Synthesis and Anti-Oxidant Activity of Novel Pyrimido[4,5-b]quinolin-4-one Derivatives With a New Ring System

Abstract

Reaction of 2-Hydrazino-derivative 6b with aliphatic acids yielded the triazolopyrido-pyrimidines 7a, b. Also, reaction of 6b with carbon disulfide or potassium thiocyanate afforded 10-mercapto/aminotriazolopyridopyrimidine (9,10), respectively. Compound 6b reacted with nitrous acid gave tetrazolopyridopyrimidine 11, the latter compound 11 reduced to 10-amino-derivative 12. Pyridopyrimidine derivatives 4b reacted with hydrazonoylchloride derivatives yielded triazolopyridopyrimidines 14a–c. Also, the reaction of 6b with aromatic aldehydes afforded the arylidines derivatives 16a–d, which were cyclized to triazolopyridopyrimidines deivatives 17a–d. Compound 6b reacted with α-haloketones to give triazines derivatives 18 with new ring systems. On the other hand, reaction of 6b with β-ketoesters afforded 10-pyrazolyl-pyridopyrimidines derivatives 19,20a–c, and 22. The latter compound was coupled with aldehydes and arylamine to give the derivatives 23,24, respectively. The antioxidant activity using ABTS revealed that compound 9 exhibited an inhibitory effect (80%), compound 17c protected the hemolysis of erythrocytes induced by AAPH.