Imidazole → Ethyl 4-tert-butyldimethylsilyloxymethyl-3,5-difluoro-6-pivaloylamino-2-(2-tetrahydropyranyloxy)benzoate

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Reaction Steps

213 mg (0.50 mmol) of the above ethyl 3,5-difluoro-4-hydroxymethyl-6-pivaloylamino-2-(2-tetrahydropyranyloxy)benzoate was dissolved in 5 mL of dichloromethane, 68 mg (1.0 mmol) of imidazole and 302 mg (2.00 mmol) of tert-butyldimethylsilyl chloride were added and the mixture was heated at reflux for 30 minutes. The reaction solution was cooled on ice, water was added and the mixture was extracted once with ethyl acetate. The organic layer was washed once with water and once with an aqueous saturated solution of sodium chloride and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure and the residue was purified by silica gel column chromatography (n-hexane:ethyl acetate=4:1) to give 256 mg of ethyl 4-tert-butyldimethylsilyloxymethyl-3,5-difluoro-6-pivaloylamino-2-(2-tetrahydropyranyloxy)benzoate (yield: 98%).

Provenance & Evidence