Trifluoroacetic acid → 1-(2,2,4,6,7-Pentamethyl-3-(4-methylphenyl)-2,3-dihydro-1-benzofuran-5-yl)-4-(4-methoxyphenyl)piperazine

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Reaction Steps

To trifluoroacetic acid was added 1-(3-hydroxy-2,2,4,6,7-pentamethyl-3-(4-methylphenyl)-2,3-dihydro-1-benzofuran-5-yl)-4-(4-methoxyphenyl)piperazine (350 mg, 0.72 mmol) obtained in Example 33 (3.5 mL) under ice cooling. The mixture was warmed to room temperature, and then triethylsilane (0.3 mL, 1.9 mmol) was added at room temperature. The mixture was stirred for 15 minutes and concentrated under reduced pressure. The residue was made to basic with saturated aqueous sodium bicarbonate and extracted with ethyl acetate. The organic extract was washed with water and saturated aqueous sodium chloride, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was crystallized from hexane to obtain 270 mg (yield 80%) of the title compound. mp. 189–191° C.

Provenance & Evidence