Publications by authors named "Radhey S Srivastava"

A series of novel hybrids comprising of 1,3,4-oxadiazole/thiadiazole and 1,2,4-triazole tethered to 5,6-diphenyl-1,2,4-triazin-3(2H)-one were designed, synthesised and evaluated as COX-2 inhibitors for the treatment of inflammation. The synthesised hybrids were characterised using FT-IR, 1H NMR, 13C NMR, elemental (C,H,N) analyses and assessed for their anti-inflammatory potential by in vitro albumin denaturation assay. Compounds exhibiting activity comparable to indomethacin and celecoxib were further evaluated for in vivo anti-inflammatory activity.

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A novel iron-catalyzed synthesis of substituted N-aryl oxazolidines was developed via C-N bond formation and methylenation. The reaction of aryl hydroxylamines with allyl alcohols, in the presence of formaldehyde or its equivalents, afforded variety of oxazolidine heterocycles in very good yields. This catalytic method is most effective for para-substituted aryl hydroxylamines and 3-methyl allyl alcohols.

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A series of triazin-3(2H)-one derivatives bearing 1,3,4-oxadiazole (4a-4o) were synthesized, characterized and evaluated for anti-inflammatory and analgesic activities. Preliminary in vitro anti-inflammatory activity was assessed using an albumin denaturation assay. The promising compounds were further evaluated in acute, sub-chronic and chronic animal models of inflammation.

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A direct Fe-catalyzed α-amination of 1,3-dicarbonyl compounds has been accomplished using arylhydroxylamines as aminating agents. This novel protocol allows convenient access to α-amino carbonyl derivatives without the need for any postreaction manipulations. This is an operationally simple procedure that works at low temperatures in shorter reaction times and produces high yields with excellent N-selectivity.

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A new catalytic approach for the synthesis of substituted quinolines via C-N and C-C bond formation using 2-haloaryl hydroxylamines and allylic C-H substrates is described. Fe-catalyzed allylic C-H amination followed by Pd-catalyzed intramolecular Heck-coupling and aerobic dehydrogenation deliver the valuable quinoline and naphthyridine heterocycles in good to excellent overall yields. In this process, Pd(OAc)2 plays a dual role in catalyzing Heck coupling as well as aerobic dehydrogenation of dihydroquinolines.

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In an attempt to develop potent anticancer agents, a series of 4-arylideneamino/cycloalkylidineamino-1, 2-naphthoquinone thiosemicarbazones were synthesized and characterized using FT-IR, (1)H NMR, (13)C NMR spectroscopy and elemental analysis. The compounds were screened for antiproliferative activity against three human cancer cell lines (Hep-G2, MG-63 and MCF-7) using the MTT assay. Significant anticancer activity was observed for several members of the series.

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A new approach for the direct Fe-catalyzed synthesis of β-alkyl N-aryl aza Baylis-Hillman (ABH) adducts is reported. This approach involves the formation of a C-N bond via a nitroso-ene reaction. This is a simple, fast, and best alternate method to overcome the substrate scope limitations of the ABH reaction, which converts allyl esters and carbonyl compounds to novel ABH adducts.

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Thiazolidinedione (TZD) derivatives are the novel class of oral antidiabetic drugs which are selective agonist for the nuclear PPAR γ that enhances the transcription of several insulin responsive genes but TZDs are known to cause weight gain, hepatotoxicity and fluid retention. So a new series of coumarin coupled thiazolidinedione derivatives and its bioisosters (oxazolidinedione and imidazolidinedione) were synthesized by Knoevenagel condensation of 4-((7-hydroxy-2-oxo-2H-chromen-4-yl) methoxy) benzaldehyde with 2,4 thiazolidinedione and its bioisosteres. The structures of these compounds were established by means of FT IR, 1H-NMR, elemental analysis and mass spectroscopy.

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A series of new water soluble Ru(III) pyrazole complexes mer-[RuCl(3)(DMSO-S)(pyz)(2)] 1, mer-[RuCl(3)(DMSO-S)(DMSO-O)(pyz)] 2, mer-[RuCl(3)(bpy)(dmpyz)] 3, and mer-[RuCl(3)(DMSO-S)(dmpyz)(2)] 4 (pyz=pyrazole; dmpyz=3,5-dimethylpyrazole, bpy=2,2'-bipyridine) have been synthesized and characterized by use of a combination of spectroscopy (IR and UV-visible), X-ray diffraction, and cyclic voltammetry. The molecular X-ray structure of all reported compounds (1-4) revealed distorted octahedral coordination around ruthenium. The cytotoxicity assay on human breast cancer cells (MCF7) demonstrated that compounds 1 and 4 affect cell viability, whereas compounds 2 and 3 do not show appreciable activity.

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Synthesis and characterization of seven ruthenium (II) and ruthenium (III) chloro sulphoxide complexes with 1, 2, 3-benzotriazole are reported. Three different formulations exist: [cis, fac-RuCl2(so)3(btz)]; [trans-RuCl2(so)3(btz)] and [trans-RuCl4(so)(btz)]-[X]+; where so=dimethylsulphoxide/ tetramethylenesulphoxide; btz = 1, 2, 3-benzotriazole and [X]+ = [(btz)H]+ or Na+. These complexes were characterized by elemental analysis, conductivity measurements, magnetic susceptibility, FT-IR, 1H-NMR, 13C1H-NMR and electronic spectroscopy.

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Ruthenium complexes [1-3] with oxalato, amido and pyridine ligands have been synthesized and characterized. Biological tests showed that the ruthenium complexes 2 and 3 have modest cytotoxicity on both murine cell line NIH3T3 and human cancer colon cell lines HCT116 and HT29 while complex 1 has no obvious growth defect. We further tested why complexes 2 and 3 exhibit modest cytotoxicity.

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Aim Of The Study: To evaluate the antidiabetic and antioxidant effects of various fractions of Phyllanthus simplex on alloxan induced diabetes in rats.

Materials And Methods: Hypoglycemic effect of Phyllanthus simplex fractions was evaluated in normal and diabetic rats. Diabetes was induced by intraperitoneal injection of alloxan monohydrate (120 mg/kg).

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The title mol-ecule, [RuCl(2)(C(4)H(8)OS)(3)(H(2)O)], is the isomer with the two chloride ligands cis and the three S-coordinated tetra-methyl-ene sulfoxide ligands facial relative to the Ru(II) center. The Ru-Cl distances are 2.4161 (7) and 2.

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The reactions of nitrosobenzene and N,N'-diethyl-4-nitrosoaniline with [Cu(CH3CN)4]PF6 provide novel Cu(I) complexes, [Cu(PhNO)3]PF6 (1) and [Cu(Et2NPhNO)3]PF6 (2); in 2 the copper atom is N-coordinated to the nitrosoarenes in a distorted trigonal planar geometry. Complex 1 is strongly implicated as a reactive intermediate in the Cu(I)-catalyzed allylic amination of olefins based on (i) its isolation from the catalytic reaction, (ii) its stoichiometric regioselective allylic amination of alpha-methyl styrene (AMS), (iii) the non-involvement of free PhNO in its amination of AMS, and (iv) its function as a catalyst for the amination of alkenes from phenylhydroxylamine. The reaction between AMS and 1 (80 degrees C, dioxane) is first order in both alkene and 1.

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Reactions of nitrosobenzene and N,N'-diethyl-4-nitrosoaniline with [Cu(CH3CN)4]PF6 produce novel homoleptic Cu(I)-nitrosoarene complexes, [Cu(ArNO)3]PF6, 1 (Ar = Ph) and 2 (Ar = 4-Et2NC6H4NO). The X-ray structure of 2 reveals that the copper is coordinated in a severely distorted trigonal planar geometry to the N-atom of the nitrosoarene ligand. Reactions of the PhNO complex 1 with olefins and an olefin/diene mixture provide evidence for its role as an intermediate and possibly the active nitrogen transfer agent in the Cu-catalyzed allylic amination of olefins by aryl hydroxylamines.

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