2-(TRIFLUOROMETHYL)BENZOPHENONE

2-(trifluoromethyl)benzophenone is an ultraviolet absorber and a pharmaceutical and pesticide chemical intermediate with wide applications in these fields. It can also be used in the synthesis of fluorine-containing polymers. Furthermore, 2-(trifluoromethyl)benzophenone is an important pharmaceutical intermediate.

yellow crystal powde

Assymmetric reduction of 2-(trifluoromethyl)benzophenone by lithium aluminium hydride treated with (S)-(+) or (R)-(−)-2 (2-iso-indolinyl)butan-1-ol has been investigated.

Tetrahedron Letters, 35, p. 1047, 1994 DOI: 10.1016/S0040-4039(00)79962-X

Assymmetric reduction of 2-(trifluoromethyl)benzophenone by lithium aluminium hydride treated with (S)-(+) or (R)-()-2 (2-iso-indolinyl)butan-1-ol has been investigated.

The literature Bull.Soc.Chim.France 1962, 587-93 mentions the preparation of 2-(trifluoromethyl)phenyl ketone by the Grignard reaction using the Grignard reagents m-trifluoromethylphenylmagnesium bromide and m-trifluoromethylbenzonitrile feedstock, but the Grignard reaction is difficult to industrialize.

The raw material 10 g of 2-(trifluoromethyl)benzyl methane, 100 g of solvent chloroform and 0.2 g of catalyst phosphorus pentachloride were mixed, and then 7 g of chlorine gas was passed under 100 w incandescent light, 60 reflux for 20 hours, and the reaction process was tracked by GC and NMR; 

End of the reaction, cooling, adding water, extraction with chloroform, stratification, the oil layer was concentrated to get the intermediate colorless oil 2-(trifluoromethyl)phenyl dichloromethane; 

Intermediate 2-(trifluoromethyl)phenyl dichloromethane, 30 grams of water, 12 grams of acetonitrile and 3 grams of sodium hydroxide were mixed and refluxed for 4 hours, cooled and filtered to obtain the crude product, which was recrystallized with ethanol to obtain 7.8 grams of the target product 2-(trifluoromethyl)phenyl ketone as white crystals.  

Yield of the above two steps by recrystallization was about: 74.5%.