Effect of the Amide Connecting Tether Type of Pirkle-Concept Chiral Stationary Phases Derived from (S)-N-(3,5-Dinitrobenzoyl)Leucine on Enantiomeric Separations
作者:
Wonjae Lee,
期刊:
Analytical Letters
(Taylor Available online 1999)
卷期:
Volume 32,
issue 2
页码: 423-432
ISSN:0003-2719
年代: 1999
DOI:10.1080/00032719908542830
出版商: Taylor & Francis Group
关键词: Chiral Stationary Phase;N-Protected α-amino acid derivatives;Enantiomeric separation
数据来源: Taylor
摘要:
Liquid chromatographic comparisons are made between a secondary amide linked chiral stationary phase (CSP 1) and a tertiary amide double-tethered CSP (CSP 2) derived from (S)-N-3,5-[dinitrobenzoyl(DNB)]leucine. For the enantioseparation of the anilide derivatives of N-9-fluorenylmethoxycarbonyl (FMOC), benzyloxycarbonyl (CBZ) and t-butoxycarbonyl (BOC) protected α-amino acids, CSP 2 shows performance superior to that of CSP 1. It is considered that the amide hydrogen of the connecting tether of CSP 1 serves as a nonproductive adsorption site, while the enhanced basicity of the carbonyl oxygen of the tertiary amide tethered CSP 2 is responsible for the increased enantioselectivity of these analytes. For the same reason, it is observed that CSP 2 provides better separation of the enantiomers of N-CBZ α-amino acids as ethyl ester, n-butylamide and diethylamide derivatives than CSP 1.
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