Synthesis and molecular docking studies of coumarin-imidazole conjugates as potential antimicrobial agents

110-125One-pot multi-component synthesis of tri and tetra-substituted coumarin-imidazole conjugates have been achieved in good to excellent yield under conventional and microwave methods in optimized catalyst condition. Further, they have been evaluated for antimicrobial activity against Gram positive Bacillus flexus and Gram negative Pseudomonas Spp. bacterial strains and two strains of fungi Scopulariopsis spp. and Aspergillus tereus organisms. The results of microbial activity are promising against tested organisms. The molecular docking study has been performed for all the compounds and docking scores are excellent. Synthesized compounds have been characterized by IR, NMR, mass and a few of them by single crystal X-ray analysis

Green approach for the synthesis of 4-coumarin-4<i>H</i>-pyrans from 4-formylcoumarins and their antibacterial study

<p>A series of 4<i>H</i>-pyranocoumarin derivatives have been successfully synthesized under eco-friendly condition using triethylamine as a catalyst in short reaction time with excellent yield at room temperature. All the synthesized compounds were characterized by spectral analysis and screened for their antibacterial activity against <i>Escherichia coli</i> and <i>Staphylococcus aureus</i>, the results are quite promising.</p

Synthesis of coumarin analogous of decursivine derivatives

<p>The first synthesis of decursivine derivatives of coumarins is described via intramolecular Friedel–Craft aromatic alkylation. The Lewis acid (LA)–catalyzed reaction facilitated the rapid construction of the desired product. The targeted molecule obtained has been confirmed by spectral analysis.</p

Highly stereoselective direct aldol reaction of 4-formylcoumarins with acetone catalyzed by L-proline in water–acetone mixtures

<p>Organocatalyzed direct intermolecular aldol reactions have been developed for substituted 4-formylcoumarins with acetone in water using L-proline and phthalimido-prolinamide catalysts without use of additives. Stereoselective products obtained were in excellent yields (up to 97%) with high purity (up to 99%) and enatioselectivities (up to 95%). The isolated compounds were confirmed by infrared, NMR, high-performance liquid chromatography, and mass spectrometry and some of them by single-crystal x-ray crystallography.</p

Synthesis, molecular docking, and biological evaluation of methyl-5-(hydroxyimino)-3-(aryl-substituted)hexanoate derivatives

Beta-aryl keto hexanoic acids (5a-l) were synthesized efficiently, followed by esterification that afforded beta-aryl keto methylhexanoates (6a-l). The chemo-selective ketoxime beta-aryl methyl hexanoates (7a-l) were isolated in good yields. Spectroscopic methods were used to characterize the obtained moieties. The antioxidant, anti-inflammatory, and antibacterial properties of the effectively synthesized compounds 7a-l were also investigated. The anti-inflammatory activity of the compounds 7c, 7f, 7i, and 7l was excellent, with a low IC50 value at micromolar concentration, which was much better than the reference diclofenac. All synthesized compounds 7a-l were assessed for their in vitro antibacterial activity against S. aureus, B. subtilis and E. coli.  Most of the compounds exhibited promising activity against Gram-positive bacterial strain, compound 7i showed excellent activity compared to standard streptomycin and in the case of E. coli, compounds 7b, 7c, 7j, 7k and 7l have shown moderate activity. Further, the cytotoxic activities of the compounds were assessed against lung cancer cells (A549) by using MTT assay. The possible interaction mechanism of the molecules 7c and 7g with Gram-negative strain E. coli DNA gyrase B in complex with PDB ID: 4DUH was studied

An efficient and catalyst free methylthiolation of 4-(bromomethyl)-2<i>H</i>-chromen-2-ones with DMSO

<p></p> <p>The first simple, metal free, and efficient protocol has been established for the methylthiolation of structurally diverse 4-bromomethyl-2<i>H</i>-chromen-2-ones using dimethyl sulfoxide (DMSO) as methylthiolation source at higher temperature. The experimental method is highly economical and provides excellent yields of highly pure products which do not require further purification. All novel 4-[(methylthio)methyl]-2<i>H</i>-chromen-2-ones were characterized by ¹H, ¹³C NMR, and single-crystal X-ray analysis.</p

Design, synthesis, characterization, photophysical and pH chemosensor studies of novel 2,4,6-trisubstituted pyridines

<p>For the application in organic electronics as well as pH meters, a series of novel 2,4,6-trisubstituted pyridines have been synthesized by the reaction of substituted aromatic aldehydes and substituted 3-acetylcoumarin with ammonium acetate. The structures of all the new compounds were characterized by IR, NMR, and GC–MS analysis. The important photo physical prerequisites for organoelectronic such as optical absorption and thermal stability were determined for the synthesized molecules. Optical properties were studied by UV–visible absorption and fluorescence spectroscopy. Optical band gaps of the 2,4,6-trisubstituted pyridines were found to be around 3.01–3.06 eV as calculated from their onset absorption edge. The pH-dependent changes in the fluorescence intensity suggest that 2,4,6-trisubstituted pyridines are useful applicants in intracellular pH meters.</p