反应详情

温度

15 °C

To a solution of 30.0 g of the title compound of Step A in 200 mL of glacial acetic acid was added dropwise a solution of 11.7 g of sodium nitrite in 35 mL of water while maintaining the reaction temperature at about 15° C. with external cooling. Following addition, the external cooling was removed and the suspension was stirred at room temperature overnight and then poured into excess water (about 400 mL). The aqueous suspension was acidified by dropwise addition of concentrated hydrochloric acid (until red to litmus paper) and then extracted with methylene chloride. The organic solution was dried (MgSO4), filtered and concentrated to give 32.5 g of the title compound of Step B as an oil. 1H NMR (CDCl3): δ 8.3 (s,1H), 8.2 (m,1H), 7.9 (m,1H), 7.65 (m,1H); IR (neat) 1670.2 cm-1.

1. additionaddition
2. temperaturethe external cooling
3. customwas removed
4. additionpoured into excess water (about 400 mL)
5. additionThe aqueous suspension was acidified by dropwise addition of concentrated hydrochloric acid (until red to litmus paper)
6. extractionextracted with methylene chloride
7. dry with materialThe organic solution was dried (MgSO4)
8. filtrationfiltered
9. concentrationconcentrated