2-取代氨基-5-去氢枞基-1,3,4-噁二唑衍生物的合成及除草活性

Synthesis and Herbicidal Activity of 2-Substituted Amino-5-dehydroabietyl-1,3,4-oxadiazole Derivatives

以去氢枞酸为原料,经酰化后与水合肼反应合成去氢枞酰肼3,再与芳基异硫氰酸酯反应,得到中间体1-去氢枞酰基-4-取代基氨基硫脲4,4在Hg(OAc)2/EtOH条件下关环,合成得到一系列新型2-取代氨基-5-去氢枞基-1,3,4-噁二唑化合物5.采用IR,MS,1H NMR,13C NMR和元素分析等方法对中间体4和目标产物5进行了分析和表征.初步的除草活性测试表明,化合物4和5对油菜的胚根生长以及对稗草的幼苗生长有一定的抑制作用,其中化合物4d在浓度为100 mg/L时对油菜胚根生长的抑制率达88.2%.

Dehydroabietic acid chloride was prepared by the reaction of dehydroabietic acid with thionyl chloride, followed by the reaction of the dehydroabietic acid chloride with hydrazine hydrate to provide dehydroabietacyl hydrazine. A series of target compounds 2-substituted amino-5-dehydroabietyl-1,3,4-oxadiazoles 5 were synthesized by the cyclization of 1-dehydroabietacyl-4-substituted thiosemicarbazides （4） under catalysis of Hg（OAc）2/EtOH. And the intermediates 4 were prepared by the reaction of dehydroabietacyl hydrazine with aryl isothiocyanates. The intermediates 4 and target compounds 5 were analyzed and characterized by means of IR, MS, 1H NMR, 13C NMR techniques and elemental analysis. The preliminary herbicidal assay showed that all the compounds 4 and 5 exhibited a certain growth inhibition on rape root （Brassica campestris） and barnyard grass （Echinochloa crusgalli （L.））. Among the tested compounds, 4d displayed 88.2% inhibition on rape root （Brassica campestris） at 100 mg/L concentration in herbicidal tests.