The reaction of aniline with 5-Nitro-2-furaldehyde. A model for non-enzymic browning reactions

Abstract

The condensation between 5-nitro-2-furaldehyde and aniline, a model for food browning reactions, yields the corresponding Schiff base, 5-nitro- 2-furfurylideneaniline, cleanly. The corresponding reaction with 2- furaldehyde itself yields, in contrast, a mixture of products. Since the equilibrium constant for formation of the Schiff base from 5-nitro- 2-furaldehyde and aniline, 177 dm³ mol^-1, is not large enough to drive the reaction to completion at moderate concentrations of aniline, phenylhydrazine was employed to trap the Schiff base as it was formed: that is, the reaction with aniline was studied by examining aniline-catalysed phenylhydrazone formation.