反应详情

Methyl 2-(trifluoromethoxy)phenyl carbonate (200 mg, 0.85 mmol) was added portion-wise to H2SO4 (600 μL) at 0° C. to generate a colorless homogeneous solution. KNO3 (103 mg, 1.02 mmol) was added portion-wise maintaining the internal temperature below 5° C. The reaction was stirred for 2 h and then poured on ice water. The aqueous layer was extracted with dichloromethane (3×10 mL). The combined organic extracts were dried over Na2SO4, filtered and concentrated. Purification by silica gel chromatography (0-10% ethyl acetate/hexanes) provided the two regioisomers methyl 5-nitro-2-(trifluoromethoxy)phenyl carbonate (Isomer A, 120 mg) and methyl 4-nitro-2-(trifluoromethoxy)phenyl carbonate (Isomer B, 75 mg).

1. temperaturemaintaining the internal temperature below 5° C
2. additionpoured on ice water
3. extractionThe aqueous layer was extracted with dichloromethane (3×10 mL)
4. dry with materialThe combined organic extracts were dried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated
7. customPurification by silica gel chromatography (0-10% ethyl acetate/hexanes)