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1.
Arijit BanerjeeSamir Kumar Maji Michael G.B. DrewDebasish Haldar Arindam Banerjee 《Tetrahedron letters》2003,44(4):699-702
A single-crystal X-ray diffraction study of the terminally protected tetrapeptide Boc-β-Ala-Aib-Leu-Aib-OMe 1 (Aib: α-aminoisobutyric acid; β-Ala: β-Alanine) reveals that it adopts a new type of double turn structure which self-associates to form a unique supramolecular helix through intermolecular hydrogen bonds. Scanning electron microscopic studies show that peptide 1 exhibits amyloid-like fibrillar morphology in the solid state. 相似文献
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Indole-2-yl-prop-2-ynyl sulfides, under thiophenol-mediated alkenyl radical cyclization conditions, afforded exclusively 4-thiophenyl-2,3,4,9-tetrahydrothiopyrano[2,3-b]indoles or 3-thiophenylmethyl-2,3,8-trihydrothieno[2,3-b]indoles depending on the substituent at the indole nitrogen. 相似文献
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Chloramphenicol and thiamphenicol have been enantioselectively synthesized using an asymmetric halohydrin reaction as a key step. In particular, halomethoxylation reaction was used, where O-methyl functions as a hydroxyl protecting group and eliminates an additional protection step. 相似文献
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Subhajit Laha Nimish Dwarkanath Abhishek Sharma Darsi Rambabu Sundaram Balasubramanian Tapas Kumar Maji 《Chemical science》2022,13(24):7172
Light hydrocarbon separation is considered one of the most industrially challenging and desired chemical separation processes and is highly essential in polymer and chemical industries. Among them, separating ethylene (C2H4) from C2 hydrocarbon mixtures such as ethane (C2H6), acetylene (C2H2), and other natural gas elements (CO2, CH4) is of paramount importance and poses significant difficulty. We demonstrate such separations using an Al-MOF synthesised earlier as a non-porous material, but herein endowed with hierarchical porosity created under microwave conditions in an equimolar water/ethanol solution. The material possessing a large surface area (793 m2 g−1) exhibits an excellent uptake capacity for major industrial hydrocarbons in the order of C2H2 > C2H6 > CO2 > C2H4 > CH4 under ambient conditions. It shows an outstanding dynamic breakthrough separation of ethylene (C2H4) not only for a binary mixture (C2H6/C2H4) but also for a quaternary combination (C2H4/C2H6/C2H2/CO2 and C2H4/C2H6/C2H2/CH4) of varying concentrations. The detailed separation/purification mechanism was unveiled by gas adsorption isotherms, mixed-gas adsorption calculations, selectivity estimations, advanced computer simulations such as density functional theory (DFT), grand canonical Monte Carlo (GCMC) and ab initio molecular dynamics (AIMD), and stepwise multicomponent dynamic breakthrough experiments.Industrially important C2H4 purification from multi-component hydrocarbon mixtures. 相似文献
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A new AB type of monomer 4′-fluoro-3,5-dimethyl-3′-trifluoromethyl-biphenyl-4-ol has been synthesized that leads to a new poly(arylene ether) by self polycondensation reaction. The monomer and the polymer have been well characterized by elemental analyses, FT-IR and NMR spectroscopy. Both FT-IR and NMR spectra of the polymers did not show any terminal phenoxy group indicating high conversion. The polymer showed glass transition at 278°C and very good thermal stability in synthetic air. GPC results indicate high molar mass development; Mw = 53200 and MWD = 2.29. 相似文献
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S. Maji Satendra Kumar K. Sankaran 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(3):1277-1281
A fluorescence based method has been developed for the determination of trace amounts of uranium in thorium matrix using a mixture of phosphoric acid (H3PO4) and sulfuric acid (H2SO4), as fluorescence enhancing reagent for uranyl (UO2 2+) ion fluorescence. Synthetic samples mimicking the composition of ThO2 fuel were prepared and the concentration of U(VI) was estimated. Satisfactory results are obtained when uranium is present at a concentration of 10 ppm in solid thorium samples with good precision. 相似文献