Potassium Carbonate → Piperazine, 1-(5-isoquinolinylsulfonyl)-4-methyl-

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Reaction Steps

In 100 ml of chloroform was dissolved 5.0 g of 1-methylpiperazine, and to the solution was added 6.9 g of anhydrous potassium carbonate. To the mixture was added dropwise 200 ml of a chloroform solution containing 1.4 g of 5-isoquinolinesulfonyl chloride under cooling with ice. After the dropwise addition of the chloroform solution, the mixed solution thus obtained was stirred for one hour under cooling with ice, and then the reaction solution was washed with 50 ml of a 5N aqueous sodium hydroxide solution and extracted twice with 50 ml of a 5N aqueous hydrochloric acid solution. The aqueous hydrochloric acid layer was rendered alkaline, extracted three times with 100 ml of chloroform, and the chloroform layer extracted was washed with water and dried with anhydrous magnesium sulfate. After the chloroform was distilled therefrom under reduced pressure, 50 ml of a 5N aqueous hydrochloric acid solution was added to the residue and the mixture was condensed to dryness under reduced pressure. The crystalline residue thus obtained was recrystallized from ethanol to give 14.9 g of 1-(5-isoquinolinesulfonyl)-4-methylpiperazine [i.e., Compound (36)] dihydrochloride in a yield of 82%.

Provenance & Evidence