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■ An Efficient Ton Scale Process of Chlorfluazuron

Kai Yin,* Xin Yin, Hao Wu, Jiang Yu, Youlan He, Xin Yang, Minmin Gu, Wenliang Wu, Jiangyu Yang, and Yiwei Zhang*

*School of Chemistry and Chemical Engineering, Southeast University, SuYuan road No.79 in Nanjing 211189, China

Abstract

An efficient and novel synthetic route of chlorfluazuron (1) on a ton scale has been developed, from the commercially available chemicals 3,5-dichloronitrobenzene, 2,3-dichloro-5-(trifluoromethyl)pyridine, and 2,6-difluorobenzamide. The key intermediate, 4-amino-2,6-dichlorophenol (2), was synthesized in one step by 3,5-dichloronitrobenzene with 78.1% yield and 99.5% purity. At the same time, 3,5-dichloroaniline (15), a co-product with great market demand, was also obtained with 20.9% yield and 99.2% purity. Chlorfluazuron (1) was obtained from 4-amino-2,6-dichlorophenol (2) in 91.9% yield over two steps and 99.2% purity. Compared with the original process route, the new synthetic route has the advantages of fewer reaction steps, higher overall yield, less process safety hazard and environmental impact.