Regioselective reaction: synthesis and pharmacological study of Mannich bases containing ibuprofen moiety.

A series of 4-[(4-aryl)methylidene]amino-2-(substituted-4-ylmethyl)-5-{1-[4-(2-methylpropyl)phenyl]ethyl}-2,4-dihydro-3H-1,2,4-triazole-3-thione (6) were synthesized from an arylpropionic acid namely, ibuprofen by a three-component Mannich reaction. Aminomethylation of 4-[(4-aryl)methylidene]amino-5-{1-[4-(2-methylpropyl)phenyl] ethyl}-4H-1,2,4-triazole-3-thiol (5) with formaldehyde and a secondary amine furnished this novel series of Mannich bases (6). Both Schiff bases (5) and Mannich bases (6) were well characterized on the basis of IR, NMR, mass spectral data and elemental analysis. They were screened for their anti-inflammatory, analgesic, antibacterial and antifungal activities. Some of the Mannich bases (6) carrying morpholino and N-methylpiperazino residues were found to be promising anti-inflammatory and analgesic agents.