A versatile route to 2-alkyl-/aryl-amino-3-formyl- and hetero-annelated-chromones, through a facile nucleophilic substitution at C2 in 2-(N-methylanilino)-3-formylchromones

The N-methylanilino group in 2-(N-methylanilino)-3-formylchromones, obtained in high yield by rearrangement of C(4-oxo-4H[1]-benzopyran-3-yl)-N-phenylnitrones to 2-anilino-3-formyl-chromones followed by N-methylation, undergoes facile nucleophilic substitution by a variety of nitrogen nucleophiles, thereby paving the way for synthesis of a variety of novel 2-substituted-3-formylchromone derivatives as well as hetero-annelated chromones.