Hydrazine → 1-Piperazinebutanamine, 4-(1,2-benzisothiazol-3-yl)-

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Reaction Steps

The compound prepared in Example 1 (13.00 g, 28.2 mmol) was converted to the freebase by washing a methylene chloride solution of the compound with saturated aqueous sodium bicarbonate. After drying over Na2SO4, filtration, and evaporation in vacuo, the residue was dissolved in 400 mL of methanol. To this solution was added 4 mL of hydrazine (124 mmol) and the reaction was refluxed overnight. The resulting solution was evaporated in vacuo. The residue was redissolved in methylene chloride and washed with aqueous sodium carbonate. The aqueous layer was re-extracted with 2 additional portions of methylene chloride. The combined organic layers were dried with Na2SO4, filtered and evaporated to yield 8.07 g of free base. A 1 g sample of free base was crystallized from isopropanol with the addition of 4N HCl in isopropanol to yield 500 mg of the title compound as the dihydrochloride hydrate, m.p. 262°-265° C.

Provenance & Evidence