Hydrochloric Acid → 2-[4-(6-Fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]ethanol hemifumarate

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Reaction Steps

2-[4-(6-Fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]ethyl acetate (10.58 g, 34.6 mmol), 15% NaOH (100 ml) and ethanol (100 ml) was heated at reflux for 4 hours. The solution was cooled (~5° C.) and neutralized with HCl to pH~7. The ethanol was removed under reduced pressure. The aqueous solution was basified with NaHCO3 and extracted with DCM (2×200 ml). The DCM solution was washed with brine and dried over MgSO4 and evaporated to give a white solid: 6.88 g (75%). A sample (2.03 g) was dissolved in ethanol and treated with fumaric acid (660 mg, 1.0 eq). Crystallization was induced with drops of isopropyl ether to yield off-white crystals: 1.43 g, m.p.=159°-161° C.

Provenance & Evidence