[(1R,3R,4R,7S)-3-(2-amino-6-oxo-1H-purin-9-yl)-7-[[(1R,3R,4R,7S)-3-(2-amino-6-oxo-1H-purin-9-yl)-7-[[(1R,3R,4R,7S)-3-(2-amino-6-oxo-1H-purin-9-yl)-7-[[(1R,3R,4R,7S)-3-(2-amino-6-oxo-1H-purin-9-yl)-7-[hydroxy-[[(2R,3S,5R)-3-hydroxy-5-(5-methyl-2,4-dioxopyrimidin-1-yl)oxolan-2-yl]methoxy]phosphoryl]oxy-2,5-dioxabicyclo[2.2.1]heptan-1-yl]methoxy-hydroxyphosphoryl]oxy-2,5-dioxabicyclo[2.2.1]heptan-1-yl]methoxy-hydroxyphosphoryl]oxy-2,5-dioxabicyclo[2.2.1]heptan-1-yl]methoxy-hydroxyphosphoryl]oxy-2,5-dioxabicyclo[2.2.1]heptan-1-yl]methyl [(2R,3S,5R)-2-(hydroxymethyl)-5-(5-methyl-2,4-dioxopyrimidin-1-yl)oxolan-3-yl] hydrogen phosphate