Potassium tert-butoxide → 6-cyano-2,2-dimethyl-4-(4-ethoxycarbonyl-1,2-dihydro-2-oxo-1-pyridinyl)-2H-benzo[b]pyran

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Reaction Steps

In 8 ml of anhydrous tetrahydrofuran, is dissolved 250 mg of trans-3-methanesulfonyloxy-6-cyano-3,4-dihydro-2,2-dimethyl-4-(4-ethoxycarbonyl-1,2-dihydro-2-oxo-1-pyridinyl)-2H-benzo[b]pyran obtained in Example 20. Then, 112 mg of potassium t-butoxide is added at room temperature, and the resulting mixture is reacted at that temperature for 40 minutes. The reaction mixture is concentrated under reduced pressure and the residue is dissolved in methylene chloride, washed with saturated aqueous solution of sodium chloride, and dried over anhydrous magnesium sulfate. The inorganic matter is filtered off, and the filtrate is concentrated under reduced pressure. The residue is purified by silica gel column chromatography using 1/2 mixture of ethyl acetate/n-hexane as a developing solvent. Thus, 109 mg of 6-cyano-2,2-dimethyl-4-(4-ethoxycarbonyl-1,2-dihydro-2-oxo-1-pyridinyl)-2H-benzo[b]pyran is obtained.

Provenance & Evidence