反应详情

温度

-6 °C

A solution of 4-difluoromethoxy-phenylamine (2 g, 13 mmol) was cooled at −6° C. and phosphoric acid (85%, 13 mL) followed by nitric acid (65%, 9 mL) very slowly. When the mixture reached the room temperature it was stirred 15 minutes for complete dissolution. The solution was cooled again to −6° C. and solid sodium nitrite (0.954 g, 13.8 mmol) was added during 5 minutes followed by crushed ice. The reaction mixture was added into a suspension of pentane-2,4-dione (1.32 g, 13.2 mmol) and potassium acetate (24.1 g, 251 mmol) in ethanol (130 mL) at 0° C. Stirring is continued for 15 min at 0-5° C. and an aqueous solution 2M of sodium carbonate is added until the pH is 9-10. The solution is extracted with dichloromethane (4×200 mL). The combined organic layers were washed with water, dried with magnesium sulphate, filtrated and the solvent was removed in the vacuum to obtain 3.6 g (100%) of the final product that was used as a crude on the next step. MS: M=269.1 (M−H)+

1. customthe room temperature it
2. customby crushed ice
3. stirringStirring
4. waitis continued for 15 min at 0-5° C.
5. extractionThe solution is extracted with dichloromethane (4×200 mL)
6. washThe combined organic layers were washed with water
7. dry with materialdried with magnesium sulphate
8. filtrationfiltrated
9. customthe solvent was removed in the vacuum