"wherein R1, R2, and R3 each, independently of the others, is a hydrogen atom, an alkyl group, including linear and branched, saturated and unsaturated, cyclic and acyclic, and substituted and unsubstituted alkyl groups, and wherein hetero atoms either may or may not be present in the alkyl group, an arylalkyl group, including substituted and unsubstituted arylalkyl groups, wherein the alkyl portio" . . . . .