title: Performance of brush-type HPLC chiral stationary phases with tertiary amide in the connecting tether.
abstract: The replacement of the N-H hydrogen of the secondary amide-tethered Pirkle-concept N-(3,5-dinitrobenzoyl)-L-leucine derived chiral stationary phase with various pi-basic or aliphatic groups improved the chiral discrimination ability of new chiral stationary phases, based on the leucine- or alanine-derived chiral selector, for the enantiomers of various racemic neutral analytes with amide functional groups. Retention times decreased while separation and resolution factors increased, thus proving the role of pi-donor aromatic unit as an electron-rich shield in the front of a silica surface. In general, chiral stationary phase (CSP) 5 with the 3,5-dimethylphenyl unit showed best performance, while CSP 3, with phenyl unit, and CSP 7, with 1-naphthyl unit in the tertiary amide connecting tether, were less efficient.
authors.affiliation: Laboratory for Stereoselective Catalysis and Biocatalysis, Ruder Bosković Institute, P.O. Box 180, Bijenicka Cesta 54, HR-10002 Zagreb, Croatia.
authors.forename: Davorka Moslavac
authors.initials: DM
authors.lastname: Forjan
authors.forename: Darko
authors.initials: D
authors.lastname: Kontrec
authors.forename: Vladimir
authors.initials: V
authors.lastname: Vinković
mesh_terms: D000577:Amides / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000577:Amides