Green, unexpected synthesis of bis-coumarin derivatives as potent anti-bacterial and anti-inflammatory agents.

A green and efficient protocol has been developed and a series of coumarin based pyrano[3,2-c]chromene derivatives (2) have been synthesized using multi-component reaction (MCR) approach. Unexpected 3-coumarinyl-3-pyrazolylpropanoic acids (3) and C4-C4 chromenes (5) have been isolated instead of expected product 4 by the reaction of compound (2) in formic acid at 90 °C for about 4-5 h and at 130 °C for about 8-10 h respectively. Further, C4-C4chromenes (5) formation was confirmed by intramolecular cyclization of compounds (3). These compounds were screened for their biological activities and most of them exhibited promising antibacterial activity. The anti-inflammatory assay was evaluated against HRBC membrane stabilization method and the compounds exhibit excellent anti-inflammatory activity. Molecular docking study has been performed for all the synthesized compounds with Klebsiella pneumoni aeacetolactate synthase and results obtained are quite promising.

Design and synthesis of novel phenyl -1, 4-beta-carboline-hybrid molecules as potential anticancer agents.

A series of beta-carbolines with other heterocycles linked by phenyl ring has been designed and synthesized. The key intermediates 3 and 5 were synthesized by condensing tryptamine and teraldehyde via Pictet- Spengler method. All the newly synthesized compounds were tested for their anticancer activity against sixty human cell lines at NCI. The five dose results of compounds 3 and 7a showed enhancement of anticancer activity (GI50 values range from 1.00 to 7.10 µM) against all the cell lines in comparison with some of earlier molecules. In addition to this protein binding and CT-DNA intercalation studies showed molecules are highly potential. The molecular docking studies, which support the multiple mode of interaction with DNA, moreover the synthesized compounds 3 and 7a are more potential and possess drug -like nature.

Synthesis, Characterization and Photophysical Studies of Tricoumarin-Pyridines.

A series of novel tricoumarin-pyridines have been synthesized by the reaction of 4-formyl coumarins and substituted 3-acetylcoumarin with ammonium acetate for the application in organic electronics as well as fluorescent dyes. The structures of all new compounds were confirmed and characterized by IR, 1H NMR and ESI-Mass analysis. All the important photo physical prerequisites for organic electronic application such as strong and broad optical absorption, thermal stability were determined for the synthesized molecules. Optical properties were studied by UV-Vis absorption and fluorescence spectroscopy. Optical band gaps of the tricoumarin-pyridines were found to be 2.72-3.10 eV as calculated from their onset absorption edge. The tricoumarin-pyridines were thermally stable up to 290-370 °C as determined by thermogravimetric analysis (TGA). Photophysical studies indicate the synthesized materials are promising candidates for organic electronic applications.

Synthesis, characterization and molecular docking studies of substituted 4-coumarinylpyrano[2,3-c]pyrazole derivatives as potent antibacterial and anti-inflammatory agents.

A green, eco-friendly and efficient protocol has been developed and synthesized a series of coumarin based pyrano[2,3-c]pyrazole derivatives (3) by multi-component reaction (MCR). Unexpected 3-coumarinyl-3-pyrazolylpropanoic acids (4) have been isolated by the reaction of compound (3) in acidic conditions. Further, intramolecular cyclization of compounds (4) leads to C4C4 chromons (9) and these compounds were screened for their biological activities using array of techniques. Most of the compounds exhibited promising antibacterial activity, in particular Gram-positive bacteria. The anti-inflammatory assay was evaluated against protein denaturation as well as HRBC membrane stabilization methods and compounds exhibit excellent anti-inflammatory activity in both methods. Molecular docking study has been performed for all the synthesized compounds with S. aureus dihydropteroate synthetase (DHPS) and results obtained are quite promising.