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Venkatapuram Padmavathi Guda Dinneswara Reddy Gali Sudhakar Reddy Konda Mahesh Adivireddy Padmaja 《Journal of heterocyclic chemistry》2011,48(4):973-976
The reactivity of barbituric/thiobarbituric ketene dithiolates with bromoacetic ester and phenacyl bromide is studied. J. Heterocyclic Chem., (2011). 相似文献
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Patanair Bindu Babu Varghese Madhugiri N. Sudheendra Rao 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2373-2386
Synthesis of the hypervalent tris(catecholato)silicate ion, [(C6H4O2)3-Si]2? having five different primary ammonium cations viz. n-propylammonium (1), isopropylammonium (2) n-butylammonium (3), cyclohexylammonium (4), benzylammonium (5), and a bulky secondary ammonium cation, namely diisobutylammonium (6), have been achieved by the reaction of catechol and tetraethoxysilane (TEOS) in presence of the corresponding amine. Elemental analysis, IR, NMR (1H, 13C, and 29Si), and mass spectral data have been used for their characterization. Single crystal x-ray structures of 1 and 6 indicate nearly same distortion of the “SiO6” octahedron but interesting differences in the hydrogen bonding interactions arising from the catecholato oxygens and the N—H bonds of the ammonium cations. While compound 1 exhibits hydrogen bonding more discretely and by revealing strong interaction between the n-propylammonium ions, compound 6 shows an extended intermolecular hydrogen bonding aided by a water molecule present in the lattice to lead to infinite one dimensional chain arrangement. TG and EG analyses of compounds, 1–5 indicate 1) the formation of the previously observed spirosilane intermediate, [Si(C6H4O2)2] and 2) their less thermal stability compared to those having secondary or tertiary ammonium cations. 相似文献
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A convenient and practical approach for the total synthesis of naturally occurring lactone synargentolide-B has been accomplished in 14 steps from the commercially available l-ascorbic acid and d-ribose involving Bestmann–Ohira reaction, zinc mediated allylation, ring closing-metathesis, and cross-metathesis reactions. The highlight of our strategy describes a one-pot reaction involving stereoselective addition of allylzinc reagent and selective reduction of terminal alkyne to obtain the key advanced intermediates. 相似文献
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Pornthep Chivavibul Manabu Enoki Shigeru Konda Yasushi Inada Tamotsu Tomizawa Akira Toda 《Journal of magnetism and magnetic materials》2011,323(3-4):306-310
An important issue in development of electrical steels for core-laminated products is to reduce core loss to improve energy conversion efficiency. This is usually obtained by tailoring the composition, microstructure, and texture of electrical steels themselves. A new technique to reduce core loss in electrical steel has been investigated. This technique involves electroless plating of magnetic thin coating onto the surface of electrical steel. The material system was electroless Ni–Co–P coatings with different thicknesses (1, 5, and 10 μm) deposited onto the surface of commercially available Fe–3% Si electrical steel. Characterization of deposited Ni–Co–P coating was carried out using X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray (EDX) spectrometer. The deposited Ni–Co–P coatings were amorphous and composed of 56–59% Ni, 32–35% Co, and 8–10% P by mass. The effect of coatings on core loss of the electrical steel was determined using single sheet test. A core loss reduction of 4% maximum was achieved with the Ni–Co–P coating of 1 μm thickness at 400 Hz and 0.3 T. 相似文献
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Sanjay R Borhade Ulrika Rosenstr?m Jonas S?vmarker Thomas Lundb?ck Annika Jenmalm-Jensen Kristmundur Sigmundsson Hanna Axelsson Fredrik Svensson Vivek Konda Christian Sk?ld Mats Larhed Mathias Hallberg 《ChemistryOpen》2014,3(6):256-263
The inhibition of insulin-regulated aminopeptidase (IRAP, EC 3.4.11.3) by angiotenesin IV is known to improve memory and learning in rats. Screening 10 500 low-molecular-weight compounds in an enzyme inhibition assay with IRAP from Chinese Hamster Ovary (CHO) cells provided an arylsulfonamide (N-(3-(1H-tetrazol-5-yl)phenyl)-4-bromo-5-chlorothiophene-2-sulfonamide), comprising a tetrazole in the meta position of the aromatic ring, as a hit. Analogues of this hit were synthesized, and their inhibitory capacities were determined. A small structure–activity relationship study revealed that the sulfonamide function and the tetrazole ring are crucial for IRAP inhibition. The inhibitors exhibited a moderate inhibitory potency with an IC50=1.1±0.5 μm for the best inhibitor in the series. Further optimization of this new class of IRAP inhibitors is required to make them attractive as research tools and as potential cognitive enhancers. 相似文献
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Diastereodivergent Catalysis Using Modularly Designed Organocatalysts: Synthesis of both cis‐ and trans‐Fused Pyrano[2,3‐b]pyrans 下载免费PDF全文
Dr. Huicai Huang Swapna Konda Prof. Dr. John C.‐G. Zhao 《Angewandte Chemie (International ed. in English)》2016,55(6):2213-2216
Both enantiomers of cis‐ and trans‐fused 3,4,4a,8a‐tetrahydro‐2H,5H‐pyrano[2,3‐b]pyran‐7‐carboxylates have been obtained in high diastereoselectivities and enantioselectivities from the same starting materials using a tandem inverse‐electron‐demand hetero‐Diels–Alder/oxa‐Michael reaction catalyzed by modularly designed organocatalysts (MDOs). Diastereodivergence was achieved in these reactions through the direct control of the stereochemistry of the bridgehead atoms of the fused ring using new MDOs self‐assembled from both enantiomers of proline and cinchona alkaloid thiourea derivatives. 相似文献