New opportunities with the Duff reaction

The Duff reaction (HMTA, AcOH or TFA) was studied on substituted [6 + 5] heterocyclic compounds. This reaction provides a useful route to aldehydes for Compounds bearing sensitive amide functions. It gives also access to tricyclic lactams of potential biological interest. The formation of an aminomethyl intermediate in the Duff reaction mechanism is unequivocally demonstrated.