An efficient method for the synthesis of 9-β-D-2′-deoxyribofuranosyl-6-methylpurine

Abstract

A new method for the preparation of 9-β-D-2´-deoxyribofuranosyl-6-methylpurine from inosine (1) is described. Inosine was converted to 6-chloropurinenucleoside (4) via acetylation, chlorination, and deacetylation. Compound 4 was transformed to the key intermediate 6-methylpurinenucleoside (7) via protection of the 2´,3´,5´-hydroxy groups of 4 with 3,4-dihydropyran to give compound 5, then methylation at the 6-position of 5 with dimethyl copper lithium gave compound 6; depyranylation of 6 led to the subsequent selective protection of the 3´,5´-hydroxy groups of 7 with O[Si(I-Pr)2Cl]2 followed by reaction with phenyl chlorothionoformate to give compound 9. Compound 9 was then converted to the target compound 11 via 2´-deoxidation and 3´, 5´-desilylation. The structures of these products were identified by Mass Spectrum (MS), ¹H-NMR (Nuclear Magnetic Resonance) spectra and elemental analysis.