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排序方式: 共有140条查询结果,搜索用时 109 毫秒
31.
Abbas?ShockraviAbbas_Shockravi@yahoo.co.uk" title="Shockravi@saba.tmu.ac.ir Abbas_Shockravi@yahoo.co.uk" itemprop="email" data-track="click" data-track-action="Email author" data-track-label="">Email author T.?Samad?Bavili 《Journal of inclusion phenomena and macrocyclic chemistry》2005,52(3-4):223-227
Some new dibenzosulfide macrocyclic diamides (6–12) are synthesized. The macrocyclization process is performed by reaction of the dimethyl ester (5) and diacid chloride (4) with appropriate diamines by two methods. Also the results of two methods are discussed and compared.This revised version was published online in July 2005 with a corrected issue number. 相似文献
32.
A novel, one-pot reductive mono-alkylation method of amines (primary and secondary), 1,2-phenylenediamine, O-trimethylsilylhydroxylamine, and N,N-dimethylhydrazine was developed using LiClO4 (5 mol %) as a source for in situ generation of imine, iminium ion, oxime, and hydrazone, and zirconium borohydride-piperazine complex as reducing agent. This condition is especially useful for situations in which it is not practical to use the amine in excess (as is typically the case under acid-catalyzed conditions) or for acid-sensitive compounds. 相似文献
33.
We have achieved the synthesis of C15-C27 fragment of venturicidine X using desymmetrization protocol, substrate-controlled Grignard reaction, Barton-McCombie reaction, Sharpless epoxidation, and TBSOTf-mediated rearrangement to produce the aldol product through a non-aldol route as the key step following 23 longest linear sequences with 6.4% overall yield starting from a known intermediate 11. 相似文献
34.
A simple and efficient protocol for the chemoselective mono-N-Boc protection of various structurally diverse amines with di-tert-butyl dicarbonate using thioglycoluril as the catalyst is described. The catalyst can be readily separated from the reaction products by simple filtration and recovered for reuse. No competitive side reactions, such as formation of isocyanate, urea, oxazolidinone, and N,N-di-Boc derivatives were observed. 相似文献
35.
Ricardo Elgul Samad Lilia Coronato Courrol Ademar Benévolo Lugão Anderson Zanardi de Freitas Nilson Dias Vieira 《Radiation Physics and Chemistry》2010,79(3):355-357
We report here the creation of color centers in commercial, transparent PMMA samples by ultrashort pulses from a Ti:Sapphire laser emitting at 800 nm, with spatial control. Although the 800 nm photon energy is not sufficient to ionize the polymer, the centers are created following a multiphotonic absorption that causes the ionization. We propose that the free electrons quivering motion on the pulse electric field displaces atoms from its equilibrium positions, creating free radicals and double bonds that coalesce into color centers. The absorption and emission spectra of the centers were measured, but a dose-like curve could not be built due to the presence of damages created along with the centers that scatter the excitation and emission lights due to the commercial sample's poor optical quality. 相似文献
36.
S. Mustafa Samad Yar Hussain A. Naeem Khan 《Reaction Kinetics and Catalysis Letters》1992,47(1):125-131
The kinetics of phosphate sorption on Amberlite IRA-400 has been studied as a function of temperature, nature of counterions, at two different concentrations. The film and particle diffusion coefficients and the activation parameters of the process are calculated.
IRA-400 , . .相似文献
37.
Dr. Abdus Samad Dr. Aamir Shafique Prof. Udo Schwingenschlögl Dr. ZongWei Ji Prof. Guangfu Luo 《Chemphyschem》2022,23(10):e202200041
Monolayer, bilayer, and bulk BSi are studied to explore their application potential as anode materials of Li-ion batteries. Structural stability and metallicity are obtained in each case. The Li storage capacities of monolayer and bilayer BSi are 1378 and 689 mAh g−1, respectively, with average open circuit voltages of 1.30 and 0.47 V as well as Li diffusion barriers of 0.48 and 0.27 eV. Bulk BSi realizes a layered structure in the presence of a small amount of Li and its Li diffusion barrier of 0.48 eV is identical to that of graphite and lower than that of bulk Si (0.58 eV). The Li storage capacity of bulk BSi is found to be 689 mAh g−1, i. e., much higher than that of graphite (372 mAh g−1). The volume expansion turns out to be 33 % and the chemical bonds remain intact at full lithiation, outperforming the 72 % volume expansion of bulk Si at the same capacity and thus pointing to excellent cyclability. 相似文献
38.
A novel, chemoselective mono-N-Boc protection of various structurally diverse amines with di-tert-butoxypyrocarbonate (Boc)2O is described that relies on selective carbonyl activation by hydrogen bond formation. This mild, acid- and metal-free process requires only catalytic amounts of thiourea as hydrogen bond donor. 相似文献
39.
40.
二氧化钛纳米粒子催化合成Hantzsch酯和多氢喹啉衍生物(英文) 总被引:2,自引:0,他引:2
Mahmood TAJBAKHSH Ehsan ALAEE Heshmatollah ALINEZHAD Mohammad KHANIAN Fatemeh JAHANI Samad KHAKSAR Parizad REZAEE Mahgol TAJBAKHSH 《催化学报》2012,(9):1517-1522
1,4-Dihydropyridine and polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using nanosized titanium dioxide as a heterogeneous catalyst.The present methodology offers several advantages such as excellent yields,short reaction times (30-120 min),environmentally benign,and mild reaction conditions.The catalyst can be readily separated from the reaction products and recovered in excellent purity for direct reuse. 相似文献