The process according to the invention for the preparation of herbicidal pyridylsulfonylureas of the formula (I) ##STR1## in which R.sup.1 to R.sup.5 and X are as defined in claim 1 comprises the reaction of the zwitterion (II) with the amino heterocycle (III) ##STR2## The novel zwitterionic 1,1,3-trioxo-1,2,4-thiadiazolo-[4,5-a]pyridines can be obtained according to the invention by the reaction of phosgene with compounds IV, or the reaction of phosgene with compounds V ##STR3## in the presence of an alkyl isocyanate.
本发明涉及一种制备杀草剂
吡啶磺酰
脲化合物的方法,其
化学式为(I),其中R1到R5和X的定义如权利要求1所述。该方法包括将离子复合物(II)与
氨基
杂环化合物(III)反应。本发明还涉及通过将
光气与化合物IV反应或将
光气与化合物V在烷基
异氰酸酯存在下反应,制备新型离子复合物1,1,3-三氧代-
1,2,4-噻二唑并[4,5-a]
吡啶。