Potassium Hydroxide → 2-[2-(4-methyl-1-piperazinyl)ethylthio]-5-phenyl-7-chloro-3H-1,4-benzodiazepine difumarate

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Reaction Conditions

Reaction Steps

To a solution of 5.7 g of 1,3-dihydro-5-phenyl-7-chloro-2H-1,4-benzodiazepine-2-thione in a solvent mixture comprising 57 ml of a 10% aqueous potassium hydroxide solution and 6 ml of tetrahydrofuran is added at room temperature with stirring 7.0 g of 1-chloro-2-(4-methyl-1-piperazinyl)ethane dihydrochloride, and the resulting mixture is stirred at 40° C. for 4 hours. The reaction mixture is diluted with an aqueous sodium chloride solution and then extracted with ethyl acetate. The extract is washed with water and dried over magnesium sulfate, and the solvent is removed by distillation under reduced pressure. An oily product obtained as the residue is dissolved in ethyl alcohol and added with 3.8 g of fumaric acid, and the solvent is distilled off under reduced pressure to obtain a crystalline product. Recrystallization from tetrahydrofuran to obtain 5.4 g of 2-[2-(4-methyl-1-piperazinyl)ethylthio]-5-phenyl-7-chloro-3H-1,4-benzodiazepine difumarate, m.p. 193°-194° C. (decomposition), yield 42%.

Provenance & Evidence