Structural revision in the reactions of 3-cyanochromones with primary aromatic amines. Improved synthesis of 2-amino-3- (aryliminomethyl)chromones

摘要

3-Cyanochromones react with primary aromatic amines to give 2-arnino-3-(arylirninomethyl)chromones as the sole products or as their mixtures with Z- and E-3-anilino-2-salicyloylacrylonitriles, depending on the reaction conditions. With aliphatic amines, 2-amino-3-(alkyliminomethyl)chromones are obtained in good yields. The reaction of 3-cyanochromone with o-phenylenediamine is reinvestigated and proof for the product structure and a possible reaction pathway are presented.