反应详情

To a solution of 44 g of 3-(aminosulfonyl)-4-methyl benzoic acid (Example 1) in 500 ml H2O was added 11.0 g of sodium carbonate and 72 g of potassium permanganate in 8 g portions at 50°-60° over 5.5 hours. Then, 1 ml formic acid was added to decompose excess oxidant and the solution was filtered hot (60°) through Celite. The filter pad was washed with hot water. The combined filtrate was concentrated, in vacuo to approximately 300 ml and brought to pH 6 with concentrated HCl. A small amount of solid was filtered off. The filtrate was brought to pH 3.5 with concentrated HCl. The resulting solid was collected, washed with water and dried to give 33 g of solid; m.p. 259-290 (known m.p. 312-314). This material was used, without further purification, in Example 3.

1. filtrationthe solution was filtered hot (60°) through Celite
2. washThe filter pad was washed with hot water
3. concentrationThe combined filtrate was concentrated, in vacuo to approximately 300 ml
4. filtrationA small amount of solid was filtered off
5. customThe resulting solid was collected
6. washwashed with water
7. customdried