The design of chiral separation media using monodisperse functionalized macroporous beads: effects of polymer matrix, tether, and linkage chemistry.
Porous size monodisperse methacrylate beads containing amino and hydroxyl groups, which can be used as a platform for the production of chiral separation media, have been prepared using the staged templated suspension polymerization process. The monomers 2-hydroxyethyl methacrylate and several tert-butoxycarbonyl-protected aminoalkyl methacrylates were used for the preparation of both hydroxyl- and amino-functionalized beads. Attachment of a chiral selector based on L-valine-3,5-dimethylanilide through a carbamate and a urea linkage, respectively, provides chiral stationary phases with excellent enantioselectivities in the separation of the enantiomers of 3,5-dinitrobenzamido derivatives of alpha-amino acids. For comparison purposes, a separation medium was also prepared by the direct polymerization of a chiral monomer analogous to the hydroxyethyl methacrylate-based stationary phase. The chiral stationary phases prepared with the N-methyl-2-aminoethyl methacrylate platform exhibit the best selectivity, and separation factors as high as 15 were achieved under normal-phase HPLC conditions.
Lewandowski
K
K
Department of Chemistry, University of California, Berkeley 94720-1460, USA.
Murer
P
P
Svec
F
F
Fréchet
J M
JM
D002219:Carbamates / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004655:Emulsions; D008689:Methacrylates; D008863:Microspheres; D011108:Polymers; D013237:Stereoisomerism; D014508:Urea / Q000737:chemistry; D014633:Valine / Q000031:analogs & derivatives
D002219:Carbamates; D004655:Emulsions; D008689:Methacrylates; D011108:Polymers; C005044:hydroxyethyl methacrylate; D014508:Urea; D014633:Valine