Identification, synthesis and spectral characterization of impurities in process development of Escitalopram

Synthesis and identification of five process-related impurities of escitalopram are described. Structures of all the four impurities were identified by employing LC-MS (liquid chromatography-mass spectrometry) and subsequently characterized by other spectral techniques e.g. IR and NMR. Based on the spectral data, the structures of these impurities were characterized as 1-[3-(dimethylamino)propyl]-1-(4-fluorophenyl)-1,3-dihydro-2-benzofuran-5-carboxamide 4, 1-[3-(dimethylamino)propyl]-1-(4-fluorophenyl)-1,3-dihydro-2-benzofuran-5-carboxylicacid 5, N-{3-[5-cyano-1-(4-fluorophenyl)]-1,3-dihydro-2-benzofuran-1-yl]propyl}formamide 6 and 1-(4-fluorophenyl)-1-[3-(methyl amino)propyl]-1,3-dihydro-2-benzofuran-5-carbonitrile 7.