2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 10-bromo-2-methoxy-4H-pyrido[3,2,1-jk]carbazole-4-one

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Reaction Steps

10-bromo-5,6-dihydro-2-methoxy-4H-pyrido[3,2,1-jk]carbazole-4-one (3.6 g) obtained in Example 1, step 3 was dissolved in anhydrous dioxane (300 ml), and DDQ (3.0 g) was added at room temperature. The mixture was heated under reflux in an argon atmosphere for 5 hours. After allowing to cool, the reaction mixture was added to 1N aqueous solution of sodium hydroxide (500 ml), and extracted with ethyl acetate. The ethyl acetate layer was washed with 1N aqueous solution of sodium hydroxide and saturated aqueous solution of sodium chloride in succession, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: methylene chloride containing 3% methanol) to obtain the title compound (2.9 g, 79%).

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