Synthesis of Benzimidazole and Phthaloylamino Acid derivatives and Antibacterial Activity

Seven novel benzimidazole and phthaloylamino acid derivatives were synthesized. In the presence of acetic acid, the phthalic anhydride reacted with benzidine in a cyclization reaction to obtain the biphenyl of 7 products. Likewise, when phthalic anhydride is reacted with different amino acids including D-glycine, D-alanine, and D-valine under solventless and fusion conditions using an oil bath, the N-phthaloylamino acids 1a to 1c were obtained. These were, in turn, reacted and again in a cyclization reaction with o-phenylenediamine (OPDA) under reflux conditions in the presence of dilute hydrochloric acid affording their corresponding benzimidazole derivatives 2a to 2c. The last compound 3a was synthesized in the existence of benzidine and acetic acid. The structures of synthesized complexes were identified by chromatographic, 1H-NMR, and mass spectrometry. The melting point and other physicochemical properties were found in this investigation. The biological screening of the products was made to evaluate and prove their antibacterial importance.