Patent ID: 6855821

Claim:
A process for preparing a D- or L-dioxolane nucleoside of formulae III-VI: wherein R is H, halogen, OH, OR′, SH, SR′, NH 2 , NHR′, NR′ 2 , lower alkyl of C 1 -C 4 , CH═CH 2 , N 3 C═CH 2 , CO 2 H, CO 2 R′, CONH 2 , CN, CONHR′, CH 2 OH, CH 2 CN, CH 2 CH 2 OH, CF 3 , CH 2 CH 2 F, CH═CHCO 2 H, CH═CHCO 2 R′, CH═CHCl, CH═CHBr, or CH═CHI; R′ is lower alkyl (C 1 -C 4 ); each X and Y is independently H, halogen, OH, OCH 3 , SH, SCH 3 , NH 2 , NHR′, NR′ 2 , or CH 3 ; and Z is CH, or C—X; comprising the steps of: 1) preparing compounds of formula VII or VIII: by: a) oxidation of 1,2-O-protected-glycerol to an acid salt, or hydrolysis of methyl (R)- or (S)-1,2-O-protected-glycerate to form intermediate 1: b) alkylation of intermediate 1 with a compound of formula X′CH 2 CH(OR 6 ) 2 , wherein X′ is halogen or pseudohalogen, and R 6 is alkyl or aralkyl (C 1-20 ); c) cyclization with an acid catalyst optionally with hydrolysis of the acetal; 2) hydrolyzing the ester group of the compound of formula VII or VIII followed by protection of the resulting alcohol under basic conditions to form a compound of formula 6 (including D- and L-isomers): wherein R 7 is a protecting group; 3) decarboxylating the carboxylic group of compound 6; and 4) coupling with a purine or pyrimidine base or its derivative, followed by deprotection to form a D- and L-dioxolane nucleoside of formulae III-VI.