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121.
A facile, high yielding, and stereospecific method for olefin aziridination is described. This process capitalizes on the unique reactivity of sulfamate esters in combination with 1-2 mol % Rh2(tfacam)4 and PhI(OAc)2 as the terminal oxidant to promote N-atom transfer reactions. A range of structurally and electronically disparate alkenes are found to react under conditions that employ substrate as the limiting reagent and only a slight excess of H2NSO3CH2CCl3 as the nitrogen source. The product alkoxysulfonyl aziridines are useful intermediates that react smoothly with nucleophiles to generate 1,2-amine derivatives. Following aziridine ring-opening, the N-trichloroethoxysulfonyl group can be removed under mild reductive conditions (Zn(Cu)/AcOH-MeOH) to give the corresponding 1 degrees amine. The efficient and convenient performance of this chemistry should establish it as a useful tool for synthesis. 相似文献
122.
Zhai HJ Kiran B Dai B Li J Wang LS 《Journal of the American Chemical Society》2005,127(34):12098-12106
Elucidating the chemisorption properties of CO on gold clusters is essential to understanding the catalytic mechanisms of gold nanoparticles. Gold hexamer Au(6) is a highly stable cluster, known to possess a D(3)(h) triangular ground state structure with an extremely large HOMO-LUMO gap. Here we report a photoelectron spectroscopy (PES) and quasi-relativistic density functional theory (DFT) study of Au(6)-CO complexes, Au(6)(CO)(n)(-) and Au(6)(CO)(n) (n = 0-3). CO chemisorption on Au(6) is observed to be highly unusual. While the electron donor capability of CO is known to decrease the electron binding energies of Au(m)(CO)(n)(-) complexes, CO chemisorption on Au(6) is observed to have very little effect on the electron binding energies of the first PES band of Au(6)(CO)(n)(-) (n = 1-3). Extensive DFT calculations show that the first three CO successively chemisorb to the three apex sites of the D(3)(h) Au(6). It is shown that the LUMO of the Au(6)-CO complexes is located in the inner triangle. Thus CO chemisorption on the apex sites (outer triangle) has little effect on this orbital, resulting in the roughly constant electron binding energies for the first PES band in Au(6)(CO)(n)(-) (n = 0-3). Detailed molecular orbital analyses lead to decisive information about chemisorption interactions between CO and a model Au cluster. 相似文献
123.
A rapid and sensitive RP-HPLC method with UV detection (260 nm) for routine analysis of voriconazole in a pharmaceutical formulation (Vfend®) was developed. Chromatography was performed with mobile phase containing a mixture of acetonitrile and water (50:50, v/v) with flow rate was of 1.0 ml min−1. Quantitation was accomplished with internal standard method. The procedure was validated for linearity (correlation coefficient = 0.9999), accuracy, robustness and intermediate precision. Experimental design was used for validation of robustness and intermediate precision. To test robustness, three factors were considered. Percentage of acetonitrile in mobile phase, flow rate and pH; an increase in the flow rate results in a decrease of the drug found concentration, while the percentage of organic modifier and pH have no important effect on the response. For intermediate precision measure the variables considered were: analyst, equipment and number of days. The R.S.D. value (0.45%, n = 24) indicated a good precision of the analytical method. The proposed method was simple, highly sensitive, precise and accurate and retention time less than 4 min indicating that the method is useful for routine quality control. 相似文献
124.
Bhagyashri B. Kamble Tawade Anita K. Kamble Pravin Padavi Mukesh N. Sharma Kiran Kumar K. Ajalkar Balu D. Tayade Shivaji N. 《Russian Journal of Electrochemistry》2020,56(9):766-774
Russian Journal of Electrochemistry - A micro-bricks shaped tungsten oxide (WO3) was prepared by hydrothermal method. The prepared material was characterized by field emission scanning electron... 相似文献
125.
Chong Ou Sunaina Kiran Prabhu Dr. Xiao Zhang Dr. Guanghui Zong Dr. Qiang Yang Prof. Lai-Xi Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(16):e202200146
Monoclonal antibodies (mAbs) are one of the most rapidly growing drug classes used for the treatment of cancer, infectious and autoimmune diseases. Complement-dependent cytotoxicity (CDC) is one of the effector functions for antibodies to deplete target cells. We report here an efficient chemoenzymatic synthesis of structurally well-defined conjugates of a monoclonal antibody with a rhamnose- and an αGal trisaccharide-cluster to recruit natural anti-rhamnose and anti-αGal antibodies, respectively, to enhance the CDC-dependent targeted cell killing. The synthesis was achieved by using a modular antibody Fc-glycan remodeling method that includes site-specific chemoenzymatic Fc-glycan functionalization and subsequent click conjugation of synthetic rhamnose- and αGal trisaccharide-cluster to provide the respective homogeneous antibody conjugates. Cell-based assays indicated that the antibody-rhamnose cluster conjugates could mediate potent CDC activity for targeted cancer cell killing and showed much more potent efficacy than the antibody-αGal trisaccharide cluster conjugates for CDC effects. 相似文献
126.
Subia Ambreen Kiran Gupta Sadhana Singh D. K. Gupta Stephane Daniele N. D. Pandey Ashutosh Pandey 《Transition Metal Chemistry》2013,38(8):835-841
Reactions of Ti(OBus)4 and Ti(OBun)4 with chloroacetic acids (mono-, di-, and tri-) were carried out in toluene in 1:1 and 1:2 molar ratios at room temperature to generate new precursors of titania. These modified alkoxides/oxo-alkoxides were characterized by spectroscopic methods. A solution of Ti(OBun)2(OOCCCl3)2 in toluene left for crystallization at ?30 °C yielded single crystals of the product Ti6(μ2-O)2(μ3-O)2(μ2-OC4H9)2(OC4H9)6(OOCCCl3)8. Single-crystal X-ray diffraction revealed the molecular structure to be composed of a hexanuclear unit in which two Ti2O10 units (made by two edge-sharing octahedra) are linked with two corner-sharing octahedra. 相似文献
127.
128.
Soudagar Manzoore Elahi M. Afzal Asif Safaei Mohammad Reza Manokar A. Muthu EL-Seesy Ahmed I. Mujtaba M. A. Samuel Olusegun David Badruddin Irfan Anjum Ahmed Waqar Shahapurkar Kiran Goodarzi Marjan 《Journal of Thermal Analysis and Calorimetry》2022,147(1):525-542
Journal of Thermal Analysis and Calorimetry - In the present work, a series of experiments were designed and conducted to prepare biodiesel from cottonseed oil and to blend it with octanol. The... 相似文献
129.
Jani D. B. Bhabhor Kiran Dadi Mohsin Doshi Sachindra Jotaniya P. V. Ravat Harish Bhatt Kumar 《Journal of Thermal Analysis and Calorimetry》2020,140(5):2011-2031
Journal of Thermal Analysis and Calorimetry - Solid desiccant-assisted cooling and dehumidification systems are becoming very popular nowadays for maintaining the required thermal comfort in... 相似文献
130.
Soudagar Manzoore Elahi M. Afzal Asif Safaei Mohammad Reza Manokar A. Muthu ELSeesy Ahmed I. Mujtaba M. A. Samuel Olusegun David Badruddin Irfan Anjum Ahmed Waqar Shahapurkar Kiran Goodarzi Marjan 《Journal of Thermal Analysis and Calorimetry》2022,147(1):543-543
Journal of Thermal Analysis and Calorimetry - In the original publication of the article, the affiliations of the third, fourth and fifth authors were incorrectly published. 相似文献