反应详情

Freshly fused ZnCl2 (82 g, 0.6 mole) was dissolved in dry Et2O (400 ml) and added dropwise to the Grignard reagent prepared from 4-bromobenzotrifluoride (112.5g, 0.5 mole) and Mg (12.2 g, 0.5 g-atom) in Et2O (600 ml). Maleic anhydride (44 g, 0.45 mole) in Et2O (400 ml) was added over 30 minutes with stirring at reflux. After 2 hours, the mixture was cooled and acidified to pH 2 with 10% HCl. The Et2O layer was separated and dried (MgSO4), and the Et2O evaporated. The residue was recrystallized from C6H6 (x3) to yield the title compound, 24.5 g (21%), mp 149°-151°. Anal. (C11H7F3O3) C, H, F. An alternative procedure is as follows. A mixture of 4-trifluoromethylacetophenone (18.8 g) glyoxylic acid monohydrate (18.8 g), Ac2O(20 ml) and a drop of Et3N was heated to 135°, internal temperature. More Et3N (2 ml) was added, and the mixture was held at 135° for 20 minutes. The mixture was cooled and evaporated to dryness in vacuo. The solid residue was digested with H2O, filtered, dried and recrystallized from C6H6 to give the title compound, 12.2 g (50%), mp 149°-151°.

1. temperatureat reflux
2. temperaturethe mixture was cooled
3. customThe Et2O layer was separated
4. dry with materialdried (MgSO4)
5. customthe Et2O evaporated
6. customThe residue was recrystallized from C6H6 (x3)