Synthesis, Characteriztion and Antimicrobial Activities of Novel Pyrrolyl Benzimidazole Derivatives

Abstract

Background Tuberculosis TB caused by the Mycobacterium tuberculosis complex remains a major health threat with an estimated 1.3 million cases of multidrug-resistant TB. Most TB drugs are over 40 years old highlighting the urgent need for new antimicrobial agents with novel mechanisms to combat rising resistance.Objectives Development and standardization of the methods to synthesize the new pyrrolyl benzimidazole derivatives. Synthesized derivatives were characterized using various analytical techniques including IR sup1H NMR sup1sup3C NMR and mass spectral data. All compounds were screened for antitubercular and antibacterial activities. Methodology Pyrrolyl benzimidazole series were prepared by refluxing substituted orthophenylenediamine 1 and para-aminobenzoic acid 2 with ethanol for 8 h and 10 of sodium hydroxide solution was added to obtain substituted-1H-benzo d imidazole-2-yl aniline 3a-d. This was treated with 25-dimethoxy tetrahydrofuran in glacial acetic acid and refluxed for 30 mins to get substituted 2-4-1H-pyrrol-1-yl phenyl 1H-benzodimidazole 4 a-d further these 3a-d were refluxed with acetonyl acetone in glacial acetic acid to get 4- substituted 2-4-25-dimethyl-1H-pyrrol-1-yl phenyl-1H-benzodimidazole 5a-d.nbsp The mixture was filtered and dried. Recrystallized from ethanol and obtained as brown crystals.Results Synthesized derivatives with a melting point of 140-210 degC. Results indicate that the compounds exhibit antibacterial activity expressed as MIC in the range of 6.25 to 100 microgmL against both gram-positive and gram-negative bacteria. Compounds 4a4d5a5d showed significant antibacterial activity at an MIC value of 6.25 microgmL and compounds 4d5dnbsp showed antitubercular activity at an MIC value of 3.12 microgmL.Conclusion These compounds can be further modified to get more potent antibacterial and antitubercular agents.