Synthesis of 4-substituted 2-aminopyrrolo[2,3-d]pyrimidine 2′,3′-dideoxyribonucleosides

A number of new 2‐aminopyrrolo[2,3‐d]pyrimidine N‐7‐(2′,3′‐dideoxyribonucleosides) (11–13 and 15) were synthesized. These are related to 7‐deaza‐2′,3′‐dideoxyguanosine (14), but carry various substituents at C‐4. 2‐Amino‐4‐chloro‐7‐(2′,3′‐dideoxy‐β‐D‐glycero‐pentofuranosyl)‐7H‐pyrrolo[2,3‐d]‐pyrimidine (3) was used as a common intermediate, and was obtained from the corresponding 2′‐deoxyribonucleoside 4 by selective silylation of 5′‐OH and Barton deoxygenation of 3′‐OH.