Thermal rearrangement of ethyl 5-nitro-4-phenyl-2-oxa-3-azabicyclo[3.1.0]hex-3-ene-1-carboxylate into a quinoxaline system

Abstract

The title compound 2 is found to undergo thermal isomerization into the quinoxaline derivative 3, as shown by a crystal structure determination of the latter; a mechanistic rationale for this unusual rearrangement is suggested.