Synthesis and Microbial Evaluation of Versatile Base Catalyzed Chiral Tetrahydrobenzofuran Derivatives via Multicomponent Reaction

A base catalyzed sequential one-pot protocol for an effective preparation of 3-(substitutedphenyl) -6,6-dimethyl-2-(substitutedphenylcarbonyl)-3,5,6,7-tetrahydro-1-benzofuran-4(2H)-one derivatives have been described. One-pot reaction of aromatic aldehydes, various phenacyl bromide and dimedone gives corresponding substituted benzofurans in economically affordable yields with stereo specificity at 2nd and 3rd position via formation of substituted pyridinium ylides. Newly synthesized compounds were characterized by different spectral techniques such as IR, H-1 NMR, C-13 NMR and Mass spectrometry. Furthermore, the structure of compound 4f was unambiguously assigned by X-ray crystallography. All the synthesized compounds were subjected to in-vitro antimicrobial screening against a panel of pathogenic strains of bacteria to evaluate their potency as a MIC. Some of the compounds were found to be equipotent or extra potent than commercial antibiotics against some active strains.