Design Synthesise and Biological Evaluation of some Benzimidazole Derivatives as Antimicrobials

Abstract

Benzimidazole and its derivatives represent one of the most biologically active class newlineof compounds, possessing a wide spectrum of activities and these are well newlinedocumented in the literature. Some derivatives of benzimidazole were synthesized by newlinenucleophilic substitution. The present work comprises of synthesis of new newlineantimicrobial agent, in which 4- chloro-ortho phenylene diamine are used as a starting newlinematerial to which formic acid/acetic acid reacts and form 2-substituted 6-chlorobenzo[d]imidazole, this further heated with ethylbromoacetate and forms 2- newlinesubstituted Ethyl 2-(6-chloro-benzo[d]imidazol-1-yl)acetate. The resulting newlineintermediate on treatment with hydrazine hydrate yields Ethyl 2-(6-chloro-2- newlinesubstituted-1H-benzo[d]imidazol-1-yl)hydrazide which on further reaction with one newlineequivalent of different substituted aromatic carboxylic acids and aldehydes in the newlinepresence of phosphoryl chloride afforded the corresponding target compounds 6- newlinechloro-2-substituted-1-[{(5-substituted aryl)-1,3,4-oxadiazol-2-yl} methyl]-1Hbenzimidazole and N-substituted-benzylidene-6-chloro-2-substituted-1Hbenzo[d]imidazol-1-amine. 22 novel benzimidazole derivatives were synthesized newlinefrom 4 series as mentioned in scheme. The compounds were synthesized in newlineappreciable yields and the structures of the synthesized compounds were evaluated by newlinespectral methods of analyses. All the synthesized compounds were screened for their newlineantimicrobial activity against Escherichia coli representing Gram negative bacteria, newlineBacillus subtilis and Staphylococcus aureus representing Gram - positive bacteria, newlineSaccharomyces Cerevisiae representing Fungi. The result revealed that most of newly newlinesynthesised compounds exhibited promising antibacterial and antifungal activities. newlineGenerally the test compounds showed good activity against Gram positive bacteria, newlineGram positive bacteria, fungi. Other compounds showed moderate activity against newlineGram positive bacteria, Gram positive bacteria, fungi. The results showed that all newlineof the compounds