Green synthesis of pyrimido-isoquinolines and pyrimido-quinoline using ZnO nanorods as an efficient catalyst: Study of antioxidant activity

In this paper, we report the synthesis of pyrimido[2,1-a] isoquinoline and pyrimido[1,2-a]quinoline derivatives in high yields from the reaction of isoquinoline or quinoline, activated acetylenic compounds, and amides in the presence of ZnO nanorods (ZnO-NRs) as catalyst under solvent-free conditions at room temperature. ZnO-NRs show good improvement in the yield of the product and significant reusability. Also, the antioxidant activities of the some of the newly synthesized compounds were carried out by 1,1-diphenyl-2-picrylhydrazyl (PDDH) radical trapping and ferric ion reducing potential tests and compared with those of the synthetic antioxidants 2-tert-butylhydroquinone (TBHQ) and butylated hydroxytoluene (BHT). These compounds do not show good DPPH radical scavenging but display good ferric ion reducing power.