Potassium Carbonate → 9-[(2-pyridyl)methyl]-5-carbomethoxy-1,2-dihydrocarbazol-4(3H)-one

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A 0° C. suspension of 5-carbomethoxy-1,2-dihydro-9H-carbazol-4(3H)-one (1.50 g, 6.17 mmol), potassium carbonate (2.60 g, 18.8 mmol), and catalytic amount of sodium iodide (ca. 10 mg), was treated with 2-picolyl chloride hydrochloride (1.10 g, 6.70 mmol). The cold bath was removed and the reaction stirred at ambient temperature 72 hours. The reaction was poured into H2O (100 mL) and the mixture extracted four times with ethyl acetate. The combined organic layers were washed four times with H2O, once with saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated. The residue was purified by flash chromatography on silica gel (elution with 70% then 80% then 85% EtOAc in hexanes) to afford 1.70 g (82%) of the 9-[(2-pyridyl)methyl]-5-carbomethoxy-1,2-dihydrocarbazol-4(3H)-one as an oil which solidified on standing. 1H NMR (CDCl3) δ8.52 (br s, 1H), 7.54-7.47 (m, 1H), 7.34-7.26 (m, 2H), 7.18-7.11 (m, 2H), 6.67 (d, J=7.8 Hz, 1H) 5.34 (s, 2H), 3.99 (s, 3H), 2.87 (t, 2H, J=6.0 Hz), 2.50 (t, 2H, J=6.3 Hz), and 2.20-2.13 (m, 2H). IR (CDCl3, cm−1) 3010, 2953, 1725, 1654, 1463, 1446, 1288 and 1121. MS (ES) m/e 335 (M+1).

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