The Preparation Of Bilayer Functionalized ?-Cyclodextrins-Based Chiral Stationary Phases And Their Applications In High Performance Liquid Chromatography

With the rapid economic development,the demand for single-isomer chiral molecules is ever-increasing in the fields of pesticides,biology and medicine.High performance liquid chromatography(HPLC)has evoluted as one of the most roubst tools for the analysis and preparation of chiral compounds due to its fast analysis speed,high sensitivity and versatile manipulation modes.Among of this technique,the chiral stationary phases(CSPs)equipped with cyclodextrins(CDs)as chiral selectors and silica gel as support have presented great potentials in HPLC enantioseparations.This dissertation is focused on the systematical comparison study of the enantioseparation performance of four perphenylcarbamated CD-CSPs in HPLC.Meanwhile,we dealed with high selectively clicked preparation of bilayer cationic perphenylcarbamated CD-CSPs,which have exhibited excellent chiral separation ability in HPLC.Firstly,we evaluated the enantioseparations of 12 isoxazoline racemates using four perphenylcarbamated CD-CSPs by HPLC including 6A-azido-heptakis[2,3-di-O-(3-chloro-4-methylphenylcarbamate)]-6B,6c,6D,6E,6F,6G-hextakis-O-(3-chloro-4-methylphenylcarbamate)-?-CD(CCC3M4-CSP),6A-azido-heptakis[2,3-di-O-(4-chloro-3-methylphenylcarbamate)]-6B,6C,6D,6E,6F,6G-hextakis-O-(4-chloro-3-methylphenylcarbamate)-?-CD(CCC4M3-CSP),6A-azido-heptakis[2,3-di-O-(5-chloro-2-methylphenylcarbamate)]-6B,6c,6D,6E,6F,6G-hextakis-O-(5-chloro-2-methylphenylcarbamate)-?-CD(CCC5M2-CSP)and 6A-azido-6c-[(3-methoxylpropyl)-1-ammonium]-heptakis[2,3-di-O-(3-chloro-4-methylphenylcarbamate)]-6B,6D,6E,6F,6G-pentakis-O-per(3-chloro-4-methylphenylcarbamate)-?-CD chloride(MPCCC3M4-CSP).The results demonstrated that the position of substituent group of substitutes on phenylcarbamated moiety greatly determined the chiral separation ability.Among of them,CCC3M4-CSP exhibited the best enantioseparation ability,affording 4CIPh-OPr and 3NPh-OPr enantiomers with chiral resolution(Rs)of 20.08 and 15.01 in normal phase(NP)HPLC with ternary mobile phases,which offered the production of pure chiral molecules with great possibility.Secondly,a novel bilayer positive-type CD-CSP(TMPCD-CSP)was prepared in order to enhance the loading amount of CD on silica gel and its broad-spectrum resolution ability.Mono-(6-deoxy-6-propargylamine)-?-CD was bonded to silica gel via ?-(2,3-epoxypropoxy)propytrimethoxysilane(KH-560)to obtain a single-layer cyclodextrin CSP,followed by the clicked immobilization of 6A-azido-6C-(3-methoxypropylammonio)-perphenylcarbamated?-CD chloride.Fourier transform infrared spectroscopy(FTIR)spectra and solid-state carbon(13C-NMR)spectra verified the successful immobilization of second layer of cationic CD with a surface loading amount of 1.67%calculated from the thermogravimetric analysis.The performance of as-prepared TMPCD-CSP was evaluated by HPLC using 3'-hydroxyflavanone as model molecule in the reverse mode(RP).The relative standard deviation of precision and reproducibility are all less than 1%,the linear correlation of the two enantiomers in the linear correlation is greater than 0.99,so the performance of the stationary phase is well.In the NP and RP mode,the enantioseaprtions of 19 compounds was conducted.It was found that the chiral resolutions of flavanone and isoxazoline enantiomers were better than that of aryl alcohols in the two elution modes.Meanwhile,the reverse mode results were better than that of normal mode.In the resolution process,the structure of enantiomers,the composition of the mobile phase system and organic modifier greatly influenced the enantioseparations.The enantioseparation of 6-methoxyflavanone(Rs=3.60,a=1.75)and 7-methoxyflavanone(Rs=3.55,a=1.92)by TMPCD-CSP was better than that of single-layer and bilayer native CD-CSPs.