The invention relates to compounds of the formula ##STR1## wherein R.sub.1 is hydrogen or methyl; ##STR2## wherein R.sub.2 is lower alkyl; R.sub.3 is phenyl, or phenyl substituted by 1 to 3 substituents selected from the group consisting of halo, lower alkyl, and lower alkoxy; and R.sub.4 is hydrogen or methyl or the corresponding hydroxy acid of formula ##STR3## and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are as described above; or a pharmaceutically acceptable salt of said acid, a C.sub.1-4 alkyl ester of said acid, an acetylamino-substituted-C.sub.1-4 alkyl ester of said acid, a phenyl-dimethylamino ester of said acid or a .alpha.-monoglyceride of said acid. The compounds of formulas I and II are useful as agents for the treatment of hyperproliferative skin diseases such as psoriasis.
本发明涉及公式## STR1 ##的化合物,其中R.sub.1是氢或甲基; ## STR2 ##其中R.sub.2是较低的烷基; R.sub.3是苯基,或苯基取代物,取代物由卤素,较低的烷基和较低的烷氧基中选择1至3个取代基组成; R.sub.4是氢或甲基或公式## STR3 ##的相应羟基酸,其中R.sub.1,R.sub.2,R.sub.3和R.sub.4如上所述;或该酸的药学上可接受的盐,该酸的C.sub.1-4烷基酯,该酸的乙酰
氨基取代的C.sub.1-4烷基酯,该酸的苯基二甲基
氨基酯或该酸的α-单
甘油酯。公式I和II的化合物可用于治疗过度增生性皮肤疾病,如
银屑病。