新除草剤ピラゾスルフロンエチルの開発と企業化

抄録

Pyrazosulfuron-ethyl (1) is a new rice herbicide discovered and commercialized by Nissan Chemical Ind., Ltd. Research and development were started by introduction of heterocyclic moieties into an existing sulfonylurea herbicide as a lead compound which showed excellent herbicidal activities. Extensive investigations suggested a potent herbicidal activity in pyrazole rings as the heterocyclic moiety which led to the discovery of pyrazosulfuron-ethyl. Development of new synthetic methods for intermediate pyrazolesulfonamides with various functional groups made it possible to investigate pyrazolesulfonylureas (Fig.3). Various new 3, 4 and 5-pyrazolesulfonamides were synthesized to obtain the pyrazolesulfonylureas including pyrazosulfuron-ethyl. Six synthetic methods for the important intermediate pyrazolesulfonamide 14 were also developed for manufucturing pyrazosulfuron-ethyl. In this paper these synthetic methods and a final step to pyrazosulfuron-ethyl are described.