Convenient synthesis of mono(6A-N-allylamino-6A-deoxy)permethylated β-cyclodextrin: a promising chiral selector for an HPLC chiral stationary phase

Preparation of perphenylcarbamoylated β-cyclodextrin-silica hybrid monolithic column with "one-pot" approach for enantioseparation by capillary liquid chromatography

Perphenylcarbamoylated β-cyclodextrin-silica (Ph-β-CD-silica) hybrid monolithic columns for enantioseparation in capillary liquid chromatography (cLC) have been prepared by a "one-pot" approach via the polycondensation of alkoxysilanes and in situ copolymerization of mono (6(A)-N-allylamino-6(A)-deoxy)-Ph-β-CD and vinyl group on the precondensed siloxanes. The morphologies of the Ph-β-CD-silica hybrid monolithic columns were characterized by optical microscopy and scanning electron microscopy (SEM), showing the uniform monolithic matrixes tightly bonded onto the capillary wall. The content of Ph-β-CD incorporated in monolithic matrix by the "one-pot" approach was ca. 2.9 times higher than that by postmodification method. The permeability of the Ph-β-CD-silica chiral hybrid monolithic column was 3.63 × 10(-14) m(2), and the minimum plate height was 12 μm corresponding to 83,300 theoretical plates/meter. Enantioseparations of 13 racemates were achieved by the Ph-β-CD-silica hybrid monolithic column. In this work, since the prepolymerization system mainly consisted of organic solvent (methanol (MeOH), N,N-dimethylformamide (DMF)), the limitation and difficulty of the use of water insoluble organic monomers in the previously reported "one-pot" method was circumvented. Therefore, various β-CD derivatives as well as other hydrophobic monomers could thus be used to prepare organic-silica hybrid monolithic columns with the "one-pot" process.

Enantioseparation on mono(6A-N-allylamino-6A-deoxy)permethylated β-cyclodextrin covalently bonded silica gel

A chiral selector, mono(6A-N-allylamino-6A-deoxy)permethylated beta-cyclodextrin, was synthesized through a facile synthetic route and chemically immobilized onto porous silica gel via hydrosilylation to afford a cyclodextrin based chiral stationary phase MeCD-CSP. This chiral stationary phase exhibited good enantioselectivity under standard HPLC conditions. The optimal resolution of 1-(p-bromophenyl)ethanol and bromopheniramine was achieved under normal-phase conditions using a mobile phase comprising n-hexane (hexane) and 2-propanol (IPA). The enantioseparation of warfarin, suprofen and a series of flavanones under reversed-phase conditions were optimized and efficient enantioseparations for these analytes were obtained.