2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 9-[(Phenyl)methyl]-4-hydroxy-5-carbomethoxy carbazole

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Reaction Steps

A solution of the 9-[(phenyl)methyl]-5-carbomethoxy-1,2-dihydrocarbazol-4(3H)-one (1.5 g, 4.5 mM) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (1.12 g, 5.0 mM) in 25 mL of toluene was stirred between 80-90° C. for 6 h. The mixture was purified directly by column chromatography on silica gel (elution with methylene chloride/ethyl acetate) to afford 420 mg (28%) of the 9-[(phenyl)methyl]-4-hydroxy-5-carbomethoxy carbazole as a yellow solid. 1H NMR (DMSO-d6) δ10.25 (s, 1H), 7.7 (d, 1H, J=8 Hz), 7.4 (t, 1H, J=8 Hz), 7.4-7.0 (m, 8H), 6.6 (d, 1H, J=8 Hz), 5.6 (s, 2H), and 3.8 (s, 3H). IR (CHCl3, cm−1) 1723, 1685, 1621, 1597, 1568, 1496, 1453, 1442, 1392, 1286, 1267, 1156, and 1138. MS (ES) m/e 330, 332.

Provenance & Evidence