C([NH:5][S:6](/[CH:9]=[CH:10]/[C:11]1[CH:16]=[CH:15][N:14]=[CH:13][CH:12]=1)(=[O:8])=[O:7])(C)(C)C>FC(F)(F)C(O)=O>[N:14]1[CH:13]=[CH:12][C:11](/[CH:10]=[CH:9]/[S:6]([NH2:5])(=[O:7])=[O:8])=[CH:16][CH:15]=1(E)-N-tert-Butyl-2-(4-pyridyl)ethenesulfonamide (3.8 g) was dissolved in trifluoroacetic acid (38 ml) and the mixture was stirred in an oil bath at 50° C. for 4 hr. The reaction mixture was concentrated to dryness under reduced pressure. The residue was dissolved in trifluoroacetic acid (19 ml) and stirred in an oil bath at 50° C. for 45 min. The reaction mixture was concentrated to dryness under reduced pressure and the residue was partitioned between chloroform:methanol(9:1) and a saturated aqueous solution of sodium hydrogen carbonate. The aqueous layer was extracted twice with chloroform:methanol(9:1) and once with ethyl acetate. The aqueous layer was saturated with sodium chloride and extracted 4 times with ethyl acetate. All extracts with ethyl acetate were combined, dried over magnesium sulfate, and concentrated to dryness under reduced pressure. The residue was powdered from diethyl ether to give (E)-2-(4-pyridyl)ethene-sulfonamide(2.34 g) as a pale-brown powder.
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