3-[8-cyclopentyl-1-[3-(4-fluorosulfonylbenzoyl)oxypropyl]-2,6-dioxo-7H-purin-3-yl]propyl 4-fluorosulfonylbenzoate
4-fluorosulfonylbenzoic acid 3-[8-cyclopentyl-1-[3-[(4-fluorosulfonylphenyl)-oxomethoxy]propyl]-2,6-dioxo-7H-purin-3-yl]propyl ester
4-fluorosulfonylbenzoic acid 3-[8-cyclopentyl-1-[3-(4-fluorosulfonylbenzoyl)oxypropyl]-2,6-diketo-7H-purin-3-yl]propyl ester
3-[8-cyclopentyl-1-[3-(4-fluorosulfonylphenyl)carbonyloxypropyl]-2,6-dioxo-7H-purin-3-yl]propyl 4-fluorosulfonylbenzoate