HCl tetrahydrofuran → Ethyl 6-(N-(2-chloro-4-fluorophenyl)sulfamoyl)-3-oxocyclohex-1-ene-1-carboxylate

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Reaction Steps

To 2.55 g (6.07 mmol) of ethyl 8-[N-(2-chloro-4-fluorophenyl)sulfamoyl]-1,4-dioxaspiro[4.5]dec-6-ene-7-carboxylate obtained in Example 1 was added 100 ml of a mixed solution of 1N hydrochloric acid-tetrahydrofuran (1:1), and the reaction solution was stirred at room temperature for 64 hours. Tetrahydrofuran was distilled off under reduced pressure, the residue was extracted by addition of ethyl acetate, and the organic layer was washed with water and dried over anhydrous magnesium sulfate, followed by concentration under reduced pressure. The residue was subjected to silica gel column chromatography (solvent; hexane:ethyl acetate=4:1), to give 2.19 g of the title compound as a pale brown powder (yield: 96%).

Provenance & Evidence