Acetic Acid → diethyl 6-acetyl-3,4-dihydro-8-propyl-7-hydroxy-2H-1-benzopyran-2,2-dipropanoate

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Reaction Steps

To a solution of 790 mg (2.01 mmol) of the title product of Example 44 in 4 ml of acetic acid was added 547 mg (4.02 mmol) of anhydrous zinc chloride. The mixture was stirred for six hours at reflux, and then permitted to cool. The mixture was partitioned between ethyl acetate and dilute hydrochloric acid. The aqueous layer was further extracted with two portions of ethyl acetate. The combined organic extracts were washed successively with five portions of aqueous sodium bicarbonate, water, and then brine. The extracts were dried over sodium sulfate, filtered, and the solvent removed under reduced pressure. Chromatography of the residue over silica gel using 25% ethyl acetate/hexane as eluent gave the title compound, 230 mg.

Provenance & Evidence