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51.
Synthesis of substituted phenanthridinones and dibenzoazepinones has been realized from 2-halo-benzamides in the presence of potassium tert-butoxide and a catalytic amount of 1,10-phenanthroline or AIBN. This new carbon-carbon bond forming reaction gives direct access to various biaryl lactams containing six- and seven-membered rings chemoselectively. Carbon-carbon coupling seems to proceed by the generation of a radical in the amide ring which leads to C-H arylation of aniline. 相似文献
52.
Background
Use of enzymes in low water media is now widely used for synthesis and kinetic resolution of organic compounds. The frequently used enzyme form is the freeze-dried powders. It has been shown earlier that removal of water molecules from enzyme by rinsing with n-propanol gives preparation (PREP) which show higher activity in low water media. The present work evaluates PREP of the lipase (from Rhizomucor miehei) for kinetic resolution of (R,S)-β-citronellol. The acylating agent was vinyl acetate and the reaction was carried out in solvent free media. 相似文献53.
Isothiocyanates are bioactive molecules that show various biological activities such as antifungal and anathematic activities. They play a vital role in the synthesis of various heterocyclic compounds. Various isothiocyanates were prepared in good to high yield using triphosgene. 相似文献
54.
Harshika Agarwal Shweta Yadav Gautam Jaiswar 《Journal of Thermal Analysis and Calorimetry》2017,129(3):1471-1479
The thermal, morphological and optical studies of BaSO4 and MMT (nanoclay) embedded in PVDF were investigated. Nanocomposites samples of PVDF–BaSO4–MMT were prepared by varying the loadings (1–4 mass%) in case of BaSO4 and MMT nanomaterials, respectively. Polyvinylidene fluoride–barium sulfate-montmorillonite (PVDF–BaSO4–MMT) nanocomposites were prepared by solvent-mixing technique. Nanoparticles were synthesized by in situ deposition technique with the help of nonionic polymeric surfactant, and the particle size of nanoparticles was recognized by scanning electron microscopy (SEM) analysis which confirms that the particle has diameter of 80–90 nm. As prepared, nanocomposites films (thickness, 25 μm) were characterized by Fourier transform infrared microscopy (FTIR), SEM and electron diffraction spectroscopy (EDS). FTIR shows that all the chemical constituents were present in the nanocomposites, whereas SEM analysis suggested that the nanofillers dispersed well in polymer matrix and EDS showed the elemental composition of nanocomposite samples. Thermal properties of nanocomposites were studied by using TG/DTA/DTG. TG/DTA studies showed decomposition temperature of pure PVDF is 473.5 °C. The decomposition temperature (T d) of nanocomposites was increased by 93 °C in case of nanocomposites with addition of both BaSO4 and MMT nanomaterials. The difference in the thermal degradation temperature was found to be 1.2% higher in case of addition of BaSO4 nanoparticle as compared to nanoclay. The obtained transparent nanocomposite films were characterized by using UV–Vis spectrophotometer which shows that transparencies of nanocomposites are maintained in visible region, the intensity of absorption band in UV region is increased with the addition of BaSO4 nanoparticles, while in case of addition of nanoclay the UV region does not show drastic changes. Addition of both nanoparticle and nanoclay shows higher absorption in comparison with the individual samples. But further, doubling the amount of nanoparticle and nanoclay shows decrease in UV absorption. Overall, the results of thermal studies show that the incorporation of BaSO4 and MMT could significantly improve the thermal properties of nanocomposites. 相似文献
55.
Shweta Verma Sulekh Chandra Usha Dev Nidhi Joshi 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,74(2):370-374
Mn(II), Co(II), Ni(II) and Cu(II) complexes have been synthesized with 22 and 24 membered tetramide macrocyclic ligands viz; 1,9,12,20-tetraaza-2,8,13,19-tetraone-5,16-dithiacyclodocosane [L1] and 1,9,13,21-tetraaza-2,8,14,20-tetraone-5,17-dithiacyclotetracosane [L2] and characterized by elemental analysis, molar conductance, magnetic susceptibility measurements, mass, IR, electronic EPR spectral studies and electrochemical properties. The molar conductance of all the complexes in DMSO solution is corresponding to 1:2 electrolyte. Thus these complexes may be formulated as [M(L′)]Cl2 [where M = Mn(II), Co(II), Ni(II) and Cu(II) L′ = L1 and L2]. On the basis of spectral studies a distorted octahedral geometry has been assigned for all the complexes. The ligands and their complexes were also screened in vitro against two pathogenic fungi (F. moniliformae and R. solani) to assess their growth inhibiting potential. 相似文献
56.
S.E. Lofland S.I. PatilS.M. Bhagat A.A. ArsenovS.G. Karabashev Y. Mukovskii 《Solid State Communications》2003,127(1):17-19
We have investigated the magnetic phase diagram of polycrystalline and single-crystal La1−xSrxMnO3 near 0.46≤x≤0.50. It turns out that for x<0.48, the polycrystalline material is ferromagnetic (FM), but for x≥0.48, incipient charge ordering takes place along with antiferromagnetism. At x=0.48, the ferromagnetic-antiferromagnetic phase transition in ceramics occurs at less than 85 kOe but requires significantly larger field for increasing x. These observations are in contrast to what is found in the single crystals, which are all FM. 相似文献
57.
S.M. Bhagat D.J. Webb M.A. Manheimer 《Journal of magnetism and magnetic materials》1985,53(3):209-220
We report measurements on magnetic resonance in a number of transition metal-glass former complexes. Data were taken over a wide range of frequencies (2–35 GHz) and temperatures (2–300 K). In the ferromagnetic regime all the systems have a term in their linewidth which points strongly to noncolinearity of spin in glassy magnets even in a nominally saturated state. At low temperatures, in the reentrant alloys, there is a characteristic exponential term describing the increase in linewidth, with reducing T. Such a contribution appears in most random spin systems. There is no adequate microscopic picture to account for many of the results. 相似文献
58.
Gananadhamu Samanthula Debasish Swain Gayatri Sahu Shweta Bhagat P. V. Bharatam 《Journal of Analytical Chemistry》2018,73(6):560-569
The fixed dose combination of azilsartan medoxomil potassium and chlorthalidone has been introduced for the effective treatment of hypertension. In the present work a rapid, simple and accurate stability indicating ultra HPLC assay method has been developed. The separation of azilsartan medoxomil, chlorthalidone and their degradation products were accomplished on an Acquity UPLC BEH C18 (100 mm × 2.1 mm, 1.7 μm) column using mobile phase combination of 0.02% trifluoroacetic acid in water and acetonitrile in gradient mode. The forced degradation products were identified using liquid chromatography?electrospray ionisation-quadrupole time of flight-tandem mass spectrometry (LC?ESIQTOF–MS/MS) and accurate mass experiments. The in silico toxicities of the degradation products for both the drugs were evaluated. The proposed method was validated as per the ICH Q2 (R1) guideline for selectivity, linearity, precision, accuracy and robustness. 相似文献
59.
We describe the integration of a small-molecule hydrogen-bond-donor template into a cascade reaction that is comprised of a combination of molecular and supramolecular events. The cascade is performed mechanochemically and in the presence of μL amounts of water. The small-molecule template is generated (molecular) using water-assisted vortex grinding and is then used to assemble an alkene (supramolecular) to undergo an intermolecular [2 + 2] photodimerization reaction (molecular). The chemical cascade results in a cyclobutane photoproduct that we show serves as a building block of a hydrogen-bonded network with a topology that conforms to T-silica. Remarkably, the molecular–supramolecular–molecular chemical cascade occurs stepwise and entirely regioselectively within the continuous mechanochemical conditions employed.Mechanochemistry is applied to molecular and supramolecular chemistry to support a template-directed photochemical reaction. 相似文献
60.
Mehrotra R.C. Singh A. Bhagat M. Godhwani J. 《Journal of Sol-Gel Science and Technology》1998,13(1-3):45-49
In view of the advantages of employing heterometallic alkoxides as precursors for ceramic materials by the sol-gel process, efforts are being made to develop novel routes for their synthesis and to design single source precursors suited to the final targeted material. Three such new pathways are briefly presented in this paper: (i) varying the ratio of constituent metals; (ii) dissolution of metal chlorides in alkoxides of tetravalent metals; and (iii) reactions of acidic protons of metal glycolate derivatives with alkoxides of another metal yielding derivatives containing other alkoxometallates in cationic form. 相似文献