Design,Synthesis And Biological Activity Of Benzothiazole Derivatives

Herbicides play a key role both in protecting crops and increasing yields in agriculture,and the applications of herbicides have greatly promoted the development of modern agriculture.Developing new herbicides which are of high efficiency,low toxicity,environmental friendship and without cross-resistance,is one of the most important novel pesticide discovery.Among them,discovering new herbicidal compounds,especially those with novel modes of action,is considered as a marvelous approach to the problems.Benzothiazole derivatives are a group of important heterocyclic compounds showing a broad range of biological activity,and benzothiazole as a unit structure is exited in many efficient herbicides.D1 protease was considered as a potential target for herbicides,and our previous work shows that benzothiazole compounds with triangle topology structure have good inhibitory activity against D1 protease.Thus,two kinds of benzothiazole derivatives,including N-?benzo[d]thiazol-2-yl?-2-phenoxyacetamides and N-?benzo[d]-thiazol-2-yl?alkylsulfonamides were reasonably designed by combinating active substructures and synthesized in this paper.Moreover,the structures of the target compouds were confirmed by ¹H NMR,¹³C NMR,MS and FTIR spectra,and their herbicidal activity was also tested.The details are described as follows:1.The structure and function of D1 protease and the development of its inhibitors were overviewed.The applications of benzothiazole derivatives as herbicides,insecticides,fungicides and plant growth regulators in agriculture were also described.At the same time,the common synthetic methods of benzothiazole derivatives were also summarized.2.Design and synthesis of the target compounds:the ring closure reaction between anilines or substituted anilines and ammonium thiocyanate produced the intermediates 2-aminobenzothiazoles,which underwent alkylating with benzyl alcohols,thus affording 2-benzylaminobenzothiazoles.As a result,66 benzothiazole derivatives that have not been reported in the literature,were obtained by acylation reaction or sulfonylation reaction between the intermediates 2-benzylaminobenzothiazoles and phenoxyacetic acids or alkylsulfonyl chlorides.3.By using the method of indoor petri dish test,the herbicidal biological activity of the target compounds was assayed.The results demonstrated that all compounds showed certain inhibitory activity against the growth of roots and stems of cole and barnyard grass.In addition,some compounds still greatly inhibited the roots of dicotyledonous plants from growing up at low concentrations,which indicated that these compounds could selectively inhibit the growth of roots of dicotyledonous plants.