反应详情

A mixture of 5-amino-2-chloro-4-nitrobenzotrifluoride (synthesized according to the method described in J. Org. Chem., 60, 18, 1995, 5838-5842, 24.9 g) and 48% aqueous hydrogen bromide (400 ml) was ice-cooled. Sodium nitrite (12.9 g) was dissolved in a small amount of water and added dropwise thereto. The reaction mixture was stirred for 4 hr while warming from −5° C. to 15° C., ice-cooled and alkalified with a 6N aqueous sodium hydroxide solution. The precipitated solid was collected by filtration and washed with water to give a brown solid. The solid was purified by silica gel column chromatography (elution solvent:ethyl acetate-hexane (1:50)) to give 5-bromo-2-chloro-4-nitrobenzotrifluoride (17.7 g, yield 56%).

1. customsynthesized
2. temperaturecooled
3. additionadded dropwise
4. temperaturewhile warming from −5° C. to 15° C.
5. temperatureice-cooled
6. filtrationThe precipitated solid was collected by filtration
7. washwashed with water
8. customto give a brown solid
9. customThe solid was purified by silica gel column chromatography (elution solvent:ethyl acetate-hexane (1:50))