METHOD OF PREPARARING SULPHONYL UREAS WITH HERBICIDAL PROPERTIES AND N-PYRIMIDINYL OR N-TRIAZINYL CARBAMATES AS INTERMEDIATES IN THE REACTION.

摘要

The invention concerns a method of preparing a carbamate of formula (IV) Ar-O-CO-NR-B by reacting a salt of formula (II-S) with a diaryl carbonate of formula (III) (ArO)2CO, Ar, B and R being as defined in claim (1). The carbamate can be reacted, without having to isolate it, with sulphonamides of formula (V) A-SO2NH2 to give sulphonyl ureas of formula (I) A-SO2-NH-CO-NR-B. The method avoids the need to use alkali-metal hydrides as bases.