3-[(2,6-dioxo-1,3-dipropyl-7H-purin-8-yl)methylcarbamoyl]benzenesulfonyl fluoride 3-[[(2,6-dioxo-1,3-dipropyl-7H-purin-8-yl)methylamino]-oxomethyl]benzenesulfonyl fluoride 3-[(2,6-diketo-1,3-dipropyl-7H-purin-8-yl)methylcarbamoyl]benzenesulfonyl fluoride