A PANI-Fe 3 O 4 @ZnO nanocomposite: a magnetically separable and applicable catalyst for the synthesis of chromeno-pyrido[ d ]pyrimidine derivatives.

We report herein green, practical, PANI-Fe 3 O 4 @ZnO-nanocomposite-catalyzed cyclocondensation reactions involving 4-aminocoumarin, 1,3-dimethylbarbituric acid, and aromatic aldehydes in an aqueous medium at room temperature to synthesize 9,11-dimethyl-7-aryl-6 H -chromeno[3',4':5,6]pyrido[2,3- d ]pyrimidine-6,8,10(9 H ,11 H )triones. This research aims to provide an applicable and high-yield protocol that follows the principles of green chemistry, with the use of water as an environmentally benign medium and the PANI-Fe 3 O 4 @ZnO nanocomposite as a magnetically recoverable catalyst.