Chlorosulfonic acid → 4-(Oxazol-4-yl)benzene-1-sulfonyl chloride

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence