Dibromomethane → Ethyl 6-[N-(2-chloro-4-fluorophenyl)sulfamoyl]-1-oxaspiro[2.5]oct-4-ene-5-carboxylate

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Reaction Steps

50 mg (0.133 mmol) of ethyl 6-[1-(2-chloro-4-fluorophenyl)sulfamoyl]-3-oxo-1-cyclohexene-1-carboxylate obtained in Example 7 and 0.01 ml (0.146 mmol) of dibromomethane were dissolved in 1 ml of tetrahydrofuran, and 0.18 ml (0.279 mmol) of n-butyllithium/hexane solution (1.58 M) was added dropwise thereto at −78° C., followed by stirring at room temperature for 4 hours. After the reaction solution was cooled with ice, a saturated aqueous ammonium chloride solution was added and the mixture was extracted with ethyl acetate. 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 thin layer chromatography (solvent; hexane:ethyl acetate=2:1) to give 7 mg of the title compound as a yellow oil (yield: 14%).

Provenance & Evidence