A Study on Bromination of Deactivated Aromatics

NBS/H2SO4-HOAc as brominating reagent directly brominates some strong deactivated aromatics such as 1,3-bis(trifuoromethyl)benzene with good results.The effects of reaction conditions,such as the ratio of sulfuric acid and acetic acid,reaction temperature,addition time and the ratio of NBS and raw material,were investigated and the optimal reaction condition were determined.The excellent yield 93.1% was obtained when 1,3-bis(trifuoromethyl)benzene reacted with 1.15 equivalent NBS in H2SO4/HOAc 6∶1 at 45 ℃ for 8 h.