Sodium hydride → Ethyl 7-chloro-2H-chromene-3-carboxylate

Participants

Reaction Steps

4-Chloro-2-hydroxybenzaldehyde (Acta. Chem. Scand., vol. 53, p. 258 (1999)) (510 mg) was dissolved in tetrahydrofuran (40 mL), and sodium hydride (60% in oil, 157 mg) was added thereto, followed by stirring at room temperature for 2 hours. To the reaction mixture was added a solution of 2-diethylphosphonoacrylic acid ethyl ester (J. Org. Chem., vol. 43, p. 1256 (1978)) (769 mg) in tetrahydrofuran (10 mL), and the thus-obtained mixture was stirred at room temperature for 2 hours, followed by heating under reflux overnight. After the reaction mixture was cooled to room temperature, the mixture was partitioned between water and diethyl ether. The organic layer was dried over sodium sulfate anhydrate, and the solvent was distilled away under reduced pressure. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=10:1), to thereby give the title compound (247 mg).

Provenance & Evidence