Synthesis of Acyclic Nucleotide Analogues Derived from 6-(sec- or tert-Alkyl)purines via Coupling of 6-Chloropurine Derivatives with Organocuprates

Abstract

Coupling of 9-[2-(diisopropyloxyphosphonylmethoxy)ethyl]-6-chloropurine (23) (and (R)-9-[2-(diisopropyloxyphosphonylmethoxy)propyl]-6-chloropurine (24), respectively) with organocuprates derived from Grignard reagents afforded after deprotection 6-(sec- or tert-alkyl) substituted phosphonates 31-36. As a model a series of 6-(sec- or tert-alkyl)purines 2-12 was also prepared.