Effect of the residual silanol group protection on the liquid chromatographic resolution of racemic primary amino compounds on a chiral stationary phase based on optically active (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6.
A liquid chromatographic chiral stationary phase (CSP) based on (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6, which has been utilized in the resolution of alpha-amino acids, amines and amino alcohols, was treated with excess of n-octyltriethoxysilane to prepare a new improved CSP. The residual silanol groups of the original CSP were protected by n-octyl groups in the new CSP. The chiral recognition ability of the new CSP was superior to that of the original CSP in the resolution of alpha-amino acids, amines and amino alcohols. Retention factors (k1) for the resolution of alpha-amino acids were lower on the new CSP than on the original CSP while those for the resolution of amines and amino alcohols were higher on the new CSP than on the original CSP. The improved chiral recognition ability of the new CSP and the retention behaviors of the two enantiomers on the new CSP have been rationalized to stem from the removal of the non-enantioselective interactions between the analytes and the residual silanol groups of the original CSP and the improved lipophilicity of the CSP.
Hyun
Myung Ho
MH
Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Kuemjeong-Ku, Busan 609-735, South Korea. mhhyun@pusan.ac.kr
Han
Sang Cheol
SC
Choi
Hee Jung
HJ
Kang
Bu Sung
BS
Ha
Hyun Ju
HJ
D000588:Amines / Q000032:analysis / Q000737:chemistry; D000596:Amino Acids / Q000032:analysis / Q000737:chemistry*; D000605:Amino Alcohols / Q000032:analysis / Q000737:chemistry; D002853:Chromatography, Liquid / Q000379:methods*; D015203:Reproducibility of Results; D012821:Silanes / Q000737:chemistry*; D013237:Stereoisomerism
D000588:Amines; D000596:Amino Acids; D000605:Amino Alcohols; D012821:Silanes; C082343:silanol