Chlorosulfonic acid → 5-((4-Chlorobenzamido)methyl)thiophene-2-sulfonyl chloride

Participants

Reaction Steps

Chlorosulfonic acid (20.1 ml, 198 mmol) in CH2Cl2 (80 ml) is added dropwise to a solution of 1a (10 g, 40 mmol) in CH2Cl2 (500 ml) at −80° C. The mixture is allowed to reach room temperature in 5 h. The reaction mixture is poured on ice and quickly extracted with CH2Cl2. The organic layer is dried over MgSO4 and the solvent is evaporated to dryness which affords 8.8 g (63%) of desired sulfonyl chloride 1b; mp 133-35° C., 1H NMR (DMSO) δ 9.21 (t, J=6.4 Hz, 1H), 7.87 (d, J=8.67 Hz, 2H), 7.53 (d, J=8.67 Hz, 2H), 6.91 (d, J=3.9 Hz, 1H), 6.77 (d, J=3.39 Hz, 1H), 4.53 (d, J=3.77 Hz, 2H).

Provenance & Evidence