Del Alamo, Aurora (1995) Studies of hexahelicene bonded phases for the HPLC resolution of enantiomers. PhD thesis, University of Warwick.

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Abstract

The thesis presents a review of the literature on the HPLC resolution of enantiomers
using chiral stationary phases and discusses the mechanisms of separation and the utility
of these phases. The synthesis and chemical, chiroptical and spectroscopic properties of
helicenes are also reviewed and the potential utility of helicene-based for the HPLC
resolution of enantiomers is discussed.
The work carried out involved the preparation of a hexahelicene-based chiral stationary
phase and demonstrations of its utility for the resolution of chiral analytes. This phase
was chemically bonded rather than physically coated, in order to make it stable to
hydrolysis and solvent stripping, and therefore to permit its employment with a wide
range of mobile phases.
This thesis describes the synthesis of hexahelicen-7-ylacetic acid methyl ester, including
confirmation of the structure of the key synthetic intermediates by spectroscopic analysis,
and the investigation of several proceduresfor the resolution of hexahelicen-7-ylacetic
acid methyl ester into its enantiomers, one of which enabled around 100 mg amounts of
each of (+) and (-) enantiomers of hexahelicen-7-ylacetic acid to be obtained in highly
chemically and optically pure form. The thesis also gives an account of several synthetic
approaches to covalently bonding of the chiral selector (hexahelicen-7-ylacetic acid) to a
modified silica stationary phase.
Chiral stationary phases were prepared from each of the enantiomers in sufficient amount
to permit the packing of analytical columns of these phases. Chiral solutes containing
nitroaryl functionalities were synthesised to investigate the chiral resolving power of
these novel phases. Adequate separations were obtained with both chiral stationary
phases and, as anticipated, the eluting order of chiral analytes was reversed between the
(+) and (-) stationary phases. The work demonstrated the utility of these columns for the
resolution of nitroaryl-containing chiral analytes.

Item Type:	Thesis (PhD)
Subjects:	Q Science > QD Chemistry
Library of Congress Subject Headings (LCSH):	High performance liquid chromatography, Enantiomers, Aromatic compounds, Esters -- Synthesis
Official Date:	June 1995
Dates:	Date Event June 1995 Submitted
Institution:	University of Warwick
Theses Department:	Department of Chemistry
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Matlin, S. A.
Extent:	x, 183 p.
Language:	eng

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