Patent ID: 6977300

Claim:
A compound of the Formula I or Formula II: wherein: R 1 and R 2 are independently chosen from hydrogen, optionally substituted alkyl, or a group -D-E, in which D is a covalent bond or alkylene, and B is optionally substituted alkoxy, optionally substituted cycloalkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted alkenyl, or optionally substituted alkynyl, with the proviso that when D is a covalent bond E cannot be alkoxy; R 3 is hydrogen, optionally substituted alkyl or optionally substituted cycloalkyl; X is optionally substituted pyrazolene that is attached to the purine ring at a carbon atom; Y is alkylene in which one carbon atom can be optionally replaced by —O—, —S—, or —NH—, and is optionally substituted by hydroxy, alkoxy, optionally substituted amino, or —COR, in which R is hydroxy, alkoxy or amino; with the proviso that when the optional substitution is hydroxy or amino said substitution cannot be present on a carbon atom that is adjacent to a heteroatom; and Z is optionally substituted monocyclic aryl or optionally substituted monocyclic heteroaryl.