反应详情

A mixed solution of 2,3,4-trifluorobenzoic acid (10.3 g, 58.5 mmol), thionyl chloride (6.4 ml, 87.8 mmol) and a catalytic amount of dimethylformamide was heated under reflux for 30 minutes. After letting the reaction solution cool, the reaction solution was concentrated under a reduced pressure, toluene (30 ml) was added to the residue, and concentration under a reduced pressure was performed again. The residue obtained was then dissolved in tetrahydrofuran (20 ml), and the resulting solution was added to a tetrahydrofuran (40 ml) solution of ethyl β-dimethylaminoacrylate (9.20 g, 64.3 mmol) and triethylamine (10.2 ml, 73.1 mmol) while stirring and cooling with ice. The reaction mixture was then stirred at room temperature for 1.5 hours and then heated under reflux for 16.5 hours. After letting the reaction solution cool, the precipitated solids were removed by filtration and the filtrate was concentrated under a reduced pressure. The residue was then applied to a silica gel chromatography, and 15.1 g (86%) of the title compound was obtained from an n-hexane:ethyl acetate=3:1 eluate.

1. temperatureunder reflux for 30 minutes
2. temperaturecool
3. concentrationthe reaction solution was concentrated under a reduced pressure, toluene (30 ml)
4. additionwas added to the residue, and concentration under a reduced pressure
5. customThe residue obtained
6. temperaturecooling with ice
7. stirringThe reaction mixture was then stirred at room temperature for 1.5 hours
8. temperatureheated
9. temperatureunder reflux for 16.5 hours
10. temperaturecool
11. customthe precipitated solids were removed by filtration
12. concentrationthe filtrate was concentrated under a reduced pressure