is a polypeptide having 65 amino acids, is a specific thrombin inhibitor isolated from the salivary glands of the medicinal leech (Biochemistry 25, 4622-4628, 1986).

Variants of hirudin that can be used as thrombin inhibitors have already been described. Examples are the compounds described in Patents EP 209061 and EP 332523.

Moreover, synthetic analogues of hirudin fragments having anticoagulant properties have also been described: for example, the compounds claimed in Patents EP 276014, EP 291981, EP 291982 and EP 333356.

The present invention relates to new synthetic peptides which have proved to be especially valuable on account of the intensity of their anticoagulant and antithrombotic properties, and as platelet anti-aggregants, without these effects being accompanied by a marked haemorrhagic action.

These properties manifest themselves even at doses that are 10 times lower than those of the other compounds described in the prior art.

Furthermore, the compounds of the invention display enhanced stability compared to the natural sequence (hirudine 54-65) in in vitro tests used as models of the duration of action in vivo.

Potency, selectivity and stability of these synthetic peptides and pseudopeptides are due especially to the introduction into the peptide sequence of synthetic amino acids, of pseudopeptide bonds, of non-cysteine cyclisations, or to a combination of these factors.

The invention relates more especially to new peptide compounds corresponding to the general formula (I): X—Aj—A2~A3—A4-A5—A5-A7—Ag-Ag-A^o-Y (I) in which: represents - a terminal amino group that is optionally substituted by 1 or 2 linear or branched (Cj-C6)-alky1 groups, a linear or branched (Ci-Cg)acyl group, a benzyloxycarbonyl group (Z), a tert.-butoxycarbonyl group (Boc), a 9-fluorenylmethyloxycarbonyl group (Fmoc), a linear or branched (Ci-Ce)-guanidinoacyl group, such as the branched such as H2N or X’o = 1c-NH-(CH2)4-CO- , a linear or H2NZ branched (Ci-Cg)~guanidinoa1ky1 group, a pyroglutamyl group (Glp), a succinyl group (Sue), or any one of the following groups: HO X3 HOCO —^_y-WH-C0-CH2-MH-C0-(CH2)2-C0O-COCH3 X4 = HOCOCO^ χ5 = C02H X6 = HOCO—NH-C0-CH2-NH-C0-(CH2)2-C0HO X8 = — OC — CH2-v^C02H Al a2A3 a4 A5 A6 represents a bond or a peptide residue containing from 1 to 3 amino acids of any kind, represents a bond or a phenylalanine residue (Phe), a tyrosine residue (Tyr), an isoleucine residue (lie), a norvaline residue (Nva), a 1,2,3,4-tetrahydroisoquinoline-3-carbonyl residue (Tic), an α-aminobutyric acid residue (Abu), a glutamic acid residue (Glu), or an amino acid residue containing an aryl group, represents a bond or a glutamic acid residue (Glu), an aspartic acid residue (Asp), a β-alanine residue (PAla) or a tyrosine residue (Tyr), represents a bond or a glutamic acid residue (Glu), an aspartic acid residue (Asp), a proline residue (Pro), a 2,3-diaminopropionic acid residue (Dpr), a 2,4-diaminobutyric acid residue (Dab), an ornithine residue (Orn), a lysine residue (Lys), a 2-azabicyclo[2.2.2]octane-3-carbonyl residue (Abo) or a 2-azabicyclo[2.2.1]heptane-3-carbonyl residue (Abh), represents a bond or an isoleucine residue (lie), a norvaline residue (Nva), a phenylalanine residue (Phe), a proline residue (Pro), an ornithine residue (Orn) or a 2,3-diaminopropionic acid residue (Dpr), represents a proline residue (Pro), an isoleucine residue (lie), a norvaline residue (Nva), a phenylalanine residue (Phe), an ornithine residue (Orn), a 2-azabicyclo[2.2.2]octane-3-carbony1 residue (Abo), a 2-azabicyclo[2.2.1]heptane-3carbonyl residue (Abh), an octahydroindole-2carbonyl residue (Oic) or a 3,4-dehydroproline residue (dhPro), A7 represents a glutamic acid residue (Glu) or an aspartic acid residue (Asp), Ag represents a glutamic acid residue (Glu), an aspartic acid residue (Asp), a 2,35 diaminopropionic acid residue (Dpr), a 2,4diaminobutyric acid residue (Dab) or a β-alanine residue (^Ala), Ag represents a tyrosine residue (Tyr) that is optionally protected by a benzyl group (Tyr(Bzl)) or an acetyle group (Tyr(COCH3)), a phenylalanine residue (Phe), an alanine residue (Ala), an isoleucine residue (lie), a norvaline residue (Nva), a p-carboxyphenylalanine residue (Pep), a 3-carboxytyrosine or 4-0-acetyl-3-carboxytyrosine residue, or a (p-CH2PO3H)-phenylalanine residue ((pCH2PO3H)Phe), A10 represents a bond, a leucine residue (Leu), a valine residue (Val), a β-naphthylalanine residue (Nal), a cyclohexylalanine residue (Cha), a β-(220 thienyl)alanine residue (Thi), an octahydroindole2-carbonyl residue (Oic), a dipeptide residue, such as Leu-Glu, Leu-Pro, Leu^Ala, Val-Glu, NalGlu, Cha-Glu, Thi-Glu, Oic-Glu or a leucine-4aminobutyric acid residue (Leu-4Abu), or a tripeptide residue, such as Nal-Nal-Leu, Y represents - a terminal carboxy group that is optionally substituted by a linear or branched (C1-C6)-alkoxy group or an amino group that is itself optionally substituted by one or two linear or branched (C1-C6)-alkyl groups, or - a terminal carboxy group reduced to the corresponding alcohol (ol), and comprising at least: one synthetic amino acid residue, such as 2-azabicyclo[2.2.2]octane-3carbonyl (Abo), 2-azabicyclo[2.2.1 ] heptane-3-carbonyl (Abh) or octahydroindole-2-carbonyl (Oic), and/or - one pseudopeptide bond, such as -ch2-nh-, -ch2-s-, -ch2—so-, -ch2SO2—, -NH-CO- or -CH=CH-, replacing a peptide bond -CO-NH-, and/or - one non-cysteine cyclisation between the side chains of two amino acids, or between a terminal amino group and a side chain of an amino acid, or between a terminal carboxy group and a side chain of an amino acid, or between a terminal amino group and a terminal carboxy group, and their addition salts with a pharmaceutically acceptable acid or base, each amino acid in the peptide sequence being optically pure and the α-carbon of each amino acid having the D- or Lconfiguration.

Of the pharmaceutically acceptable acids there may be mentioned by way of non-limiting example hydrochloric acid, hydrobromic acid, sulphuric acid, phosphonic acid, acetic acid, trifluoroacetic acid, lactic acid, pyruvic acid, malonic acid, succinic acid, glutaric acid, fumaric acid, tartaric acid, maleic acid, citric acid, ascorbic acid, oxalic acid, methanesulphonic acid, camphoric acid, etc..

Of the pharmaceutically acceptable bases there may be mentioned by way of non-limiting example sodium hydroxide, potassium hydroxide, triethylamine, tert.-butylamine, etc..

The invention also includes the process for the preparation of the compounds of formula (I), which can be obtained by various methods, such as solid-phase sequential synthesis, synthesis of fragments and coupling thereof in solution, enzymatic synthesis, genetic synthesis by cloning and expression of genes in transformed bacteria, or by various combinations of these techniques.

The general methods of solid-phase peptide synthesis have been described by B.W. ERICKSON and R.B. MERRIFIELD (The Proteins, Solid-Phase Peptide Synthesis, 3rd edition, 257527, 1976).

Solid-phase synthesis may be effected in an automated machine which, in a repetitive and programmable manner, carries out the cycles of deprotection, coupling and washing that are necessary for the sequential introduction of the amino acids into the peptide chain. The amino acid, preferably Cterminal, is fixed onto a resin conventionally used for the preparation of polypeptides, preferably a polystyrene crosslinked with the aid of from 0.5 to 3.0% divinylbenzene and provided with activated radicals, such as chloromethylene or hydroxymethylene, which allow the first amino acid to be fixed covalently onto the resin. The appropriate choice of resin permits the fixing of a C-terminal carboxylic acid, amide or alcohol function.

The amino acids are then introduced one by one in the order determined by the operator. Each synthesis cycle, which corresponds to the introduction of one amino acid, comprises deprotection, preferably N-terminal, of the peptide chain, successive washing steps in order to remove the reagents or to swell the resin, a coupling step with activation of the amino acid, and further washing steps. Each of these operations is followed by filtration, which is carried out by means of a sintered glass incorporated in the reactor in which the synthesis is being carried out.

The coupling reagents used are conventional reagents for peptide synthesis, such as dicyclohexylcarbodiimide (DCC) and hydroxybenζotriaζο 1e (HOBT) or beηζotriaζο 1-1-y 1oxytris (dimethylamino)phosphonium hexafluorophosphate (BOP), or also diphenylphosphoryl azide (DPPA).

Activation by the formation of mixed anhydrides is also possible.

Each amino acid is introduced into the reactor in approximately quadruple excess relative to the degree of substitution of the resin, and in an approximately equivalent amount relative to the coupling agents. The coupling reaction can be checked at each stage of the synthesis by the ninhydrin reaction test described by E. KAISER et al. (Analyt. Biochem., 34, 595, 1970).

After assembly of the peptide chain on the resin, treatment with a strong acid, such as trifluoroacetic acid, or hydrofluoric acid in the presence of anisole, ethanedithiol or 2-methylindole, is carried out in order to separate the peptide from the resin and, where appropriate, to free the peptide of its protecting groups. The compound is then purified by means of conventional purification techniques, especially chromatographic techniques.

The total or partial cyclisation of the compounds of the invention is carried out in solution, preferably through two functions which are selectively deprotected and are capable of forming a covalent bond, such as an amide bond.

The peptides of the present invention can also be obtained by coupling, in solution, selectively protected peptide - 9 fragments, which can be prepared either on the solid phase or in solution. The use of protecting groups and the utilisation of their differential stability is analogous to the solidphase methods, with the exception of the attachment of the peptide chain to the resin. The C-terminal carboxyl group is protected, for example, by a methyl ester or an amide function. The methods of activation during the couplings are also analogous to those employed in the solid-phase synthesis.

The synthesis of peptides containing pseudopeptide bonds, such as -CH2-NH-, -CH2-S~, —CH2—SO—, -CH2-SO2-, -NH-CO- or -CH=CH-, is effected either by solution methods or by a combination of solution methods and solid-phase synthesis using conventional methods of organic chemistry. Thus, for example, the -CH2-NHbond is introduced by preparing in solution the aldehyde FmocNH-CHR-CHO according to the technique described by FEHRENTZ and CASTRO (Synthesis, 676-678, 1983) and condensing it with the growing peptide chain either on the solid phase in accordance with the technique described by SASAKI and COY (Peptides, 8, 119-121, 1988), or in solution.

The compounds of formula (I) have very valuable pharmacological properties.

They have anticoagulant and antithrombotic properties and can therefore be used for preventing post-thromboembolic complications by dissolving clots, or as agents for preventing the progress of the thrombotic process by using them as anticoagulants having direct and rapid action. Their properties of inhibiting the thrombin-mediated pathway of platelet activation enable them to be considered for use as inhibitors of the steps of interaction of blood platelets with the vascular wall associated with the phenomena of thrombosis and atherosclerosis.

The present invention relates also to pharmaceutical compositions containing as active ingredient at least one compound of the general formula (I), or an addition salt thereof with a pharmaceutically acceptable acid or base, on its own or in combination with one or more inert, non-toxic excipients or vehicles.

Of the pharmaceutical compositions according to the invention, mention may be made more especially of those which are suitable for oral, parenteral or nasal administration, tablets, dragees, sublingual tablets, sachets, paquets, soft gelatine capsules, glossettes, lozenges, suppositories, creams, ointments, dermal gels and aerosols.

The dosage varies according to the age and weight of the patient, the nature and severity of the disorder, and the mode of administration.

Administration may be oral, nasal, rectal or parenteral. In general, the dosage ranges from 0.2 to 100 mg per treatment, in one or more doses over a 24-hour period.

The following Examples illustrate the invention and do not limit it in any way.

Amino acids the abbreviations of which begin with a capital letter have the L-configuration.

Amino acids the abbreviations of which begin with a small letter have the D-configuration.

The amino acid designated Abo has the 3S-configuration.

The letter ψ indicates the presence of a pseudopeptide bond, the nature of which is indicated in parentheses.

EXAMPLE 1; Z-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Asp-Tyr-Leu-OH The compound of Example 1 is synthesised from 2 g of a resin substituted by 0.33 mmol/g of Fmoc-Leu-OH, in accordance with the following repeating protocol: Operation no.

Function Solvent/Reagent Repetition/time 1 washing DMF 2 X 2 min 2 deprotection 20 $ piperidine/DMF 1 X 5 min 3 deprotection 20 % piperidine/DMF 1 X :5 min 4 washing DMF 3 X 2 min 5 washing dichloromethane 3 X 2 min 6 coupling activated protected amino acid 1 X 90 min 7 washing DMF 3 X 2 min 8 washing isopropyl alcohol 3 X 2 min 9 washing dichloromethane 3 X 2 min Each of these operations, which are carried out in 30 ml of solvent, with stirring and at room temperature, is followed by filtration through a sintered glass incorporated in the glass cell (reactor) in which the synthesis is progressing. The filter retains the resin on which the growing peptide chain is fixed.

The chosen protected amino acids were introduced in the following order: Fmoc-Tyr(tBu)-OH, Fmoc-Asp(OtBu)-OH, Fmoc10 Glu(OtBu)-OH, Fmoc-Pro-OH, Fmoc-Ile-OH, Fmoc-Abo-OH, FmocGlu(OtBu)-OH, Fmoc-Phe-OH, Z-Asp(OtBu)-OH. 2-aza-3-carboxybicyclo[2.2.2]-octane (Abo) is a non-coded amino acid described in Patent EP 51020. The compound FmocAbo-OH is obtained by treating Abo with 9-fluorenylmethyl chloroformate (Fmoc-Cl) in an Na2CO3 (10%)/dioxane mixture (2/1) for 4 hours at room temperature, followed, after acidification of the aqueous phase, by extraction with ethyl acetate and recrystallisation in an ether/pentane mixture. - 12 Activation for the purpose of coupling (operation 6) is brought about in each cycle by dissolving 4 equivalents (2.64 mmol) of the protected amino acid with 360 mg of HOBt in 30 ml of DMF and then, after 30 minutes at room temperature, adding 618 mg of DCC. This solution is then introduced immediately into the reaction cell with 10 ml of dichloromethane.

At the end of the nine cycles corresponding to the sequential fixing of nine amino acids, there is thus obtained, with the C-terminal leucine, a decapeptide that is protected on its side chains and fixed on the resin. The latter is then treated with a mixture of trifluoroacetic acid (18 ml), dichloromethane (1 ml) and anisole (1 ml) for 90 minutes at room temperature. The filtrate and the solvents used for washing the resin (3 x 20 ml of dichloromethane) are combined and evaporated to dryness. The product is suspended in ether, filtered and dried and then purified by preparative HPLC on a Cie column (inside diameter: 47 mm, length: 300 mm) and lyophilised.

The resulting product is analysed by decomposition into amino acids by hydrolysis with 6N hydrochloric acid for 18 hours at 110°C and quantitative determination of the resulting amino acids by HPLC.

Asp lie Glu Leu+Abo Phe Pro Tyr calculated 2 1 2 2 1 1 1 found 1.98 0.92 2.15 1.80 0.95 1.11 0.90 EXAMPLE 2 : Fmoc-Asp-Phe-Glu-Dpr-Ile-Abo-Glu-Glu-Tyr V(CH2-NH)Leu-NH2 Mass spectrum (FAB): MH+, m/z = 1411 The first cycle is identical to that described in Example 1 and allows Fmoc-Leu-OH to be introduced onto a substituted resin in such a manner as to free a C-terminal amide function on final cleavage. It is followed by a half-cycle up to operation 6 in order to free the amine function of the leucine. 2.3 mmol of Fmoc-Tyr(Bzl)-OH are then reacted separately with 2.3 mmol of phosphonium hexafluorophosphate (BOP) in the presence of O,N-dimethylhydroxylamine and triethylamine. The resulting product is isolated after customary washing steps in dichloromethane and evaporation of the solvent. The oily product is then taken up in ether and treated with 2.5 mmol of LiAlH4 for 20 minutes at room temperature. The mixture is then hydrolysed in an NaHC03 solution, and the aldehyde that forms is extracted in ether and washed, and the solvent is evaporated. The resulting oily product is then introduced into the reactor containing the resin suspended in DMF in the presence of acetic acid. The resulting imine is then reduced by the gradual addition of sodium cyanoborohydride, and stirring is maintained for 3 hours.

The synthesis is then continued using the same synthesis protocol as that described in Example 1, starting with operation 7. The protected amino acids are then introduced in the following order: Fmoc-Glu (OBzl)-OH, Fmoc-Glu (OtBu )-OH, Fmoc-Abo-OH, Fmoc-Ile-OH, Fmoc-Dpr(Boc)-OH, Fmoc-Glu(OBzl)-OH, Fmoc-Phe-OH, Fmoc-Asp(OBzl)-OH.

After operation 9 of the last cycle, the product is separated from the resin and purified using the same techniques as in Example 1. The resulting product is dissolved in DMF and treated with 4 equivalents of BOP and 12 equivalents of ethyldiisopropylamine for 2 hours at room temperature, and is then cyclised.

After evaporation of the solvent, the cyclised product is purified by chromatography and then freed of its protecting groups, with the exception of Fmoc, by catalytic hydrogenation (Pd/C).

After filtration of the catalyst, the expected product is purified by preparative liquid chromatography. Its purity is checked in the same manner as in Example 1. Analysis: Asp Phe Glu Dpr lie Abo calculated 1 1 3 1 1 1 found 0.97 0.98 3.03 0.99 0.95 0.99 10 Mass spectrum (FAB): MH+, m/z = 1469 The following Examples were prepared using the operating methods described in Examples 1 and 2 . EXAMPLE 3 : Z-Asp-Phe-Glu-Abo-Ile-Abo-Glu-Asp-Tyr-Leu -OH Analysis : 15 Asp Phe Glu lie + Abo Tyr Leu calculated 2 1 2 3 1 1 found 2.10 0.96 2.19 2.85 1.10 1.09 Mass spectrum (FAB) : MH+, m/z = 1450 EXAMPLE 4 : nal-Asp- Phe-Glu-Abo- Ile-Pro- Glu-Asp-Tyr-Leu, 20 trifluoroacetate Analysis ; calculated nal Asp Phe Glu He Pro Tyr Leu + Abo 1 2 1 2 1 1 1 2 25 found 1.07 1.97 1 .01 2.14 0.96 1.07 0.90 0.90 Mass spectrum (FAB) : MH+, m/z = 1474 EXAMPLE 5 i Z-Asp-Phe-Glu-Abo-Ile-Pro- Leu-OH, trifluoroacetate -Glu-Asp-Tyr Ψ(0Η2ΝΗ) Analysis : calculated Asp Phe Glu Abo Ile Pro 2 1 2 111 found 2.21 0.95 2.13 0.90 0.86 1.18 Mass spectrum ( FAB) : MH+ , m/z = 1397 EXAMPLE 6 : Z-Asp-Tyr Ψ (CH2NH) Glu-Abo-Ile-Pro-Glu-Asp-Tyr Ψ (CH2NH) Leu-OH, ditrifluoroacetate Analysis : Asp Abo Ile Pro Glu calculated 2 1 1 1 1 15 found 2.16 0.93 1.00 0.91 1.08 Mass Spectrum (FAB) : MH+, m/z = 1399 EXAMPLE 7 : Z-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Asp-Tyr-nal-nalLeu-OH Analysis : calculated Asp Phe 1 found 2.06 1.02 Glu Abo + Ile Pro 2 2 1 2.20 1.82 1.04 Tyr nal Leu 1 0.91 1.85 1.1 Mass spectrum (FAB) : MH+, m/z = 1804 EXAMPLE 8 : H-Glu-Orn-Pro-Glu-Glu-Tyr-Leu Analysis Glu Pro Leu Orn Tyr calculated 3 1 1 1 1 5 found 2.85 0.97 0.98 1.1 1.08 Mass spectrum (FAB) : MH+, m/z = 875 EXAMPLE 9 : Suc-Glu-Orn-Pro-Glu-Glu-Tyr-Leu - 1_ Analysis : Glu Pro Leu Orn Tyr 10 calculated 3 1 1 1 1 found 2.95 1.09 0.99 0.91 1.06 Mass spectrum (FAB) : MH+, m/z = 975 EXAMPLE 10 : H-Orn-Pro-Glu-Glu-Tyr-Leu Analysis : < Glu Pro Leu Orn Tyr calculated 2 1 1 1 1 found 1. 84 1.04 0.99 1.08 1.04 Mass spectrum (FAB) : MH+, m/z = 746 EXAMPLE 11 : r—Orn-Pro-Glu-Glu-Tyr Analysis : Glu Pro Orn Tyr calculated 2 1 1 1 found 2.05 0.91 0.99 1.06 Mass spectrum (FAB) : MH+, m/z = 633 EXAMPLE 12 : H-Glu-Orn-Pro-Glu-Glu-Tyr Analysis : calculated found Glu 2.92 Pro 1.06 Orn 1.01 Tyr 0.99 Mass spectrum (FAB) : MH+, m/z = 761 EXAMPLE 13 : H-Orn-Pro-Glu-Glu-Tyr Analysis : Glu Pro Orn Tyr calculated 2111 found 1.94 1.00 1.06 1.00 Mass spectrum (FAB) : MH+, m/z = 633 EXAMPLE 15 : Suc-Orn-Pro-Glu-Glu-Pcp-Leu-OH EXAMPLE 14 : Suc-Dpr-Pro-Glu-Glu-Pcp-Leu-OH EXAMPLE 16 : r— Orn-Pro-Glu-Glu-Tyr-Leu Analysis : Glu Pro Leu Orn calculated 2111 found 1.92 1.02 1.00 1.09 Mass spectrum (FAB) : MH+, m/z = 746 Tyr 0.97 EXAMPLE 17 : H-Asp-Phe-Glu-Glu-Orn-Pro-Glu-Glu-Tyr-Leu Analysis : calculated found Asp 1.03 Glu 3.98 Pro 1.01 Phe 0.97 Leu 1.06 Orn 1.00 Tyr 1.01 Mass spectrum (FAB) : MH+, m/z = 1266 EXAMPLE 18 : Glp-Glu-Orn-Pro-Glu-Glu-Tyr-Leu —, Analysis : Glu calculated 4 found 4.07 1.02 0.96 0.94 1.00 Pro Leu Orn Tyr 1111 Mass spectrum (FAB) : MH+, m/z = 986 EXAMPLE 19 : X2-Glu-Glu-0rn-Pro-Glu-Glu-Tyr-Leu Analysis : calculated found Glu Gly Pro Leu Orn Tyr 4 1 1 1 1 1 4.07 0.99 1.03 0.92 0.96 1.03 Mass spectrum (FAB) : MH+, m/z = 1310 X3-Asn-Gly-Asp-Phe-Glu-Glu-Ile-Pro-Glu-GluTyr(CO-CH3)-Leu-OH EXAMPLE 20 EXAMPLE 21 Xo-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Tyr-Leu-OH Analysis : calculated Asp found 1.00 Glu Gly Phe 3 11 3.06 0.95 1.08 Mass spectrum ( FAB) M + H+, m/z Leu + lie + Abo 3 2.88 Tyr 1.02 1475 EXAMPLE 22 : H-(4-Abu)-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-GluTyr-Leu-OH Analysis : Asp Glu calculated 1 3 found 1,00 3,06 Gly 4-Abu 1 1 0,95 0,99 Phe Leu + lie + Abo 1 3 1,08 2,88 Tyr 1,02 Mass spectrum (FAB) : MH+, m/z = 1433 EXAMPLE 23 : H-Arg-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-GluTy Γψ (CH2NH) Leu-OH Analysis : calculated Arg Asp 1 found 1.07 1.06 Glu Gly Pro 1 1 2.97 0.92 1.01 Phe lie + Abo 1 2 0.99 2.01 Mass spectrum (FAB) MH+, m/z 1489 •Ε 913361 EXAMPLE 24 : Xi-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Tyr-Leu-OH Analysis : calculated Asp Glu Gly Pro Phe lie + Abo Leu Tyr 5 1 3 1 1 1 2 1 1 found 1.04 3.02 1.06 1.05 1.01 1.98 1.07 0.95 Mass spectrum (FAB) : MH+, m/z = 1508 EXAMPLE 25 : CH3CO-Arg-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu10 Tyr-Leu-OH Analysis : calculated Arg Asp Glu Gly Pro Phe lie + Abo Leu Tyr 113111 2 11 found 1.00 1.00 3.02 1.04 1.08 0.98 1.82 1.10 1.01 Mass spectrum (FAB) : MH+, m/z = 1546 EXAMPLE 26 : Arg-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-TyrLeu-OH Analysis : calculated Arg Asp Glu 113 found 1.04 1.02 3.03 Gly Pro 1 1 Phe lie + Abo Leu 12 1 0.99 1.07 1.03 1.94 1.02 Mass spectrum (FAB) MH+, m/z 1504 Tyr 0.97 phe-Pro-Arg-Abu-Glu-Abo-Ile-Pro-Glu-Glu-tyrLeu-OH EXAMPLE 27 Analysis : calculated Arg Glu Abu 13 1 found 1.00 2.83 0.95 Pro Phe 1 lie Leu + Abo Tyr 12 1 2.09 1.03 1.05 2.00 0.99 Mass spectrum ( FAB) MH+, m/z = 1514 EXAMPLE 28 : Xi-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Tyr-Leuglu-OH Analysis : calculated Asp Glu Gly Pro Phe He Leu + Abo Tyr 1 4 1 1 1 1 2 1 found 1.08 4.21 1.02 1.10 0.99 0.90 1.64 1.04 Mass spectrum (FAB) : MH+, m/z = 1638 EXAMPLE 29 : Suc-Glu-Tyr-Abo-Ile-Pro-Glu-Glu-Ala-Cha-glu-OH Analysis : Glu calculated 4 found 4.15 Ala 0.99 Pro He Abo Cha Tyr 1.00 0.99 0.95 0.94 0.97 Mass spectrum (FAB) : MH+, m/z = 1369 EXAMPLE 30 ϊ Suc-Tyr-Glu-Pro-Ile-Oic-Glu-Glu-Ala-Thi-glu-OH Analysis : calculated found 4.34 Glu Ala 1 0.93 Pro lie Oic Tyr 1.05 0.89 0.96 0.95 Thi 0.89 Mass spectrum (FAB) : MH+, m/z = 1383 EXAMPLE 31 Suc-Tyr-Glu-Pro-Ile-Pro-Glu-Glu-Ala-Oic-glu-OH Analysis : Glu calculated 4 found 3.91 Mass spectrum (FAB) Ala 0.96 : MH+, Pro lie 1 2.04 1.12 m/z = 1327 Oic Tyr 1 0.99 0.97 EXAMPLE 32 : Xi~Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Ala-Oicglu-OH Analysis : Asp Glu Gly Ala Pro Phe He + Abo Oic calculated 1 4 1 1 1 1 2 1 found 1.09 4.25 0.87 0.95 0.85 0.86 2.23 0.90 Mass spectrum (FAB) : MH+, m/z = 1584 EXAMPLE 33 : Suc-Tic-Glu-Pro-Ile-Pro-Glu-Glu-Ala-Oic-glu-OH Analysis : calculated found Glu 4.08 Ala 1.07 Pro 1.92 He 0.92 Oic 0.91 Tic 1.09 Mass spectrum (FAB) : MH+, m/z = 1323 EXAMPLE 34 : Suc-tic-Glu-Pro-Ile-Pro-Glu-Glu-Ala-Oic-glu-OH Analysis : calculated found Glu 3.86 Ala 1.11 Pro 2.00 lie 0.96 Oic 0.95 tic 1.07 Mass spectrum (FAB) : MH+, m/z 1323 - 23 EXAMPLE 35 : nal-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Asp-Tyr-Leu-OH Analysis : Asp Glu Pro Phe lie Leu nal Tyr calculated 2 2 11 1 2 1 1 found 1. 97 2.14 1.07 1.01 0.96 1.90 1.07 0.90 Mass spectrum (FAB) : MH+, m/z = 1474 EXAMPLE 36 : Z-Asp- Phe-Glu-Abo-Ile-Pro-Glu -Asp- Tyr-nal- -nal- Leu-OH Analysis : Asp Glu Pro Phe He + Abo Leu nal Tyr calculated 2 2 112 1 2 1 found 2.06 2.20 1.04 1.02 1.82 1.10 1.85 0.91 Mass spectrum (FAB) : MH+, m/z = 1804 EXAMPLE 37 ϊ Z-Asp-Phe-Glu-Abo-Ile-Abo-Glu-Asp-Tyr-leu-OH Analysis : Asp Glu Phe lie + Abo Leu Tyr calculated 2 2 1 3 1 1 20 found 2.10 2.19 0.96 2.85 1.09 1.10 Mass spectrum (FAB) : MH+, m/z = 1450 EXAMPLE 38 : H-AsD-Phe-Glu-Orn-Ile-Pro-AsD-Glu-Tvr(Bzl)-Leu-NH? 1 1 25 Analysis : calculated Asp Glu Pro Phe He Leu Orn Ty 2 2 1 1 1 1 1 1 found 1.80 1.84 0.92 0.90 0.87 0.92 1.08 1.

Mass spectrum (FAB) : MH+, m/z = 1324 EXAMPLE 39 : X'0-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-TyrLeu-OH Analysis : Asp Glu Gly Pro Phe lie Leu + Abo Tyr calculated 1 3 1 1 1 1,0 2 1 found 1.5 3.19 1.06 0.97 1.00 0.90 1.86 0.55 10 Mass spectrum (FAB) : MH+, m/z = 1489 EXAMPLE 40 : Xi-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Pcp-Leu-OH EXAMPLE 41 : Xi~Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Pcp-Leuglu-OH EXAMPLE 42 EXAMPLE 43 Xl-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Pcp-leu-OH Xi-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Pcp-LeuPro-OH EXAMPLE 44 EXAMPLE 45 EXAMPLE 46 Xi-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Pcp-Leupro-OH Xi-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Pcp-Leu-ol Xi-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Pcp-LeuPAla-OH EXAMPLE 47 Xi-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu(pCH2PO3H) Phe-Leu-OH EXAMPLE 48 : Xi-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu(pCH2PO3H) Phe-Leu-glu-OH Xi-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu(pCH2PO3H) Phe-Leu-pAla-OH EXAMPLE 49 EXAMPLE 50 EXAMPLE 51 EXAMPLE 52 EXAMPLE 53 EXAMPLE 54 Xi-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu(pCH2PO3H)Phe-Leu-4Abu-OH X7-Phe-Glu-Abo-Ile-Pro-Glu-Glu-(pCH2P03H)Phe-Leuglu-OH X7-Glu-Abo-Ile-Pro-Glu-Glu-(pCH2P03H)Phe-Leuglu-OH X7-Phe-Glu-Abo-Ile-Pro-Glu-Glu-(pCH2P03H)Phe-LeuβΑΙβ-ΟΗ Xe-Phe-Glu-Abo-Ile-Pro-Glu-Glu-(pCH2PO3H)Phe-Leuglu-OH PHARMACOLOGICAL STUDY OF THE COMPOUNDS OF THE INVENTION EXAMPLE 55: Antithrombotic activity The experimental model of thrombosis used is that of a venous thrombosis induced in male Wistar rats by ligation of the inferior vena cava beneath the left renal vein.

The test animals are anaesthetised by the intraperitoneal administration of Brietal® (sodium methohexital) at a dose of 2o 1 ml/kg.

The ligation is then carried out. The test compound is injected 2 hours later by the subcutaneous route in the left subclavial region. 4 hours after the injection, blood is removed by the direct intracardiac route, the vein is excised 23 and the clot is recovered and then weighed after drying in an oven at 37°C for 12 hours.

The compounds of the invention were tested at a single dose of 250 pg/kg in comparison with non-sulphated hirudin, which was used as control compound.

The results of this test showed that the compounds of the invention bring about a reduction in the weight of the clot that is 3 to 4 times greater than that observed when non-sulphated hirudin is injected.

EXAMPLE 56: Anticoagulant activity, measurement of the thrombin time In the presence of a standard quantity of thrombin, a normal plasma coagulates in a definite and constant time, which is known as the thrombin time (TT). Any lengthening of this time indicates an anomaly in fibrin formation (coagulation).

Sprague-Dawley rats are anaesthetised with sodium pentobarbital (60 mg/kg, i.p.), the carotid artery is catheterised, and samples of blood are withdrawn into a solution of trisodium citrate (0.109 M) . A plasma that is deficient in platelets is obtained by centrifugation of the blood samples (3000 g, 15 minutes). The plasma can be stored for 8 hours at 20°C.

The thrombin time is determined using the thrombin reagent Prest and is determined automatically using a coagulometer.

The antagonist or the solvent (10 μΐ) is added to the plasma (90 μΐ) and then incubated at 37°C for 2 minutes. 100 μΐ of thrombin are added and the timer is started.

Under our conditions, the TTs obtained in the control plasma are of the order of 30 seconds. The activity of an antagonist is evaluated by its ability to prolong the thrombin time in comparison with the control.

Under these conditions, the compounds of the invention enable the thrombin time to be prolonged 3- to E j-fold. This prolongation is 2 to 3 times greater non-sulphated hirudin 55-65. than that obtained with That is the case more especially Examples 24, 28 and 30. wi th the compounds of EXAMPLE 57: Platelet aggregation In this test, the antithrombin activity of the antagonists is evaluated by measuring the inhibition of platelet aggregation induced by thrombin.

Rabbits (2-3 kg) are anaesthetised with sodium pentobarbital (30 mg/kg, i.v.). After cannulation of the left carotid artery, blood is removed into sodium citrate (0.109 M) (1 vol citrate per 9 vol blood).

Platelet-rich plasma (PRP) is obtained by centrifugation (20°C) at 250 g for 20 minutes, and platelet-deficient plasma (PDP) by centrifugation at 1000 g for 10 minutes. The number of platelets is adjusted to 300,000-350,000 pl/mm3 by dilution in autologous PDP. The PRP is stored at room temperature until the time of the test and is used within 4 hours of the sample being taken.

The PRP is again centrifuged (900 g, 15 minutes) and the platelets are washed in a saline solution buffered with Tris, containing gelatine (0.2%). The washed platelets (WP) are then resuspended in a physiological solution and stored at room temperature.

Platelet aggregation is carried out at 37°C in siliconised glass tubes using an agregometer. The PRP and the WP are stirred at 1000 rpm (revolutions per minute).

The thrombin is incubated for 3 minutes at 37°C with the test substance (at different concentrations) or with the solvent, in a volume of 50 μί. The WP (225 μί) are pre-incubated for 1 minute at 37°C in a siliconised glass container, with stirring (1000 rpm). Aggregation is brought about by the addition of 25 μί of the solution containing the thrombin and the test substance. The aggregation response is recorded for a period of at least 5 minutes.

The intensity of platelet aggregation is established by taking the maximum amplitude of the aggregation traces and is expressed as a percentage of luminous transmission (%T). An IC50 was determined for each of the compounds tested.

The compounds of the invention inhibit thrombin-induced platelet aggregation in a dose-dependent manner. The IC50S obtained are 4 to 20 times lower than the value obtained with non-sulphated hirudin. That is the case more especially with the compounds of Examples 22, 24, 26 and 39.

EXAMPLE 58: Measurement of anticoagulant activity ex vivo. Prothrombin time OFA rats, with or without an empty stomach, are anaesthetised with pentobarbital (60 mg/kg, i.p.). The carotid and the jugular are separated and catheterised. The catheters are purged with citrated physiological serum (1/40). After insertion of the catheters, a sample of 1.5 cm3 of arterial blood is withdrawn into 0.109 M citrate (1/9). minutes later, the test product is administered i.v. in a volume of 1 ml.

Arterial samples (1.5 ml) are then withdrawn at 1 minute 30, 3 minutes, 5 minutes, 15 minutes, 30 minutes and 60 minutes.

When each sample is withdrawn, 1.5 ml of citrated physiological serum are re-injected into the animal via the carotid.

The tubes of blood are centrifuged for 15 minutes at 4000 rpm (preparation of plasma). 100 μί of plasma are incubated with 200 μί of calcium neoplastine. The time taken for coagulation to occur is measured.

The compounds of the invention, tested at doses of from 4 to 16 mg/kg, increase the prothrombin time (PT) in a dose10 dependent manner. Their effect is greater than that of nonsulphated hirudin. In fact, they increase the PT 1.4- to 1.8fold. Moreover, while the in vivo activity of hirudin is of short duration (30 minutes), the increase in the PT noted with the compounds of the invention is still significant 60 minutes after their administration.

That is the case more especially with the compounds of Examples 22, 24, 28, 30 and 39.

Claims (15)

1. Compounds of the general formula (I): X-Ai-A2“A3-A4-A5-A6-A7-Ag-Ag-Aio-Y (I) in which: represents - a terminal amino group that is optionally substituted by 1 or 2 linear or branched (Ci~C6)-alkyl groups, a linear or branched (Ci~ C6)-acyl group, a benzyloxycarbonyl group (Z), a tert.-butoxycarbonyl group (Boc), a 9-fluorenylmethyloxycarbonyl group (Fmoc), a linear or branched (Ci-C 6 )guanidinoacyl group, such as the HN^ group X o = C-NH-(CH2)3-CO- or H2N z HN X'o = ^C-NH-(CH2)4-CO- , a linear or Η2ΪΓ branched (Ci-Ce)-guanidinoalkyl group, a pyroglutamyl group (Glp), a succinyl group (Sue), or any one of the following groups: ’ = h 2 n> c -“ h ^> c °*2 H3CO-CO NH-CO-CH2-NH-CO-(CH2)2-C0HO X3 = HOCO—y_J>-NH-CO-CH2-NH-CO-(CH2)2-COO-COCH3 Xa HO CO— CO2CH3 X5 = HO-/^~^>~CO — CO2H X6 HOCO NH-CO-CH2-NH-CO-(CH2)2-COHO Al A 2 represents a bond or a peptide residue containing from 1 to 3 amino acids of any kind, represents a bond or a phenylalanine residue (Phe), a tyrosine residue (Tyr), an isoleucine residue (lie), a norvaline residue (Nva), a 1,2,3,4-tetrahydroisoquinoline-3-carbonyl residue (Tic), an α-aminobutyric acid residue (Abu), a glutamic acid residue (Glu), or an amino acid residue containing an aryl group, A3 represents a bond or a glutamic acid residue (Glu), an aspartic acid residue (Asp), a β-alanine residue (βΑΠ) or a tyrosine residue (Tyr), A4 represents a bond or a glutamic acid residue (Glu), an aspartic acid residue (Asp), a proline residue (Pro), a 2,3-diaminopropionic acid residue (Dpr), a 2,4-diaminobutyric acid residue (Dab), an ornithine residue (Orn), a lysine residue (Lys), a 2-azabicyclo[2.2.2]octane-3-carbonyl residue (Abo) or a 2-azabicyclo[2.2.1]heptane-3-carbonyl residue (Abh), A5 represents a bond or an isoleucine residue (lie), a norvaline residue (Nva), a phenylalanine residue (Phe), a proline residue (Pro), an ornithine residue (Orn) or a 2,3-diaminopropionic acid residue (Dpr), Αβ represents a proline residue (Pro), an isoleucine residue (lie), a norvaline residue (Nva), a phenylalanine residue (Phe), an ornithine residue (Orn), a 2-azabicyclo[2.2.2]octane-3-carbonyl residue -(Abo), a 2-azabicyclo[2.2.1]heptane-3carbonyl residue (Abh), an octahydroindole-2carbonyl residue (Oic) or a 3,4-dehydroproline residue. (dhPro), A7 represents a glutamic acid residue (Glu) or an aspartic acid residue (Asp), Ag represents a glutamic acid residue (Glu), an aspartic acid residue (Asp), a 2,3diaminopropionic acid residue (Dpr), a 2,4diaminobutyric acid residue (Dab) or a β-alanine residue (βΑΐ8), Ag represents a tyrosine residue (Tyr) that is optionally protected by a benzyl group (Tyr(Bzl)) or an acetyle group (Tyr(COCH3)), a phenylalanine residue (Phe), an alanine residue (Ala), an isoleucine residue (lie), a norvaline residue (Nva), a p-carboxyphenylalanine residue (Pep), a 3carboxytyrosine or 4-0-acetyl-3-carboxytyrosine residue, or a (P-CH2PO3H)-phenylalanine residue ((pCH 2 PO 3 H)Phe), Αχο represents a bond, a leucine residue (Leu), a valine residue (Val), a β-naphthylalanine residue (Nal), a cyclohexylalanine residue (Cha), a β-(2thienyl)alanine residue (Thi), an octahydroindole2-carbonyl residue (Oic), a dipeptide residue, such as Leu-Glu, Leu-Pro, Leu^Ala, Val-Glu, NalGlu, Cha-Glu, Thi-Glu, Oic-Glu or a leucine-4aminobutyric acid residue (Leu-4Abu), or a tripeptide residue, such as Nal-Nal-Leu, Y represents - a terminal carboxy group that is optionally substituted by a linear or branched (Οχ-Οβ)-alkoxy group or an amino group that is itself optionally substituted by one or two linear or branched (Οχ-Οβ) alkyl groups, or -a terminal carboxy group reduced to the corresponding alcohol (ol), and comprising at least: - one synthetic amino acid residue, such as 2-azabicyclo[2.2.2]octane3-carbonyl (Abo), 2-azabicyclo [2.2.1]heptane-3-carbonyl (Abh) or octahydroindole-2-carbonyl (Oic), and/or - one pseudopeptide bond, such as -CH2NH-, -CH2-S-, -CH2-SO-, -CH2-SO2-, NH-CO- or -CH=CH-, replacing a peptide bond -CO-NH-, 5 and/or one non-cysteine cyclisation between the side chains of two amino acids, or between a terminal amino group and a side chain of an amino acid, or between a terminal carboxy group and 10 a side chain of an amino acid, or between a terminal amino group and a terminal carboxy group, their addition salts with a pharmaceutically acceptable acid or base, 15 each amino acid in the peptide sequence being optically pure and the α-carbon of each amino acid having the D- or Lconfiguration.

2. Compounds according to claim 1 that comprise at least one synthetic amino acid residue, such as 2-azabicyclo20 [2.2.2]octane-3-carbonyl (Abo), 2-azabicyclo[2.2.1]heptane-3carbonyl (Abh) or octahydroindole-2-carbonyl (Oic).

3. Compounds according to claim 1 that comprise at least one pseudopeptide bond, such as -CH2-NH-, -CH2-S-, -CH2-SO-, -CH2SO2-, -NH-CO- or -CH=CH-, replacing a peptide bond -CO-NH-. 25

4. Compounds according to claim 1 that comprise at least one non-cysteine cyclisation between the side chains of two amino acids, or between a terminal amino group and a side chain of an amino acid, or between a terminal carboxy group and a side chain of an amino acid, or between a terminal amino group and 30 a terminal carboxy group.

5. Compound according to either claim 1 or claim 2 which is Xi-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Tyr-Leu-OH, HN Xl representing a radical H2N and Abo representing a 2-azabicyclo[2.2.2]octane-3-carbonyl 5 residue.

6. Compound according to either claim 1 or claim 2 which is Xl-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Tyr-Leu-glu-OH, Xi representing a radical >C-MH—//“CO— H2N z Xl-// and Abo representing a 2-azabicyclo[2.2.2]octane-3-carbonyl 10 residue.

7. Compound according to either claim 1 or claim 2 which is suc-Tyr-Glu-Pro-Ile-Oic-Glu-Glu-Ala-Thi-glu-OH, Oic representing an octahydroindole-2-carbonyl residue and Thi representing a β-(2-thienyl)alanine residue. 15

8. Compound according to either claim 1 or claim 2 which is H4Abu-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Tyr-Leu-OH , 4 Abu representing a 4-aminobutyric acid residue and Abo representing a 2-azabicyclo[2.2.2]octane-3-carbonyl residue.

9. Compound according to either claim 1 or claim 2 which is X'o-Gly-Asp-Phe-Glu-Abo-Ile-Pro-Glu-Glu-Tyr-Leu-OH, ΗΝλ X'o representing a radical /C-NH-(CH2)4-C0 — H2N z and Abo representing a radical 2-azabicyclo[2.2.2]octane-3carbonyl residue.

10. Process for the preparation of the compounds of formula (I), characterised in that they can be obtained by solid-phase sequential synthesis from protected amino acids, by synthesis of peptide fragments in solution, 5 optionally by a combination of these two techniques, if desired, by total or partial cyclisation through two functions which are selectively deprotected and are capable of forming a covalent bond, and, if desired, by introduction, according to the 10 conventional techniques of organic chemistry, of a pseudopeptide bond at any time during the synthesis of the peptide sequence, which compounds of formula (I) are converted, if necessary, into their addition salts with a pharmaceutically acceptable 15 acid or base.

11. Pharmaceutical compositions that contain as active ingredient at least one compound according to any one of claims 1 to 9, on its own or in combination with one or more pharmaceutically acceptable, inert, non-toxic excipients or 20 vehicles.

12. Pharmaceutical compositions according to claim 11 that contain at least one active ingredient according to any one of claims 1 to 9 and that can be used as anticoagulants, in the treatment of acute venous thromboses, pulmonary embolism, 25 arterial embolism of the extremities, myocardial infarction, atherosclerosis and the symptoms of thromboembolism, and for maintaining homeostasis of the blood, especially in extracorporeal circulation. - 37

13. A compound substantially as hereinbefore described with reference to the Examples.

14. A composition substantially as hereinbefore described with reference to the Examples.

15. Use of a compound as claimed in any of claims 1 to 9 for the preparation of a medicament for use in a method of prophylaxis or treatment.