Toluene → Fexofenadine Hydrochloride

Participants

Reaction Steps

To the Fexofenadine Form A (170 g; prepared as per procedure in step 1), toluene (1700 ml) is added followed by slow addition of isopropanol hydrogen chloride (prepared by purging hydrogen chloride to isopropyl alcohol) to pH 2. The reaction mass is then stirred for 10 hours 15 minutes. The solid obtained is filtered, washed with toluene (170 ml) and dried under vacuum at 75-80° C. Solid thus obtained (140 g) is refluxed in ethyl acetate (2800 ml) for about 1 hour. The reaction mixture is then cooled to room temperature and stirred for 1 hour 30 minutes. The reaction mass is filtered and washed with ethyl acetate (140 ml). The desired Form X of Fexofenadine hydrochloride is obtained after drying at 78-85° C. under atmospheric pressure till constant weight.

Provenance & Evidence