Among benzazoles, biologically active substances with a variety of important properties have been discovered, which are used in agriculture, medicine and other fields. To synthesize new organic compounds based on benzimidazolin-2-ones, determine the relative activity series of the aromatic acid chlorides involved in the reaction, determine the reaction duration, and determine the amount of catalyst used, the reactions of benzimidazolin-2-ones (Ia, b) with aromatic acid chlorides (IIa–h) in the presence of FeCl₃∙6H₂O. Based on the yield of 5(6)-aroylbenzimidazolin-2-ones formed in the acylation reactions, optimal conditions for the acylation reaction were found, according to which the ratio of reagents Ia,b:IIa-h:FeCl₃∙6H₂O = 1:1.2:1∙10^-2, the reaction temperature was 200-205°C, the reaction duration was 3 hours. Under these conditions, the yield of 5(6)-aroylbenzimidazolin-2-ones (IIIa-p) was 40-79%. It was shown that the yield of the products depends on the degree of nucleophilicity of the benzimidazolin-2-ones and the degree of electrophilicity of the acylating agent. A number of relative activities of various substituted benzoyl chlorides were also found. The structure of the synthesized compounds was confirmed by IR, ¹H NMR spectroscopy, mass spectrometry and elemental analysis.

doi.org/10.32737/0005-2531-2026-1-64-73