Synthesis and characterization of some heterocyclic schiff bases: potential anticonvulsant agents

摘要

A series of novel schiff bases of 3-aminomethyl pyridine have been synthesized through condensation reaction with substituted aryl aldehydes/ketones and/cyclic ketones. These schiff bases were screened for anticonvulsant activity. The chemical structures of synthesized compounds were confirmed by FT-IR, 1H-NMR, spectroscopy, and elemental analysis. A number of compounds were observed to exhibit seizures protection after intraperitoneal administration at the dose 30 and 100 mg kg−1 in various models employed. In MES screen we found five potent compounds i.e., (1_c) N-(2-chlorobenzylidene) (pyridin-3-yl) methanamine, (1_f) 2-methoxy-4-{(pyridine-3-ylmethyl imino) methyl} phenol, (2_a) N-(3phenylallylidene) (pyridin-3-yl) methanamine, (3_b) 3-{1-(pyridin-3-ylmethylimino) ethyl} benzenamine, and (4_a) N-(diphenyl-methylene) (pyridin-3-yl) methanamine, emerged as most active compounds in series (ED₅₀) 11.70, 6.39, 11.70, 8.64, and 9.13 mg kg−1 with high protective index (PI) > 10. Four compounds (1_e) 4-{(Pyridine-3-ylmethylmino) methyl}benzene-1,3-diol, (1_g) N-(3,4,-dimethoxybenzylidene) (pyridin-3-yl)methanamine, (2_b) N-{(1H-indol-3-yl)methylene}(pyridin-3-yl) methanamine, and (5) N-cyclohexylidene (pyridine-3-yl) methanamine) showed remarkable protection over clinically used drugs in sc.PTZ screen (ED₅₀) 6.44, 11.70, 6.47, and 14.16 with (PI > 10). Compound (4_b) showed good anticonvulsant activity (ED₅₀) 20.79, but with relatively higher neurotoxicity (PI, 0.57). Compound (1_e) was active in both sc.PTZ and in sc.STR seizures. Some selected compounds were subjected to oral MES screen (30 mg kg−1) in rats, most of the compounds showed peak activity after 0.5 h of oral administration.