• Deepak Kumar

      Articles written in Journal of Chemical Sciences

    • Design, synthesis and antidiabetic evaluation of oxazolone derivatives

      G Mariappan B P Saha Sriparna Datta Deepak Kumar P K Haldar

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      A series of ten novel (2a-j) 4-arylidine 2-[4-methoxy phenyl] oxazol-5-one derivatives were synthesized and assayed in vivo to investigate their antidiabetic activities by streptozotocin-induced model in rat. These derivatives showed considerable biological efficacy when compared to rosiglitazone, a potent and wellknown antidiabetic agent as a reference drug. All the compounds were effective, amongst them 2d shows more prominent activity at 50 mg/k.g.p.o. The experimental results are statistically significant at P < 0.01 level.

    • Investigation of the reaction of 3-aroylmethylene-indol-2-ones with 2-hydrazinobenzothiazole

      Renuka Jain Kanti Sharma Deepak Kumar

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      The reactions of 3-aroylmethylene-indol-2-ones with 2-hydrazinobenzothiazole in different media and solvent were investigated. The impact of substitution on indolyl nitrogen was also studied. The chemical structure of the products was proven on the basis of their spectral (IR, 1H-NMR, 13C-NMR, Mass) and analytical studies.

    • Ruthenium, rhodium and iridium complexes containing diazafluorene derivative ligands: synthesis and biological studies


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      Reaction of [(arene)MCl2]2 with bidentate 4, 5-diazafluorene-9-one (dafo) and derived Schiff base ligands (L1–L3) in the presence of ammonium hexafluorophosphate yielded mononuclear cationic complexes having general formula [(arene)MLCl]PF6 {M = Ru, arene = benzene (1, 5, 9); M = Ru, arene = p-cymene (4, 8); M = Rh, arene = Cp* (2, 6, 10); M = Ir, arene = Cp* (3, 7, 11); L = 4, 5-diazafluorene-9-one(L1), N-(4, 5-diazafluoren-9-ylidene)aniline (L2), N-(4, 5-diazafluoren-9-ylidene)phenyl hydrazine (L3)}.All these complexes were isolated as hexafluorophosphate salts and characterized by spectral and analyticaltechniques such as FT-IR, UV-vis, NMR spectroscopy and ESI-Mass spectrometry. Complexes 1-3 werecharacterized by X-ray crystallographic studies, which indicated NN0 bidentate coordination of the ligandsthrough pyridine nitrogen atoms of the ligand. To evaluate the biological properties of these complexes,antibacterial and antioxidant experiments have been carried out. The complexes 8, 9 and 11 exhibitedantibacterial activity against Gram-positive bacteria. Results also show that the compounds possess prominentantioxidant activity against DPPH radicals.

      The reaction of [(arene)MCl2]2 with 4, 5- diazafluorene-9-one (dafo) and derived Schiff-base ligands yielded mononuclear cationic complexes having the general formula [(arene)MLCl]PF6-. Some of the complexes exhibited antibacterial activity against Gram-positive bacteria. Results also show that the compounds possess prominent antioxidant activity against DPPH radicals.

    • Metal-mediated reactions of bromoform with electron-rich and electron-deficient carbon-carbon and carbon-hetero atom multiple bonds


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      The addition of bromoform to carbon-carbon and carbon-heteroatom multiple bonds has gatheredinterest from the synthetic community as it leads to brominated molecules that find applications inagrochemicals, pharmaceuticals, polymers, and radiolabeled agents. The chemistry of di- and tri-brominatedfunctionalized olefins remains scarcely explored. It may be due to their high steric demand and theirpropensity to form halogen bonds. The addition of bromoform to olefins in the presence of protic bases and aphase-transfer catalyst is well-established. However, their metal-mediated versions leading to new brominatedcompounds did not receive much attention. The addition of bromoform mediated by metals provides anopportunity to construct various synthetic intermediates and understand the underlying mechanistic aspects.Herein, we present the approaches reported in the last two decades on the bromocyclopropanation, atomtransfer radical additions, hydroalkylations, and conjugate additions of bromoform to electron-rich andelectron-deficient olefins under metal-mediated conditions. These approaches are expected to set the stage forhitherto unexplored asymmetric transformations and synthesis of complex molecules, including naturalproducts, involving metal-mediated bromoform addition as the key step.

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