Friedel-crafts acylation of benzimidazolin-2-ones with aliphatic acid chlorides

The acylation of benzimidazolin-2-one and its 5,6-disubstituted derivatives with aliphatic acid chlorides in the presence of anhydrous aluminum chloride was studied. The corresponding 5(6)-acyl-, 5-R-6-acyl-, and 5,6-dimethyl-4-acylbenzimidaz-olin-2-ones, the structures of which were confirmed by the results of elementary analysis and IR, PMR, and mass spectroscopy, were obtained. The yields of the acylation products depend on the electronic effects of the substituents in the benzene ring of the benzimidazolin-2-one and on steric factors.