反应详情

Caesium carbonate (10.19 g, 31.38 mmol), 1-chloro-2-methyl-4-nitro-benzene (0.98 g, 5.75 mmol) and 1-(4,6-dimethyl-pyridin-2-yl)-piperazine (1.0 g, 5.23 mmol) were taken in toluene (35 mL) and degassed with argon for 15 min. A slurry of 2-dicyclophosphino-2′-(N,N-dimethylamino)-biphenyl (0.2 g, 0.52 mmol) and palladium acetate (0.116 g, 0.52 mmol) in toluene (5 mL) was added, the mixture degassed for another 10 min and then heated at reflux for 16 h. The mixture was cooled to room temperature and filtered, washing with ethyl acetate. The filtrate was washed with 2N hydrochloric acid, water, and brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum to obtain the crude compound. Purification by column chromatography over silica gel (100-200 mesh) using 0-12% ethyl acetate in petroleum ether as eluent gave 1-(4,6-dimethyl-pyridin-2-yl)-4-(2-methyl-4-nitro-phenyl)-piperazine (0.463 g, 27%) as a solid.

1. customdegassed with argon for 15 min
2. customthe mixture degassed for another 10 min
3. temperatureheated
4. temperatureat reflux for 16 h
5. filtrationfiltered
6. washwashing with ethyl acetate
7. washThe filtrate was washed with 2N hydrochloric acid, water, and brine
8. dry with materialdried over anhydrous sodium sulfate
9. filtrationfiltered
10. concentrationconcentrated under vacuum
11. customto obtain the crude compound
12. customPurification by column chromatography over silica gel (100-200 mesh)