Nucleoside phosphonates: part 7. Studies on the oxidation of nucleoside phosphonate esters

Abstract

Oxidation of phosphonate mono- and di-esters with various oxidizing agents including diaryl disulphides, hexachloroacetone, and iodine, has been investigated under various reaction conditions. The most efficient oxidation procedure consists of treatment of phosphonate esters with iodine in pyridine–water. When the phosphonate esters were presilylated by treatment with trimethylsilyl chloride, the subsequent oxidation with aqueous iodine was faster. 31P N.m.r. spectroscopic studies have enabled us to propose the most likely pathway for the majority of the oxidations.