Hymexazol is an efficient and low-toxicity soil fungicide. In this work, a fully continuous flow process for the synthesis of hymexazol has been developed. This process begins with combining ethyl acetoacetate and hydroxylamine hydrochloride to form a hydroxamic acid intermediate. The reaction solution is then quenched with concentrated hydrochloric acid to obtain the final product, hymexazol. Under the optimized process conditions, the total yield of the target product reached 86%. In addition, production was successfully scaled-up to a kilogram scale. The continuous flow method not only greatly decreases the reaction time but also significantly inhibits the side reactions.

• Catalytic Hydrogenation Research Center
• Zhejiang University of Technology
• Zhejiang Green Pesticide Collaborative Innovation Center
• Zhejiang Key Laboratory of Green Pesticides and Cleaner Production Technology

• API

1. API
2. continuous flow synthesis
3. Cyclization
4. fungicide
5. Hymexazol 
6. Research Article