Study of the Reaction of Hydroxybenzoyl Chlorides and Their Derivatives with Imidazole

Abstract

The reaction of hydroxybenzoyl chlorides with imidazole was studied on an example of the Schotten-Baumann reaction of salicyloyl and acetylsalicyloyl chlorides with imidazole, which, according to soe published data, can take two different ways. It was shown that the Schotten-Baumann reaction with imidazole involves imidazole ring opening (Bamberger cleavage) to form l,2-bis(salicyloylamino)ethylene and l,2-bis(acetylsalicyloylamino)ethylene rather than N-salicyloylimidazole and N-acetylsalicyloylimidazole. N-Hydroxybenzoylimidazoles were synthesized by the reaction of hydroxybenzoyl chlorides (and derivatives) with a double excess of imidazole in an aprotic solvent (chloroform, benzene, or diethyl ether) at room temperature. The highest yields (about 80%) of N-hydroxybenzoylimidazoles were obtained in chloroform. Some of the newly synthesized compounds were tested for psychotropic (open field and passive avoidance response tests) and analgesic activities (vocalization threshold test). The best results were obtained with N-(2-hydroxybenzoyl)imidazole, which showed an evident analgesic activity, and, therewith, the motor score and oriented exploratory activity parameters were higher than in the control group.