| 摘要 |
The process according to the invention for the preparation of herbicidal pyridylsulfonylureas of the formula (I) (* CHEMICAL STRUCTURE *) (I) in which R1 to R5 and X are as defined in claim 1 comprises the reaction of the zwitterion (II) with the amino heterocycle (III) (* CHEMICAL STRUCTURE *) (II) (* CHEMICAL STRUCTURE *) (III) 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 (* CHEMICAL STRUCTURE *) (IV) (* CHEMICAL STRUCTURE *) (V) in the presence of an alkyl isocyanate. |
