Synthesis of novel bis(pyrimido[5,4-c]quinoline-2,4(1H,3H)-dione) and its derivatives: evaluation of their antioxidant properties.

One pot cyclocondensation reaction of barbituric/thiobarbituric acid with aromatic aldehydes and p-phenylenediamine/2,6-diaminopyridine by refluxing in glacial acetic acid afforded novel bis(pyrimido[5,4-c]quinoline-2,4(1H,3H)-diones)/pyrido bis(pyrimido[5,4-c]quinoline-2,4(1H,3H)-diones. All the synthesized compounds were screened for their antioxidant activities using FRAP and DPPH methods. Compounds with chloro substituents showed relatively good antioxidant properties.