L-酒石酸正丁酯的合成

以L-酒石酸和正丁醇为原料合成了手性选择子L-酒石酸正丁酯,其结构经IR确证。通过正交实验得优化反应条件为:L-酒石酸0.1mol,n(L-酒石酸)∶n(正丁醇)=1.0∶2.8,对甲苯磺酸0.5g,甲苯50mL,慢速搅拌,回流反应约5h。酯化率达99%,收率在93%以上。

Chiral ionic liquids as chiral selectors for separation of tryptophan enantiomers by ligand exchange chromatography

Chiral ionic liquids (CILs) containing imidazolium cations and L-Proline (L-Pro) anions were applied as chiral selector to separate tryptophan (Trp) enantiomers on a C18 column by ligand exchange chromatography. Several factors influencing Trp enantiomers separation, such as alkyl chain length of CILs, concentrations of Cu2+ and CILs, pH of the mobile phase, flow rate, organic solvent and temperature, were studied. Under the optimal conditions, the Trp enantiomers could be successfully separated within 21 min with the resolution of 2.30. At the same time, some thermodynamical parameters were obtained. The experimental results show that the enthalpy values of the Trp enantiomers are negative, indicating that the separation process is exothermic. And the enthalpy values of D-Trp are larger than those of L-Trp, which indicates that L-Trp could form more stable ternary complexes with tryptophan enantiomers.

Bio-inspired enantioseparation for chiral compounds

Biomacromolecules including protein and nucleic acids are considered as promising chiral selectors in the fields of enantioselective separation, owing to their inherent chirality, polymorphous structures, stable physicochemical properties, good biocompatibility as well as susceptible modification and regulation. In this review, firstly,enantioselective recognition mechanism of proteins and nucleic acids toward different enantiomers is discussed,as well as their potential applications on the chiral separation of racemic compounds. Secondly, preparative enantioseparation adopting biomolecule-modified hybrid materials including porous microspheres, magnetic nanoparticles and affinity membranes, are introduced respectively. Finally, novel chiroptical materials constructed on the basis of chiral induction, transfer, amplification and transcription, are recognized as promising candidates in future applications.

Review for chiral-at-metal complexes and metal-organic framework enantiomorphs

This review discusses chiral-at-metal complexes and introduces enantiomorphs from assembly structure.Owing to the diverse coordination number and activity of metal ions as chiral centers, abundant structures for chiral selectivity, catalysis, and polarized light-response are the notable advantages of the chiral-at-metal complexes. The rational design and preparation of linear multi-dentate ligands is a good choice to improve the stability of chiral complexes, such as multi-bonding structure for high stability as a self-limiting system. The bio-significance and potential application of chiral-at-metal complexes are discussed, such as the synergistic effect of catalysis and chiral selectivity of the metal center in enzymes.Enzyme could be remolded to replace the original central metal ions with highly active rare earth or precious metal ions to form artificial metalloenzyme or to remove the ‘‘redundant" part around the metal center to improve the accessibility of substrate. The polarized light-response mechanism of chiral opsin is introduced in relation to its role in animal migration. Metal-organic frameworks(MOFs) are crystalline and porous materials built from metal nodes or clusters and organic linkers and provide the possibility to prepare artificial enantiomorphs. The preparations, applications, and characterization methods of MOF enatiomorphs are therefore introduced. We hope this review inspires researchers at all levels of their career to consider the title topic in their own research in terms of its application and potential value.

Novel supramolecular organocatalysts of hydroxyprolinamide based on calix[4]arene scaffold for the enantioselective Biginelli reaction

A series of novel supramolecular organocatalysts of hydroxyprolinamide based on the upper rim of calix[4]arene scaffold have been developed to catalyze enantioselective multi-component Biginelli reaction. Under the optimal conditions, the reactions occurred with moderate-to-excellent enantioselectivities (up to 98% ee). A plausible transition state constructed by the supra- molecular interaction of hydrogen bond and cation-π between catalysts and substrates has been proposed.