- Eluent tolerance and enantioseparation recovery of chiral packing materials based on chitosan bis(phenylcarbamate)-(n-octyl urea)s for high performance liquid chromatography
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The goal of the present work was to study the influence of the swelling of chitosan derivatives on the enantioseparation and the separation performance recovery of chiral stationary phases (CSPs) based on these derivatives. Therefore, six chitosan bis(phenylcarbamate)-(n-octyl urea)s were synthesized, which were coated on macroporous 3-aminopropyl silica gel affording new CSPs. Most of the CSPs demonstrated strong enantioseparation capability for the tested chiral compounds. The swelling capacity of the chitosan bis(phenylcarbamate)-(n-octyl urea)s in ethyl acetate, acetone and tetrahydrofuran (THF) was evaluated. Among the chitosan derivatives, the chitosan bis(3,5-dichlorophenylcarbamate)-(n-octyl urea) polymer showed the highest swelling capacity in ethyl acetate and THF. The polymer-based CSPs could be utilized with pure ethyl acetate and a normal phase containing 70% THF, but was damaged by pure THF. On the other hand, the separation performance of the damaged CSP could be recovered after it was allowed to stand for a period of time. The observations are important for the development and application of polysaccharide derivative-based CSPs.
- Wang, Jing,Huang, Shao-Hua,Chen, Wei,Bai, Zheng-Wu
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supporting information
(2016/12/02)
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- A dual-catalysis anion-binding approach to the kinetic resolution of amines: Insights into the mechanism via a combined experimental and computational study
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Racemic benzylic amines undergo kinetic resolution via benzoylation with benzoic anhydride in the presence of a dual catalyst system consisting of a readily available amide-thiourea catalyst and 4-dimethylaminopyridine (DMAP). An evaluation of various exp
- Mittal, Nisha,Lippert, Katharina M.,De, Chandra Kanta,Klauber, Eric G.,Emge, Thomas J.,Schreiner, Peter R.,Seidel, Daniel
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supporting information
p. 5748 - 5758
(2015/05/20)
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- Chiral self-discrimination of the enantiomers of α-phenylethylamine derivatives in proton NMR
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Two types of chiral analytes, the urea and amide derivatives of α-phenylethylamine, were prepared. The effect of inter- molecular hydrogen-bonding interaction on self-discrimination of the enantiomers of analytes has been investigated using high-resolutio
- Huang, Shao-Hua,Bai, Zheng-Wu,Feng, Ji-Wen
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experimental part
p. 423 - 427
(2010/04/05)
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- Catalytic metathesis of simple secondary amides
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(Chemical Equation Presented) Trading places: The metathesis of secondary amides through a transacylation mechanism has been achieved by employing catalytic quantities of an organic imide and a Bronsted base (see scheme). Equilibrium-controlled exchange between various amide pairs is demonstrated for substrates bearing N-alkyl and N-aryl substituents.
- Bell, Christen M.,Kissounko, Denis A.,Gellman, Samuel H.,Stahl, Shannon S.
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p. 761 - 763
(2007/10/03)
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- 3-Acyl-2-(N-cyanoimino)oxazolidine derivative, a new asymmetric acylating agent for racemic secondary alkyl amines
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A 3-acyl-2-(N-cyanoimino)oxazolidine derivative was found to serve as an enantioselective acylating agent for sec-alkyl amines. These reagents differentiate the enantiomers of 1-phenylethylamine derivatives up to 85% ee, and the recovered chiral auxiliary is reusable.
- Maezaki, Naoyoshi,Furusawa, Akemi,Uchida, Shuji,Tanaka, Tetsuaki
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p. 9309 - 9315
(2007/10/03)
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