Rapid synthesis of novel 1,8-dioxoacridine carboxylic acid derivatives by microwave irradiation and their free radical scavenging activity

Synthesis of novel acridine carboxylic acid compounds 4–18 was performed with the reaction of 4-aminobenzoic acid 1, aromatic aldehyde 2a–n, 1,3-diketone 3a, 3b using microwave irradiation. These compounds were synthesized efficiently in one-pot procedure for 6 min without catalyst in high yields of 65–90 % using little ethanol. Radical scavenging activities of synthesized compounds 4–18 were determined by means of in vitro test using 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid radicals (ABTS·+). The activities of tested compounds were compared to the positive control such as butylated hydroxyanisole, butylated hydroxytoluene, and trolox. The results showed that the synthesized compounds 4, 6, 14, and 15 had effective free radical scavenging activity.