反应详情

A solution of 4-bromo-7-hydroxy-2-phenyl-oxazolo[4,5-c]pyridine-6-carboxylic acid methyl ester (0.1 g, 0.286 mmol; example 3a), trimethylacetyl chloride (42.3 μL, 0.344 mmol), triethylamine (79.7 μL, 0.572 mmol), and 4-(dimethylamino)pyridine (3.5 mg, 0.03 mmol) in methylene chloride (2.5 mL) was stirred at room temperature for 2 hours. The reaction mixture was diluted with ethyl acetate and washed with saturated sodium bicarbonate solution, brine, saturated ammonium chloride solution, and brine. The organic fraction was dried over anhydrous sodium sulfate, and concentrated. The crude product was purified by flash chromatography eluting from silica gel with a gradient of 0-70% ethyl acetate in hexanes to give 51 mg of the title compound as a white solid. MS: (+) m/z 432.8, 434.8 (M+1, 79Br/81Br).

1. washwashed with saturated sodium bicarbonate solution, brine, saturated ammonium chloride solution, and brine
2. dry with materialThe organic fraction was dried over anhydrous sodium sulfate
3. concentrationconcentrated
4. customThe crude product was purified by flash chromatography
5. washeluting from silica gel with a gradient of 0-70% ethyl acetate in hexanes