| abstract |
The present invention relates to a process for the preparation of olopatadine and, more particularly, to an improved method of synthesizing olopatadine which comprises reacting a dibenz[b,e]oxepin-11-one derivative of formula (III) and a suitable reagent under Witting condition, and to the intermediate 11-[(Z)-3-(dimethylamino)-propylidene]-6-11-dihydrodibenz[b,e]-oxepin-2-acet-amide p-toluensulfonate salt. |