SE360662

The present invention relates to a new process for the preparation of unsymmetrical substituted dihydroxy diphenyl ethenes or esters thereof comprising both new and known compounds and having valuable pharmacological activity. According to the new process acetals of the dihydroxy diphenyl ethenes are used instead of their esters for protecting the phenol groups, whereupon the mono- or diacetals of the carbinols corresponding to the desired diphenyl ethenes are debydrated in a manner known per se to form mono- or diacetals, of the desired diphenyl ethenes and either cleaving said acetals in a way known per se to form the desired dihydroxy diphenyl ethenes and, if desired, esterifying said dihydroxy compounds in a way known per se, or converting said acetals directly in a way known per se to the desired esters of the dihydroxy diphenyl ethenes. In all said cases the dehydration step and the cleavage step or the conversion step resp. may be combined into a single step. The invention also relates to certain new dihydroxy diphenyl ethenes prepared according to the invention.