Using ethyl cyanoacetate, triethyl orthoformate and methylhydrazine as main raw materials, the herbicide pyrazosulfuron was prepared through the reactions of substitution, amination, cylclization, diazotization and chlorosulfonation.

• 摘要以氰乙酸乙酯、原甲酸三乙酯和甲肼等为主要原料，通过取代、胺化、环化、重氮化和氯磺化等反应制得了除草剂吡嘧磺隆原料药。