STEREOSELECTIVE SYNTHESIS OF NUCLEOSIDE ANALOGUES

摘要

The invention is a process for stereoselec-tivelyproducing a dioxolane nucleoside analogue from ananomeric mixture of .beta. and .alpha. anomers represented byfor-mula (A) or formula (B), wherein R is selected from thegroup consisting of C1-6 alkyl and C6-15 aryl and Bz isben-zoyl. The process comprises hydrolyzing said mixture withan enzyme selected from the group consisting of ProteaseN, Alcalase, Savinase, ChiroCLEC-BL, PS-30, andChi-roCLEC-PC to stereoselectively hydrolyze predominantlyone anomer to form a product wherein R1 is replaced with H. The process alsoincludes the step of separating the product fromunhydrolyzed starting material. Additionally, the functional group at the C4position is stereoselectively replaced with a purinyl orpyrimidinyl or derivative thereof.