Synthesis of 4-(Biphenyl-4-yl)-2-(Substituted Phenyl)-1-Phenyl-1H-Imidazoles

Author(s): Bipin Kumar Verma* and Girendra Kumar Gautamb

Abstract: Current interest in the new molecules containing the imidazole nucleus remains high in both laboratory and in clinical areas because of the increasing spectrum of biological activity found among these derivatives. In this project we have synthesized and evaluated a number of derivatives containing an imidazole moiety. The used imidazole rings an essential component in antimicrobial activity and plays an important role in biological function. The derivatives were prepared according to previous literature. The widespread application of these procedures is to synthesize these small molecules with proves its utility in treatment of microbial infection disease. In continuation of our efforts in search of potent antimicrobial agents which can be developed as safer and effective, we have been decided to study new derivatives which contain imidazole moiety in it and to further evaluate their pharmacological activity in order to improved & better therapeutic action. Imidazole played an important role for this purpose and this nucleus may serve as new template for the synthesis of safer & potential antimicrobial agents. In view of the wide spectrum of important biological activities including antibacterial, antifungal, antiprozoal, anti-inflammatory, anticancer, anti-anthelmintic and analgesics etc of imidazole derivatives, it was considered worthwhile to work on this system i.e. imidazole skeleton. The aim of the present studies has been to synthesize a new series of imidazole which, may be used as antimicrobial drugs based on their efficacy, lesser or no side effects and low cost involved in their preparation. The title compounds (3i-xii) were synthesized as per synthetic protocol (scheme-2). In this scheme biphenyl ethanone (1; starting material) was treated with selenium dioxide to get 2-(biphenyl-4-yl)-2-oxoacetaldehyde (2). Compound 2 was refluxed with different aromatic aldehydes in presence of ammonium acetate and glacial acetic acid, followed by treatment with chlorobenzene in THF to get twelve new imidazole derivatives (3i-xii). The title compounds (4i-xii) were synthesized as per synthetic protocol (scheme-3). In this scheme biphenyl ethanone (1; starting material) was prepared by heating biphenyl with anhy. AlCl3 in presence of CS2 and acetic anhydride. The biphenyl ethanone (1; starting material) was treated with selenium dioxide to get 2-(biphenyl-4-yl)-2-oxoacetaldehyde(2).Biphenyl-2-oxoacetaldehyde (2) was refluxed with different aromatic aldehydes in presence of ammonium acetate and glacial acetic acid to get new imidazole derivatives (3i-xii). 4-(Biphenyl-4-yl)-2-(substituted phenyl)-1-phenyl-1H-imidazoles (3i-xii) were refluxed with chlorobenzene in THF to get desired compounds (4i-xii). These final compounds showed different TLC spot, Rf value and melting point while comparing with starting compound (3i-xii).

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