Triethylamine → 2,6-Dichloro-3-(propylsulfonamido)benzoic acid

3-Amino-2,6-dichlorobenzoic acid (1.40 g, 6.82 mmol) was dissolved in dry dichloromethane (66.7 mL). Triethylamine (4.09 mL, 29.4 mmol) was added, and the mixture was chilled to 0° C. Propane-1-sulfonyl chloride (2.48 mL, 22 mmol) was then added via syringe. Once the addition was complete, the mixture was allowed to warm to ambient temperature and stir for 1 hour. The mixture was concentrated in vacuo and diluted with diethyl ether. The mixture was washed with 0.25M NaOH (80 mL), and the aqueous layer was acidified to a pH of 1 using 1.0M HCl. The aqueous layer was extracted with 15% 2-propanol:DCM (2×300 mL). The organic layer was collected, dried over sodium sulfate, and concentrated to afford 2,6-dichloro-3-(propylsulfonamido)benzoic acid (1.55 g, 4.96 mmol, 74.4% yield). 1H NMR (400 MHz, d6-DMSO) δ 9.77-9.75 (s, 1H), 7.84-7.80 (d, 1H), 7.71-7.68 (d, 1H), 3.82-3.72 (m, 2H), 1.89-1.70 (m, 2H), 1.05-1.03 (m, 3H).