[3-(2,6-dioxo-1,3-dipropyl-7H-purin-8-yl)cyclopentyl] 2-bromoacetate 2-bromoacetic acid [3-(2,6-dioxo-1,3-dipropyl-7H-purin-8-yl)cyclopentyl] ester 2-bromoacetic acid [3-(2,6-diketo-1,3-dipropyl-7H-purin-8-yl)cyclopentyl] ester [3-(2,6-dioxo-1,3-dipropyl-7H-purin-8-yl)cyclopentyl] 2-bromoethanoate