STEREOSELECTIVE SYNTHESES OF NUCLEOSIDE ANALOGS EMPLOYING INTERMEDIATE BICYCLIC COMPOUNDS

摘要

PCT No. PCT/CA94/00311 Sec. 371 Date Feb. 2, 1995 Sec. 102(e) Date Feb. 2, 1995 PCT Filed Jun. 7, 1994 PCT Pub. No. WO94/29301 PCT Pub. Date Dec. 22, 1994The present invention relates to a process for producing predominantly pure cis nucleoside analogues of formula (I), wherein X is S, or O; Y is S, CH2, O or CH(R); wherein R is azido or halogen; and R2 is a purine or pyrimidine base; via the coupling of a silylated purine or pyrimidine base in the presence of an appropriate Lewis acid with a bicyclic intermediate of formula (III) wherein Z is S or O; followed by conversion of the resulting intermediate of formula (II) to an alkyl ester and reduction to yield a compound of formula (I). IMAGE (I) IMAGE (II) IMAGE (III)