Hitesh A. Barad

An efficient one-pot synthesis, structure, antimicrobial and antioxidant investigations of some novel quinolyldibenzo[b,e][1,4]diazepinones

A highly improved one-pot procedure for the synthesis of diazepinones, which incorporate a bioactive quinoline nucleus, under catalyst-, and solvent-free environment has been developed. The method allowed us to achieve the products in high yields without requiring a chromatographic separation. All new quinolyldibenzo[b,e][1,4]diazepinones 6a-h thus obtained were further treated to achieve N10-allylated products 7a-h by a simple allylation. The structure of all new synthesized compounds was established based on elemental analysis, mass, (1)H NMR, (13)C NMR, IR spectral data, 2D NMR experiments, and single crystal X-ray study. From in vitro antimicrobial activity studies it revealed all are active against Gram positive (Streptococcus pneumoniae, Clostridium tetani, and Bacillus subtilis), Gram negative (Salmonella typhi, Vibrio chlolerae and Escherichia coli), M. Tuberculosis H37RV bacteria, and fungus like Candia albicans and Aspergillus fumigatus. All were also found to display good antioxidant activity of a ferric reducing power.

A highly efficient, rapid one-pot synthesis of some new heteroaryl pyrano[2,3-c]pyrazoles in ionic liquid under microwave-irradiation

A highly efficient, rapid one-pot procedure has been developed for a three-component domino intermolecular Knoevenagel–intermolecular hetero-Diels–Alder reaction, to afforded indolyl- and quinolylpyrano[2,3-c]pyrazoles from corresponding heteroarylaldehyde, pyrazolone and enol ether in ionic liquid triethylammonium acetate (TEAA) under microwave (MW) irradiation. The reaction advantageously precedes in highly regio- and stereoselective manners in combination with the ease of recovering ionic liquid used in the reaction. According to literature, the heterocycles are expected to display antitubercular activity. 2D NMR NOESY (nuclear overhauser effect spectroscopy) experiments confirm the cis-orientation of the two pyran ring hydrogens; one attached to the anomeric carbon and the second to which a heteroaryl attached.

Efficient One-Pot Synthesis of Precursors of Some Novel Aminochromene Annulated Heterocycles via Domino Knoevenagel–hetero-Diels–Alder Reaction

Abstract An efficient, one-pot synthetic approach to precursors of some new aminochromene/xanthene annulated heterocycles via a tetrabutylammonium hydrogen sulfate–mediated intramolecular domino Knoevenagel–hetero-Diels–Alder reaction is described. The method is general and efficient. The stereochemistry of the product was confirmed by various NMR experiments and single-crystal x-ray diffraction data. Supplemental materials are available for this article. Go to the publishers online edition of Synthetic Communications® to view the free supplemental file. GRAPHICAL ABSTRACT

Chelation and extraction of copper(II) with 5-pyrazolone-based Schiff bases

Copper(II) chelates of the Schiff bases (H2L), obtained by condensation of 4-butyryl-3-methyl-1-phenyl-pyrazoline-5-one (HBMPP) with o-phenylene diamine (H2L1) and p-phenylene diamine (H2L2), have been prepared and characterized by elemental analyses, thermogravimetric analyses, magnetic measurements, diffuse reflectance spectra, IR and mass spectra, and conductance measurements. The extractability of copper(II) with H2L in chloroform was examined. Effective extraction was observed with 1 × 10−3 mol dm−3 of ligands at pH 6.5 using H2L1 and pH 7.0 using H2L2. The nature of the extracted species was ascertained by the slope analysis method. The ligand can effectively be used in solvent extraction of copper(II) from aqueous phase to organic phase.

Triethylammonium acetate-mediated domino-Knoevenagel-hetero-Diels–Alder reaction: synthesis of some angular polyheterocycles

A solvent-cum catalyst, ionic liquid triethylammonium acetate-mediated one-pot procedure for the synthesis of some new angular benzopyrano[3,4-c]pyrano-fused pyrazoles, all of which incorporate a tertiary ring junction carbon, has been developed. The stereochemistry of the products has been confirmed by single-crystal X-ray diffraction data.Graphical abstract

An improved microwave assisted one-pot synthesis, and biological investigations of some novel aryldiazenyl chromeno fused pyrrolidines

An improved microwave assisted one-pot method for the synthesis of twelve new aryldiazenylchromeno [4,3-b] pyrrolidines via intramolecular azomethine ylide cycloaddition route is described. The method is efficient and advantageous over conventional and solvent-free thermal methods. The stereochemistry of the compounds was confirmed on the basis of various NMR experiments, and finally by single crystal X-ray diffraction data. N-Methyl or ethyl pyrrolidine based heterocycles gave good biological activities.

An efficient domino Knoevenagel/hetero-Diels–Alder route to some novel thiochromenoquinoline-fused polyheterocycles

The 2-alkenylthiopyranoquinoline-3-carbaldehyde derived from 2-mercaptoquinoline-3-carbaldehyde and citral underwent smooth domino Knoevenagel/hetero-Diels–Alder reaction with heterocyclic mono- or diketones in tetrabutylammonium hydrogensulfate under solvent-free conditions and afforded a new class of thiochromenoquinoline-fused heterocycles in good yields. The reaction is highly diasteroselective and can be applied to analogues of carbocyclic diketones as well. The stereochemistry of the products was confirmed by single-crystal X-ray diffraction and 2D NMR NOESY data.Graphical abstract

A catalyst- and solvent-free multicomponent synthesis and docking study of some new antiproliferative N5-allyl-quinolylpyrido[2,3-b][1,4]benzodiazepinone precursors

A multicomponent reaction has been developed by incorporating quinoline-3-carbaldehyde, 1,3-cyclohexanedione and 2,3-diaminopyridine into some new quinolylpyrido[2,3-b][1,4]benzodiazepinone assemblies under catalyst- and solvent-free conditions at 120 °C. Further reaction of the resulting intermediates with allyl bromide led to the formation of the corresponding N5-allylated products, in situ, with higher yields in the same pot. Many candidates of this new class revealed noticeable activities against the representative human solid tumour cell lines A549 (lung), HBL-100 (breast), HeLa (cervix), SW1573 (lung), T-47D (breast) and WiDr (colon). The most active compounds resemble the standard drug etoposide in antiproliferative activity against HeLa, T-47D and WiDr cell lines. Docking studies in the active site of MDM2 led us to consider this protein a plausible target for the antiproliferative effects of the compounds.