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Shanghai, China

Donghua University is a public research university in Shanghai, China. Established in 1951, it is a member of China's Project 211 group of national key universities, with a heavy focus on high level technological and scientific research. Among its various departments it is especially well known for engineering, business, and textile design, among which its fashion design, textile engineering, international trade, material science, and information technology departments have been consistently ranked highly in China for decades. Wikipedia.

Chu L.,CAS Shanghai Institute of Organic Chemistry | Qing F.-L.,CAS Shanghai Institute of Organic Chemistry | Qing F.-L.,Donghua University
Accounts of Chemical Research | Year: 2014

ConspectusThe trifluoromethyl group is widely prevalent in many pharmaceuticals and agrochemicals because its incorporation into drug candidates could enhance chemical and metabolic stability, improve lipophilicity and bioavailability, and increase the protein bind affinity. Consequently, extensive attention has been devoted toward the development of efficient and versatile methods for introducing the CF3 group into various organic molecules. Direct trifluoromethylation reaction has become one of the most efficient and important approaches for constructing carbon-CF3 bonds. Traditionally, the nucleophilic trifluoromethylation reaction involves an electrophile and the CF3 anion, while the electrophilic trifluoromethylation reaction involves a nucleophile and the CF3 cation. In 2010, we proposed the concept of oxidative trifluoromethylation: the reaction of nucleophilic substrates and nucleophilic trifluoromethylation reagents in the presence of oxidants.In this Account, we describe our recent studies of oxidative trifluoromethylation reactions of various nucleophiles with CF3SiMe3 in the presence of oxidants. We have focused most of our efforts on constructing carbon-CF3 bonds via direct trifluoromethylation of various C-H bonds. We have demonstrated copper-mediated or -catalyzed or metal-free oxidative C-H trifluoromethylation of terminal alkynes, tertiary amines, arenes and heteroarenes, and terminal alkenes. Besides various C-H bonds, aryl boronic acids proved to be viable nucleophilic coupling partners for copper-mediated or -catalyzed cross-coupling reactions with CF3SiMe3. To further expand the reaction scope, we also applied H-phosphonates to the oxidative trifluoromethylation system to construct P-CF3 bonds. Most recently, we developed silver-catalyzed hydrotrifluoromethylation of unactivated olefins. These studies explore boronic acids, C-H bonds, and P-H bonds as novel nucleophiles in transition-metal- mediated or -catalyzed cross-coupling reactions with CF3SiMe 3, opening new viewpoints for future trifluoromethylation reactions. Furthermore, we also achieved the oxidative trifluoromethylthiolation reactions of aryl boronic acids and terminal alkynes to construct carbon-SCF3 bonds by using CF3SiMe3 and elemental sulfur as the nucleophilic trifluoromethylthiolating reagent. These oxidative trifluoromethylation and trifluoromethylthiolation reactions tolerate a wide range of functional groups, affording a diverse array of CF3- and CF3S-containing compounds with high efficiencies, and provide elegant and complementary alternatives to classical trifluoromethylation and trifluoromethylthiolation reactions. Because of the importance of the CF 3 and SCF3 moieties in pharmaceuticals and agrochemicals, these reactions would have potential applications in the life science fields. © 2014 American Chemical Society. Source

Novel spinning solution, prepared by dissolving hydroxyethyl cellulose (HEC) owning a low molar substitution (MS) into NaOH/urea/thiouea aqueous solution with a specific weight ratio of 8:8:6.5, was employed to fabricate a new type of regenerated fibers by wet-spun method. The structure and properties of the resultant HEC fibers were characterized by (13)C NMR, FTIR, synchrotron WAXS, SEM, and tensile tester. The results showed that HEC fibers exhibited structure identical with HEC because of the physical dissolution and coagulation processes, but quite different from native cellulose due to partial breakage of hydrogen bonds and crystal transformation from cellulose I to cellulose II during cellulose modification. The resultant HEC fibers with relatively dense and homogenous structure displayed good moisture related properties and stayed stable in alkali solution with low concentration. Moreover, the novel fibers owned good dry mechanical properties in spit of their slightly poor wet mechanical properties comparable to viscose rayon, showing great potential in substituting the traditional viscose fibers. Copyright © 2013 Elsevier Ltd. All rights reserved. Source

Chu L.,CAS Shanghai Institute of Organic Chemistry | Qing F.-L.,Donghua University
Organic Letters | Year: 2012

An efficient C(sp 3)-CF 3 bond-forming reaction via Cu-catalyzed oxidative trifluoromethylation of terminal alkenes has been developed, which proceeds under mild conditions using readily available, less expensive CF 3SiMe 3 as the source of the CF 3 group. This method allows access to a variety of trifluoromethylated allylic compounds. © 2012 American Chemical Society. Source

Nawaz Y.,Donghua University
Computers and Mathematics with Applications | Year: 2011

In this article, linear and nonlinear boundary value problems for fourth-order fractional integro-differential equations are solved by variational iteration method and homotopy perturbation method. The fractional derivatives are described in the Caputo sense. The solutions of both problems are derived by infinite convergent series which are easily computable and then graphical representation shows that both methods are most effective and convenient one to solve linear and nonlinear boundary value problems for fourth-order fractional integro-differential equations. © 2010 Elsevier Ltd. All rights reserved. Source

Wu G.-C.,Donghua University
Computers and Mathematics with Applications | Year: 2011

Recently, fractional differential equations have been investigated by employing the famous variational iteration method. However, all the previous works avoid the fractional order term and only handle it as a restricted variation. A fractional variational iteration method was first proposed in [G.C. Wu, E.W.M. Lee, Fractional variational iteration method and its application, Phys. Lett. A 374 (2010) 25062509] and gave a generalized Lagrange multiplier. In this paper, two fractional differential equations are approximately solved with the fractional variational iteration method. © 2010 Elsevier Ltd. All rights reserved. Source

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