FACILE SYNTHESIS OF 2'-DEOXYISOGUANOSINE AND RELATED 2',3'-DIDEOXYRIBONUCLEOSIDES

Abstract

The 2'-deoxyisoguanosine (1) was synthesized by a two-step procedure from 2'-deoxyguanosine (5). Amination of silylated 2'-deoxyguanosine yielded 2-amino-2'-deoxyadenosine (6) which was subjected to selective deamination of the 2-NH2 group resulting in compound 1. Also 2',3'-dideoxyisoguanosine (2) was prepared employing the photo-substitution of the 2-substituent of 2-chloro-2',3'-dideoxyadenosine (4). The latter was synthesized by Barton deoxygenation from 2-chloro-2'-deoxyadenosine (3) or via glycosylation of 2,6-dichloropurine (12) with the lactol 13. Compound 1 was less stable at the N-glycosylic bond than 2'-deoxyguanosine (5). The dideoxynucleoside 2 was deaminated by adenosine deaminase affording 2',3'-dideoxyxanthosine (17).