ON-LINE CD DETECTION IN CHIRAL SEPARATION OF SPIRO-λ4-SULFANES
作者:
Gy. Szókán,
Sz. Szarvas,
Zs. Majer,
D. Szabó,
I. Kapovits,
M. Hollósi,
期刊:
Journal of Liquid Chromatography & Related Technologies
(Taylor Available online 1999)
卷期:
Volume 22,
issue 7
页码: 993-1007
ISSN:1082-6076
年代: 1999
DOI:10.1081/JLC-100101713
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
Enantiomers of chiral spiro-λ4-sulfanes with equatorial diaryl and axial bis(acyloxy), (alkoxy)-(acyloxy) or (acylamino)-(acyloxy) S-substituents were separated on a Kromasil-based chiral sorbent, namely on O,O′-bis(3,5-dimethylbenzoyl)-N,N′- diallyl-L-tartardiamide silica CSP, by using n-hexane (or n-heptane) – dioxane (or 2-propanol) isocratically mixed mobile phases. Direct chiral separation was monitored by a home-made HPLC-CD system consisting of a circular dichroism (CD) spectrophotometer (Jobin-Yvon Model III Dicrograph) and a high performance liquid chromatograph. The system was used in conjunction with HPLC-UV to study the chemical and stereochemical purity of the samples. By the stopped-flow technique CD spectra were measured in the 350–230 nm spectral range. Monitoring at a selected wavelength enabled high-sensitivity detection. Racemic spiro-λ4-sulfanes were also separated into pure enantiomers on preparative scale. Regardless of the structural type of diaryl-spiro-λ4-sulfanes, the first-eluted enantiomer was always found to show a CD spectrum marked by an intense positive band near 240 nm and a negative one at ≈210 nm (positive couplet) that allows prediction of absolute configuration.
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