The Synthesis Process Optimization And New Process Development Of Penoxsulam

Penoxsulam is a kind of post-emergence herbicide developed by Dow AgroSciences. Its structure is triazolopyrimidine sulfamide, and it effects weeds by inhibiting acetolactate synthase(ALS). Penoxsulam has been focused more and more attention because of its efficiency, low toxicity, long-lasting effect and safety to crops. Based on the current researches related synthesis process, this article designed a greener synthesis process to promote the production industrialized.Term of patent protection of penoxsulam will be opened in 2016. Although penoxsulam has a bright market now and future, but part of its raw materials are very toxic and expensive in its synthetic process, which leaded to the high price of penoxsulam. Penoxsulam can be synthesized by two fragments of pyrimidineamine and sulfuryl chloride. In the synthesis of pyrimidineamine fragment, a high-risk and expensive cyanogen bromide was used to synthetize fragment of pyrimidineamine, and the synthetic progress is complex and rigorous.To work out above problems, this paper proposed isothiocyanate route to prepare fragment of pyrimidineamine. In the synthetic progress of sulfuryl chloride, a high risk, tough-operating,expensive organic alkali butyllithium was used to nucleophilic substitution, which constrained the cost of sulfuryl chloride. In order to solve this problem, 2-fluoro-6-trimethylaniline was used to prepare target product 2-fluoro-6-trimethyl benzene sulfonyl chloride by diazo-reaction. This progress is simple to operate, and the cost of the raw materials is low.Due to the proper optimum desigh of the two fragments, the synthetic progress of penoxsulam is simple to operate, low-cost, green and environment friedly.By a large number of optimized experiments, the operate is more simple and the cost is lower compared with the relative literatures.