The 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, CH.sub.2, O or CH(R); wherein R is azido or halogen; and R.sub.2 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). ##STR1##
本发明涉及一种生产主要纯的顺式核苷类似物的方法,其
化学式为(I),其中X为S或O;Y为S、CH.sub.2、O或CH(R),其中R为偶氮基或卤素;R.sub.2为
嘌呤或
嘧啶碱基;通过在适当的Lewis酸存在下,将
硅基
嘌呤或
嘧啶碱基与
化学式(III)的双环中间体偶联,其中Z为S或O;然后将所得的
化学式(II)中间体转化为烷基酯,并还原以得到
化学式(I)的化合物。##STR1##