7-Halogenated 7-deazapurine 2′- C -methylribonucleosides

Abstract

7-Halogenated 7-deazapurine 2′-C-methylribonucleosides related to adenosine, inosine and guanosine were synthesized employing a “one-pot” glycosylation protocol (Vorbruggen glycosylation). The immunosine 2′-C-methylribonucleoside 4 was prepared by the same glycosylation strategy. By this route, the synthesis of the anti-HCV active compound 7-fluoro-7-deaza-2′-C-methyladenosine (1b) was notably simplified, while other nucleosides were synthesized for the first time. A single-crystal X-ray analysis of 7-fluoro-7-deaza-2′-C-methylinosine (2b) was performed showing that the glycosylic bond adopts an anti orientation (χ = –139.9(2)°), while the sugar moiety has an N conformation (C3′-endo; P = 4.3(1)°, τm = 42.4(1)°).