1,4-Butanediol → Ethyl 3-[N-(2-chloro-4-fluorophenyl)sulfamoyl]-7,12-dioxaspiro[5.6]dodec-1-ene-2-carboxylate

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Reaction Steps

34 mg (0.61 mmol) of 1,4-butanediol was dissolved in 5 ml of dichloromethane, 0.32 ml (1.83 mmol) of isopropoxytrimethylsilane, and 200 mg (0.47 mmol) of ethyl 6-[N-(2-chloro-4-fluorophenyl)sulfamoyl]-3,3-dimethoxy-1-cyclohexene-1-carboxylate obtained in Example (16a) and 4 μl (0.024 mmol) of trimethylsilyl trifluoromethanesulfonate were sequentially added thereto with stirring under ice-cooling, followed by stirring for 2 hours at the same temperature. Saturated aqueous sodium hydrogencarbonate was added to the reaction solution 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 column chromatography (solvent; hexane:ethyl acetate=3:1), and the resulting solid was further washed with hexane to give 6 mg of the title compound as a white powder (yield: 3%).

Provenance & Evidence