摘要 |
Prodn. of diphenhydramine (I) comprises reacting approx. equimolar amts. of benzhydrol (II) and 2-dimethylamino-ethanol (III) in presence of a slight molar excess of p-toluene sulphonic acid (IV) at the b.pt. of toluene. Opt. the (I) formed is converted to a pharmaceutically acceptable acid addn. salt. - Water formed during reaction can be eliminated as its azeotrope with toluene.
|