排序方式: 共有100条查询结果,搜索用时 15 毫秒
31.
Subash C. Jonnalagadda Jonathan S. Cruz Ryan J. Connell Patricia M. Scott 《Tetrahedron letters》2009,50(30):4314-1895
Novel α-carboranyl-α-acyloxy-amides were prepared as potential BNCT agents utilizing three-component Passerini reaction. Preliminary cytotoxicity of the representative compounds on two brain tumor cell lines (U-87 and A-172) showed no effect on cell viability; an essential requirement for utility as potential BNCT agents. 相似文献
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The leaf and bark paste of Holoptelea integrifolia is traditionally used for the treatment of obesity in Asian countries. However, no scientific studies have been undertaken to reveal the actual mechanism of action. The present study aimed to investigate the hypolipidaemic effect of H. integrifolia and its mechanism in diet-induced obese rat model. After 4 weeks of oral administration, blood samples were collected for the estimation of serum lipids, lecithin: cholesterolacyltransferase (LCAT) apolipoproteins (apo) and liver for HMG-CoA reductase (HMGR) assay. The faecal samples were also collected to estimate the faecal fat content. The H. integrifolia treatment markedly lowered body weight, serum lipids and apo B and increase high-density lipoprotein-cholesterol and apo A1 concentrations. In this study, HMGR activity was enormously reduced, which helps to reduce cholesterol biosynthesis and an increase in LCAT activity was also observed. The detailed faecal analysis showed a remarkable increase in faecal lipids, which indicates the ability to inhibit intestinal fat absorption. The methanol fraction of H. integrifolia on LC-MS and tandem mass spectrometry analysis shows the presence of a compound, 3-(7-ethoxy-4-methyl-2-oxo-2H-chromen-3-yl)propanoate (C1). The result showed that the significant hypolipidaemic effect of H. integrifolia may be linked to its ability to inhibit HMGR activity and block intestinal fat absorption. 相似文献
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Matthew J. Just Srinivas TekkamMohammad A. Alam Subash C. JonnalagaddaJoseph L. Johnson Venkatram R. Mereddy 《Tetrahedron letters》2011,52(41):5349-5351
Novel stereoselective synthesis of α-methylene-β-substituted pyroglutamates, and α-alkylidene-pyroglutamates has been achieved via substrate controlled asymmetric alkylation of l-threonine derived oxazole with Baylis-Hillman reaction based allyl bromides and acetates, respectively. The synthesized compounds were evaluated for their proteasome inhibition and cytotoxicity on multiple myeloma cells. 相似文献
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Uvais Valiyaneerilakkal Amit Singh Kulwant Singh C. K. Subash S. M. Abbas Rama Komaragiri Soney Varghese 《Applied Physics A: Materials Science & Processing》2014,117(3):1535-1540
A metal–ferroelectric–insulator–semiconductor (MFIS) structure has been made using poly(vinylidene difluoride–trifluoroethylene)/barium titanate [P(VDF–TrFE)/BaTiO3] nanocomposite as ferroelectric layer, on silicon/silicon dioxide (Si/SiO2) substrate. Different concentrations of BaTiO3 were added to P(VDF–TrFE) polymer using bath sonication method, and the films were prepared using spin coating method. The structure was annealed to 120 °C for 2 h and then the top aluminium electrode was deposited by thermal evaporation method. Capacitance–voltage shows an increase in accumulation capacitance as the BaTiO3 nanoparticle concentrations increases. Dielectric constant was estimated from the capacitance voltage (C–V) characteristics and found to be changing as the concentration of BaTiO3 is varied. Polarization–electric field analyses show hysteresis behaviour of the nanocomposite. A comparison of MFIS and metal–ferroelectric–semiconductor structures was done with varying ferroelectric film thicknesses. All these results suggest that this polymer nanocomposite can be a promising material which can be used in non-volatile memory devices. 相似文献
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Md. Musawwer Khan Sumbulunnisan Shareef Sarfaraz Khan Saigal Subash C. Sahoo 《合成通讯》2013,43(21):2884-2894
AbstractAn organo base catalyzed diverse pyrrole-fused 1,4-dihydropyridines were synthesized. This one-pot, three-component domino reaction of enamino imides, aromatic aldehydes, and malononitrile/ethyl cyanoacetate was achieved by 10?mol% of DMAP under refluxing ethanol. In addition, novel bis-pyrrole-fused 1,4-dihydropyridine derivatives were also prepared by using terephthalaldehyde as a linker instead of simple aromatic aldehydes. This transformation proceeds via Knoevenagel condensation/Michael addition and N-cyclization reaction sequence and have some salient features including the use of a cost-effective catalyst, short reaction time and high atom economy. Moreover, the reusability of the catalyst was also performed up to five runs without any significant loss in activity. 相似文献
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Neelgund GM Magadum SR Budni ML 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(1):480-487
The electron donor–acceptor (EDA) interaction between 2,3-dicyano-1,4-naphthoquinone (DCNQ) and 3,4-dimethylaniline (3,4-DMA) is studied in chloroform, dichloromethane and 1:1 (v/v) mixture of chloroform and dichloromethane. The rate of formation of the product was measured as a function of time using UV–vis spectrophotometer. The formation constant (K) and molar extinction coefficient (?) values for the formation of EDA complex were evaluated in the temperature range of 20–35 °C. The pseudo-first-order rate constant (k1) and the second-order rate constant (k2) for the disappearance of EDA complex and for the formation of product were evaluated. The activation parameters (ΔH#, ΔS# and ΔG#) of the reaction were determined by temperature dependence of rate constants using the Arrhenius plots. The effect of relative permittivity of the medium on the reaction is discussed. The observed results indicate that formation of final product proceeds through initial formation of EDA complex as an intermediate. The product of the reaction was purified by column chromatography method and identified as 3-(N-3,4-dimethyl-phenylamino)-2-cyano-1,4-naphthoquinone by elemental analysis, IR and NMR spectroscopy. On the basis of kinetic, analytical and spectroscopic results, a plausible mechanism for the formation of EDA complex and its transformation into product is proposed. 相似文献
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Mohapatra SC Mathur P 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(2):612-616
Monomeric Cu(II) and Cu(I) complexes bound to a tetradentate bis-benzimidazole diamide ligand N,N'-bis(N-octyl benzimidazolyl-2yl)(methyl)pentane diamide (O-GBGA) have been isolated and characterized. X-Band EPR spectra of the copper(II) complexes in CH2Cl2 were recorded in a frozen solution as solvent at liquid nitrogen temperature. Solution spectra typically indicate a d(x2-y2) ground state (g||>g⊥>2.0023) and show less than four nuclear hyperfine lines with broadening of g⊥ line in some cases, thus indicating distorted tetragonal geometry. One of the copper(II) complexes shows a five line N-SHF structure (16±1G) implying the binding of imine nitrogen of the benzimidazole to copper ion. α2 ranges from 0.57-0.97 indicating considerable amount of covalent character in Cu-L bond. Anodic shifts in E1/2 values indicate the retention of anion in the coordination sphere of Cu(II), E1/2 values becoming anodic in the order C6H5COO-相似文献
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Satheesh Kumar Palanisamy Velusamy Arumugam Samyutha Rajendran Anandhan Ramadoss Subash Nachimuthu Magesh Peter D. 《Natural product research》2019,33(14):2120-2124
The chemical diversity of three macroalgae (Ulva reticulata, Sargassum wightii, Gracilaria sp) were determined using the GC-MS method with principal component analysis (PCA) and their potential efficacy against human pathogens and cervical carcinoma cells evaluated using MTT bioassay method. Our results showed that >30 metabolites were detected in three seaweeds, among these, steroids and fatty acids are the most dominant chemical group that highly contributes to discriminate this species. The PCA of GC-MS mass spectral variables showed a clear discrimination between three different species based on the phytochemical diversity of seaweeds. The extracts of U. reticulata exhibited anti-microbial activity with Pseudomonas aeruginosa (6.00?mm) and showed potential anti-proliferative activity against the HeLa cells (IC50 37?µmol/L) at concentration 1–50?µM treatment. Results of this study concluded that PCA analysis of mass spectral variables could be utilized as a reliable tool for species discrimination and chemotaxonomic classification of seaweeds. 相似文献