Abstract
An efficient, a hitherto unreported, sustainable, and environmentally friendly microwave-assisted synthesis of 2,3-disubstituted quinolines by reductive cyclization of 2-nitrobenzaldehydes and various active methylene compounds via tandem Knoevenagel condensation promoted by an efficient eco-friendly, chemoselective reducing catalyst ammonium chloride (NH4Cl) and zinc powder was developed. This present methodology is a mild, green, efficient, and environmentally benign process as it eliminates the harsh reaction conditions, non-volatile solvents, relatively expensive reagents, high catalyst loading, and also provides a number of other benefits like fast synthesis, simple reaction set-up, and good to the excellent yield of the products.