报道了苯基硫脲与脂肪醛(酮)及三氯化磷进行的类Mannich反应,除生成预期产物3-苯基-4-氯-4-氧代-1,3,4-二氮磷杂环戊-2-硫酮(Ⅰ)外,还生成了少量3-苯基-4-氯-4-硫代-1,3,4-二氮磷杂环戊-2-硫酮(Ⅱ).当Ⅰ与Lawesson试剂在甲苯中反应时,可顺利地转化为Ⅱ.生物测定结果表明,Ⅱ具有较好的选择性除草活性.晶体结构测定表明,Ⅱ的五元磷杂环为平面结构. A Mannich-like reaction of phenylthiourea with fatty aldehydes (ketones) and phosphorus trichloride was reported, except that the expected product 3-phenyl-4-chloro-4-oxo-1,3,4- 2-thione (I), a small amount of 3-phenyl-4-chloro-4-thioxo-1,3,4-diazaphosphorin-2-thione (II ) .It was successfully converted to Ⅱ when Lawesson’s reagent was reacted with toluene in the presence of I. The bioassay results showed that Ⅱ has good selective herbicidal activity.The crystal structure determination showed that the five-membered phosphorus heterocycle of Ⅱ is planar .