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

HRID 1944710

Reaction equation

[C:1]1([C:7]2[N:8]=[CH:9][O:10][CH:11]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[Cl:12][S:13](O)(=[O:15])=[O:14]>ClCCl>[O:10]1[CH:11]=[C:7]([C:1]2[CH:2]=[CH:3][C:4]([S:13]([Cl:12])(=[O:15])=[O:14])=[CH:5][CH:6]=2)[N:8]=[CH:9]1

Participants

Conditions

Temperature: 2.5 °C

Procedure

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.

Workup

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

Sources & evidence

ORD record: ord-71827a9a67b2463dbe437185ac6aa80e
Source dataset: uspto-grants-2013_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08394858B2

Linked notes

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