2-((4-chlorophenyl)sulfonyl)ethyl (((2R,3S,5R)-3-hydroxy-5-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)tetrahydrofuran-2-yl)methyl) carbonate

5'-O-[(2-cyano-1-phenylethoxy)carbonyl]thymidine

5'-O-[(2-cyano-2-phenylethoxy)carbonyl]thymidine

5'-O-{[1-(4-nitrobenzyl)2-(4-nitrophenyl)ethoxy]carbonyl}thymidine

N3-pivaloylthymidine