Lithium Carbonate → 9-Benzyl-6-methoxy-9H-carbazol-4-ol

Participants

Reaction Conditions

Reaction Steps

To a mixture of 9-benzyl-6-methoxy-1,2,3,9-tetrahydro-4H-carbazol-4-one (4.23 g, 13.85 mmol) in ethylene glycol: p-dioxane ((1:1) 150 mL) is added copper (II) chloride (9.31 g, 69.26 mmol). The mixture is heated at 80° C. for 30 minutes. The mixture is partitioned between water and Et2O. The layers are separated and the organic layer washed with water (100 mL). The ether layer is dried over anhydrous sodium sulfate, filtered and concentrated. The residue is dissolved in DMF (50 mL) to which is added lithium bromide (2.45 g, 28.3 mmol) and lithium carbonate (2.09 g, 28.3 mnmol). The mixture is heated at 120° C. for 5 h. The mixture is partitioned between water and ethyl acetate. The layers are separated and the organic layer washed twice with water (200 mL). Column chromatography (250 mL) silica gel using ethyl acetate/ hexanes (20/80) gave 2.5 g (73%) of the title compound; IR (drift) 3471, 1482, 1469, 1450, 1328, 1198, 1171, 1144, 805, 799, 780, 745, 724, 717, 701 cm−1. 1H NMR (DMSO-d6) δ3.82, 5.54, 6.56, 6.97), 7.14, 7.23, 7.43, 7.72; Anal. Calcd for C20H17NO2: C, 79.18; H, 5.65; N, 4.62. Found: C, 78.99; H, 5.75; N, 4.63.

Provenance & Evidence