Hydrochloric Acid → Ethyl 2-(4-oxocyclohexyl)acetate

50 ml of a 1N aqueous solution of hydrochloric acid was added to a solution of 5.0 g of ethyl 4-oxocyclohexylacetate ethylene acetal, as obtained in Example 58, in 50 ml of acetone. The reaction mixture was stirred for 10 minutes at room temperature, neutralized by the addition of a saturated aqueous solution of sodium hydrogencarbonate, and then concentrated by evaporation under reduced pressure. The resulting residue was extracted with ethyl acetate. The organic extract was washed with a saturated aqueous solution of sodium chloride, dried over anhydrous magnesium sulfate and concentrated by evaporation under reduced pressure. The resulting residue was subjected to column chromatography using 100 g of silica gel with a 4:1 v/v mixture of hexane and ethyl acetate as the eluent, to yield 3.9 g of the title compound as an oil.