3-CHLOROSULFONYL-2,6-DIFLUORO-BENZOIC ACID synthesis

Yield:142576-91-8 54%

Reaction Conditions:

with chlorosulfonic acid at 120; for 2 h;Inert atmosphere;

Steps:

20.A Step A. 3-(Chlorosulfonyl) -2 ,6-difluorobcnzoic acid.

2,6-Difluorobcnzoic acid (230 g, 1.455 mol) in C1SO3H (700 mL, 10.2 mol) was stirred at 120 C for 2 h. The mixture was poured into ice and stirred for 20 minutes. The slurry was filtered. The filter cake was dissolved with DCM, dried (Na2SO4) and concentrated under reduced pressure to give the title compound (200 g, 54%) as gray solid. 1H NMR (400MHz, CD3OD) 5 = 8.192-8.247(m, 1H), 7.34-7.42 (m, 1 H).

References:

WO2015/164520,2015,A1 Location in patent:Page/Page column 74