| Title of Invention | SYNTHETIC POLYSACCHARIDES WITH ANTITHROMBOTIC ACTIVITY COMPRISING AT LEAST A COVALENT BOND WITH BIOTIN OR A BIOTIN DERIVATIVE |
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| Abstract | Synthetic polysaccharides with anti-thrombotic activity and their pharmaceutically acceptable salts wherein said polysaccharide is of formula: in which: - the wavy line denotes a bond situated either below or above the plane of the pyranose ring, Po denotes a polysaccharide, comprising n identical or different monosaccharide units, bonded via its anomeric carbon to Pe, is a diagrammatic representation of a monosaccharide unit with a pyranose structure chosen from hexoses, pentoses and the corresponding deoxy sugars, this unit being bonded via its anomeric carbon to another monosaccharide unit and the hydroxyl groups of this unit being substituted by identical or different Ri groups, Ri being as defined below, - Pe represents a pentasaccharide of structure: h is equal to 1 or 2, - n is an integer and can take any value from 0 to 25, Ri represents the -T-Biot linkage, a (Ci-Cs) alkoxy group or an -0S03~ group, R2 represents the -T-Biot linkage, a (Ci-Ce) alkoxy group or an -OSO3" group, R3 represents the -T-Biot linkage or a {Cx-Cs)alkoxy group, R4 represents the -T-Biot linkage, a (Ci-C6)alkoxy group or an -0S03" group, or else R4 constitutes an -O-CH2- bridge, the -CH2- group being bonded to the carbon atom carrying the carboxyl functional group on the same ring; it being understood that at least one of the Ri, R2, R3 or R4 substituents represents a -T-Biot group, W represents an oxygen atom or a methylene group T represents one of the linkages chosen from: NH, in which j and k, which are identical or different, are integers which can take any value from 1 to 10; - Biot represents the group: characterized in that they exhibit at least one covalent bond with biotin or a biotin derivative. |
| Full Text | FORM 2 THE PATENTS ACT, 1970 [39 OF 1970] COMPLETE SPECIFICATION [See Section 10; Rule 13] "SYNTHETIC POLYSACCHARIDES WITH ANTITHROMBOTIC ACTIVITY COMPRISING AT LEAST A COVALENT BOND WITH BIOTIN OR A BIOTIN DERIVATIVE" AKZO NOBEL N.V. a French societe anonyme, having its Reg office at Velperweg 76,6824 BM in Arnhem , The Netherlands The following specification particularly describes the nature of the invention and the manner in which it is to be performed:- The present invention relates to novel synthetic oligo- and polysaccharides exhibiting at least one covalent bond with biotin or a biotin derivative and having the anticoagulant and antithrombotic pharmacological activities of heparin. Heparin catalyses, in particular via antithrombin III (AT III), the inhibition of two enzymes which are involved in the blood coagulation cascade, namely factor Xa and factor Ila (or thrombin). Preparations comprising low molecular weight heparins (LMWHs) comprise chains formed of 4 to 30 monosaccharides and have the property of acting more selectively with respect to factor Xa than with respect to thrombin. It is known that the inhibition of factor Xa requires attachment of heparin to AT III via the antithrombin-binding domain (Domain-A) and that inhibition of factor Ila (thrombin) requires attachment to AT III, via the Domain-A, and to thrombin via a less well defined binding domain (Domain-T). Synthetic oligosaccharides corresponding to the Domain-A domain of heparin are known. They are disclosed, for example, in Patents EP 84 999 and EP 529 715, the patent application published under the number WO 99/36428 and the publication Bioorg. Med. Chem., 1998, 6, 1509-1516. These synthetic oligosaccharides have the property of selectively inhibiting, via antithrombin III, factor Xa of the 5 coagulation without any activity with respect to thrombin. They display an antithrombotic activity in venous thrombosis. Synthetic oligosaccharides capable of inhibiting thrombin and factor Xa via activation of 10 AT III have been disclosed in the patent applications published under the numbers WO 98/03554 and WO 99/36443. Novel biologically active sulphated and alkylated polysaccharide derivatives are disclosed in 15 these patent applications. They are in particular anticoagulants and antithrombotics. It has in particular been shown that these sulphated and alkylated polysaccharides can be powerful antithrombotics and anticoagulants depending upon the 2 0 arrangement of the alkyl groups and sulphate groups carried by the glucide backbone. More generally, it has been found that, by preparing polysaccharide sequences, it is possible to precisely adjust the activities of GAGs type in order to obtain very active products 25 exhibiting the anticoagulant and antithrombotic pharmacological properties of heparin. In comparison with heparin, they exhibit the advantage of having a specific structure and of not reacting with platelet factor 4, the cause of the thrombocytopenic effects of heparin. However, the use in human therapeutics of some products disclosed in the patent applications 5 published under the numbers WO 98/03554 and WO 99/36443 and in Patent EP 529 715 can prove to be problematic, in particular if these products have a long half-life. In the field of the prevention or treatment of thrombosis with the above products, the fluidity of the 10 blood has to be reestablished or maintained while preventing a haemorrhage from being brought about. This is because it is well known that a haemorrhage can be triggered in a patient under treatment for any accidental cause. It may also be 15 necessary to intervene surgically in a patient under antithrombotic treatment. Furthermore, during some surgical procedures, anticoagulants may be used at a high dose so as to prevent blood coagulation and it is necessary to neutralize them at the end of the 20 operation. It is therefore advantageous to have antithrombotic agents which can be neutralized in order to stop the anticoagulant activity at any time. In point of fact, the known synthetic oligosaccharides described above cannot be easily neutralized by the 25 known antidotes for heparin or LMWHs, including protamine sulphate. The present invention relates to novel synthetic; polysaccharides with a structure similar to that of the compounds disclosed in the patent applications published under the numbers WO 98/03554 and WO 99/36443 and in Patent EP52_9 715: the structures of the synthetic oligosaccharides which are 5 a subject-matter of the invention are modified in the sense that they exhibit a covalent bond with biotin (hexahydro-2-oxo-2H~thieno[3,4-d]imidazole-4-pentanoic acid) or with a biotin derivative. Surprisingly, it appears that the introduction of biotin or a biotin 10 derivative $oes not! modify the pharmacological activity df the polysaccharides. In fact, the novel polysaccharides which are a subject-matter of the invention have an antithrombotic activity comparable with that of the oligosaccharides of the prior art. 15 However, they additionally have the advantage of being able to be rapidly neutralized by a specific antidote in an emergency situation. This specific antidote is avidin (The Merck Index, Twelfth edition, 1996, M.N. 920, pages 151-152) or streptavidin, two tetrameric 20 proteins with respective masses equal to approximately 66 000 and 60 000 Da which have a very high affinity for biotin. Generally, the invention relates to synthetic polysaccharides with antithrombotic activity having at 25 least one covalent bond with biotin or a biotin derivative. Mention may be made, as biotin derivative, of the biotin derivatives shown in the Pierce catalogue, 1999-2000, pages 62 to 81, for example 6-biotinamidohexanoate, or 6-(6-biotinamidohexanamido)hexanoate, 5 or 2-biotinamidoethanethiol or the compounds of the following formulae: In particular, a subject-matter of the present invention is the polysaccharides of formula 5 (I) : in which: the wavy line denotes a bond situated either below or above the plane of the pyranose ring, 5 Po denotes a polysaccharide, comprising n identical or different monosaccharide units, bonded via its anomeric carbon to Pe, is a diagrammatic representation of a monosaccharide 10 unit with a pyranose structure chosen from hexoses, pentoses and the corresponding deoxy sugars, this unit being bonded via its anomeric carbon to another monosaccharide unit and the hydroxyl groups of this unit being substituted by identical or different Ri 15 groups, Ri being as defined below, - Pe represents a pentasaccharide of structure: h is equal to 1 or 2, n is an integer and can take any value from 0 to 20 25, Ri represents the -T-Biot linkage, a (Ci-Ce) alkoxy group or an -OSO3" group, R2 represents the -T-Biot linkage, a (Ci-Ce) alkoxy group or an -0S03" group, 5 - R3 represents the -T-Biot linkage or a (Ci- Ce) alkoxy group, R4 represents the -T-Biot linkage, a (C1-C6) alkoxy group or an -OSO3" group or else R4 constitutes an -0-CH2- bridge, the -CH2- group being bonded to the 10 carbon atom carrying the carboxyl functional group on the same ring; it being understood that at least one of the Ri, R2, R3 or R4 substituents represents a -T-Biot group, 15 W represents an oxygen atom or a methylene group, T represents one of the linkages chosen from: NH, » or 20 in which j and k, which are identical or different, are integers which can take any value from 1 to 10; - Biot represents the group: and their pharmaceutically acceptable salts. As indicated above, it should be noted that, generally in the present description, a wavy line 5 denotes a bond situated either below or above the plane of the pyranose ring. The monosaccharides present in Po can be identical to or different from one another and the interglycoside bonds can be of the a or |3 type. 10 These monosaccharides are advantageously chosen from the D or L hexoses alose, altrose, glucose, mannose, galose, idose, galactose or talose (in this case, h = 2) or from the D or L pentoses ribose, arabinose, xylose or lyxose (in this case, h = 2). 15 Other monosaccharides, such as, for example, deoxy sugars, can also be used (h = 1 and/or -CH2R1 = CH3). The polysaccharide part Po can be composed of 0 to 25 alkylated and di~ or trisulphated monosaccharide units. 20 The polysaccharide part Po can also be composed of 0 to 25 alkylated and mono- or disulphated monosaccharide units. The polysaccharide part Po can be composed of 0 to 25 uncharged and/or partially charged and/or completely charged alkylated monosaccharide units. The charged or uncharged units can be dispersed along the chain or, on the other hand, they 5 can be grouped into charged or uncharged saccharide domains. The bonds bet-ween tbe -emits can be 1,2; 1,3; 1,4; 1,5; 1,6; and of the a or (3 type. In the present description, the choice has 10 been made to represent the xd conformation for L- iduronic acid and the 4Ci conformation for D-glucuronic acid but it is well known that, generally, the conformation in solution of monosaccharide units fluctuates. 15 Thus, L-iduronic acid can have the 1C4, 2£o or 4Ci conformation. According to one of its aspects, the invention relates to the polysaccharides of formula (1.1) : 20 in which: denotes a specific family of polysaccharides Po which are bonded via their anomeric carbon to Pe as defined for (I), 5 is as defined for (I), the Ri groups are as defined for (I) and, for the same monosaccharide, can be identical or different, 10 - the monosaccharide present in []m is repeated m times, the monosaccharide present in []t is repeated t times and the monosaccharide present in []p is repeated p times, m is an integer varying from 1 to 5, t is an 15 integer varying from 0 to 24 and p is an integer varying from 0 to 24, it being understood that l and Biot being as defined for (I), and their pharmaceutically acceptable salts, constitute another aspect of the invention. According to a specific aspect, the invention 5 relates to the hexadecasaccharides of formula (1.2): in which: - T represents one of the linkages chosen from: NH, 10 or in which j and k, which are identical or different, are integers which can take any value from 1 to 10; 15 - Biot represents the group: - Pe represents a pentasaccharide of structure: in which: Ri represents a (Ci-Ce) alkoxy group or an -OSO3" group, 5 R2 represents a (Ci-C6) alkoxy group or an -0S03~ group, R3 represents a (Ci-Ce) alkoxy group, R4 represents a (Ci-Ce) alkoxy group or an -OSCV group, or else R4 constitutes an -0-CH2- bridge, 10 the -CH2- group being bonded to the carbon atom carrying the carboxyl functional group on the same ring, W represents an oxygen atom or a methylene group, and their pharmaceutically acceptable salts. 15 According to another of its aspects, the invention relates to the pentasaccharides of formula (1.3): in which Ri, R2, R3, R4 and W are as defined for (I) , and 20 their pharmaceutically acceptable salts. Among these pentasaccharides of formula (1.3), the pentasaccharides in which only one of the Ri, R2, R3 or R4 substituents represents the -T-Biot linkage with T and Biot being as defined for (I), and their pharmaceutical^ acceptable salts, constitute another aspect of the invention. Among these pentasaccharides of formula 5 (1.3), another subject-matter of the invention is the pentasaccharides of formula (1.4): in which: T represents one of the linkages chosen from: 10 NH, or in which j and k, which are identical or different, are 15 integers which can take any value from 1 to 10; - Biot represents the group: Ri represents a (Ci-Ce) alkoxy group or an -OSO3" group, R2 represents a (C1-C6) alkoxy group or an -OSC^ group, 5 R3 represents a (Ci~C6) alkoxy group, R4 represents a (C1-C6) alkoxy group or an -OSCb" group, or else R4 constitutes an -0-CH2- bridge, the -CH2- group being bonded to the carbon atom carrying the carboxyl functional group on the same 10 ring, W represents an oxygen atom or a methylene group, and their pharmaceutically acceptable salts. According to another of its aspects, the invention relates to the following polysaccharides: 15 - Methyl (2, 3 , 4, 6-tetra-O-sulphonato-CC-D-gluco-pyranosyl) - (1—»4) -(2,3, 6-tri-0-sulphonato-(X-D-glucopyranosyl) - (1—>4) -(2,3, 6-tri-0-sulphonato-|3-D-glucopyranosyl) - (1—»4) - (6-biotinamido-6-deoxy-2,3-di-O-methyl-a-D-glucopyranosyl)-(1—>4) -20 (2, 3, 6-tri-O-methyl-P-D-glucopyranosyl)-(l-»4) - [(2,3,6-tri-O-methyl-a-D-glucopyranosyl)-(l->4) -0-(2,3,6-tri-O-methyl-P-D-glucopyranosyl)-(l-»4) ]3-(6-0-sulphonato-2,3-di-O-methyl-a-D-gluco-pyranosyl) - (1—»4) - (2, 3-di-O-methyl-p-D-glucopyrano-25 syluronic acid)-(1—»4)-(2, 3 , 6-tri-O-sulphonato-a-D-glucopyranosyl)-(1—»4) -(2, 3-di-O-methyl-cc-L-idopyranosyluronic acid)-(1—»4) -2,3, 6-tri-0-sulphonato-a-D-glucopyranoside, sodium salt, Methyl (2 , 3, 4, 6-tetra-O-sulphonato-cc-D-gluco-pyranosyl) - (1—»4) -(2,3, 6-tri-O-sulphonato-a-D-glucopyranosyl)-(1—>4) -(2,3, 6-tri-O-sulphonato-P-D-glucopyranosyl)-(1—»4) -(6-[6-(biotinamido)-5 hexamido]-6-deoxy-2,3-di-O-methyl-a-D-gluco- pyranosyl)- (l->4) -(2,3, 6-tri-0-methyl-|3-D-gluco-pyranosyl) - (1—>4) -[(2,3, 6-tri-O-methyl-a-D-gluco-pyranosyl)- (1—»4) -O- (2,3, 6-tri-0-methyl-j3-D-gluco-pyranosyl) - (1—>4) ]3- (6-0-sulphonato-2 , 3-di-0-10 methyl-a-D-glucopyranosyl) - (1^4) - (2, 3-di-O-methyl-P-D-glucopyranosyluronic acid)- (1—>4)-(2,3,6-tri-O-sulphonato-a-D-glucopyranosyl)-(1—»4)-(2,3-di-O-methyl-a-L-idopyranosyluronic acid) - (l->4) -2,3, 6-tri-O-sulphonato-a-D-15 glucopyranoside, sodium salt, Methyl (2, 3, 4, 6-tetra-O-sulphonato-cc-D-gluco-pyranosyl) - (1—>4) -(2,3, 6-tri-O-sulphonato-a-D-glucopyranosyl) - (l—»4) -(2,3, 6-tri-0-sulphonato-|3-D-glucopyranosyl)-(1—>4) -(6-[6-(6-20 biotanamidohexamido)hexamido]-6-deoxy-2,3-di-O-methyl-a-D-glucopyranosyl)-(1—»4) -(2,3,6-tri-O-methyl-(3-D-glucopyranosyl) - (1—>4) -[(2,3, 6-tri-O-methyl-oc-D-glucopyranosyl) - (l->4) -0- (2,3, 6-tri-O-methyl-P-D-glucopyranosyl) - (1^4) ]3- (6-0-25 sulphonato-2,3-di-O-methyl-CC-D-glucopyranosyl)-(1—>4)-(2,3-di-0-niethyl-{3-D-glucopyranosyluronic acid)- (1—>4)-(2,3,6-tri-O-sulphonato-cc-D-glucopyranosyl)-(1—>4) -(2 , 3-di-O-methyl-a-L- idopyranosyluronic acid)-(1—>4) -2,3, 6-tri-0-sulphonato-a-D-glucopyranoside, sodium salt. Methyl (2-biotinamido-2-deoxy-3,4-di-0-methyl-6-0-sulphonato-a-D-glucopyranosyl)-(1—>4) -(2, 3-di-0-5 methyl-p-D-glucopyranosyluronic acid)-(1—»4)-(2,3, 6-tri-O-sulphonato-CC-D-glucopyranosyl) -(1—»4)-(2,3-di-O-methyl-a-L-idopyranosyluronic acid) - (1—»4) -2,3, 6-tri-O-sulphonato-CC-D-gluco-pyranoside, sodium salt, 10 - Methyl (2-[N-(6~biotinamidohexanoyl)]-2-deoxy-3,4-di-0-methyl-6-0-sulphonato~a-D-gluco-pyranosyl) - (1—»4) - (2, 3-di-0-methyl-f3-D~gluco-pyranosyluronic acid) - (1—»4) -(2,3, 6-tri-O-sulphonato-cc-D-glucopyranosyl) - (1—»4) - (2, 3-di-O-15 methyl-cc-L-idopyranosyluronic acid)-(1—»4) - 2,3,6~tri-0-sulphonato~a-D-glucopyranoside, sodium salt, Methyl (2-[6-(6-biotinamidohexamido)hexamido]-2-deoxy-3,4-di-0-methyl-6-0-sulphonato-oc-D-gluco-2 0 pyranosyl)-(l-»4) -(2, 3-di-O-methyl-P-D-gluco-pyranosyluronic acid)-(1—>4) -(2,3, 6-tri-O-sulphonato-a-D-glucopyranosyl)-(1—»4) -(2 , 3-di-O-methyl-a-L-idopyranosyluronic acid)-(1—»4) -2,3,6-tri-O-sulphonato-a-D-glucopyranoside, sodium 25 salt. The invention encompasses the polysaccharides in their acid form or in the form of any one of their pharmaceutically acceptable salts. In the acid form, the -COO^ and -SO3' functional groups are respectively in the -COOH and -S03H form. The term "pharmaceutical^ acceptable salt of the polysaccharides of the invention" is understood to 5 mean a polysaccharide in which one or more of the -COO" and/or -SO3- functional groups are bonded ionically to a pharmaceutically acceptable cation. The preferred salts according to the invention are those for which the cation is chosen from -the cations of alkali metals and 10 more preferably still those for which the cation is Na+ or K+. The compounds of the above formula (I) also comprise those in which one or more hydrogen or carbon atoms have been replaced by their radioactive isotope, 15 for example tritium or carbon-14. Such labelled compounds are of use in research, metabolic or pharmacokinetic studies and in biochemical assays, as ligands. The principle of the process for the 20 preparation of the compounds according to the invention involves the use of di- or oligosaccharide base synthons prepared as reported above in the literature. Reference will in particular be made to Patents or Patent Applications EP 300 099, EP 529 715, EP 621 282 25 and EP 649 854 and to the documents C. van Boeckel, M. Petitou, Angew. Chem. Int. Ed. Engl., 1993, 32, 1671-1690. These synthons are subsequently coupled to one another so as to provide a fully protected equivalent of a polysaccharide according to the invention. This protected equivalent is subsequently converted into a compound according to the invention. One of the base synthons mentioned above 5 comprises a specific protected functional group making possible the subsequent introduction of biotin or a biotin derivative, for example a latent amine functional group in the form of the azido group or protected in the form of the N-phthalimido group. 10 In the coupling reactions mentioned above, a "donor" di- or oligosaccharide, activated on its anomeric carbon, reacts with an "acceptor" di- or oligosaccharide having a free hydroxyl. The present invention relates to a process 15 for the preparation of the compounds of formula (I), characterized in that: in a first stage, a fully protected equivalent of the desired polysaccharide (I), comprising a protected precursor of the Pe domain extended at its nonreducing end by a protected 20 precursor of the sulphated polysaccharide Po, is synthesized, one of these precursors comprises in particular a suitably protected amine functional group for the subsequent introduction of biotin or a biotin derivative; in a second stage, the negatively charged 25 groups are introduced and/or unmasked; in a third stage, the amine functional group is deprotected and then biotin or the biotin derivative is introduced. The synthesis of Pe is carried out according to the methods described in particular in the patent applications published under the numbers WO 98/03554 and WO 99/36443 and in the literature (cited above). The polysaccharide part which is the 5 precursor of Po is synthesized according to reactions well known to a person skilled in the art using the methods for the synthesis of oligosaccharides (G.J. Boons, Tetrahedron, 1996, 52, 1095-1121, WO 98/03554 and WO 99/36443) or an oligosaccharide when 10 an oligosaccharide which is a glycoside bond donor is coupled with an oligosaccharide which is a glycoside bond acceptor to result in another oligosaccharide, the size of which is equal to the sum of the sizes of the two reactive species. This sequence is repeated until 15 the desired compound of formula (I) is obtained. The nature and the profile of the charge of the final compound desired determine the nature of the chemical entities used in the various stages of the synthesis, according to rules well known to a person skilled in 20 the art. Reference may be made, for example, to C. van Boeckel and M. Petitou, Angew. Chem. Int. Ed. Engl., 1993, 32, 1671-1690, or to H. Paulsen, "Advances in selective chemical syntheses of complex oligosaccharides", Angew. Chem. Int. Ed. Engl., 21, 25 155-173 (1982). The compounds of the invention are obtained from their fully protected polysaccharide precursors by using the following series of reactions: the alcohol functional groups which have to be converted into an O-sulpho group and the carboxylic acids are deprotected by removing the protective groups used during the preparation of 5 the backbone, then, the sulpho groups are subsequently introduced, the amine functional group which makes possible the introduction of biotin or the biotin derivative is deprotected, 10 - biotin or the biotin derivative is introduced by a conventional amino/acid coupling reaction. The compounds of the invention can naturally be prepared by using various strategies known to a person skilled in the art for the synthesis of 15 oligosaccharides. The process described above is the preferred process of the invention. However, the compounds of formula (I) can be prepared by other methods well known in the chemistry of sugars, described, for example, in 20 Monosaccharides, their chemistry and their roles in natural products, P.M. Collins and R.J. Ferrier, J. Wiley & Sons, 1995, and in G.J. Boons, Tetrahedron, 1996, 52, 1095-1121.- The pentasaccharides Pe can thus be obtained 25 from disaccharide synthons in the way described in the publication by C. van Boeckel and M. Petitou, Angew. Chem. Int. Ed. Engl., 1993, 32, 1671-1690. The protective groups used in the process for the preparation of the compounds (I) are those commonly used in the chemistry of sugars, for example in Protective Groups in Organic Synthesis, T.W. Greene, John Wiley & Sons, New York, 1981. 5 The protective groups are advantageously chosen, for example, from the acetyl, halomethyl, benzoyl, levulinyl, benzyl, substituted benzyl, optionally substituted trityl, tetrahydropyranyl, allyl, pentenyl, tert-butyldimethylsilyl (tBDMS) or 10 trimethylsilylethyl groups. The activating groups are those conventionally used in the chemistry of sugars according to, for example, G.J. Boons, Tetrahedron, 1996, 52, 1095-1121. These activating groups are 15 chosen, for example, from imidates, thioglycosides, pentenylglycosides, xanthates, phosphites or halides. As regards the way in which biotin is bonded to the oligosaccharide and the nature of the biotin derivative, the chemical literature offers other 20 possibilities which can be made use of by sets of protective groups well known to a person skilled in the art. Use will preferably be made of an amine functional group, or a thiol functional group, or a carboxylic acid functional group, or an aldehyde functional group, 25 which will be reacted with a biotin derivative comprising a reactive group of the activated ester, maleimide, iodoacetyl or primary amine type, the reaction taking place according to the conditions described in the literature (cf. Savage et al. , Avidin-Biotin Chemistry: A Handbook; Pierce Chemical Company, 1992) . The process described above makes it possible 5 to obtain the compounds of the invention in the form of salts. To obtain the corresponding acids, the compounds of the invention in the form of salts are brought into contact with a cation-exchange resin in the acid form. The compounds of the invention in the form of 10 acids can subsequently be neutralized with a base to obtain the desired salt. Any inorganic or organic base which gives pharmaceutically acceptable salts with the compounds of formula (I) can be used for the preparation of the salts of the compounds of formula 15 (I). Sodium hydroxide, potassium hydroxide, calcium hydroxide or magnesium hydroxide is preferably used as base. The sodium and calcium salts of the compounds of formula (I) are the preferred salts. The compounds according to the invention have 20 formed the subject of biochemical and pharmacological studies. The overall antithrombotic activity of these products and their neutralization has been studied in a venous thrombosis model composed of an injection of 25 tissue factor, followed by a stasis of the vena cava of rats, as described by J.-M. Herbert et al., Blood, 1998, 91, 4197-4205. In this model, inhibition of 60% of the thrombosis is obtained after intravenous injection of 0.1 to 30 mmol/kg of the compounds. The injection of avidin in a molar ratio of 1 to 1 000 greatly reduces the antithrombotic effect of these compounds, it being possible for the reduction obtained 5 to be greater than 50%. In the same way, the prohaemorrhagic activity of the compounds is neutralized by injection of avidin at the abovementioned doses. Likewise, the circulating activity of the oligosaccharides, measured by the anti-10 Xa activity and/or the anti-IIa activity, is neutralized by injection of avidin. Thus, another subject-matter of the present invention is a process employing avidin or streptavidin, characterized in that it makes it 15 possible to neutralize the polysaccharides according to the invention. Avidin or streptavidin can be used for the preparation of medicaments intended to neutralize the polysaccharides according to the present invention. By virtue of their biochemical and 20 pharmaceutical activity, the oligosaccharides of the present invention constitute highly advantageous medicaments. Their toxicity is entirely compatible with this use. They are also very stable and are thus particularly suitable for constituting the active 25 principle of patented pharmaceutical products. They can be used in various pathologies resulting from a modification of the homeostasis of the coagulation system appearing in particular during disorders of the cardiovascular and cerebrovascular system, such as thromboembolic disorders associated with atherosclerosis and diabetes, for example unstable angina, apoplexy, postangioplasty restenosis, 5 endarterectomy or the insertion of endovascular prostheses; or thromboembolic disorders associated with post-thrombolysis rethrombosis, with infarction, with dementia of ischaemic origin, with peripheral arterial diseases, with haemodialysis or with auricular 10 fibrillations, or during the use of vascular prostheses for aortocoronary bypasses. Furthermore, these products can be used for the treatment or prevention of thrombo¬embolic pathologies of venous origin, such as pulmonary embolisms. They can be used or to prevent or treat the 15 thrombotic complications observed, for example, following surgical operations, the growth of tumours or disturbances to coagulation induced by bacterial, viral or enzymatic activators. In the case of their use during the insertion of prostheses, the compounds of 20 the present invention can cover prostheses and thus render them haemocompatible. In particular, they can be attached to intravascular prostheses (stents). In this case, they can optionally be modified chemically by introduction at the nonreducing or reducing end of an 25 appropriate arm, as disclosed according to EP 649 854. The compounds of the present invention can also be used as adjuvants during endarterectomy carried out with porous balloons. The compounds according to the invention can be used in the preparation of medicaments intended for the treatment of the above diseases. According to another of its aspects, a 5 subject-matter of the present invention is thus a pharmaceutical composition comprising, as active principle, a synthetic polysaccharide according to the invention or one of its pharmaceutically acceptable salts, optionally in combination with one or more inert 10 and appropriate excipients. The said excipients are chosen according to the desired pharmaceutical form and the desired administration method: oral, sublingual, subcutaneous, intramuscular, intravenous, transdermal, transmucosal, 15 local or rectal. The active principle can also be presented in the form of a complex with a cyclodextrin, for example a-, 3- or y-cyclodextrin, 2-hydroxypropyl-p-cyclodextrin or methyl-P-cyclodextrin. 20 The active principle can also be released by a balloon comprising it or by an endovascular expander introduced into the blood vessels. The pharmacological effectiveness of the active principle is thus unaffected. 25 In each dosage unit, the active principle is present in the amounts suited to the daily doses envisaged in order to obtain the desired prophylactic or therapeutic effect. Each dosage unit can comprise from 0.1 to 100 mg of active principle, preferably 0.5 to 50 mg. These doses of anticoagulant compounds might be neutralized by doses of avidin or streptavidin ranging from 1 to 1 000 mg by iv (intravenous) 5 injection, bolus or infusion. The compounds according to the invention can also be used in combination with one or more other active principles of use in the desired therapy, such as, for example, antithrombotics, anticoagulants, 10 platelet aggregation inhibitors, such as, for example, dipyridamole, aspirin, ticlopidine or clopidogrel, or glycoprotein Ilb/IIIa complex antagonists. The following methods, preparations and schemes illustrate the synthesis of the various 15 intermediates of use in the preparation of the polysaccharides according to the invention. The following abbreviations are used: Bn: benzyl; Bz: benzoyl; TLC: thin layer chromatography; Ts: tosyl; Lev: levulinyl; Et: ethyl; 20 Ph: phenyl; Me: methyl; Ac: acetyl; SE: trimethylsilylethyl; ESI: electron spray ionization; Biotin: hexahydro-2-oxo-Iff-thieno [3 , 4-d] imidazole-4-pentanoic acid; Z:- benzyloxycarbonyl. Subsequently, examples of the synthesis of 25 the compounds of the invention are described in detail by way of illustration. SCHEME 1 - synthesis of the trisaccharide 9 PREPARATION 1 2- (Trxmethylsilyl)ethyl 4, 6-0-benzylidene-2, 3-di-0-5 methyl-f}-D-glucopyranoside (2) Sodium hydride (18 g) is added portionwise at 0°C to a solution of the compound 1 (15.8 g, 42.8 mmol) (prepared according to K. Jansson et al., J. Org, Chem., 1988, 53, 5629-5647) and of methyl iodide 10 (20 ml, 319 mmol) in tetrahydrofuran (350 ml). The reaction mixture is stirred for 4 hours at ambient temperature. The excess sodium hydride is destroyed with methanol and the reaction mixture is poured into ice-cold water (1.5 1). After extracting with ethyl acetate, the organic phase is washed with a saturated sodium chloride solution and water, dried over sodium 5 sulphate and then concentrated under vacuum. The residue is purified by chromatography on a column of silica gel (15/1 (v/v) eyelohexane/ethyl acetate) to give 16.8 g of the compound 2. [ 3A molecular sieve powder (82 g), methyl orange (coloured indicator), sodium cyanoborohydride 15 (34 g, 526 mmol) and then, dropwise, a saturated solution of hydrochloric acid in diethyl ether are successively added to a solution of the compound 2 (16 g, 40.3 mmol) in tetrahydrofuran (600 ml), until a pink colouring is obtained. After filtering and 20 extracting with ethyl acetate, the organic phase is washed with a saturated sodium hydrogencarbonate solution and water, dried over sodium sulphate and then concentrated under vacuum. Chromatography on a column of silica gel (3/1 (v/v) toluene/ethyl acetate) makes 25 it possible to obtain 12.5 g of the compound 3. [oc]D = -42° (c = 1.2, dichloromethane). PREPARATION 3 2- (Trimethylsilyl) ethyl (2, 3-di-0-benzoyl-4, 6-0-benzylidene-CC-D-glucopyranosyl) - (1-+4) - (2, 3, 6-tri-0-benzoyl-fi-D-glucopyranosyl) ~ (1-+4) -6-0-benzyl~2,3-di-0-5 methyl-f3-D-glucopyranoside (5) A mixture of thioglycoside 4 (16.52 g, 16.60 mmol) (obtained according to Preparation 1 of the patent application published under the number WO 99/36443), of the compound 3 (6.0 g, 15.05 mmol) and 10 of 4A molecular sieve powder (16.7 g) in toluene (3 00 ml) is stirred under an argon atmosphere for 1 hour. The mixture is then cooled to -20°C. A solution of jW-iodosuccinimide (3.9 g, 17.4 mmol) and of tri-fluoromethanesulphonic acid (0.17 ml, 1.97 mmol) in a 15 1/1 (v/v) dichloromethane/dioxane mixture (86 ml) is added dropwise to the reaction mixture. After 10 minutes, the reaction mixture is filtered, diluted with dichloromethane, washed excessively with a 1M sodium thiosulphate solution, a 10% sodium 20 hydrogencarbonate solution and water, dried over sodium sulphate and then concentrated under vacuum. The residue is purified by chromatography on a column of silica gel (6/1 (v/v) toluene/ethyl acetate) to give 18.8 g .of the trisaccharide 5. 25 [a]D = +34° (c = 1.26, dichloromethane). PREPARATION 4 2- (Trimethylsilyl) ethyl (4, 6-O-benzylidene-a-D-glucopyranosyl) - (l->4) - (p-D-glucopyranosyl) - (l—>4) -6-0-benzyl -2f 3 -di -O-metbyl -fi-D-glucopyranoside (6) 5 Potassium tert-butoxide (3.15 g) is added to a solution of the compound 5 (18.7 g, 14 mmol) in a 1/1 (v/v) methanol/dioxane mixture (140 ml). The reaction mixture is stirred for 2 hours at ambient temperature. It is neutralized with Dowex® 50WX4 H+ resin, filtered 10 and concentrated under vacuum. The residue is purified by chromatography on a column of silica gel (2 0/1 (v/v) dichloromethane/methanol) to give 10.0 g of the compound 6. [oc]D = +29° (c = 1.11, dichloromethane). 15 PREPARATION 5 2- (Trimethylsilyl) ethyl (4, 6-0-benzylidene-2, 3-di-O- methyl-cc-D-glucopyraixosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-/}- D-glucopyranosyl) - (l—>4) ~6-0~benzyl-2',3-di-O-methyl-fi-D~ glucopyranoside (7) 20 Sodium hydride (5.2 g, 216 mmol) is added portionwise under an argon atmosphere to a cooled mixture (0°C) of the compound 6 (9.93 g, 12.24 mmol) and of methyl iodide (9.0 ml, 138 mmol) in anhydrous tetrahydrofuran (100 ml). The mixture is stirred for 25 20 hours at ambient temperature. The excess sodium hydride is destroyed with methanol and the reaction mixture is poured into ice-cold water (500 ml). After extracting with ethyl acetate, the organic phase is washed with a saturated sodium chloride solution, dried over sodium sulphate and then concentrated under vacuum to give 11 g of the compound 7, which is used in the following stage without purification. TLC: Rf = 0.38, silica gel, 3/2 (v/v) toluene/ethyl 5 acetate. PREPARATION 6 2- (Trimethylsilyl) ethyl (2, 3-di-O-methyl-a-D-gluco-pyranosyl) - (l—>4) - (2, 3, 6-tri-0-methyl-f}-D~gluco-pyranosyl) - (l—>4) -6-0-benzyl~2, 3-di-0-methyl~fi-D~gluco-10 pyranoside (8) The compound 7 (11 g) is dissolved in 60% acetic acid (180 ml) and stirred for 1 hour 30 at 80°C. The mixture is concentrated and coevaporated with toluene. The residue is purified by chromatography on a 15 column of silica gel (2/1 (v/v) toluene/acetone) to give 8.46 g of the compound 8. TLC: Rf = 0.36, silica gel, 1/1 (v/v) toluene/acetone. PREPARATION 7 2- (Trimethylsilyl) ethyl (6-0-benzoyl-2,3~di-0-methyl-CC-2 0 D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri -O-methyl-fi-D-gluco-pyranosyl) - (l—>4) -6-0-henzyl-2, 3-di-O-methyl-fi-D-gluco-pyranoside (9) l-Benzoyloxy-lif-benzotriazole (5.36 g, 22.4 mmol) and triethylamine (3.32 ml) are added to a 25 solution of the compound 8 (8.41 g, 10.6 mmol) in dichloromethane (110 ml). The mixture is stirred for 20 hours at ambient temperature and then diluted with dichloromethane, washed with a saturated sodium hydrogencarbonate solution and water, dried over sodium sulphate and then concentrated under vacuum. The residue is purified by chromatography on a column of silica gel (5/0.5/0.25 (v/v/v) eyelohexane/ethyl 5 acetate/ethanol) to give 8.40 g of the compound 9. [CC]D = +15° (c = 2, dichloromethane) . SCHEME 2 - Synthesis of the pentasaccharide 14 PREPARATION 8 2-(Trimethylsilyl)ethyl (2,3-di~0-benzoyl-4,6-0-benzylidene-a-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O-benzoyl-fi-D-glucopyranosyl) - (l—>4) - (6-0-benzoyl-2, 3-di-5 0-methyl-a-D-glucopyranosyl) - (l->4) - (2, 3, 6-tri-O- methyl-fi-D-glucopyranosyl) - (l—>4) -6-0-benzyl-2,3-di-0-methyl-fi-D-glucopyranoside (10) The compound 9 is converted into compound 10 according to the procedure described in PREPARATION 3. 10 [oc]D = +42° (c = 2, dichloromethane) . PREPARATION 9 2- (Trimethylsilyl) ethyl (4, 6-O-benzylidene-a-D-gluco-pyranosyl) - (l—>4) - (/3-D-glucopyranosyl) - (l—>4) - (2,3-di-O-methyl-CC-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-fi-15 D-glucopyranosyl) - (l—>4) -6-0-benzyl-2,3-di-O-methyl-fi-D-glucopyranoside (11) The compound 10 is converted into compound 11 according to the procedure described in PREPARATION 4. TLC: Rf = 0.35, silica gel, 10/1 (v/v) dichloro-20 me than e/methano1. PREPARATION 10 2-(Trimethylsilyl)ethyl (4, 6-0-benzylidene-2,3-di-O-methyl-a-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-fi-D-glucopyranosyl) -(l—>4) - (2, 3, 6-tri-O-methyl-GC-D-25 glucopyranosyl)-(l->4)-(2,3,6-tri-0-methyl-f}-D- glucopyranosyl) - (l—>4) -6-0-benzyl-2, 3-di-0-methyl-f3-D-glucopyranoside (12) The compound 11 is converted into compound 12 according to the procedure described in PREPARATION 5. TLC: Rf = 0.11, silica gel, 1/2 (v/v) eyelohexane/ethyl acetate. PREPARATION 11 5 2-(Tr±methyls±lyl)ethyl (2,3-di-0-methyl-a~D-gluco-pyranosyl) - (l—>4) - (2,3, 6-tri-O-methyl-fi-D-gluco-pyranosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-a-D-gluco-pyranosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-fi-D-gluco-pyranosyl) - (l—>4 ) - 6-O-benzyl -2,3-di -O-methyl -f$-D-10 glucopyranoside (13) The compound 12 is converted into compound 13 according to the procedure described in PREPARATION 6. TLC: Rf = 0.33, silica gel, 2/0.5/0.5 (v/v/v) cyclo-hexane/ethyl acetate/ethanol. 15 PREPARATION 12 2- (Trimethylsilyl)ethyl (6-0-benzoyl-2,3-di-O-methyl-a-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri -O-methyl -fi-D-gluco-pyranosyl) - (l—>4) - (2,3, 6-tri-O-methyl-CC-D-gluco-pyranosyl) - (l—>4) - (2,3, 6-tri-O-methyl-fi-D-gluco-20 pyranosyl) - (l->4) -6-O-benzyl-2,3-di-O-methyl-f}-D-gluco~ pyranoside (14) The compound 13 is converted into compound 14 according to the procedure described in PREPARATION 7. TLC: Rf = 0.16, silica gel, 3/0.5/0.5 (v/v/v) cyclo-25 hexane/ethyl acetate/ethanol. SCHEME 3 - Synthesis of the heptasaccharide 19 PREPARATION 13 2- (Trimethylsilyl) ethyl (2,3-di-0-benzoyl-4,6-0-benzylidene-a-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O-benzoyl-fi-D-glucopyranosyl) - (l—>4) - (6-0-benzoyl-2, 3-di-5 O-methyl-CC-D-glucopyranosyl) - (l->4) - {2, 3, 6-tri-O- methyl-fi~D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-a- D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-fi-D- glucopyranosyl) - (l—>4) -6-0-benzyl-2, 3-di-O-methyl-fi-D- glucopyranoside (15) 10 The reaction of coupling the compound 14 with the disaccharide 4 is carried out according to the procedure described in PREPARATION 3 to provide the compound 15. [a]D = +52° (c = 1.1, dichloromethane). 15 PREPARATION 14 2- (Trimethylsilyl) ethyl (4, 6-O-benzylidene-a-D-gluco-pyranosyl) - (l—>4) - (fi-D-glucopyranosyl) - (l—>4) - (2, 3-di-O-methyl-a-D-glucopyranosyl) - (l—>4) - (2,3, 6-tri-O-methyl-fi-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-cc-D-gluco-2 0 pyranosyl) - (l-*4 )- (2,3,6- tri -O-methyl -fi-D-gluco¬pyranosyl ) - (l->4) -6-O-benzyl-2, 3-di-O-methyl-fi-D-gluco-pyranoside (16) The compound 15 is converted into compound 16 according to the procedure described in PREPARATION 4. 25 TLC: Rf = 0.31, silica gel, 10/1 (v/v) dichloro¬methane /methanol . PREPARATION 15 2- (Trimethylsilyl) ethyl (4, S-O-benzylidene-2, 3-di-O-methyl-a-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-fi-D-glucopyranosyl) - (l—>4) -[ (2,3, 6-tri-O-methyl-CC-D-5 glucopyranosyl) - (l—>4) - (2, 3, 6-tri~0-methyl-p-D-gluco~ pyranosyl) - (l->4) ]3-6-0-benzyl-2,3-di -O-methyl-fi-D-glucopyranoside (17) The compound 16 is converted into compound 17 according to the procedure described in PREPARATION 5. 10 TLC: Rf = 0.46, silica gel, 10/1 (v/v) dichloro-methane/methanol. PREPARATION 16 2- (Trimethylsilyl) ethyl (2, 3-di -O-methyl -a-D-gluco-pyranosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-fi-D-gluco-15 pyranosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-a-D-gluco-pyranosyl) - (l—>4) - (2,3, 6-tri-0-mathyl-f}-D-gluco-pyranosyl) - (l->4) - (2, 3, 6-tri-O-methyl-a-D-glucopyranosyl) - (l—>4) - (2, 3r 6-tri-O-methyl-fi-D-gluco-pyranosyl) - (l—>4) -6-0-benzyl-2, 3-di-O-methyl ~P~D-20 glucopyranoside (18) The compound 17 is converted into compound 18 according to the procedure described in PREPARATION 6. TLC: R£ = 0.42, silica gel, 1/0.5/0.5 (v/v/v) eyelohexane/ethyl acetate/ethanol. PREPARATION 17 2- (Trimethylsilyl) ethyl (6-O-benzoyl -2, 3-di -O-methyl -a- D-glucopyranosyX) - (l->4) - (2, 3, 6-tri-O-methyl-fi-D- glucopyranosyl) *■ (l—>4) - (2, 3, 6-trx-O-methyl-a-D-gluco- 5 pyranosyl) - (1^4) - (2, 3, 6-trx-O-metbyl-fi-D-gluco- pyranosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-a-D-gluco- pyranosyl) - (l->4) - (2, 3, 6-tri-O-methyl-fi-D-gluco- pyranosyl) - (l—>4) -6-0-benzyl-2,3-dx-0-methyl-j3-D-gluco- pyranosx de (19) 10 The compound 18 is converted into compound 19 according to the procedure described in PREPARATION 7. TLC: Rf = 0.25, silica gel, 3/0.5/0.5 (v/v/v) cyclo-hexane/ethyl acetate/ethanol. SCHEME 4 - Synthesis of the nonasaccharide 23 PREPARATION 18 2- (Trimethylsilyl)ethyl (2, 3-di-0-benzoyl-4, 6-0-benzylidene-a-D-glucopyranosyl) - (1-+4) - (2, 3, 6-tri-O-benzoyl-fi-D-glvicopyranosyl) - (l—>4) - (6-0-benzoyl-2, 3-di-5 O-methyl-a-D-glucopyranosyl) - (l->4) - (2, 3, 6-tri-O- methyl-p-D-glucopyranosyl) - (l—>4) -1 (2, 3, 6-tri-0~methyl- a-D-glucopyranosyl) - (l->4) - (2, 3, 6-tr±-0-metbyl-f$-D- glucopyranosyl) - (1~>4) ]2-6-0-benzyl-2,3-dx-0-methyl-f}-D- glucopyranoside (20) 10 A mixture of the thioglycoside 4 (5.2 g, 5.23 mmol), of heptasaccharide 19 (4.72 g, 2.75 mmol) and of 4A molecular sieve powder in toluene is stirred under an argon atmosphere for 1 hour. A solution of N-iodosuccinimide (1.36 g, 5.85 mmol) and of trifluoro-15 methanesulphonic acid (0.140 ml, 1.56 mmol) in 1/1 (v/v) dichloromethane/dioxane (32 ml) is then added dropwise at 0°C. After 15 minutes, the reaction mixture is filtered, diluted with dichloromethane, washed successively with a 1M sodium thiosulphate solution, a 20 10% sodium hydrogencarbonate solution and water, dried over sodium sulphate and concentrated under vacuum. The residue is purified by chromatography on a column of silica gel (3/0.5/0.5 (v/v/v) eyelohexane/ethyl acetate/ethanol) to give 7.13 g of the compound 20. 25 [a]D = +65° (c = 1.4, dichloromethane). PREPARATION 19 2- (TrimethylsiiyD ethyl (4, 6-O-benzylidene-a-D- glucopyranosyl) - (1-+4) - (fi-D-glucopyranosyl) - (l->4) - (2,3-di-O-methyl-CC-D-glucopyraaosyl) - (l—>4) - (2,3, 6-tri-5 O-methyl-f}-D-glVcopyranosyl) - (l—>4) - [ (2, 3, 6-tri-O- methyl-cc-D-glucopyranosyl) - (l->4) - (2, 3, 6-tri -O-methyl-/?- D-glucopyranosyZ) - (l—>4) J 2-S-0-benzyl-2, 3-di -O-methyl -fi- D-glucopyranoside (21) The compound 20 is converted into compound 21 10 according to the procedure described in PREPARATION 4. TliC: Rf = 0.27, silica gel, 10/1 (v/v) dichloromethane/ methanol. PREPARATION 20 2- (TrimethylsiiyD ethyl (4, 6~0-benzylidene-2, 3-di-O-15 methyl-a-D-glucOPyranosyl) - (1-+4) - (2, 3, 6-tri-O-methyl-P- D-glucopyranosyX) - (l—>4) - (2, 3, 6-tri-O-methyl-CC-D- glucopyranosyl) *• (l—>4) - (2, 3, 6-tri-O-methyl-fi-D- glucopyranosyl) " (l->4)]3-6-0-benzyl-2,3~di-0~methyl-p-D~ glucopyranoside (22) 20 The compound 21 is converted into compound 22 according to the procedure described in PREPARATION 5. TLC: Rf = 0.31, silica gel, 5/1/1 (v/v/v) cyclohexane/ ethyl acetate/ethanol. PREPARATION 21 2- (Trimethylsllyl)ethyl (2, 3-di-O-methyl-a-D-glucopyranosyl) - (l->4) - (2, 3, 6-tri-0-methyl-(3-D-glucopyranosyl) - (l->4) - [ (2, 3, 6-tri-O-methyl-a-D-5 glucopyranosyl) - (l->4) - (2, 3, 6-tri-O-methyl-fi-D- glucopyranosyl) - (l->4) ]3-6~0-benzyl-2,3-di-0-methyl~fi-D-glucopyranoside (23) The compound 22 is converted into compound 23 according to the procedure described in PREPARATION 6. 10 TLC: Rf = 0.35, silica gel, 2/1/1 (v/v/v) cyclohexane/ ethyl acetate/ethanol. PREPARATION 22 2- (Trimethylsilyl) ethyl (2, 3-di-O-methyl -6-0-tosyl-a-D-glucopyranosyl) - (1-+4) - (2, 3, 6-tri-0-methyl-f5-D-glucopyranosyl) - (l-¥4) -1(2, 3, 6-tri-O-methyl-a-D-5 glucopyranosyl) - (l->4) - (2, 3, 6~tri-0-methyl-f}-D- glucopyranosyl) - (1—¥4) ]3-6-0-benzyl-2,3-di-0-methyl-f}-D-glucopyranoside (24) The compound 23 (1.09 g) is dissolved in pyridine (10 ml) under an argon atmosphere and then 10 tosyl chloride (1.03 g) is added. After stirring for 2 hours, the reaction mixture is diluted with dichloromethane (100 ml). The organic phase is washed successively with a 10% potassium hydrogen sulphate solution and then water, dried and evaporated to 15 dryness. After chromatography on a column of silica gel (2.3/2 (v/v) toluene/acetone), 1.77 g of the compound 24 are obtained. TLC: Rf = 0.5, silica gel, 3/1/1 (v/v/v) cyclohexane/ ethyl acetate/ethanol. 20 PREPARATION 23 2- (Trimethylsilyl)ethyl (6-deoxy-2,3-&i-0-methyl-6-phthalimido~cc-D-glucopyranosyl) - (l—>4) - (2,3, 6-tri-O-methyl-p-D-glucopyranosyl) - (l->4) - [ (2, 3, 6-tri-O-methyl-a-D-glucopyranoByl) - (l—>4) - (2, 3, 6-tri-0-methyl-f}-D-25 glucopyranosyl) - (l—>4) ] 3-6~0-benzyl~2f3-di-0-methyl-fi-D-glucopyranoside (25) Potassium phthalimide (22 5 mg, 1.38 mmol) and then 18-crown-6 crown ether (121.5 mg, 0.46 mmol) are added to a solution of the compound 24 (500 mg, 0.23 mmol) in anhydrous N,N-dimethyIformamide (11 ml) comprising 4A molecular sieve powder. The mixture is stirred for 4 hours at 80°C. After having been cooled, 5 the reaction mixture is diluted with dichloromethane, filtered through Celite and concentrated. The residue is purified by chromatography on Sephadex® LH20 gel (3 x 100 cm) (1/1 (v/v) dichloromethane/ethanol), followed by chromatography on a column of silica gel 10 (11/2 (v/v) toluene/ethanol), to give 417.4 mg of the compound 25. TLC: Rf = 0.38, silica gel, 11/2 (v/v) toluene/ethanol. PREPARATION 24 2- (Trimethylsilyl) ethyl (2, 3, 4, 6-tetra-O-acetyl-CC-D-15 glucopyranosyl) - (l—>4) - (2, 3, 6—tri-0~acetyl-CC-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O-acetyl-fi-D-glucopyranosyl) - (l—>4) - (6-deoxy-2, 3-di-0-methyl-6-phthalimido-cc-D-fflucopyranosyl) - (l->4) - (2,3, 6-tri-O-methyl-fi-D-glucopyranosyl) - (l—>4) - [ (2, 3, 6-tri-O-methyl-a-20 D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-0-methyl-f}-D~ glucopyranosyl) - (l—>4) J 3-6-0-benzyl~2, 3-di-O-methyl-fi-D-glucopyranoside (21) A mixture of thioglycoside 26 (1.515 g, 1.564 mmol) (prepared according to compound 41, 25 Preparation 36 of Patent WO 99/36443), of the acceptor 25 (840 mg, 0.391 mmol) and of 4A molecular sieve powder (2.15 g) in toluene (33 ml) is stirred under an argon atmosphere for 1 hour. The reaction mixture is cooled to 0°C and a solution of itf-iodosuccinimide (387 mg) and of trifluoromethanesulphonic acid (55.4 ^il) in 1/1 (v/v) dichloromethane/dioxane (7 ml) is introduced therein. After 10 minutes, the mixture is 5 filtered, diluted with toluene, washed successively with a 1M sodium thiosulphate solution, in a 10% sodium hydrogen carbonate solution and in water, dried over sodium sulphate and then concentrated under vacuum. The residue is purified by chromatography on Sephadex® LH20 10 gel (1/1 (v/v) dichloromethane/ethanol), followed by chromatography on a column of silica gel (5/4 (v/v) toluene/acetone), and results in 887 mg of the compound 27. [a]D = +70° (c = 0.35, dichloromethane). 15 PREPARATION 25 2- (Trimethylsilyl)ethyl (2, 3, 4, 6-tetra-O-acetyl-a-D-glucopyranosyl) - (1—>4) - {2, 3, 6-tri-O-acetyl-CC-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O-acetyl-fi-D-glucopyranosyl) - (l—>4) - (6~deoxy-2,3~di-0-methyl-6-2 0 phtha.limido-a-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O- methyl-fi-D-glucopyraziosyl) - (l-¥4) - [ (2, 3, 6-tri -O-methyl -cc- D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-P-D- glucopyranosyl) - (l—>4) ]3-2, 3-di-O-methyl-fi-D- glucopyranoside (2B) 25 A solution of the compound 27 (750 mg, 0.245 mmol) in acetic acid (37 ml) is treated under hydrogen pressure (5 bar) in the presence of 10% palladium-on-charcoal (750 mg) for 2 hours 30. After filtering, the solution is concentrated and the residue is purified by chromatography on a column of silica gel (6/1 (v/v) toluene/ethanol) to give 728 mg of the compound 28. 5 TLC: Rf = 0.32, silica gel, 6/1 (v/v) toluene/ethanol. PREPARATION 26 2- (Trimethylsilyl)ethyl (2,3,4, 6-tetra-O-acetyl-a-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-0~acetyl-CC-D~gluco-pyranosyl) - (l—>4) - (2,3, 6-tri-O-acetyl-fi-D-gluco-10 pyranosyl) - (l->4) - (6-deoxy-2,3-di~0-methyl-6-phthal- imido-a-D-glucopyranosyl) - (l-~>4) - (2, 3, 6-tri-O-methyl-fi-D-glucopyranosyl) - (l—>4) - [ (2, 3, 6~tri-0-methyl-a-D-glucopyranoByl) - (l—>4) - (2, 3, 6-tri~0-metbyl-P-D-gluco-pyranosyl) - (l->4 )]3- 6-O-acetyl -2, 3 -di -O-methyl -fi~D-15 glucopyranoside (29) Triethylamine (51.1 (j.1, 0.368 mmol) , acetic anhydride (32.5 /xl, 0.344 mmol) and dimethylamino-pyridine (6.0 mg, 0.049 mmol) are added to a solution of the compound 28 (728 mg, 0.245 mmol) in dichloro-20 methane (10 ml). After stirring for 1 hour, the reaction mixture is diluted with dichloromethane, washed successively with a 10% potassium hydrogen sulphate solution, water, a saturated sodium hydrogen carbonate solution and water, dried over sodium 25 sulphate and concentrated under vacuum. Purification of the residue, carried out by chromatography on a column of silica gel, makes it possible to obtain 0.618 mg of the compound 29. TLC: Rf = 0.37, silica gel, 6/1 (v/v) toluene/ethanol. SCHEME 6 - Synthesis of the oligosaccharide 31 29 31 PREPARATION 27 5 (2, 3, 4, 6-Tetra-O-acetyl-a-D-glucopyranosyl) - (l->4) -(2,3, 6-tri-O-acetyl-a-D-glucopyranosyl) - (l->4) -(2, 3, 6-tri-O-acetyl-^-D-glucopyranosyl) - (l—>4) - (6-deoxy-2,3-di-0-methyl-6-phthalimido-a-D-glucopyranosyl) -(1-+4) - (2, 3, 6-tri-0-methyl~f3-D-glucopyranosyl) - (l->4) -10 [ (2, 3, 6-tri-O-methyl-a-D-glucopyranosyl) - (l->4) - (2, 3, 6-tri-0-m&thyl-f}-D-glucopyranosyl) - (l—>4) ]3-6-0-acetyl-2,3-di-0-methyl-D-glucopyranose (30) A solution of the compound 29 (579 mg, 0.192 mmol) in a 2/1 (v/v) trifluoroacetic 15 acid/dichloromethane mixture (11.5 ml) is stirred for 1 hour. The reaction mixture is diluted with a 2/1 (v/v) toluene/rz-propyl acetate mixture (69 ml) , concentrated and coevaporated with toluene. The residue is purified by chromatography on a column of silica gel (5/1 (v/v) toluene/ethanol) to produce 523 mg of of the compound 3 0. TLC: Rf = 0.31, silica gel, 5/1 (v/v) toluene/ethanol. PREPARATION 28 5 (2, 3, 4, 6-Tetra-0-acetyl~a-D-glucopyranosyl) - (l—*4) -(2,3, 6-tri-O-acetyl-a-D-glucopyranosyl) - (1-+4) -(2,3, 6~tri-0-acetyl-fJ~D-glucopyranosyl) - (l—¥4) - (6-deoxy-2, 3-di-0~methyl-6-phthalimido-a-D-glucopyranosyl) -(l—>4) - (2, 3, 6-tri-O-iaethyl-P-D-glucopyranosyl) - (l—>4) -10 [ (2, 3, 6-tri-O-methyl-a-D-glucopyraxiosyl) - (l—>4) - (2,3, 6-tri-0-methyl~f}-D-glucopyranosyl) - (l->4) ]3-6-0~ acetyl-2, 3-di-O-methyl-D-glucopyranose trichloro-acetimidate (31) Trichloroacetonitrile (65.5 ill, 0.85 mmol) 15 and caesium carbonate (88.4 mg, 0.27 mmol) are added to a solution of the compound 30 in dichloromethane (3 ml). After stirring for 2 hours, the mixture is filtered and concentrated. The residue is purified by chromatography on a column of silica gel (6/1 (v/v) 20 toluene/ethanol + 0.1% of triethylamine) to give 477 mg of the compound 31. TLC: Rf = 0.35, silica gel, 6/1 (v/v) toluene/ethanol. PREPARATION 29 Methyl (2,3,4,6-tetra-O-acetyl-a-D-glucopyranosyl)-(l->4) - (2, 3, 6-tri-O-acetyl-a-D-glucopyranosyl) - (l—>4) -(2, 3, 6-tri-O-acetyl-fi-D-glucopyranosyl) - (l—>4) - (6-deoxy-5 2, 3-di-0-methyl~6-phthalimido-a-D-glucopyranosyl) -(l—>4) - (2, 3, 6-tri-0-methyl-f}-D-glucopyranosyl) - (l—>4) -f [2, 3, 6-tri-0-metbyl~Ct-D-glucopyranoByl) - (l->4) -O-(2,3, 6-tri-O-methyl-p-D-glucopyranosyl) - (l—>4)]3- (6-0-acetyl-2, 3-di-O-methyl-cc-D-glucopyranosyl) - (l—>4) -10 (benzyl 2,3-di~0-methyl-P-D-glucopyranosyluronate) - (l->4) -(3, 6-di-O-acetyl-2-O-benzyl-a-D-glucopyranosyl) - (l—>4) - (benzyl 2, 3-di-O-methyl-a-L-idopyrano- syluronate) - (l—>4) -2, 3, 6-tri-O-benzyl-CC-D-gluco- pyranoside (33) 15 The imidate 31 (370 mg, 0.121 mmol) and the compound 32 (336 mg, 0.242 mmol) (obtained according to P. Westerduin et al., BioOrg. Med. Chem., 1994, 2, 1267) are dissolved in a 1/2 (v/v) dichloromethane/ diethyl ether mixture (5.5 ml). After addition of 4A 20 molecular sieve powder, the mixture is cooled to -20°C and a 0.1M solution of trimethylsilyl trifluoromethane-sulphonate in dichloromethane (181.5 ixl) is added. After 25 minutes, the mixture is neutralized by addition of solid sodium hydrogen carbonate. After 25 filtering and concentrating, the residue is purified by chromatography on Sephadex LH2 0 gel, followed by chromatography on a column of silica gel (6/5 (v/v) toluene/acetone) to give 302 mg of the compound 33. [oc]D = +86° (c = 1, dichloromethane) . PREPARATION 30 Methyl (2, 3,4, 6-tetra-O-acetyl-a-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O-acetyl-cc-D-glucopyranosyl) - (l->4) - 5 (2,3, 6-tri-O-acetyl-ff-D-glucopyranosyl) - (l—>4) - (6-deoxy- 2, 3-di-O-methyl-6-phthalimido-a-D-glucopyranosyl) - (l—>4) - (2r 3, 6-tri-O-methyl-p-D-glucopyranosyl) - (l—>4) - [ (2, 3, 6-tri-0-methyl-a,~D-glucopyraxiosyl) - (l—>4) -O- (2,3, 6-tri-0-methyl-f}-D-glucopyranosyl) - (l—>4) ] 3- (6-0- 10 acetyl-2, 3-di-O-methyl-a-D-glv.copyranosyl) - (l->4) -(2,3- di-O-methyl-p-D-glucopyranosyluronic acid) - (l—>4) - (3, 6- di-O-acetyl-a-D-glucopyranosyl) - (l—>4) - (2,3-di -O- methyl-cc-L-idopyranosyiuronic acid) - (l—>4) -a-D-gluco- pyranoside (34) 15 A solution of the compound 33 (104 mg, 0.024 mmol) in acetic acid (5 ml) is treated under hydrogen pressure (4 bar) in the presence of 10% palladium-on-charcoal (104 mg) for 4 hours. After filtering, the solution is lyophilized to give the 20 compound 34 (87 mg), which is used in the following stage without purification. PREPARATION 31 Methyl (a-D-glucopytanosyl) - (l—>4) - (cc-D-gluco-pyranosyl) - (l—>4) - (fi-D-glucopyranosyl) - (l—>4) - (6-deoxy-25 2, 3-di-O-methyl-6-phthaliittido-a-D-glucopyranosyl) - (l->4) - (2, 3f 6-tri-O-methyl-P-D-glucopyranosyl) - (l->4) -[ (2, 3, 6-tri-O-methyl-a-D-glucopyranosyl) - (l—>4) -O-(2, 3, 6-tri-O-methyl-P-D-glucopyranosyl) - (l—>4) ]3- (2, 3-di-O-methyl-a-D-glucopyranosyl) - (l->4) - (2,3-di-O-methyl-f}-D-glucopyranosyluronic acid) -(l—>4) -(a-D-glucopyranosyl) - (l—>4) - (2,3-di-O-methyl-a-L-idopyrano-syluronic acid) - (l—>4) -a-D-glucopyranoside (35) 5 A molar solution of sodium methoxide in methanol (140 ptl) is added to a solution of the compound 34 (80 mg, 0.021 mmol) in anhydrous methanol (6.9 ml) in the presence of 3A molecular sieve powder (875 mg). After 20 hours at ambient temperature, the 10 reaction mixture is filtered and the filtrate is neutralized with acetic acid. The solution is concentrated by half and deposited on a column of Sephadex® G-25 Fine (3 x 92 cm). After eluting with water and lyophilizing, the compound 35 (66 mg) is 15 obtained. PREPARATION 32 Methyl (2,3,4,6-tetra-O-sulphonato-a-D-glucopyranosyl)-(l—>4) - (2, 3, 6-tri-O-sulphonato-cc-D-glucopyranosyl) -(1-+4) - (2, 3, 6-tri-O-sulphonato-0-D~glucopyranosyl) -5 (1-+4) - (6-deoxy-2, 3-di-0-methyl-6-phthalimido-a-D-glucopyranosyl) - (l->4) - (2, 3, 6-tri-0-methyl-f3-D-gluco-pyranosyl) - (l->4) - [ (2, 3, 6-tri-O-methyl-a-D-gluco-pyranosyl) - (l—>4) -0- (2,3, 6-tri-0-methyl-P-D~gluco~ pyranosyl) - (l—>4)]3- (6-0-sulphonato-2, 3-di~0-methyl~a-D- 10 glucopyranosyl) - (l—>4) - (2,3-di-O-methyl-p-D-glucopyrano-syluronic acid) - (l—>4) - (2, 3, 6-tri -O-sulphonato-a-D-glucopyranosyl) - (l~->4) - (2, 3 -di -O-methyl -a-L-idopyrano-syluronic acid) - (l—>4) -2, 3, 6-tri-O-sulphoxiato-a-D-glucopyranoside, sodium salt (36) 15 The polyol 35 (66.4 mg, 0.021 mmol) is dissolved in iV,J\7-dimethylformamide (1.8 ml). The sulphur trioxide-triethylamine complex (320 mg, 1.77 mmol) is added and the mixture is stirred for 20 hours at 55°C. The solution is deposited on a column 20 of Sephadex® G-25 Fine (3 X 92 cm) eluted with 0.2M sodium chloride. The fractions comprising the product are concentrated and desalting is carried out using the same column eluted with water. After lyophilization, 83 mg of the compound 3 6 are obtained. 25 Mass: ESI method, negative mode: chemical mass = 4968.92; experimental mass = 4966.52 ±0.16 a.m.u. PREPARATION 33 Methyl (2,3,4,6-tetra-O-sulphonato-a-D-glucopyranosyl)-(l->4) - (2,3, 6-tri-O-sulphonato-CC-D-glucopyranosyl) -(l—>4) - (2, 3, 6-tri-0-sulphonato-f5-D-glucopyranosyl) -5 (l—>4) - (6-amino-6-deoxy-2,3~di-0-methyl-(X-D- glucopyranosyl) ~ (l—>4) - (2, 3, 6-tri-0-methyl-f}-D-glvico~ pyranosyX) - (l—>4) -[ (2, 3, 6-tri-O-methyl-a-D-gluco- pyranosyl) - (l->4) -0- (2,3, 6-tri-0~methyl-P~D-gluco- pyranosyl) - (l—>4) ] 3- (6-0-sulphonato-2, 3-di-O-methyl-a-D- 10 glucopyranosyl) - (l—>4) - (2,3-di-0-methyl-fl-D~glucopyrano- syluronic acid) - (l-~>4) - (2, 3, 6-tri-0-sulphonato~cc-D- glucopyranosyl) -(l—>4) - (2, 3-di-O-methyl-a-L-idopyrano- syluronic acid) - (l-¥4) -2, 3, 6-tri-O-svlphonato-a-D- glucopyranoside, sodium salt (37) 15 The compound 36 (83 mg, 0.017 mmol) is dissolved in a 2/1 (v/v) ethanol/water mixture (1.67 ml). Hydrazine hydrate (81.2 (il, 1.67 mmol) is added and the mixture is brought to reflux for 20 hours. The solution is deposited on a column of 2 0 Sephadex® G-25 Fine (3 X 92 cm) eluted with water. After concentrating the fractions comprising the product, the residue is dissolved in 2/1 (v/v) ethanol/water (5.00 ml) and again treated as under the preceding conditions with hydrazine hydrate (81.2 til) 25 to give 71 mg of the compound 37. Mass: ESI method, negative mode: chemical mass = 4838.32; experimental mass = 4814.6 ± 0.70 a.m.u. SCHEME 9 - Synthesis of the pentasaccharide 39 PREPARATION 34 Methyl (6-0-acetyl-2-azido-2-deo3ty-3,4-di-0~methyl~a-D-5 glucopyranosyl) - (l—>4) - (benzyl 2,3-di~0-methyl-f}-D-glucopyranosyluronate) - (l—>4) - (3, 6-di-0~acetyl-2~0-benzyl -a-D-glucopyranosyl) - (l—>4 ) - (benzyl 2,3 -di -O-methyl-a-L-idopyranosyluronate) - (l—>4) -2, 3, 6-tri-O-benzyl-a-D-glucopyranoside (39) 10 The compound 6-0-acetyl-2~azido-2-deoxy~ 3, 4-di-0-methyl- 15 0.420 iranol) (obtained according to P. Westerduin et al., Bioorg. Med. Chem., 1994, 2, 1267) are dissolved in a 1/2 (v/v) dichloromethane/diethyl ether mixture (28.5 ml). After addition of 4A molecular sieve powder, the mixture is cooled to -20°C and a 0.1M solution of 20 trimethylsilyl trifluoromethanesulphonate in dichloromethane (94.6 MD is added. After 10 minutes, imidate (53.8 mg) is again added, followed by a 0.1M solution of trimethylsilyl trifluoromethanesulphonate in dichloromethane (19.2 \il) . After 10 minutes, the mixture is neutralized by addition of solid sodium 5 hydrogen carbonate. After filtering and concentrating, the residue is purified by chromatography on a column of silica gel (3/1 (v/v) toluene/ethyl acetate) to give 499 mg of the compound 39. [a]D = +66° (c = 1.07, dichloromethane). 10 SCHEME 10 - Synthesis of the pentasaccharide 44 (Process I) PREPARATION 35 Methyl (6-0-acetyl-2-amino-2-deoxy-3f4-di-0-methyl-a-D-glucopyranosyl) - (l->4) - (2, 3-di-O-methyl-fi-D-glucopyrano-syluronic acid) - (l->4) - (3, 6-di-O-acetyl-a-D-gluco-5 pyranosyl) - (l->4)-(2,3-di -O-methyl -a-L-idopyrano-syluronic acid)-(l—>4) -a-D-glucopyranoside (40) A solution of the compound 39 (552.6 mg, 0.335 mmol) in a 5/1 (v/v) tert-butanol/ethyl acetate mixture (16 ml) is treated under hydrogen pressure 10 (10 bar) in the presence of 10% palladium-on-charcoal (1.10 g) and of 1M hydrochloric acid (0.336 ml) for 4 hours 30. After filtering, the solution is concentrated and gives the compound 40, which is used in the following stage without purification. 15 PREPARATION 36 Methyl (2~amino-2-deoxy-3, 4 -di -O-methyl -a-D-gluco-pyranosyl) - (l—>4) - (2, 3-di-O-methyl-fi-D-glucopyrano-syluronic acid) - (l—>4) - (a-D-glucopyranosyl) - (l—>4) -(2, 3-di-O-methyl -cc~L-idopyranosyluronic acid) - (l—>4) -a-20 D-glucopyranoside (4.1) The compound 40 (324 mg, 0.300 mmol) is dissolved in methanol (8.8 ml). A 5M sodium hydroxide solution (2.2 ml) is added and the reaction mixture is stirred at ambient temperature for 16 hours. It is 25 neutralized with a Dowex 50 H+ resin and filtered. The solution is passed through a Sephadex® G-25 Fine column eluted with water. The fractions comprising the product are concentrated and 254.2 mg of the compound 41 are obtained. At this stage, it is confirmed by NMR that the protective groups (benzyl and acetyl groups) have been removed. TLC: Rf = 0.26, silica gel, 5/5/1/3 (v/v/v/v) ethyl 5 acetate/pyridine/acetic acid/water. PREPARATION 37 Methyl (2- (benzyloxycarbonyl)amino-2-deoxy-3,4-di-O-methyl-a-D-glucopyranosyl) - (l—>4) - (2,3-di-O-methyl-fi-D-glucopyranosyluronic acid) - (l—>4) - (a-D-glucopyranosyl) - 10 (l—>4) - (2, 3-di-O-methyl~cc-L-idopyranosyluronlc acid) -(l—>4) -a-D-glucopyranoside (42) The compound 41 (241.1 mg, 0.253 mmol) is dissolved in water (12.4 ml) and sodium hydrogen carbonate (63.7 mg) is added, followed dropwise by 15 benzyl chloroformate (41 nl). After stirring for 12 hours, the reaction mixture is passed through a column of Sephadex G-25 Fine eluted with water. The fractions comprising the product are concentrated. Purification by chromatography on a column of silica 20 gel (21/17/3.6/10 v/v/v/v ethyl acetate/pyridine/acetic acid/water) gives 221 mg of the compound 42. TLC: Rf = 0.63, silica gel, 5/5/1/3 (v/v/v/v) ethyl acetate/pyridine/acetic acid/water. PREPARATION 38 25 Methyl (2~ (benzyloxycarbonyl) amixxo-2-d&oxy-3, 4-di-O-methyl-6-0-sulphonato- (2, 3 -di ~0-methyl -a-L-idopyraaosyluronic acid) - (l->4) -2, 3, 6-tri-0-sulphonato-cc~D-glucopyranoside, sodium salt (43) The polyol 42 (19.6 mg, 0.018 mmol) is 5 dissolved in N,N-dimethylformamide {1.62 ml). The sulphur trioxide-triethylamine complex (114 mg) is added and the mixture is stirred for 20 hours at 55°C with light excluded. The solution is deposited on a column of Sephadex G-25 Fine eluted with 0.2M sodium 10 chloride. The fractions comprising the product are concentrated and desalting is carried out using the same column eluted with water. After lyophilizing, 28.5 mg of the compound 43 are obtained. [a]D = +48° (c = 2.75, water). 15 PREPARATION 39 Methyl (2-amino-2-deoxy-3,4-di-O-methyl-6-O-sulphonato-cc-D~glucopyranosyl) - (l—>4) - (2,3-di-O-methyl-fi-D-gluco-pyrahosyluronic acid) - (l—>4) - (2, 3, 6-tri-0-sulphonato~Ct-D-glucopyraziosyl) - (1~>4) - (2, 3-di-O-methyl-cc-L-ido-2 0 pyranosyluronic acid) - (l—>4) -2, 3, 6-tri-O-sulphonato-a-D-glucopyranoside, sodium salt (44) A solution of the compound 43 (27.5 mg, 0.015 mmol) in a 'terfc-butanol (333 MD /water (500 /xl) mixture is treated under hydrogen pressure (5 bar) in 25 the presence of 10% palladium-on-charcoal (8.25 mg) for 16 hours. After filtering, the solution is concentrated and the residue is deposited on a column of Sephadex G-25 Fine (3 x 92 cm). After eluting with water and lyophilizing, 23.7 mg of the compound 44 are obtained. [a]D = +58° (c = 1, water). SCHEME 11 - Synthesis of the tetrasaccharide 48 PREPARATION 40 Methyl (4~0-levulinyl-2,3-di-O-methyl-fi-D-glucopyrano-syluronic acid) - (l—>4) - (3, 6-di-O-acetyl-cc-D-gluco-pyranosyl) - (l—>4) - (2, 3-di-O-methyl-a-L-idopyrano-5 syluronic acid) - (l—>4)-a-D-glvLcopyranosi.de (46) A solution of the compound 45 (4.50 g, 3.02 mmol) (obtained according to P. Westerduin et al., BioOrg. Med. Chem., 1994, 2, 1267) in an ethyl acetate/tert-butanol (72 ml, 1/1, v/v) mixture is 10 treated under hydrogen pressure (4 bar) in the presence of 10% palladium-on-charcoal (9.0 g) for 6 hours. After filtering and concentrating, the compound 46 obtained is used directly in the following stage without purification. 15 TLC: Rf = 0.54, 26/22/4.6/17 v/v/v/v ethyl acetate/pyridine/acetic acid/water. PREPARATION 41 Methyl (methyl 4-0-levulinyl-2,3-di-0-methyl-f}-D-glucopyranosyluronate) - (l—>4) - (2, 3, 6-txri-O-acetyl-a-D-20 glucopyranosyl) - (l—>4) -(methyl 2/3~di-0-methyl-cc-L-idopyranosyluronate) - (1~*4) -2, 3, 6-tri-O-acetyl-cc-D-glucopyranoside (47) Potassium'hydrogen carbonate (2.71 g) and then methyl iodide (3.4 ml) are added at 0°C to a 25 solution of the compound 46 (2.57 g, 2.71 mmol) in anhydrous N,N-dimethylformamide (35 ml). After stirring for 16 h at ambient temperature, the reaction mixture is cooled to 0°C. Dimethylaminopyridine (132 mg) and then acetic anhydride 1.5 ml) are subsequently added in succession. The mixture is stirred for 16 h. After neutralizing the excess acetic anhydride, the mixture is diluted with ethyl acetate. The organic phase is 5 washed successively with a 10% potassium hydrogen sulphate solution and water and then with a saturated sodium hydrogen carbonate solution and water, dried over sodium sulphate, filtered and then evaporated to dryness. The residue is purified by chromatography on a 10 column of silica gel [9/5 cyclohexane/(1/1 ethyl acetate/ethanol)] to give 2.51 g of the compound 47. TLC: Rf = 0.41, 2/1 v/v toluene/acetone. PREPARATION 42 Methyl (methyl 2,3-di-O-methyl-fi-D-glucopyranosyl- 15 uroxxate) - (l->4) - (2, 3, 6-tri-O-acetyl-CC-D- fflucopyranosyl) - (l—>4) - (methyl 2r 3-di-O-methyl-a-L-idopyranosyluronate) - (l->4) -2,3, 6-tri-O-acetyl-a-D-glucopyranosxde (48) The compound 47 (2.5 g, 2.56 mmol) is 20 dissolved in a 1/1 v/v toluene/ethanol mixture (500 ml). Hydrazine acetate (1.01 g) is added. After stirring for 2 h at ambient temperature, the reaction mixture is concentrated to dryness. The residue is dissolved in dichloromethane. The organic phase is 25 washed successively with a 2% sodium hydrogen carbonate solution and water, dried over sodium sulphate, filtered and then evaporated to dryness. After chromatography on a column of silica gel (1/4 v/v toluene/ethyl acetate), 2.01 g of the compound 48 are obtained. TLC: Rf = 0.37, 2/1 v/v toluene/acetone. SCHEME 12 Synthesis of the pentasaccharide 49 5 PREPARATION 43 Methyl (6-0-acetyl-2-azido-2-deo3cy-3,4-di-0-methyl- glucopyranosyluronate) - (l—>4) - (2, 3, 6-tri-O-acetyl-a-D- 10 glucopyranosyl) - (l—>4) - (methyl 2, 3, -di-O-methyl-cc-L-idopyranosyluronate) - (1-^4) -2,3, 6-tri-O-acetyl-a-D-glucopyranosi.de (49) The imidate 38 (1.18 g, 2.81 mmol) (obtained according to J. Basten et al., Bioorg. Med. Chem. Lett. 15 (1992), 2(9), 901) and the compound 48 (1.83 g, 1.75 mmol) are dissolved in a 1/2 (v/v) dichloromethane/diethyl ether mixture (12 6 ml). After addition of 4A molecular sieve powder, the mixture is cooled to -2 0°C and a 1M solution of tert- 20 butyldimethylsilyl trifluoromethanesulphonate in dichloromethane (421 jxl) is added. After 30 minutes, a further amount of imidate (266 mg) and a 1M solution of tert-butyldimethylsilyl trifluoromethanesulphonate in dichloromethane (168 fil) are added. After 10 minutes, the mixture is neutralized by addition of solid sodium 5 hydrogen carbonate and filtered. The solution is topped up with dichloromethane, washed successively with a 2% sodium hydrogen carbonate solution and water, dried over sodium sulphate and then concentrated under vacuum. The residue obtained is purified by 10 chromatography on a column of silica gel (4/3 and then 1/1 v/v dichloromethane/ethyl acetate) to give 1.814 g of the compound 49. TLC: Rf = 0.57, 3/1 v/v toluene/ethyl acetate. [oc]D = +93° (c = 1.15, dichloromethane). SCHEME 13- Synthesis of pentasaccharide 44 (Process II) PREPARATION 44 Methyl (2-azido-2-deoxy-3, 4~di -O-methyl -a-D-5 glv.copyreua.osyl) - (l—>4) - (2, 3-di -O-methyl ~f$-D- glucopyranosyluronic acid)-(l—>4)- ( cc-D-glucopyranosyl)-(l—>4) - (2, 3-di -O-methyl -a~L-idopyranosyluronic acid) -(l-~>4) -CC-D-glucopyranoside (50) 30% aqueous hydrogen peroxide solution 10 (42 ml) is added at -5°C to a solution of the compound 49 (845.3 mg) in tetrahydrofuran (104 ml). After stirring for 5 minutes, a 0.7M aqueous lithium hydroxide solution (19.2 ml) is added dropwise. The reaction mixture is stirred for 1 h at -5°C, then for 4 h at 0°C and finally for 16 h at ambient temperature. It is neutralized with a 1M hydrochloric acid solution. 5 The solution is deposited on a column of Sephadex® G-25 Fine (5x1 000 cm) eluted with water. The fractions comprising the expected compound are combined, concentrated and deposited on a column of Dowex AG 50 WX4 H+ resin (50 ml) . The compound is 10 collected at 0°C and concentrated to produce 618 mg of the compound 50. TLC: Rf = 0.56, 26/22/4.6/17 v/v/v/v ethyl acetate/pyridine/acetic acid/water. PREPARATION 45 15 Methyl (2-azido-2-deoxy~3,4-di-0-methyl-6-0-sulphonato-a-D-glucopyranosyl) - (l—>4) - (2, 3-di-O-methyl-fJ-D-glucopyranosyluronate) - (l—>4) - (2, 3, 6-tri-O-sulphonato-cc-D~glucopyranosyl) - (l—>4) - (2,3-di-O-methyl-a-L-idopyranosyluronate) - (l—>4) -2,3, 6-tri-O-sulphonato-a-D-20 glucopyTano8i.de, sodium salt (51) Immediately before using it, the compound 50 is codistilled with 2^IV-dimethylformamide (3 x 29 ml) . The sulphur trioxide-triethylamine complex (3.84 g) is added to a solution of the compound 50 (612 mg, 25 0.624 mmol) in iWiV-dimethylformamide (58 ml). The mixture is stirred for 16 hours at 55°C with light excluded. The mixture, cooled to 0°C, is added dropwise to a solution of sodium hydrogen carbonate (5.33 g) in water (200 ml). The mixture is stirred for 16 h at ambient temperature and concentrated to dryness. The residue is dissolved in water and the solution is deposited on a column of Sephadex® G-25 5 Fine eluted with 0.2M sodium chloride. The fractions comprising the product are concentrated and desalting is carried out using the same column eluted with water. After lyophilizing, 1.06 g of the compound 51 are obtained. 10 TLC: Rf = 0.5, 3/5/1/3 v/v/v/v ethyl acetate/pyridine/-acetic acid/water. PREPARATION 46 Methyl (2-amino-2-deo2ty-3,4-di-0~methyl-6-0~sulphonato-a-D-glucopyranosyl) - (l—>4) - (2, 3-di~0-methyl~P-D~ 15 glucopyranosyluronic acid) - (1-+4) - (2, 3, 6-tri -O-sulphonato- (X-D-glucopyranosyl) - (l—>4) - (2,3, -di~0~ methyl-CC-L-idopyranosyluronic acid) - (l—>4) -2, 3, 6-tri-O-BVLlphonato-a-D-glucopyranoside, sodium salt (44) This hydrogenolysis was carried out twice 20 and, on each occasion, on 534.4 mg of the compound 51. A solution of the compound 51 (534.4 mg) in a tert-butanol (6.7 ml, 12.6 ml/g)/water (10 ml, 19 ml/g) mixture is treated under hydrogen pressure (5 bar) in the presence of 10% 'palladium-on-charcoal (160 mg) at 25 40°C for 4 hours. After filtering (Millipore® LSWP 5 Mm filter), the solution is concentrated to dryness to give 530 mg of the compound 44. TLC: R£ = 0.49, 3/5/1/3 v/v/v/v ethyl acetate/pyridine/-acetic acid/water. EXAMPLE 1 Methyl (2, 3, 4, 6-tetra-O-sulphonato-a-D-glucopyranosyl) - (l~->4) - (2r 3, 6-tri~0-sulphonato-a-D-glucopyranosyl) -(l—>4) - (2, 3, 6-tri-O-sulphonato-p-D-glucopyranosyl) -(l->4) - (6-biotinamido-6-desoxy-2f 3-di-O-methyl-a-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-fi-D-5 glucopyranosyl) - (l—>4) - [ (2, 3r 6-tri-O-methyl-a-D-glucopyranosyl) - (l—>4) -O- (2, 3, 6-tri-O-methyl-p-D-glucopyranosyl) - (l—>4) ]3- (6-0-sulphonato-2,3-di-0-methyl-a-D-glucopyraxiosyl) - (l—>4) - (2, 3-di-O-methyl-fi-D-glucopyranosyluronic acid) - (l—>4) - (2, 3, 6-tri -O-10 sulphonato-CC-D-glucopyranosyl) - (l—>4) - (2, 3-di-O-methyl-CC-L-idopyranosyluronic acid) - (l—>4) -2, 3, 6-tri-O-sulphonato-a-D-glucopyranoside, sodium salt Biotin sulphosuccinimide (16.5 mg) is added to a solution of the compound 37 (18 mg, 3.72 flmol) in 15 0.5% sodium hydrogen carbonate (1.5 ml). After stirring for 16 hours at ambient temperature, the reaction mixture is deposited on a column of Sephadex" G-25 Fine eluted with sodium chloride. 20 The fractions comprising the product are concentrated and desalting is carried out on the same column eluted with water. After lyophilizing, 15.9 mg of the compound of Example 1 are obtained. 25 [ Methyl (2, 3, 4, 6-tetra-O-sulphonato-a-D-glucopyranosyl) -(l—>4) - (2, 3, 6-tri-O-sulphonato-a-D-glucopyranosyl) -(l->4) - (2,3, 6-tri-0-sulphonato~f}-D-glucopyranosyl) -(l—>4) - (6-16- (biotinamido)hexamidoj -6-deoxy-2', 3-di-O-5 methyl-cc-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-0~methyl-fi-D-glucopyranosyl) - (l->4) - [ (2, 3, 6-tri-O-methyl-a-D-glucopyranosyl) - (l—>4) -O- (2, 3, 6-tri~0-methyl-f}-D-glucopyranosyl) - (l—>4)]3- (6-0~sulphonato-2,3-di-0-methyl-a-D-glucopyranosyl) - (l->4) - (2,3-di-O-methyl-fi-D-10 glucopyranosylsyluronic acid) - (l—>4) - (2, 3, 6-tri-O- sulphonato-a-D-glucopyranosyl) - (l—>4) - (2,3-di-O-methyl-a-L-idopyranosyluronic acid) - (1~>4) ~2, 3, 6-tri-O-Bulphonato-a-D-glucopyranoside, sodium salt [lacuna] 6-(biotinamido)hexanoate (16.5 mg) 15 is added to a solution of the compound 37 (18 mg, 3.72 |Xmol) in 0.5% sodium hydrogen carbonate (1.5 ml). After stirring for 16 hours at ambient temperature, the reaction mixture is deposited on a column of Sephadex G-25 Fine eluted with sodium chloride. 2 0 The fractions comprising the product are concentrated and desalting is carried out on the same column eluted with water. After lyophilizing, 17.9 mg of the compound of Example 2 are obtained. 25 [a]D = +60° (c = 1.0, water). Mass: ESI method, negative mode: chemical mass = 5178.28; experimental mass = 5176.3 ± 0.77 a.m.u. EXAMPLE 3 Methyl {2,3,4,6-tetra-O-sulphonato-a-D-glucopyranosyl)-(l->4) - (2, 3, 6-tri-O-sulphonato-a-D-glucopyranosyl) -(l—>4) - (2, 3, 6-tri-O-sulphonato-ft-D-glucopyranosyl) -(l—>4) - (6- [6- (6-biotinamidohexamido)hexamido]-6-deoxy-5 2, 3-di-O-methyl-a-D-glucopyranosyl) - (l—>4) - (2, 3, 6-tri-O-methyl-fl-D-glucopyranosyl) - (l—>4) - [ (2, 3, 6-tri-O-methyl-a-D-glucopyranosyl) - (l—>4) -O- (2, 3, 6-tri-O-methyl-fi-D-glucopyranosyl) - (l-?4)]3- (6-0~sulphonato-2, 3-di-O-methyl-a-D-glucopyranosyl) - (l—>4) - (2, 3-di-O-10 methyl-fi-D-glucopyranosyluronic acid) - (l—>4) - (2,3, 6-tri-O-sulphonato-a-D-glucopyranosyl)- (l—>4) - (2,3-di-O-methyl-a-L-idopyranosyluronic acid) - (l—>4) -2, 3, 6-tri-O-sulphonato-cc-D-glucopyranoside, sodium salt Sulphosuccinimidyl 6-(6-biotinamido-15 haxamido)hexanoate (23.6 mg) is added to a solution of the compound 37 (17 mg, 3.51 fxmol) in 0.5% sodium hydrogen carbonate (1.4 ml). After stirring for 16 hours at ambient temperature, the reaction mixture is deposited on a 20 column of Sephadex® G-25 Fine eluted with sodium chloride. The fractions comprising the product are concentrated and desalting is carried out on the same column eluted with water. After lyophilizing, 17.4 mg of the compound 25 of Example 3 are obtained. [cc]D = +64° (c = 1.0, water). Mass: ESI method, negative mode: chemical mass = 5291.44; experimental mass = 5292.1 ± 0.83 a.m.u. EXAMPLE 4 Methyl (2-biotinamido~2-deoxy-3f4-di-0-methyl-6-0-sulphonato-cc-D-glucopyranosyl) - (1-+4) - (2,3-di-O-methyl-P-D-glucopyranosyluronic acid) - (l—>4) - (2, 3, 6-tri-O-5 sulphonato-a-D-glucopyranosyl) - (l—>4) - (2,3-di-O-methyl-(X-L-idopyranosyluronic acid) - (l—>4) -2, 3, 6-tri-O-sulphonato-ct-D-glucopyranoside, sodium salt A solution of biotin W-hydroxysuccinimide (42 mg) in N,N-dimethylformamide (750 \xl) is added to a 10 solution of the compound 44 (21.2 mg, 0.012 mmol) in 0.5% sodium hydrogen carbonate (750 Jil) . After stirring for 16 hours at ambient temperature, the reaction mixture is deposited on a column of Sephadex G-25 Fine. 15 After eluting with water and lyophilizing, 22.3 mg of the compound of Example 4 are obtained. [cc]D = +38° (c = 0.15, water). Mass: ESI method, negative mode: chemical mass = 1938.48; experimental mass = 1937.48 ±0.11 a.m.u. 20 EXAMPLE 5 Methyl (2- [N- (6~biotinamidohexanoyl) ] ~2-deoxy-3r4~di-0-methyl-6-O-sulphonato-a-D-glucopyranosyl) - (l—>4) -(2,3-di-O-methyl-p-D-glucopyranosyluronic acid) - (l—>4) -(2, 3, 6-tri-O-sulphonato-a-D-glucopyranosyl) - (l—>4) -25 (2,3-di-O-methyl-oc-L-idopyranosyluronic acid) - (1-+4) -2,3, 6-tri-O-sulphonato-oc-D-glucopyranoside, sodium salt This reaction was carried out twice and, on each occasion, on 494.5 mg of the compound 44. The compound 44 (494.5 mg, 0.289 mmol) is dissolved in a 0.5% aqueous sodium hydrogen carbonate solution (116 ml). A solution of sulphosuccinimide 5 6-biotinamidohexanoate (1.46 g, -2.63 mmol) in a 0.5% sodium hydrogen carbonate solution (12 ml) is added thereto dropwise. After stirring for 16 hours at ambient temperature, a 1M aqueous sodium hydroxide solution is added and the mixture is stirred for 1 h. 10 The reaction mixture is deposited on a column of Sephadex® G-25 Fine (5 x 1 000 cm) eluted with sodium chloride. The fractions comprising the product and originating from the two reactions are combined. 15 After lyophilizing, 999.2 mg of Example 5 are obtained. TLC: Rf = 0.42, 3/5/1/3 v/v/v/v ethyl acetate/pyridine/ acetic acid/water. Mass: ESI method, negative mode: chemical mass = 20 2051.64; experimental mass: 2051.60 ±0.43 a.m.u. EXAMPLE 6 Methyl (2-16- (6-biotinamidohexamido)hexamido] -2-deoxy-3, 4-di-0-methyl-6-0-sulphonato-a-D-glucopyranosyl) -(l—>4) - (2,3-di-0~methyl-p-D-glucopyranosyluronic acid) -25 (l—>4) - (2, 3, 6-tri-O-sulphonato-a-D-glucopyranosyl) -(l—>4) - (2, 3-di-O-methyl-a-L-idopyranosyluronic acid) -(l—>4) -2,3, 6-tri-O-sulphonato-a-D-glucopyrajioside, sodium salt The compound 44 (30.1 mg, 17.6 fj.mol) is dissolved in a 0.5% aqueous sodium hydrogen carbonate solution (7 ml). A solution of sulphosuccinimidyl 6- (6-biotinamidohaxamido) (118 mg, 176 /imol) in a 0.5% 5 sodium hydrogen carbonate solution (1 ml) is added thereto dropwise. After stirring for 16 hours at ambient temperature, a 1M aqueous sodium hydroxide solution is added and the mixture is stirred for 1 h. The reaction mixture is deposited on a Sephadex G-25 10 Fine (2 x 85 cm) column eluted with sodium chloride. The fractions comprising the product are combined, concentrated and desalted on a Sephadex G-2 5 Fine (2 x 85 cm) column eluted with water. After lyophilizing, 26.5 mg of the compound 15 of Example 6 are obtained. Mass: ESI method, negative mode: chemical mass = 2164.48; experimental mass: 2164.29 ± 0.38 a.m.u. WE CLAIM: 1. Synthetic polysaccharides with anti-thrombotic activity and their pharmaceutically acceptable salts wherein said polysaccharide is of formula: in which: - the wavy line denotes a bond situated either below or above the plane of the pyranose ring, Po denotes a polysaccharide, comprising n identical or different monosaccharide units, bonded via its anomeric carbon to Pe, is a diagrammatic representation of a monosaccharide unit with a pyranose structure chosen from hexoses, pentoses and the corresponding deoxy sugars, this unit being bonded via its anomeric carbon to another monosaccharide unit and the hydroxyl groups of this unit being substituted by identical or different Ri groups, Ri being as defined below, - Pe represents a pentasaccharide of structure: h is equal to 1 or 2, - n is an integer and can take any value from 0 to 25, Ri represents the -T-Biot linkage, a (Ci-Cs) alkoxy group or an -0S03~ group, R2 represents the -T-Biot linkage, a (Ci-Ce) alkoxy group or an -OSO3" group, R3 represents the -T-Biot linkage or a {Cx-Cs)alkoxy group, R4 represents the -T-Biot linkage, a (Ci-C6)alkoxy group or an -0S03" group, or else R4 constitutes an -O-CH2- bridge, the -CH2- group being bonded to the carbon atom carrying the carboxyl functional group on the same ring; it being understood that at least one of the Ri, R2, R3 or R4 substituents represents a -T-Biot group, W represents an oxygen atom or a methylene group T represents one of the linkages chosen from: NH, in which j and k, which are identical or different, are integers which can take any value from 1 to 10; - Biot represents the group: characterized in that they exhibit at least one covalent bond with biotin or a biotin derivative. 2. Polysaccharides as claimed in Claim 1 wherein said polysaccharide is of formula (1.1): in which: denotes a specific family of polysaccharides Po which are bonded via their anomeric carbon to Pe as defined for (I), is as defined for (I), - the Ri groups are as defined for (I) and, for a same monosaccharide, can be identical or different, - the monosaccharide present in [ ]m is repeated m times, the monosaccharide present in [ ]t is repeated t times and the monosaccharide present in [ ]p is repeated p times, - m is an integer varying from 1 to 5, t is an integer varying from 0 to 24 and p is an integer varying from 0 to 24, it being understood that l and their pharmaceutically acceptable salts. 3. Polysaccharides as claimed in Claim 2, wherein only one of the Ri, R2, R3 or R4 substituents represents the -TM3iot linkage with T and Biot being as defined for (I). 4. Polysaccharides as claimed in claim 1 wherein said hexadecasaccharides is of formula (1.2) in which: T represents one of the linkages chosen from: NH, or in which j and k, which are identical or different, are integers which can take any value from 1 to 10; - Biot represents the group: - Pe represents a pentasaccharide of structure: in which: Ri represents a (Ci-C6)alkoxy group or an -OSO3 group, R represents a (Ci-C6)alkoxy group or an -OSO3 group, R3 represents a (Ci-Cejalkoxy group, R4 represents a (Ci-Ce)alkoxy group or an -OSO3 group, or else R4 constitutes an -O-CR2- bridge, the -CR2 group being bonded to the carbon atom carrying the carboxyl functional group on the same ring, W represents an oxygen atom or a methylene group, and their pharmaceutically acceptable salts. 5. Polysaccharides as claimed in claim 1 wherein said pentasaccharides of formula (1.3): in which Ri, R2, R3, R4 and W are as defined for (I), and their pharmaceutically acceptable salts. 6. Polysaccharides as claimed in claim 5 wherein only one of the Ri, R2, R3 or R4 substituents represents the -T-Biot linkage with T and Biot being as defined for (I). 7. Polysaccharides as claimed in either of Claims 5 and 6 of formula (1.3) of formula (1.4) in which: T represents one of the linkages chosen from: NH, in which j and k, which are identical or different, are integers which can take any value from 1 to 10; - Biot represents the group: Ri represents a (Ci-Cejalkoxy group or an -0SO3 group, R2 represents a (Ci-C6)alkoxy group or an -OS03 group, R3 represents a (Ci-C6)alkoxy group, R4 represents a (Ci-C6)alkoxy group or an -OSO3 group, or else R4 constitutes an -O-CH2- bridge, the -CH2- group being bonded to the carbon atom carrying the carboxyl functional group on the same ring, - W represents an oxygen atom or a methylene group, and their pharmaceutically acceptable salts. 8. Polysaccharides as claimed in Claim 1 wherein said polysaccharides are chosen from: Methyl (2, 3, 4, 6-tetra-O-sulphonato-Ct-D-gluco-pyranosyl) - (1—»4) - {2,3, 6-tri-0--siilphonato-a-D~ glucopyranosyl) - (l-*4) - (2,3, 6-tri-O-sulphonato-P-D-glucopyranosyl) - (l-»4) - (6-biotinamido-6-deoxy-2, 3-di-O-methyl-a-D-glucopyranosyl) - (1—»4) -(2,3,6-tri-0-methyl-J3-D-glucopyrahosyl)-(l-»4) -[(2,3, 6-tri-O-methyl-cc-D-glucopyranosyl} - (1—»4) -0-(2,3, 6-tri-0-methyi-j3-D~glucopyranosyl) - (1^4) ]3-(6-0-sulphonato-2,3-di-O-methyl-a-D-gluco-pyranosyl) - (1—»4) - (2, 3-di-0-methyl-p*-D-glucopyrano-syluronic acid)- (1^4) -(2,3, 6-trI-O-sulphonato-ct-D-glucopyranosyl)- (l-»4)- (2, 3-di-O-methyl-CC-L-idopyranosyluronic acid) - (1—>4) -2,3, 6-tri-O-sulphonato-a-D-glucopyranoside, sodium salt, Methyl (2,3,4,6-tetra-0-sulphonato-a-D-gluco-pyranosyl) - (1—>4) -(2,3, 6-tri-0-s\ilphonato-a-D-glucopyranosyl) - (l->4) -(2,3, 6-tri-0-sulphonato-{3-D~ glucopyranosyl)- (l-»4) -(6-[6-(biotinamido)- itexamido]-6-deoxy-2,3-di-O-methyl-a-D-gluco-pyranosyl}-(l-»4)-(2,3, 6-tri-O-methyl-p-D-gluco-pyranosyl) - (1-^-4) - [(2,3, 6~tri-0-methyl-a-D-gluco-pyranosyl) - (1—^4) -0- (2,3, 6-tri-0~methyl-{J-D-gluco-pyranosyl) - (l->4) h~ (6-0~sulphonato-2, 3-di-O-methyl-cc-D-glueopyraiiosyl) - (1—»4) - (2, 3-di-O-methyl-P~p-glucopyranosyluronic acid)-(l-»4) -(2,3,6-tri-O-sulphonato-a-D-glucopyranosyl)-(1—>&)-(2,3-di-O-methyl-a-L-idopyranosyluronic acid)-(l->4)-2, 3, 6-tri-O-sulphonato-a-D-glucopyranoside, sodium salt, Methyl (2,3,4, 6-tetra-0-sulphonato-a-D~gltico-pyranosyl) - {l-»4} -{2,3, 6-tri-0-sulphonato-a~D-giucopyranosyl)-(1—>4) -(2,3,6-tri-O-sulphonato-p-D-glucopyranosyl)-(1—»4)-(6-[6-(6-biotanaraido-hexamidojhexamido]-6-deoxy-2,3-di-O-methyl-a-D-glucopyranosyl) - (1™>4) - (2,3, 6-tri-O-methyl-p-D-glucopyranosyl) - (1—»4)~ [ (2, 3, 6-tri-0-metiiyl~a--D-glucopyranosyl} - (1—>4} -0- (2,3, 6-tri-0-tnethyl-p~D-glucopyranosyl} - (1—>4) ]3- (6-0-sulphonato-2, 3-di-0-methyl-cc-D-glucopyranosyl) ~(1—»4) -(2, 3-di-0-methyl-P-D-glucopyranosyluronic acid) - (1—>4) -(2,3, 6-tri™0-stilphonato-cc-D-glucopyraxiosyl) -(1—>4)-(2,3-di-0-raethyl~a-L-idopyranosyluronic acid) - {l->4) -2, 3, 6-tri-O-sulphonato-cc-D-gluco-pyranoside, sodium salt, Methyl (2-biotinamido-2-deoxy-3, 4-di-O-methyl-6-0-sulphonato-a-D-glucopyranosyl)-(1~>4) -(2, 3-di-0- methyl-P-D-glucopyranosyluronic acid)-(1—»4) -(2,3, 6-tri-0-sulphonato-cc-D-glucopyranosyl) -(l-»4)-(2,3-di-0~methyl-a-L-idopyranosyluronic acid} - (l-»4) ~2,3, 6-tri-O-sulphonato-cc-D-gluco-pyranoside, sodium salt, Methyl (2-[6-(6-biotinamidohexamido)hexamido]-2-deoxy-3,4-di-0-methyl-6-O-sulphonato-cc-D-gluco-pyranosyl) - (l-»4) - (2,3-di-0-methyl~[3~D-gluco-pyranosyluronic acid)- (1—>4}-(2,3,6-tri-0-sulphonato-a-D-glucopyranosyl) - (l-»4) - (2, 3-di-O-methyl-a-L-idopyranosyluronic acid) - (l—>4) -2,3,6-tri-O-sulphonato-a-D-glucopyranoside, sodium salt, Methyl (2-[6-(6-biotiriamidohexamido) hexamido]-2-deoxy-3,4-di-0-methyl-6-0~sulphonato-a~D-glucopyranosyl)- (1—>4) -(2, 3-di-O-methyl-P-D-glucopyranosyluronic acid)- (1—>4)-(2,3,6-tri-O-sulphonato-a-D-glucopyranosyl)- (1—>4) -(2, 3-di-0-methyl-a-L-idopyranosyluronic acid) - (1—»4) -2,3,6-tri-O-sulphonato-a-D-glucopyranoside, sodium salt. 9. Pharmaceutical compositions comprising, as active principle a polysaccharide as claimed in any one of claims 1 to 8, in a quantity of 0.1 to lOOmg per dosage unit, optionally in combination with one or more inert and appropriate recipients. Dated this 05th day of March, 2003. [DEEPAK KUMAR] OF REMFRY & SAGAR ATTORNEY FOR THE APPLICANTS] |
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283-mumnp-2003-cancelled pages(18-9-2007).pdf
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| Patent Number | 213853 | |||||||||||||||
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| Indian Patent Application Number | 283/MUMNP/2003 | |||||||||||||||
| PG Journal Number | 12/2008 | |||||||||||||||
| Publication Date | 21-Mar-2008 | |||||||||||||||
| Grant Date | 21-Jan-2008 | |||||||||||||||
| Date of Filing | 05-Mar-2003 | |||||||||||||||
| Name of Patentee | SANOFI-SYNTHELABO | |||||||||||||||
| Applicant Address | VELPERWEG 76, 6824 BM IN ARNHEM, | |||||||||||||||
Inventors:
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| PCT International Classification Number | C08B 37/00 | |||||||||||||||
| PCT International Application Number | PCT/FR01/2918 | |||||||||||||||
| PCT International Filing date | 2001-09-20 | |||||||||||||||
PCT Conventions:
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