ortho-Amidoalkylation of phenols via tandem one-pot approach involving oxazine intermediate.

ABSTRACT

A new and efficient method for ortho-amidoalkylation of phenols via Mannich-type condensation with formaldehyde and lactams using recyclable solid acid catalyst is described. This is the first report for ortho-amidoalkylation of phenols by lactams via Mannich-type condensation. LC-ESI-MS/MS based mechanistic study revealed that reaction proceeds through o-quinone methide (o-QM) and an oxazine intermediate via tandem Knoevenagel condensation, formal [4 + 2]-Diels-Alder cycloaddition and acid catalyzed oxazine ring-opening.