4-amino-1-[(2R,3S,4S,5R)-5-azido-4-hydroxy-5-(hydroxymethyl)-3-methyloxolan-2-yl]pyrimidin-2-one;[(2R,3S,4S,5R)-2-azido-5-(2,4-dioxopyrimidin-1-yl)-2-ethyl-4-methyloxolan-3-yl] benzoate;[(2R,3S,4S,5R)-2-azido-2-ethyl-4-methyl-5-[2-oxo-4-(1,2,4-triazol-1-yl)pyrimidin-1-yl]oxolan-3-yl] benzoate;1-[(2R,3S,4S)-4-hydroxy-3-methyl-5-methylideneoxolan-2-yl]pyrimidine-2,4-dione