| abstract |
Compounds of the formula <IMAGE> wherein R1, R2, R3 and R4, which may be identical to or different from each other, are each hydrogen, halogen, branched alkyl of 3 to 12 carbon atoms or cycloalkyl of 3 to 12 carbon atoms, provided, however, that at least one of R1 to R4 is other than hydrogen; the compounds are useful as dermatologics for the treatment of psoriasis, dandruff, ichthyosis and hyperkeratotic skin conditions. |