Synthesis and antimicrobial activity of some amino acids and sulfamoyl and pyrrole derivatives attached to 4-benzoimidazol-2-yl moiety

Abstract

Background and objectivesBenzoimidazole moiety is one of the heterocyclic compounds that plays a vital role in biological fields such as antioxidant, antidepressant, anticonvulsant, antimicrobial and anticancer. The aim of this study was to construct new compounds containing 4-(5-benzoyl-benzoimidazol-2) moiety incorporated into different amino acids and sulfamoyl and/or pyrrole analogues and to evaluate their antimicrobial activities.Materials and methodsThe starting material 4-(5-benzoyl-1H-benzoimidazol-2-yl)-benzonitrile ( 2 ) was prepared through the reaction of (3,4-diamino-phenyl)-phenyl-methanone ( 1 ) with 4-cyanobenzaldehyde in absolute ethanol. Stirring compound 2 with 70% sulfuric acid gave benzoic acid derivative 3 followed by esterification and refluxing with hydrazine hydrate to form the corresponding 4-(5-benzoyl-1H-benzoimidazol-2-yl)-benzoic acid hydrazide ( 5 ). A series of derivatives 6a-d were prepared by coupling of benzoic acid derivative 3 with different amino acids ethyl ester. Reacting ester compound 4 with different amines and sulfa drugs led to the formation of the amides derivatives 7a,b and 8a,b , whereas on reacting the hydrazide compound 5 with different acid anhydrides, cyclohexane-1,4-dione and 5-nitroisatin compounds 9a-c , 10 and 11 were obtained.Results and conclusionMost of the test compounds were found to be significantly effective against Bacillus subtilis and Staphylococcus aureus (gram-positive bacteria), Escherichia coli and Pseudomonas aeuroginosa (gram-negative bacteria) and Candida albicans and Aspergillus niger (fungi) .