反应详情

To a solution of 2,5-difluoro-4-nitrobenzoic acid (55 g, 291 mmol) in methanol (800 mL) at 80° C. was added a methanolic solution of potassium hydroxide (48.9 g, 873 mmol in 175 mL MeOH, pre-heated at 80° C. to dissolve) dropwise in a period of 2 h using an addition funnel. The reaction mixture was continuously stirred for 1 h after addition was completed. It was then concentrated, acidified with HCl to pH=1-2. The reaction mixture was then vigorously stirred overnight. Fine powder was filtered, washed with more water and dried to give the product as light yellow powder (55.4 g, 90%). 1H NMR (400 MHz, DMSO-d6) δ ppm 3.95 (s, 3H) 7.66 (d, J=4 Hz, 1H) 8.01 (d, J=8 Hz, 1H). [M+H] calc'd for C8H6FNO5, 216. found 216.

1. additionafter addition
2. concentrationIt was then concentrated
3. customvigorously stirred overnight
4. filtrationFine powder was filtered
5. washwashed with more water
6. customdried