反应详情

温度

75 °C

56.7 ml of 96% sulphuric acid are added dropwise over 30 min to a brown solution of 90 g (374 mmol) of 4-amino-3-chloro-5-nitro-benzotrifluoride (Maybridge; Tintagel/England) in 500 ml of ethanol (exothermic). After heating to 75° C., 64.53 g (935 mmol) of sodium nitrite are added in portions over 1 h (gas evolution). Stirring is effected for 2.5 h at 75° C., followed by cooling to RT. The reaction mixture is poured onto 1.5 l of ice water and extracted 4 times with diethylether. Washing of the organic phase with 0.1 N HCl, sat. NaHCO3 solution and brine, drying (Na2SO4) and concentrating by evaporation yield a brown oil. Column chromatography (SiO2; hexane) yields 5-chloro-3-trifluoromethyl-nitrobenzene as an oil; 1H-NMR (DMSO-d6) δ 8.62 (m, 1H), 8.46 (m, 2H).

1. temperatureby cooling to RT
2. extractionextracted 4 times with diethylether
3. washWashing of the organic phase with 0.1 N HCl, sat. NaHCO3 solution and brine
4. dry with materialdrying (Na2SO4)
5. concentrationconcentrating by evaporation
6. customyield a brown oil