Hydrochloric Acid → 9-[(2,3-Difluorophenyl)methyl]-4-hydroxy-5-carbamoyl carbazole

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Reaction Steps

A solution of the 9-[(2,3-difluorophenyl)methyl]-4-hydroxy-5-carbomethoxy carbazole (514 mg, 1.4 mM) in 5 mL THF and 20 mL concentrated aqueous ammonium hydroxide was stirred at room temperature for 94 hours. The mixture was diluted with ethyl acetate and acidified to pH 1 with 5 N HCl. The aqueous layer was extracted three times with ethyl acetate. The combined organic extracts were washed with H2O and saturated brine, dried over magnesium sulfate, filtered, and concentrated. The residue was purified by column chromatography on silica gel (elution with gradient hexanes/ethyl acetate) to afford 320 mg (65%) of the 9-[(2,3-difluorophenyl)methyl]-4-hydroxy-5-carbamoyl carbazole as a yellow solid. 1H NMR (DMSO-d6) δ 10.45 (s, 1H), 8.8 (br s, 1H), 8.4 (br s, 1H), 7.8 (d, 1H, J=8 Hz), 7.5-7.2 (m, 4H), 7.05 (d, 1H, J=8 Hz), 6.95 (m, 1H), 6.6 (d, 1H, J=8 Hz), 6.35 (t, 1H, J=8 Hz), and 5.9 (s, 2H). IR (KBr, cm−1) 3350, 3125, 1628, 1598, and 1583. MS (ES) m/e 351, 353.

Provenance & Evidence