排序方式: 共有209条查询结果,搜索用时 15 毫秒
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Divya Tripathi 《Tetrahedron》2009,65(11):2226-594
A short and enantioselective approach to medium ring ethers and its application to the syntheses of (−)-cis-lauthisan and (+)-isolaurepan are described. The synthetic strategy features Jacobson's Hydrolytic Kinetic Resolution (HKR), oxidative resolution of secondary alcohol, and highly diastereoselective Et3SiH/TMSOTf-promoted reductive cyclization of a hydroxy ketone to give exclusively the different medium-sized cis-disubstituted cyclic ethers. 相似文献
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Dowex-50W ion exchange resin-promoted solvent-free heating of an intimate mixture of an aldehyde, an active methylene compound and N,N′-dimethylurea furnished the title compounds in moderate to good yields. 相似文献
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An environment friendly method for the synthesis of 2-oxo/thioxooctahydroquinazolin-5-one derivatives has been devised using Ceric ammonium nitrate (CAN) as catalyst and polyethylene glycol (PEG) as solvent. The cytotoxic effect of these compounds was studied on U87 human glioma cells, compounds 4c, 4d and 4e are found to exhibit excellent activity at a concentration as low as 0.06 μg/ml. 相似文献
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Polyethylene glycol (PEG) was found to be an inexpensive non-toxic and effective medium for the one-pot synthesis of N-substituted decahydroacridine-1,8-diones in the presence of ceric ammonium nitrate (CAN) as the catalyst in high yields. Also, the solvent system can be recovered and reused; making this protocol economically and potentially viable. 相似文献
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Baardman Lennart Cristian Rares Perakis Georgia Singhvi Divya Skali Lami Omar Thayaparan Leann 《Mathematical Programming》2023,197(1):1-26
Mathematical Programming - In this paper, we present a new framework of bi-level unconstrained minimization for development of accelerated methods in Convex Programming. These methods use... 相似文献
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Ganeshpurkar Ankit Singh Ravi Shivhare Shalini Divya Kumar Devendra Gutti Gopichand Singh Ravibhushan Kumar Ashok Singh Sushil Kumar 《Molecular diversity》2022,26(3):1455-1479
Molecular Diversity - Structure-based drug design (SBDD) is an important in silico technique, used for the identification of enzyme inhibitors. Acetylcholinesterase (AChE), obtained from... 相似文献
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Krishnamurthy D Kasper GD Namuswe F Kerber WD Narducci Sarjeant AA Moënne-Loccoz P Goldberg DP 《Journal of the American Chemical Society》2006,128(44):14222-14223
The synthesis of a mononuclear, five-coordinate ferrous complex [([15]aneN4)FeII(SPh)](BF4) (1) is reported. This complex is a new model of the reduced active site of the enzyme superoxide reductase (SOR), which is comprised of a [(NHis)4(Scys)FeII] center. Complex 1 reacts with alkylhydroperoxides (tBuOOH, cumenylOOH) at low temperature to give a metastable, dark red intermediate (2a: R = tBu; 2b: R = cumenyl) that has been characterized by UV-vis, EPR, and resonance Raman spectroscopy. The UV-vis spectrum (-80 degrees C) reveals a 526 nm absorbance (epsilon = 2150 M-1 cm-1) for 2a and a 527 nm absorbance (epsilon = 1650 M-1 cm-1) for 2b, indicative of alkylperoxo-to-iron(III) LMCT transitions, and the EPR data (77 K) show that both intermediates are low-spin iron(III) complexes (g = 2.20 and 1.97). Definitive identification of the Fe(III)-OOR species comes from RR spectra, which give nu(Fe-O) = 612 (2a) and 615 (2b) cm-1, and nu(O-O) = 803 (2a) and 795 (2b) cm-1. The assignments for 2a were confirmed by 18O substitution (tBu18O18OH), resulting in a 28 cm-1 downshift for nu(Fe-18O), and a 46 cm-1 downshift for nu(18O-18O). These data show that 2a and 2b are low-spin FeIII-OOR species with weak Fe-O bonds and suggest that a low-spin intermediate may occur in SOR, as opposed to previous proposals invoking high-spin intermediates. 相似文献