To a stirred solution of hydroxy peroxide (30 % in H2O, 35 mL, 356 mmol) under N2 at 0℃, a solution of trifluoroacetic anhydride (56 mL, 407 mmol) in 115 mL dichloromethane was added dropwise over 2 h. After the addition was complete, a solution of 2,3- difluorobenzenamine (5 g, 39 mmol) in 115 mL dichloromethane was added dropwise at 0℃. After the addition was complete, the reaction mixture was gradually warmed to room temperature and stirred overnight. The mixture was extracted by dichloromethane and dried over anhydrous Na2SO4. The mixture was filtered and concentrated under reduced pressure. The residue was purified by flash column with 0-15 % EtOAc in hexane to yield 3.5 g of 2,3-Difluoronitrobenzene (57%).
[1] Patent: WO2008/12623, 2008, A1. Location in patent: Page/Page column 62
[2] Patent: WO2006/18443, 2006, A1. Location in patent: Page/Page column 20
