Halogenomethylene-indoxyls

摘要

Novel halogenomethylene-indoxyls [halogeno-(3-oxa-[2H]- indol-2-ylidene)-acetic acids] and a novel process for their preparation by reacting N-acylanilides with dihalogenomaleic anhydrides or derivatives thereof are described. The novel halogenomethylene-indoxyls are valuable intermediates for the preparation of pharmaceutical active compounds having anti-allergic properties.