Highly regioselective methylation of inosine nucleotide: an efficient synthesis of 7-methylinosine nucleotide.

A facile, straightforward, reliable, and an efficient chemical synthesis of inosine nucleotides such as 7-methylinosine 5'--monophosphate, 7-methylinosine 5'--diphosphate, and 7-methylinosine 5'--triphosphate, starting from the corresponding inosine nucleotide is delineated. The present methylation reaction of inosine nucleotide utilizes dimethyl sulfate as a methylating agent and water as a solvent at room temperature. It is noteworthy that the present methylation reaction proceeds smoothly under aqueous conditions that is highly regioselective to afford exclusive 7-methylinosine nucleotide in good yields with high purity (>99.5%).