反应详情

Bromine (10 g) was added dropwise with stirring to a solution of 2-(4-aminobutyl)-3-methylpyridine sulphate (21.3 g) obtained from 2-(4-aminobutyl)-3-methylpyridine and concentrated sulphuric acid) in 65% oleum (100 ml) at room temperature. The solution was then heated to 55° C. and stirred overnight. The solution was cooled and added slowly to ice (38 g). The resultant solution was poured into water (250 ml) and taken to pH 2.5 with aqueous ammonia solution (s.g. 0.88) and a dibrominated impurity crystallized which was removed by filtration. The filtrate was taken to pH 9.5 and extracted with dichloromethane and the extracts were dried (MgSO4) and decolourised with charcoal.