Synthesis of benzimidazole compounds using microwave irradiation as a new technique and screening of some biological activities

In this study, an alternative method to synthesize of benzimidazole derivative, which is very important compounds for the pharmaceutical chemistry, has been developed.Firstly we obtained benzimidazole derivative compounds (2a-g) from the reaction of iminoester hydrochlorides (1a-h) with 4,5-dichloro-o-phenylenediamine presence of acidic alumina or in methanol under the microwave irradiation. For comparing, we synthesized these compounds by using conventional method. These derivatives converted to esters (3a-g) using methyl-?-bromoacetate under microwave irradiation. Finally compound (3a-g) was converted to (4a-g) by the treatment with hydrazyne hydrate using the microwave irradiation.Second original part of work, we obtained bisbenzimidazole derivative compounds (5a-e) from the reaction of (1a-e) with 3,3?-diaminobenzidine presence of acidic alumina or in methanol under the microwave irradiation. These derivatives converted to esters (6a-e) using methyl-alpha bromoacetate under microwave irradiation. Finally via a nuchleophilic displacement of the methoxy with hydrazine hydrate was given to acyl hydrazides (7a-e) under the microwave irradiationStructures of 36 compounds were identified on the basis of spectroscopic methods. The antimicrobial activities were screened.Key Words: Microwave synthesis, Benzimidazole, Solvent-free, Iminoester hydrochlorides