Studies On Synthesis And Biological Activities Of Ureas And Thioureas With Heterocyclic-rings

The plant growth regulators of cytokinin type are promoting plant hormones. They initiate or promote cell division and cell differentiation of plants 5 induce callus tissues to split into different organs; retard the senescence of leaves; regulate the transportation and distribution of the substances in plants; promote the development of lateral buds; break the top advantage; promote cotyledon cell expansion. In addition, cytokinins promote the growth and synthesis of chlorophyl as well.By retrieving concerned literatures, this article discussed comprehensively the plant growth regulators of cytokinin type. The nucleophilic additive reactions between 1,2, 4-triazolo [_ 1, 5-a H pyrimidine, tetrazole whose biological activities are comparable to that of adenine-type compounds and substituted benzoyl-isothiocyanide and substituted phenoxyacetyl-isothiocyanide were conducted, producing I and I series of target compounds 22 in all had been ever reported. By modifying the structure of a-chloroacetyl ureas and inducing 1,2,4-triazolo [l, 5-a3pyrimidine, tetrazole, benzothiazole and 1,3,4-oxadiazole to the 桸HCONH?bridge, the compounds containing heterocyclic radical in a-chloroacetylureas of the 3rd series (8 in all) were synthesized. The structures of the target compounds were identified by IR^HNMR,. MS and elemental analysis. Their physic-chemical properties, spectrum properties, reaction conditions and synthetic methods were discussed as well. The structural formulas of the title compounds are as follows respectively:( I ): N-(substituted benzoyl)-N'-(l,2,4-triazolo[l,5-a]pyrimidinyDthioureas( I ): N-(substituted phenoxyacetyl)-N'-(heterocyclic radical) thioureas( I ): N-(a-chloroacetyl)-N'-(heterocyclic radical) ureasThe preliminary herbicidal activities of eighteen title compounds were determined in barnyard grass and coles grown on cannikins and utensils respectively. The results indicated that some compounds,such as I ., I g and I h籩xibited rather high inhibitory activities. By the methods of cole hypocotyl eldkngation,cucumber cotyledon expansion,wheat spront and sheath,as well as cucumber cotyledon striking root, their plant growth-regulating activities were also determined and part of the compounds were found to exibit certain activities of auxins.