نتایج جستجو برای: chiral non-racemic menthol

تعداد نتایج: 1354057  

Journal: :Langmuir : the ACS journal of surfaces and colloids 2014
Dian Yang Adam E Cohen

We show that the solid-solid friction between bulk chiral molecular solids can depend on the relative chirality of the two materials. In menthol and 1-phenyl-1-butanol, heterochiral friction is smaller than homochiral friction, while in ibuprofen, heterochiral friction is larger. Chiral asymmetries in the coefficient of sliding friction vary with temperature and can be as large as 30%. In the t...

2009
Peter Raynes Stephen J. Cowling John W. Goodby

Over recent years there has been a tendency to target the development of chiral materials for use in healthcare treatments. In such applications and therapies the optical purity is an important factor to consider. Two common materials, that have relevance in bio-medical applications, and which are available in their chiral and racemic forms are menthol and ibuprofen. In this article we quantita...

2011
Kay M Brummond Joshua M Osbourn

A thermal [2 + 2] cycloaddition reaction of allene-ynes has been used to transform chiral non-racemic allenyl oxindoles into chiral non-racemic spirooxindoles containing an alkylidene cyclobutene moiety. The enantiomeric excesses were determined by chiral lanthanide shift NMR analysis and the transfer of chiral information from the allene to the spirooxindole was found to be greater than 95%.

One-pot, four-component procedure for the synthesis of a small library of new chiral spiro- oxindolopyrrolidines with high regio-, diastereo- (>99:1 dr), and enantioselectivity (up to 80% ee) is described. In this process, the regio- and stereochemical 1,3-dipolar cycloaddition of azomethine ylides, which were generated insitu by the reaction of isatin derivatives and sarcosin,with optically ac...

One-pot, four-component procedure for the synthesis of a small library of new chiral spiro- oxindolopyrrolidines with high regio-, diastereo- (>99:1 dr), and enantioselectivity (up to 80% ee) is described. In this process, the regio- and stereochemical 1,3-dipolar cycloaddition of azomethine ylides, which were generated insitu by the reaction of isatin derivatives and sarcosin,with optically ac...

The distribution behavior of ofloxacin enantiomers was examined in the aqueous and organic solvent of a two-phase system containing chiral selector L-tartarate. The effect of extraction equilibrium time, buffer pH, organic solvents and length of alkyl chain of L-tartarate on the partition coefficients and enantioselectivity of racemic ofloxacin were investigated, respectively. The L-tartara...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2009
xiaoqing chen feipeng jiao xinyu jiang

the distribution behavior of ofloxacin enantiomers was examined in the aqueous and organic solvent of a two-phase system containing chiral selector l-tartarate. the effect of extraction equilibrium time, buffer ph, organic solvents and length of alkyl chain of l-tartarate on the partition coefficients and enantioselectivity of racemic ofloxacin were investigated, respectively. the l-tartarate f...

Journal: :physical chemistry research 0
hossein fakhraian imam hossein university morteza salimi faculty of chemical, gas and petroleum engineering, semnan university, semnan, iran bahman zarenezhad faculty of chemical, gas and petroleum engineering, semnan university, semnan, iran ebrahim choobdari department of chemistry, shahid beheshti university, evin, tehran, iran

experimental determination of solubility and ternary phase diagram of chiral compound are of tedious and time consuming tasks, and in many cases, there is not enough experimental data for different enantiomeric compositions to access the experimental ternary phase diagram. using thermodynamic models with predictive capability, having less dependency on experimental data, affords a great advanta...

Journal: :Chemical communications 2014
Paola Rizzo Eugenia Lepera Gaetano Guerra

The circular dichroism of non-racemic molecules, being guests of co-crystalline phases of s-PS films, has been studied. Unexpectedly, the chiral response of non-racemic guest molecules does not depend on their R or S molecular chirality but essentially only on the polymer host supramolecular chirality.

Experimental determination of solubility and ternary phase diagram of chiral compound are of tedious and time consuming tasks, and in many cases, there is not enough experimental data for different enantiomeric compositions to access the experimental ternary phase diagram. Using thermodynamic models with predictive capability, having less dependency on experimental data, affords a great advanta...

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