A Multicomponent, Catalyst-free, One-Pot Synthesis of Functionalized 1,4-Dihydroquinolines and Their Antimicrobial Studies

An atom-efficient, catalyst-free, and environmentally friendly approach towards the synthesis of substituted 1,4-dihydroquinolines (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j) through a one-pot multicomponent reaction involving resorcinol, aromatic aldehyde, acetoacetanilide, and ammonium acetate has been developed. The reactions were carried out under both conventional and microwave irradiation conditions. In general, improvement in rate and yield were observed when reactions were carried out under microwave irradiation compared with classical conditions. Most of the new compounds possessed moderate to significant antibacterial and antifungal activities.