Synthesis and Structure-Activity Relationship of 1-(2-Furoyl)Piperazine Bearing Benzamides as Butyrylcholinesterase Inhibitors

Four benzamide derivatives (5a, 5b, 8a, 8b) bearing heterocyclic furan and piperazine ring have been synthesized and evaluated for enzyme inhibition and hemolytic activity. Initial 4-(chloromethyl)benzoyl chloride (1) and 3-(chloromethyl)benzoyl chloride (6) were stirred with benzyl amine (2a) and cyclohexyl amine (2b), respectively, in aqueous medium at pH 9 – 10 maintained by aqueous sodium carbonate. The resulting benzamides (3a, 3b, 7a, 7b) were refluxed with 1-(2-furoyl)piperazine (4) in the presence of K2CO3 and CH3CN to acquire target compounds (5a, 5b, 8a, 8b). The spectroscopic techniques including 13C NMR, 1H NMR, IR and EI-MS corroborated the proposed molecular structures of final compounds. Among these, two compounds (5b, 8b) proved to be considerable inhibitors of butyrylcholinesterase enzyme. Study of the hemolytic activity potential revealed low toxicity level of compound 5b.