An Efficient Method for Synthesis of New Tricyclic Benzimidazoles by Using Sodium Metabisulphite Adsorbed on Silica and Their Antimicrobial Studies

Abstract

New tricyclic benzimidazoles have been synthesized by condensation of 3,4-dihydro-2H-benzo [b][1,4]oxazin-5-amine and different aldehydes in presence of sodium metabisulfite adsorbed on silica. The method is very efficient, and reactions are completed at room temperature with easy product isolation. The synthesized compounds showed antimicrobial potential against gram-positive bacteria S. aureus and gramnegative bacteria E. coli with MIC of 0.625 mg/ml for com-pounds 6 f (cyclohexyl substituent) and 6 h (furan substituent) and 0.312 mg/ml for compound 6 c (chlorophenyl substituent) respectively, were evaluated by Resazurin microtiter plate visual method. Molecular docking studies using Autodock 4.2 showed theoretical binding energy À 6.74 to À 8.32 Kcal/mol for S. aureus and À 5.94 to À 8.01 Kcal/mol for E. coli with PDB Id 2W9S and 2EX6 respectively.