反应详情

温度

30 °C

4-chloro-N,2-dihydroxy-benzamide (8 g, 42.7 mmol) is added to 10 ml of tetrahydrofuran under coverage of N2, while maintaining the temperature inside vessel lower than 30° C. and thereto is drop-added slowly 10 ml of SOCl2. After completion of drop-addition, the reaction is stirred for 30 minutes and evaporated to dryness. The residual SOCl2 is removed by azeotropic distillation with anhydrous benzene. The reaction is evaporated to dryness to obtain a yellow powder, which is dissolved in 10 ml of dioxane, while maintaining the temperature inside vessel at lower than 30° C., and thereto is drop-added slowly 5 ml of Et3N and stirred for 30 minutes, then thereto is drop-added 10% hydrochloric acid to pH=2. Under stirred, a large amount of light yellow deposit precipitates and is filtered out and recrystallized in methanol to obtain 6.50 g of 3-hydroxy-6-chloro-benzisoxazole, with a yield of 89%.

1. additionAfter completion of drop-addition
2. customevaporated to dryness
3. customThe residual SOCl2 is removed by azeotropic distillation with anhydrous benzene
4. customThe reaction is evaporated to dryness
5. customto obtain a yellow powder, which
6. temperaturewhile maintaining the temperature inside vessel at lower than 30° C.
7. stirringstirred for 30 minutes
8. stirringUnder stirred
9. customa large amount of light yellow deposit precipitates
10. filtrationis filtered out
11. customrecrystallized in methanol