3'-O-levulinoylthymidine 、
2-Phenylsulfonylethylchloroformate (PSEC) 以
吡啶 为溶剂,
反应 0.5h,
以80%的产率得到4-Oxo-pentanoic acid (2R,3S,5R)-2-(2-benzenesulfonyl-ethoxycarbonyloxymethyl)-5-(5-methyl-2,4-dioxo-3,4-dihydro-2H-pyrimidin-1-yl)-tetrahydro-furan-3-yl ester