[(2R,3S,5R)-3-[hydroxy-[[(2R,3S,5R)-3-[hydroxy-[[(2R,3S,5R)-3-[hydroxy -[[(2R,3S,5R)-3-hydroxy-5-(5-methyl-2,4-dioxo-pyrimidin-1-yl)oxolan-2- yl]methoxy]phosphoryl]oxy-5-(5-methyl-2,4-dioxo-pyrimidin-1-yl)oxolan- 2-yl]methoxy]phosphoryl]oxy-5-(5-methyl-2,4-dioxo-pyrimidin-1-yl)oxola n-2-yl]methoxy]phosphoryl]oxy-5-(5-methyl-2,4-dioxo-pyrimidin-1-yl)oxo lan-2-yl]methoxyphosphonic acid