Synthesis and in vitro antioxidant activity of some 8-hydoxyquinoline derivatives

A series of 8-hydroxyquinoline derivatives 3a-c, were prepared by the reaction of 5-Cyanomethyl-8- hydroxyquinoline 2a and 5-Azidomethyl-8-hydroxyquinoline2b with different secondary amines under the conditions of the Mannich reaction in refluxing ethanol. The synthesized compounds were screened for the antioxidant activity by DPPH (2,2- diphenyl-1-picrylhydrazyl) method. Ascorbic acid was used as standard. All the compounds showed DPPH radical scavenging activity, where compound 3b was the best radical scavenger.