C-4 substituted retinoic acid analogs, synthesis methods of C-4 substituted retinoic acid analogs and methods of using C-4 substituted retinoic acid analogs to treat various cancers and dermatological diseases and conditions. The C-4 substituted retinoic acid analogs include C-4 all-trans retinoic acid (ATRA) and 13-cis retinoic acid (13-CRA) analogs. The C-4 substituted retinoic acid analogs inhibit all-trans retinoic acid (ATRA) 4-hydroxylase activity, thereby inhibiting the catabolism of ATRA. The C-4 substituted retinoic acid analogs also have ATRA-mimetic activity. The preferred substitutions at C-4 are an azole group, a sulfur, oxygen, or nitrogen containing group, a pyridyl group, an ethinyl group, a cyclopropyl-amine group, an ester group, or a cyano group, or forms, together with the C-4 carbon atom, an oxime, an oxirane or aziridine group.
