合成路线1

A new synthesis of lodenosine has been described: The selective benzoylation of the 6-chloropurine riboside (I) with benzoyl chloride and triethylamine through the formation of a complex with dibutyl tin oxide, gives the 3'-O-benzoyl derivative (II), which is purified by crystallization (minor impurities, about 3%, of the 2'-O derivative are present). The protection of the primary OH group of (II) by reaction with trityl chloride, DMAP and Et3N in DMF yields the 5'-O-trityl derivative (III), which is treated with DAST and pyridine to afford the fluorinated arabinofuranoside (IV). The reaction of (IV) with ammonia in methanol displaces the 6-Cl atom and hydrolyzes the 3'-O-benzoyl group giving the fluorinated arabinofuranosyladenine (V). The reaction of (V) with phenyl chlorothionoformate and DMAP in acetonitrile yields the thiocarbonate (VI), which is treated with tris(trimethylsilyl)silane and AIBN in hot toluene to afford the 3'-deoxy compound (VII). Finally, this compound is deprotected by reaction with HCl in methanol/water.