3-Formylpyrroles from 3-Furfurylamines by Bromine Oxidation Reaction

Abstract

Oxidation of 3-furfurylamines 3a-e with bromine in acetone-water solution gave N-substituted 3-formylpyrroles 4a-e in good yields. A reaction mechanism via the Clauson-Kaas reaction followed by the cis-trans isomerization of the 2-ene-1,4-diones 13 and 14 was proposed to account for the formation of the pyrroles 4a-e.