Imidazole → 1H-Imidazole, 1-(1,2,2-trifluoroethenyl)-

Temperature

-78 °C

Into a 50 ml autoclave were poured 10.6 g (100 mmol) of potassium salt of imidazole and tetrahydrofuran (30 ml), and the inside of the autoclave was cooled to −78° C., and evacuation and replacement of atmosphere in the autoclave with nitrogen gas were carried out three times. After the inside of a system was evacuated, TFE was introduced until the inside pressure of the system reached 0.1 MPa·G. Then the temperature of the reaction system was increased to 100° C., and TFE was further introduced to maintain the inside pressure of the reaction system at 0.3 to 0.5 MPa·G. Supply of TFE was stopped when the amount of TFE reached 1.1 equivalents (11 g=110 mmol) to the potassium salt of imidazole, and stirring was continued at 100° C. Fifteen hours after starting of the stirring, the inside of the reaction system was brought to room temperature, followed by evacuation to terminate the reaction. To this crude reaction product was added 2.84 g (20 mmol) of ethyl trifluoroacetate, and it was confirmed by a 19F-NMR analysis based on ethyl trifluoroacetate that 1-(1,1,2,2-tetrafluoroethyl)imidazole had been produced at yield of 13% and 1-(1,2,2-trifluoroethenyl)imidazole had been produced at yield of 56%. Also according to gas chromatography analysis, it was confirmed that the remaining imidazole was 14%.

1. customAfter the inside of a system was evacuated
2. additionTFE was introduced until the inside pressure of the system
3. temperatureThen the temperature of the reaction system was increased to 100° C.
4. additionTFE was further introduced
5. temperatureto maintain the inside pressure of the reaction system at 0.3 to 0.5 MPa·G
6. customwas continued at 100° C
7. customFifteen hours
8. customwas brought to room temperature
9. customto terminate
10. customthe reaction
11. customTo this crude reaction product

ORD record

ord-87f329b440ab489a8b178f9a13eba877

Source dataset

uspto-grants-2012_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08252944B2