Acid-catalysed rearrangements in the furan series. III. The reaction of 2-Acetoxy-5-nitro-2,5-dihydro-2-furylmethylene diacetate with methanolic hydrogen chloride

Abstract

Vigorous treatment of 2-acetoxy-5-nitro-2,5-dihydro-2-furylmethylene diacetate with hydrogen chloride in methanol has been shown to give methyl 5,5-dimethoxy-4-oxopentanoate rather than methyl 5,5-dimethoxy-2-oxopent-3-enoate as suggested by Srogl and Peterek. In addition several other previously unreported products of the reaction have been isolated and their structures assigned. When the acid treatment is performed under mild conditions, the main product of the reaction is cis-2,5-dimethoxy-2,5-dihydrofurfuraldehyde dimethyl acetal which under more vigorous acid conditions is converted into a complex mixture similar to that obtained by vigorous acid treatment of the parent acetoxy nitro compound.