Selective Metalation of 6-Methylpurines: Synthesis of 6-Fluoromethylpurines and Related Nucleosides

Abstract

A selective metalation at the 6-CH3 over C-8 of 6-methylpurine derivative 6 was observed with softer counter cation (Na⁺ or K⁺) of the base, while the harder Li⁺ showed no selectivity. In the presence of N-fluorobenzenesulfonamide (NFSI), this property was utilized for the synthesis of 6-fluoromethylpurine derivatives 4 and 5 as potential toxins for suicide gene therapy.