Synthesis And Characterization Of Ammonium Substituted β-Cyclodextrin Chiral Ionic Liquids

Cyclodextrin chiral stationary phase and chiral ionic liquids have particular capabilities respectively, and have been studied and applied extensively in the fields of chiral separation.β-Cyclodextrin is a cyclic oligomer ofα-1 ,4-D-glucose formed by the action of certain enzymes on starch, which are torus-like macro-rings built up from seven glucopyranose units.β-Cyclodextrin has hydrophilic inner-cavity and hydrophobic outer-cavity leading to which has chiral micro-environment in a certain extent.β-Cyclodextrin can be used as chiral stationary phase through chemical modification, so in the process of chiral compounds chromatographic separation, it shows higher selectivity and wider application over other chiral stationary phases.Because of having the advantages of both ionic liquid and chiral substances. Chiral ionic liquid can be used as chiral solvent or chiral inducer, which has great potentials applying in the area of chiral synthesis, chiral separation, chiral catalyst and so on. But there are few reports about combiningβ-Cyclodextrin and Chiral ionic liquid through chemical bonding,making it both have the molecular recognition function and serve as a chiral stationary phase or chiral reagents in the application for chiral synthesis, chiral catalysts and chiral separation. Based on that consideration, after consulting lots of documents and summarizing predecessor′s research work, we adopted piece-together principle, designed suitable synthetic routes forβ-Cyclodextrin. By addition reaction with N-alkyl imidazole and pyridine, we have synthesized 10 new types of special-function Chiral ionic liquids,that is, ammonium substitutedβ-Cyclodextrin chiral ionic liquids based on N-alkylimidazolium and pyridinium. By superposition and complement between modifiedβ-Cyclodextrin and N-alkylimidazoline and pyridine, we obtained the novel chiral ionic liquids having certain thermal stability and chiral molecular recognition function, which can be used as a novel chiral stationary phase for the corresponding chiral separation.Reactive cyclodextrin intermediates are important intermediates for synthesis of ammonium substitutedβ-cyclodextrins chiral ionic liquids based on alkylimidazolium and pyridinium. We synthesised mono-6-OTs-β-CD as a transitional intermediates, then we synthesized the reactive cyclodextrin intermediate mono-6-I-CD by nucleophilic substitution reaction, which have reactive capablicity with N-alkyl imidazole (pyridine). Next we systhesised 5 differentβ-cyclodextrin iodizational quaternary ammonium salts with the reactive intermediate mono-6-I-CD and N-alkyl imidazole (pyridine) by addition reaction. Finally we synthesised the obtained novel ammonium substitutedβ-cyclodextrins chiral ionic liquids based on alkylimidazolium and pyridinium with the iodizationalβ-cyclodextrin quaternary ammonium salts and inorganic silver salt (AgBF4,AgPF6) by anion exchange. Their structures were determined by nuclear magnetic resonance spectroscopy (1H NMR),infrared spectroscopy (IR) and high-resolution mass spectrometry (MS) spectra data.Their physics-chemical properties were preliminary studied and analysised by microscopic melting point device, solubility and differential scanning calorimetry (DSC) and thermogravimetric analysis (TG).