The invention relates to compounds of the formula ##STR1## wherein R.sub.1 is hydrogen or methyl; A is ##STR2## or A is ##STR3## 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 ##STR4## wherein A is ##STR5## or A is ##STR6## 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.
该发明涉及下列式子的化合物:##STR1## 其中R.sub.1为氢或甲基;A为##STR2## 或A为##STR3## 其中R.sub.2为较低的烷基;R.sub.3为苯基,或苯基上被1至3个取自卤素、较低的烷基和较低的烷氧基的取代基所取代;R.sub.4为氢或甲基,或者是下列式子的相应羟酸:##STR4## 其中A为##STR5## 或A为##STR6## 而R.sub.1、R.sub.2、R.sub.3和R.sub.4如上所述;或者是上述酸的药学上可接受的盐、上述酸的C.sub.1-4烷基酯、上述酸的乙酰
氨基取代的C.sub.1-4烷基酯、上述酸的苯基二甲基
氨基酯或上述酸的.alpha.-单
甘油酯。式I和式II的化合物可用于治疗过度增生性皮肤疾病,如牛皮癣。