Novel rearrangement of an isoxazole to a pyrrole. X-Ray molecular structure of diethyl 5-(ethoxycarbonylmethyl)pyrrole-2,4-dicarboxylate

Abstract

A basic and novel example of mononuclear heterocyclic rearrangement the isoxazole–pyrrole conversion, was realized by the rearrangement of diethyl 2-(4-ethoxycarbonyl-5-methylisoxazol-3-yl)glutaconate to diethyl 5-(1-ethoxycarbonyl-2-oxopropyl)pyrrole-2,4-dicarboxylate. An ethoxy-migration was observed in the condensation reaction of 7-ethoxymethylene-6,7-dihydroxy-3-methylpyrano[4,3-c]isoxazole-4,6(7H)-dione with diethyl malonate.