Ajinomoto Co., Ltd.

Satoshi Takamatsu

Kunisuke Izawa

Satoshi Katayama

Naoko Hirose

Hiroshi Shiragami

Yumiko Uchida

Tokumi Maruyama

Yoshihito Koguchi

Process for producing 2&prime;,3&prime;-diethyl substituted nucleoside derivatives

Novel intermediates of nucleoside derivatives, of which the 6-position of the nucleic acid base moiety is substituted with a halogen atom, are produced. Using those novel intermediates, even substrates, of which the 3&prime;-position of the saccharide moiety is deoxylated, can be substituted at the 2&prime;-position at an extremely high yield. Specifically, by subjecting a 3&prime;-deoxy derivative of inosine to 6-halogenation to give a 6-halide of the derivative, and then subjecting it to 2&prime;-deoxylation/substitution with a fluorine atom or the like, followed by further subjecting it to substitution with an amino group, a hydroxyl group or any other intended substituent at the 6-positioned halogen atom, nucleoside derivatives are produced at a high yield. Methods for producing nucleoside derivatives including 9-(2,3-dideoxy-2-fluoro-&bgr;-D-threo-pentofuranosyl)adenine (FddA) and their related compounds, in a simplified manner, at a high yield and at low costs, and especially Economical methods for substituting substrates, of which the 3&prime;-position of the saccharide moiety is deoxylated, at the 2&prime;-position to produce those nucleoside derivatives on an industrial scale are also provided.

Methods for producing nucleoside derivatives and intermediates therefor

Novel intermediates of nucleoside derivatives, of which the 6-position of the nucleic acid base moiety is substituted with a halogen atom, are produced. Using those novel intermediates, even substrates, of which the 3'-position of the saccharide moiety is deoxylated, can be substituted at the 2'-position at an extremely high yield. Specifically, by subjecting a 3'-deoxy derivative of inosine to 6-halogenation to give a 6-halide of the derivative, and then subjecting it to 2'-deoxylation/substitution with a fluorine atom or the like, followed by further subjecting it to substitution with an amino group, a hydroxyl group or any other intended substituent at the 6-positioned halogen atom, nucleoside derivatives are produced at a high yield. Methods for producing nucleoside derivatives including 9-(2,3-dideoxy-2-fluoro-.beta.-D-threo-pentofuranosyl)adenine (FddA) and their related compounds, in a simplified manner, at a high yield and at low costs, and especially Economical methods for substituting substrates, of which the 3'-position of the saccharide moiety is deoxylated, at the 2'-position to produce those nucleoside derivatives on an industrial scale are also provided.

Herein is disclosed a novel and industrially advantageous process for synthesizing acyclic nucleosides such as acyclovir and ganciclovir from ribonucleosides, which process comprises adding an acid catalyst and an acid anhydride to a solution of a ribonucleoside such as guanosine and an ester derivative of an acyclic sugar, and heating the mixture, whereby a transglycosilation reaction takes place between the ribose moiety of the ribonucleoside and the ester derivative of the acyclic sugar. Herein is also disclosed an industrially favorable method for the separation of 9-substituted purine nucleosides which are important intermediates for the synthesis of acyclic nucleosides such as acyclovir, ganciclovir, and the like from ribonucleosides, which method comprises crystallizing only the 9-isomer from a solution or suspension containing both a 9-substituted purine nucleoside and a 7-substituted purine nucleoside by cooling the solution or/and by adding a crystallizing solvent thereto.

Process for isomerizing acyclic nucleosides and process for separating

Nucleoside derivatives such as 2'-deoxy-2'-bromo-5'-O-acetyl-5-methyluridine, etc., are important intermediates which can be converted into nucleoside derivatives, such as 3'-azido-3'-deoxythymidine, etc., which are useful as medicines.

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Kawasaki, Japan

Satoshi Takamatsu