Derivatives of alpha-alkyl polyolefinic carboxylic acid useful in the treatment of psoriasis

Compounds of the structure ##STR8## wherein n is 0 to 3,

• m is 0 to 1, and
• R.sub.1 and R.sub.4 are each independently hydrogen or an alkyl group of from 1 to 5 carbon atoms;
• R.sub.2 is an alkyl group of from 1 to 5 carbon atoms;
• R.sub.3 is ##STR9## retinoyloxy, or ##STR10## R.sub.5 is independently H, C.sub.1 -C.sub.20 alkyl, aryl, aralkyl, and Z is a cycloalkyl, cycloalkenyl or cyclodialkenyl group substituted with from 0 to 5 C.sub.1 -C.sub.5 alkyl groups, a keto group or a hydroxyl group, or a phenyl group substituted with from 0 to 4 hydroxy, C.sub.1 -C.sub.5 alkoxy, C.sub.1 -C.sub.5 alkyl or trifluoromethyl groups or halogen atoms or combinations thereof;
• and the pharmaceutically-acceptable salts thereof.