Process for preparing sulfonylureas

摘要

This invention relates to a process for preparing sulfonylureas comprising reacting a sulfonyl chloride with a cyanate salt and an amine base in the presence of an inert aprotic solvent to give an isocyanate complex which is then reacted with an amino heterocycle to form the sulfonylurea product and a process for converting the crystal form of the prepared sulfonylurea product to a more stable crystal product form.