Chlorosulfonic acid → 4-Fluoro-2-[1-(2,2,2-trifluoroacetyl)azetidin-3-yl]benzenesulfonyl chloride

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Reaction Steps

Chlorosulphonic acid (5 mL) was added to 2,2,2-trifluoro-1-[3-(3-fluorophenyl)azetidin-1-yl]ethanone (Intermediate 90, 1.15 g) with stirring and ice cooling. The mixture was stirred for 1 hour then poured carefully onto a mixture of ice and ethyl acetate. The organic layer was washed with water and concentrated in vacuo. The residue was purified by chromatography on silica, eluting with a mixture of ethyl acetate and cyclohexane with a gradient of 0-20% to give 4-fluoro-2-[1-(2,2,2-trifluoroacetyl)azetidin-3-yl]benzenesulfonyl chloride (0.910 g) as a white solid.

Provenance & Evidence