An expeditious synthesis of novel pyranopyridine derivatives involving chromenes under controlled microwave irradiation

An efficient synthesis of novel pyrano[2,3-b] pyridine derivatives has been achieved by the cyclocondensation of 2-amino-3-cyano-4H-chromenes and cyclohexanone in the presence of aluminium chloride under controlled microwave irradiation. The experimental conditions have been thoroughly optimized and established, allowing significant rate enhancements and excellent yields. The starting 4H-chromenes were obtained using one pot DBU-catalysed microwave induced multicomponent condensation of resorcinol, malononitrile and aromatic aldehydes.