反应详情

A 3 liter three neck round bottom flask is charged with 125 mL H2SO4. Fuming nitric acid is added (8.4 mL, 199 mmol) and the mixture gently stirred. 2,3,4-Trifluorobenzoic acid 1 (25 g, 142 mmol) is added in 5 g portions over 90 minutes. The dark brownish yellow solution is stirred for 60 minutes at which time the reaction is complete. The reaction mixture is poured into 1 liter of an ice water mixture and extracted with diethyl ether (3×600 mL). The combined organic extracts are dried (MgSO4) and concentrated under reduced pressure to give a yellow solid. The solid is suspended in hexanes and stirred for 30 minutes after which time it is filtered to give 29 g (92%) of clean desired product as an off-yellow solid: MS APCI (−) m/z 220 (M−1) detected.

1. stirringThe dark brownish yellow solution is stirred for 60 minutes at which time the reaction
2. extractionextracted with diethyl ether (3×600 mL)
3. dry with materialThe combined organic extracts are dried (MgSO4)
4. concentrationconcentrated under reduced pressure
5. customto give a yellow solid
6. stirringstirred for 30 minutes after which time it
7. filtrationis filtered