反应详情

温度

2.5 °C

4-Phenyl-oxazole (Intermediate 25, 550 mg, 3.79 mmol) was dissolved in a minimum of dichloromethane and was added slowly to chlorosulfonic acid (2.537 mL, 37.9 mmol) at 0° C. The reaction mixture was stirred for 20 min 0-5° C. then warmed to room temperature then to 45° C. and stirred for 2 h. The reaction mixture was cooled to room temperature and cautiously poured on ice water. The aqueous layer was extracted with ethyl acetate, dried over sodium sulfate, and concentrated to crude 4-oxazol-4-yl-benzenesulfonyl chloride. The starting material and product have Rf values in 20% EtOAc/heptane of Rf=0.47 and Rf=0.23, respectively. The crude product was purifed by chromatography on a Biotage 25M column eluting ethyl acetate/heptane to yield 4-oxazol-4-yl-benzenesulfonyl chloride (212 mg, 0.870 mmol). MH+=244.2.

1. temperaturethen warmed to room temperature
2. stirringto 45° C. and stirred for 2 h
3. temperatureThe reaction mixture was cooled to room temperature
4. additioncautiously poured on ice water
5. extractionThe aqueous layer was extracted with ethyl acetate
6. dry with materialdried over sodium sulfate
7. concentrationconcentrated to crude 4-oxazol-4-yl-benzenesulfonyl chloride
8. washeluting ethyl acetate/heptane