ON-LINE CD DETECTION IN CHIRAL SEPARATION OF SPIRO-λ4-SULFANES.

Autor: Szókán, Gy., Szarvas, Sz., Majer, Zs., Szabó, D., Kapovits, I., Hollósi, M.
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Zdroj: Journal of Liquid Chromatography & Related Technologies; 4/1/99, Vol. 22 Issue 7, p993-1007, 15p, 1 Chart
Abstrakt: 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 approx. 210 nm (positive couplet) that allows prediction of absolute configuration. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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