ChemInform Abstract: SYNTHESE EINIGER BENZOFURAN‐CARBOXAMID‐DERIVATE UND IHRE ANALGETISCHE AKTIVITAET

Abstract

Die Oxidation von Visnagin bzw. Khellin mit alkalischem Wasserstoffperoxid liefert 4‐Methoxy‐ (I) bzw. 4,7 ‐Dimethoxy‐6‐hydroxy‐benzofuran‐S‐carbon= 154 säure (II), die auf den im Formelschema angegebenen Wegen in die 4‐Methoxy‐ (V) bzw. 4,7‐Dimethoxybenzofuran‐5‐carboxamido‐6‐O‐essigsäure (VI) übergeführt werden.

Synthesis of New Furobenzoxazole and Furoflavone Derivatives

“…Compounds containing both types of heterocycles, particularly the furobenzoxazoles, and furobenzisoxazoles are of high biological importance and find wide applications as analgesic, antiinflammatory, muscle relaxant, bactericide as well as fungicide [3]. During our investigations in the benzofuran series [4], it appeared now of interest to undertake the synthesis of some new furobenzoxazole (3) and furobenzisoxazoles (5) derived from visnaginone (la) and khellinone (lb) respectively. This was achieved by condensing la and lb with hydroxylamine, followed by cyclizing the oximes 2 a and 2 b so formed, under the conditions of Beckmann rearrangement.…”

“…Compound 3 a was also obtained upon treatement of the oxime (2c), derived from visnaginone methyl ether (lc) with pyridine hydrochloride. A mixture of the oxazole (3 a) and the anilide (4) was obtained upon using hydrogen chloride gas in glacial acetic acid in the cyclization of visnaginone oxime (2 a). Similar treatment of the khellinone oxime (2 b) yielded the benzoxazole (3 b), however, as the sole reaction product.…”