A process for the preparation of a herbicidally active 1-amino-1,3,5-triazone-2,4 (1H,3H)-dione of the formula ##STR1## comprising in a first stage at a temperature from about 0.degree. to 100.degree. C. reacting an isocyanate of the formula R.sup.1 - NCO (II) with an isothio semicarbazone of the tautomeric formulas ##STR2## in which R.sup.3 and R.sup.4 each independently is hydrogen, alkyl, cycloalkyl, aralkyl o alkyl, cycloalkyl, aralkyl or aryl, thereby to form a urea derivative of the tautomeric formulas ##STR3## in a second stage at a temperature between about -50.degree. and 0.degree. C. reacting the urea derivative with phosgene (COCl.sub.2) in the presence of an auxiliary organic base and in the presence of a diluent, at least about 2 mols of phosgene and at least about 2 mols of the auxiliary base being used per mol of urea derivative, thereby to form a 1-alkylideneamino-1,3,5-triazine-2,4(1H,3H)-dione of the formula V ##STR4## and in a third stage converting the 1-alkylideneamino group to a 1-amino group.
                            一种制备具有除草活性的1-
氨基-
1,3,5-三嗪-2,4(1H,3H)-二酮的方法,其
化学式为##STR1## 包括以下步骤:第一阶段,在温度约为0℃至100℃的条件下,将
化学式为R1-NCO(II)的
异氰酸酯与具有互变异构式的
化学式为##STR2## 的异
硫脲半胱
氨酸反应,其中R3和R4各自独立地为氢、烷基、环烷基、芳基烷基或烷基、环烷基、芳基烷基或芳基,从而形成具有互变异构式的
脲衍
生物的
化学式为##STR3## 第二阶段,在温度约为-50℃至0℃的条件下,在助剂有机碱和稀释剂的存在下,将
脲衍
生物与
光气(COCl2)反应,每摩尔
脲衍
生物使用至少2摩尔
光气和至少2摩尔助剂碱,从而形成
化学式为V的1-烷基
亚胺基-
1,3,5-三嗪-2,4(1H,3H)-二酮##STR4## 第三阶段将1-烷基
亚胺基团转化为1-
氨基团。