[[(2R,3S,4R,5S)-5-(2,4-dioxopyridin-1-yl)-3,4-dihydroxyoxolan-2-yl]methoxy-hydroxyphosphoryl] phosphono hydrogen phosphate

3-chloro-5-chloromethyl-dihydro-furan-2-one

3-bromo-5-chloromethyl-dihydro-furan-2-one

5-bromomethyl-3-chloro-dihydro-furan-2-one