Synthesis and in Vitro Antiviral Activities of [(Dihydrofuran-2-yl)oxy]methyl-phosphonate Nucleosides with 2-Substituted Adenine as Base

The synthesis of [(2′,5′-dihydrofuran-2-yl)oxy]methyl-phosphonate nucleosides with a 2-substituted adenine base moiety starting from 2-deoxy-3,5-bis-O-(4-methylbenzoyl)-α-L-ribofuranosyl chloride and 2,6-dichloropurine is described. The key step is the regiospecific and stereoselective introduction of a phosphonate synthon at C(2) of the furan ring. None of the synthesized compounds showed significant in vitro activity against HIV, BVDV, and HBV.