The general procedure for the synthesis of 3,4,5-trifluoronitrobenzene from 2,3,4-trifluoro-6-nitroaniline was as follows: a solution of tert-butyl nitrite (340 mL) in N,N-dimethylformamide (DMF, 150 mL) was slowly added to a stirred solution of DMF (1 L) containing 6-nitro-2,3,4-trifluoroaniline (500 g). The reaction was carried out at 45-75 °C for 3 h under argon protection. After keeping the same temperature and continuing stirring for 1 h, the reaction mixture was treated with 20% aqueous hydrochloric acid solution (2 L). After cooling, steam distillation of the resulting solution gave 3,4,5-trifluoronitrobenzene as a yellow liquid, which was separated from the distillate (289 g, 62% yield). The purity of the resulting product was about 90% by gas chromatography (GC) analysis.1H NMR (δ): 8.13-7.92 (m, 2H).
