The reactions of 2,4-dinitrobenzenediazonium ions with furans

Abstract

The reaction of 2,4-dinitrobenzene ions with furans has been investigated. The course of the reaction is very dependent on the reaction conditions. Furan and 2-methyl- and 3-methyl-furan in an aqueous acetic acid medium undergo ring opening to yield an N-(2,4-dinitroanilino)-5-hydroxypyrrol-2(5H)-one (I), but in acetic anhydride-sodium acetate medium undergo arylation. 2,5-Dimethylfuran undergoes coupling at the 3-position in aqueous acetic acid, coupling at the 2-methyl group in acetic anhydride–sodium acetate and ring opening in ethanol. The reactions with benzo[b]furan, and 2,5-diphenylfuran were also studied and both arylation and coupling reactions were observed.