Synthesis
Methyl 3-amino-2-fluorobenzoate was charged to the reactor, followed by dichloromethane. The contents were stirred and cooled to ~15°C, and pyridine was added. After that, the reactor contents were adjusted to ~15°C, and adding 2,6-diflurorobenzenesulfonyl chloride was started via an addition funnel. The temperature during addition was kept at <25°C. After complete addition, the reactor contents were warmed to 20-25°C and held overnight. Ethyl acetate was added, and dichloromethane was removed by distillation. Once distillation was complete, the reaction mixture was diluted again with ethyl acetate (5 vol) and concentrated. Methyl 3-(2,6-difluorophenylsulfonamido)-2-fluorobenzoate was obtained through further purification.