| abstract |
Disclosed herein is a process for preparation of compound 11 - (Z) - [3 - (Dimethylamino) propylidene] - 6, 11 - dihydrodibenz [b, e] oxepin -2 - yl - acetic acid (Olopatadine) and its pharmaceutically acceptable salt; comprising reacting carboxylic acid protected 11 - oxo - 6, 11 - Dihydrodibenz [b, e] oxepin - 2 - acetic acid with 3 - dimethylaminopropyl triphenyl phosphonium halide in presence of a suitable base and an organic solvent. |