Aniline → 7-Fluoro-1-phenyl-5-trifluoromethylbenzimidazole

Temperature

110 °C

A mixture of aniline (1.12 ml, 12.3 mmol) and 2,3-difluoro-1-nitro-5-trifluoromethylbenzene (2.8 g, 12.3 mmol) was heated at 110° C. for 24 h. Dichloromethane was added and the resulting precipitate filtered off. The filtrate was concentrated under reduced pressure then redissolved in ethyl acetate. 10% Palladium on carbon (0.5 g, Degussa) was added and the resulting suspension hydrogenated at 5 bar for 1 h. The reaction mixture was filtered through celite, washed with ethyl acetate and, the filtrate concentrated under reduced pressure. Formic acid (10 mL) was added and the mixture heated at 110° C. for 24 h. Concentration under reduced pressure gave 7-fluoro-1-phenyl-5-trifluoromethylbenzimidazole as a purple solid (3.0 g, 87%) m/z, 281.0 (M+H)+.

1. filtrationthe resulting precipitate filtered off
2. concentrationThe filtrate was concentrated under reduced pressure
3. dissolutionthen redissolved in ethyl acetate
4. addition10% Palladium on carbon (0.5 g, Degussa) was added
5. filtrationThe reaction mixture was filtered through celite
6. washwashed with ethyl acetate
7. concentrationthe filtrate concentrated under reduced pressure
8. additionFormic acid (10 mL) was added
9. temperaturethe mixture heated at 110° C. for 24 h
10. concentrationConcentration under reduced pressure

ORD record

ord-32e72dcd683c45e2af50cf65922a16fc

Source dataset

uspto-grants-2010_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07700638B2