[(2R,3S,5R)-2-[bis(2,2,2-trichloroethoxy)phosphoryloxymethyl]-5-(5-methyl-2,4-dioxo-pyrimidin-1-yl)tetrahydrofuran-3-yl] acetate 生成 [(2R,3S,5R)-2-[bis(2,2,2-trichloroethoxy)phosphoryloxymethyl]-5-[5-(bromomethyl)-2,4-dioxopyrimidin-1-yl]oxolan-3-yl] acetate