. . "ere R3'is an organic moiety comprising a steroid moiety, a terpenoid moiety, an alkaloid moiety, a polyunsaturated moiety or a primarily alkyl moiety, and A is an organic moiety consisting of at least one primarily alkyl moiety and, optionally, one or more spacers; and at least one of the following conditions applies: (1) said compound comprises at least one steroid moiety, and/or at least one alk" . . .