Abstract: This invention provides compounds of the formula: wherein A and B are independent substituents selected from S, CH or N; provided that when A is S, B is CH or N; and when B is S, A is CH or N; and A and B cannot both be CH; and when A and B both equal N, one N may be optionally substituted with an C1 to C6 alkyl group; R1 and R2 are independent substituents selected from the group of H, C1 to C6 alkyl, substituted C1 to C6 alkyl, C2 to C6 alkenyl, substituted C2 to C6 alkenyl, C2 to C6 alkynyl, substituted C2 to C6 alkynyl, C3 to C8 cycloalkyl, substituted C3 to C8 cycloalkyl, aryl, substituted aryl, heterocyclic, substituted heterocyclic, CORA, or NRBCORA; or R1 and R2 are fused to form optionally substituted 3 to 8 membered spirocyclic alkyl, alkenyl or heterocyclic ring, the heterocyclic ring containing one to three heteroatoms selected from the group of O, S and N; or pharmaceutically useful salts thereof.