135052-71-0 2H-Purin-2-one, 6-amino-1,3-dihydro-3-(5-O-(hydroxy(phosphonooxy)phosphinyl)-beta-D-ribofuranosyl)- 3-Isoisoguanosine 5'-diphosphate 3-Ribofuranosylisoguanosine 5'-diphosphate