A mixture of 5-(3,7-dimethylimidazo[1,2-a]pyridin-2-yl)-2-benzothiazolinone (1.77 g) and sodium hydride (50% suspension in oil, 0.788 g) in dry dimethylformamide (24 ml) was stirred at 40° to 45° C. for 20 minutes. To the resultant mixture was added a solution of 2-diethylaminoethyl chloride hydrochloride (1.55 g) and 1.8 ml of a methanolic solution of sodium methoxide (5 mole/ml) in methanol (30 ml) at ambient temperature. The mixture was stirred for 4 hours under the same condition. The reaction mixture was poured into ice-water (300 ml) and extracted with ethyl acetate. The separated organic layer was re-extracted with 1N hydrochloric acid (25 ml) and the aqueous extract was allowed to stand for 2 hours at ambient temperature to give crystals, which was collected by filtration and dried over phosphorus pentoxide to give 5-(3,7dimethylimidazo[1,2-a]pyridin-2-yl)-3-(2-diethylaminoethyl)-2-benzothiazolinone hydrochloride (0.68 g). mp. 272° C. (dec.).
