Compounds having General Formula (I) or General Formula (II): in which R1 is chosen from C1 to C10 aliphatic or heteroaliphatic groups, optionally substituted with one or more aryl groups, substituted aryl groups, heteroaryl groups, substituted heteroaryl groups, or combination thereof; R2 is chosen from aromatic moieties, substituted aromatic moieties, heteroaromatic moieties substituted heteroaromatic moieties, and coumarin; R3 is chosen from —H, C1 to C10 aliphatic or heteroaliphatic groups, phenyl, or substituted phenyl, wherein the aliphatic or heteroaliphatic groups are optionally substituted with one or more phenyl groups, aryl groups, heteroaryl groups, substituted heteroaryl groups, or combination thereof, and wherein the aliphatic or heteroaliphatic groups are optionally bonded to R2 to form a ring; X is S or O; and Y is S or NH, may be used in pharmaceutical compositions that modify of biological signaling processes or as reagents for biological assays.