1-Ethyl-1H-3-nitrobenzopyrano[4,3,2-cd]isoindole: a novel heterocyclic ring system bearing an unusually labile deuterium-exchangeable aromatic proton

The ease of deuterium exchange of the aromatic H2 of the novel heterocycle 1-ethyl-1H-3-nitrobenzopyrano[4,3,2-cd]isoindole was studied by NMR and theoretical calculations.