Hydrogen Bromide → 2,2,4,6-Tetramethyl-5-[4-(4-methylphenyl)piperazin-1-yl]-2,3-dihydro-1-benzofuran-7-ol

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Reaction Conditions

Reaction Steps

To 1-(7-methoxy-2,2,4,6-tetramethyl-2,3-dihydro-1-benzofuran-5-yl)-4-(4-methylphenyl)piperazine (444 mg, 1.18 mmol) synthesized in Example 62, acetic acid (7 mL) and 48% aqueous solution of hydrobromic acid (7 ml) were added, followed by stirring at 100° C. for 12 hours. After cooling to room temperature, aqueous solution of saturated sodium hydrogen carbonate was added to the mixture solution, and then the mixture solution was extracted with ethyl acetate. The extract solution was dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure. The resulting residue was purified by silica gel column chromatography (hexane-ethyl acetate 100:0-90:10) and the resulting solids were recrystallized from hexane-ethyl acetate to obtain the title compound 71.0 mg (yield 16%). Melting point was 185 to 189° C.

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