251115-21-6

To a solution of N-methylpyrrolidone (40 mL) in 2,5-dibromonitrobenzene (5 g, 17.8 mmol) was sequentially added methyl fluorosulfonyl difluoroacetate (4.5 mL, 35.6 mmol) and cuprous iodide (I). The reaction mixture was stirred in an oil bath at 80°C overnight. Upon completion of the reaction, activated carbon was added to decolorize the reaction solution, which was diluted with saturated saline and subsequently extracted with ethyl acetate (3 x 30 mL). The organic phases were combined, dried with anhydrous magnesium sulfate and concentrated under reduced pressure to remove the solvent. The crude product was purified by fast column chromatography (eluent: petroleum ether/ethyl acetate, gradient 0-100%) to give 4-bromo-2-nitrobenzotrifluoromethylbenzene (4.1 g, 85% yield) as a yellow oil.

[1] Patent: WO2010/91310, 2010, A1. Location in patent: Page/Page column 100
[2] Patent: WO2006/113432, 2006, A2. Location in patent: Page/Page column 67-68; 37
[3] Patent: US2007/142460, 2007, A1. Location in patent: Page/Page column 18