Patent ID: 7598372

Claim:
A method for preparing a trisaccharide (Manβ1→4GlcNβ1→4GlcN) of a reducing terminal in the core sugar chain structure of an asparagine-linked glycoprotein, comprising (1) a process of preparing a mannose disaccharide compound (a type of ManP 1 β1→4ManP 1 ) of the formula (I) wherein P 1 , OH-protecting group selected from the group consisting of acetyl, benzyl, 4-methoxybenzyl, benzoyl, methoxymethyl, tetrahydropyranyl, trimethylsilyl and triethylsilyl, and the wavy line means that —OP 1 is linked at an axial or equatorial position, or mixture of both, by hydrolyzing a polysaccharide having mannoseβ-1,4-bonds and protecting OH groups of the resulting hydrolysate, (2) a process of preparing a glycal compound, in which mannose of a reducing terminal of the mannose disaccharide is converted to glycal, by halogenation and reduction of the mannose disaccharide (a type of ManP 1 β1→4ManP 1 ), (3) a process of preparing an azide disaccharide compound (a type of ManP 1 β1→4ManP 1 ) shown with formula (II) in which a 2-azide group of mannose in a reducing terminal is linked at an equatorial position; wherein P 1 is the same as described above, the wavy line means that —ONO 2 is linked at an axial or equatorial position, or mixture of both, by azidenitration reaction of the glycal compound above, (4) a process of substituting the nitro group of the azide disaccharide compound (a type of ManP 1 β1→4ManP 1 ) with a leaving group selected from the group consisting of fluorine atom, chlorine atom, trihaloacetoimidate, 4-pentenyl, alkylthio and arylthio, and (5) a process of preparing a trisaccharide compound (a type of Manβ1→4GlcNP 1 β1→4GlcNP 2 ) shown with the formula (III); wherein P 1 is an OH-protecting group, as described above, P 2 is an OH-protecting group selected from the group consisting of acetyl, benzyl, 4-methoxybenzyl, benzoyl, methoxymethyl, tetrahydropyranyl, trimethylsilyl and triethylsilyl, P 3 is an amino-protecting group selected from the group consisting of phthalimide, tert-butyloxycarbonyl, benzyloxycarbonyl, acetyl, benzoyl and benzyl, and P 11 is an OH-protecting group selected from the group consisting of acetyl, benzyl, 4-methoxybenzyl, benzoyl, methoxymethyl, tetrahydropyranyl, trimethylsilyl and triethylsilyl, by a reaction of the product having the leaving group with amino-protected glucopyranoside shown with the formula; wherein P 2 , P 3 and P 11 are the same as described above.