FIELD: organic chemistry, chemical technology, herbicides. SUBSTANCE: invention relates to a novel method of synthesis of sulfonylureas (I) of the formula: A-SO2-NH-CO-NR-B where Ar means unsubstituted or substituted phenyl; B means residue of pyrimidine-2-yl or 1,3,5-triazinyl-2-yl that can be substituted; R means hydrogen atom, C1-5-alkyl, C1-5-haloidalkyl, C1-5-alkoxy- -group, C1-5-haloidalkoxy-group; A means unsubstituted or substituted phenyl or their salts exhibiting herbicide action and N-(pyrimidinyl- or triazinyl)-carbamates of the formula (IV): Ar-O-CO-NR-B as intermediate compounds. Method of synthesis of sulfonylureas of the formula (I) involves conversion of compound of the formula (II): H-NR-B in situ to the corresponding salt of the formula (II-S): M+Base- using the base M+ that is alkaline metal alcoholate where Base- means equivalent of alkaline metal cation; M+-NR-B means an equivalent of alcoholate residue anion. The prepared reaction mixture is subjected for interaction with diarylcarbonate of the formula (III): (Ar-O)2-CO to yield the compound of the formula Ar-O-CO-NR-B (IV) where values Ar, B, R are given in formulas (II), (II-S), (III) and (IV) and have values indicated above. The prepared reaction mixture is subjected for interaction with sulfonamide of the formula (V): A-SO2-NH2 where A has the above indicated value followed by isolation of the compound of the formula (I) or its salt. Interaction of carbamate of the formula (IV) with sulfonamide of the formula (V) is carried out at temperature from -40 C to 180 C. Method excludes the use of alkaline metal hydrides as reagents and provides the production of compounds in industrial scales. EFFECT: simplified process, decreased consumption for accident prevention. 8 cl, 6 ex
