反应详情

5-Chlorosulfonyl-2-fluorobenzoic acid (2 g) was dissolved in dichloromethane (20 mL) under nitrogen atmosphere and cooled to 0° C. tert-Butyl 1-piperazinecarboxylate (3.12 g) was added portionwise to the solution at 0° C. and stirred for 3 hours at ambient temperature. The organic solvent was evaporated in vacuo, and the residue was dissolved in 1N-sodium hydroxide solution. The aqueous solution was washed with diethyl ether and acidified with 1N-hydrochloric acid. The precipitates were collected by filtration and washed with water to give 5-[4-(tert-butoxycarbonyl)piperazin-1-ylsulfonyl]-2-fluorobenzoic acid (2.26 g) as a colorless solid substance.

1. additionwas added portionwise to the solution at 0° C.
2. customThe organic solvent was evaporated in vacuo
3. dissolutionthe residue was dissolved in 1N-sodium hydroxide solution
4. washThe aqueous solution was washed with diethyl ether
5. filtrationThe precipitates were collected by filtration
6. washwashed with water