Synthesis, characterization, and analgesic activity of novel schiff base of isatin derivatives

In the present study, a series of novel Schiff bases of isatin [5a-5l] were synthesized by condensation of imesatin with different aromatic aldehydes. The imesatins were synthesized by the reaction of isatin with p-phenylenediamine. The chemical structures of the synthesized compounds were confirmed by means of Infrared (IR), Mass spectroscopy, and Elemental analysis. These compounds were screened for the analgesic activity by the tail-immersion method at a dose of 200 mg/kg body weight. Among the tested compounds 3-(4-(4-hydroxy-3-methoxylbenzylideneamino) phenylimino) indoline-2-one (5i) exhibited better analgesic activity when compared to standard pentazocine. From the above-mentioned results it may be concluded that compounds containing electron-donating groups exhibit better analgesic activity than the electron-withdrawing groups.