Present study focused on the synthesis of 5-carboxyescitalopram analogue (13) and evaluation of cholinesterase activity. The main objective of the study is the purification of citalopram oxalate, synthesis of 5-carboxamidoescitalopram (11), preparation of 5-carboxyescitalopram (12) and its derivative (13) with diphenylamine and acetic acid by refluxing. Compounds (11) and (12) is characterized by MS-(ESI) and compound (13) is characterized by FT-IR and UV spectroscopy. In UV spectra
compound 13 showed maximum absorption at 238 nm. biological evaluation of the synthesized compound (13) showed that ligand (13) is the most potent compound of the series having IC50 = 1.01 μM. Which is 25-fold less active than the standard serine (IC50 = 0.04±0.0001). The ligand 5-amidoescitalopram (11) also exhibited excellent AChE inhibition activity at IC50 = 1.29 μM. 5-carboxyescitalopram (12) has shown
good inhibition at 2.71 μM. Escitalopram (2) demonstrated AChE inhibition activity at IC50 = 5.84 μM. The ligand (13) has been found to be the most potent compound of the series with lowest IC50 = 1.31 μM. While 5-amidoescitalopram (2) has depicted excellent IC50 value at 1.91 μM. The escitalopram (2) also showed good BChE activity at 3.08 μM. 5-carboxyescitalopram (12) demonstrated good BChE activity at
3.90 μM. All these compounds exhibiting selectivity from 0.68- to < 1.90-fold more towards BChE than AchE.