Chlorosulfonic acid → 3-Methyl-4-(2,2,2-trifluoroacetamido)benzene-1-sulfonyl chloride

Participants

Reaction Steps

16.43 mL (5.00 equiv.) Chlorosulfonic acid was cooled in an aceton/ice-bath and 10.00 g 2,2,2-trifluoro-N-o-tolyl-acetamide was added in three portions, keeping the reaction mixture temperature below 5° C. The ice-bath was removed, the pale yellow mixture was allowed to warm to room temperature and then heated on an oil bath of 70° C. for 5.5 hours. The oil bath was removed and at about 30-35° C. the brown mixture was poured very carefully into a beaker with ice (exotermic, copious amounts of HCl evolve), giving a thick, gummy and very sticky precipitate. The mixture was extracted three times with DCM and the combined organic layers were washed with brine, dried over Na2SO4, filtered and evaporated onto silica. Purification with flash chromatography (EtOAc/PA 1:9→1:4) yielded 10.3 g (69%) of a white solid. 1H NMR (400 MHz, CDCl3) δ 2.46 (s, 3H), 7.90 (br.s., 1H), 7.94 (s, 1H), 7.98 (dd, J=8.6, 2.15 Hz, 1H), 8.35 (d, J=8.6 Hz, 1H).

Provenance & Evidence