Preparing etretinate, useful to treat severe psoriasis and ichthyosis vulgaris, comprises reacting acitretin with active reagent e.g. 1,1'-carbonyldiimidazole, followed by reacting with ethanol and/or alkali or alkaline earth ethanolate

摘要

Preparation of etretinate (I) comprises: (a) reacting acitretin (II) with an active reagent, which is 1,1'-carbonyldiimidazole, 1,1'-thiocarbonyldiimidazole or thionyl diimidazole to give 1-(3H-imidazole-1-yl)-3,7-dimethyl-9-(2,3,4,6-tetramethyl-phenyl)-nona-2,4,6,8-tetraen-1-one (III); and (b) reacting (III) with ethanol and/or an alkali or alkaline earth ethanolate to give a reaction mixture containing (I). ACTIVITY : Antipsoriatic; Dermatological. MECHANISM OF ACTION : None given.