June 2008 Meeting

MECHANISTIC ASPECTS OF CHIRAL DISCRIMINATION ON POLYSACHARIDES PHASES.

The June 2008 CSSC meeting will be held at the 95 Gathering Place in Wallingford, CT.  The meeting will feature a technical presentation by Dr. Nelu Grinberg of Boehringer Ingelheim Pharmaceutical, Inc. in Ridgefield, Connecticut, as well as dinner.  The cost of the meeting is $30 ($15 Students and Emeritus) and is to be paid at the event.

Registration deadline is Wednesday June 18th 2008 .

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Abstract:  

Chiral separation entered in a maturity phase.  This is due to the fact that at this time there are on the market over sixty types of chiral phases, able to bind with a pair of enantiomers through a wide variety of interactions ranging from hydrogen bonding, inclusion interaction, p-p interactions, and ion pairing to ligand exchange interactions. With so many interactions to take advantage of, the possibility of achieving enantiomeric separation becomes a matter of understanding their nature and the conditions which govern them determined by the mobile phase composition.

Polysaccharides phases are amongst the most versatile phases for separation of enantiomers.  Their versatility stems in their steric configuration, as well as the substitution at the hydroxyl functional groups. Unfortunately, there is a lack of understanding of the interaction of these biopolymers with pairs of enantiomers which makes the development of enantioseparation methods a matter of trial and error.  Our laboratory undertook the task of understanding of such separations, starting with structural changes occurring in the presence of solvents which constitutes the mobile phases in chromatography and in the presence of enantiomeric analytes.

Amylose tris(3,5-dimethylphenyl)carbamate (ADPC) and cellulose tris(3,5-dimethylphenyl)carbamate (CDPC) are one of the most effective chiral stationary phases for separation of enantiomers.  The retention of enantiomers on these chiral stationary phases is dominated by hydrogen bonding, while the enantioselectivity is governed by other kinds of interactions, e.g. inclusion in the calyxes which exists along the ADPC and CDPC chains as well as p-stacking. Vibrational circular dichroism (VCD) is a relatively new technique which allows the examination of chiral compounds at the molecular level.  We used this technique in order to understand the behavior of these polymers during the enantiomeric separation process.  The influence of different solvents on the enantiomeric separation of N-,O-blocked amino acids will be examined upon separation.

Biography:

Dr. Nelu Grinberg is a Distinguished Scientist in the Chemical Development Department at Boehringer Ingelheim Pharmaceutical, Inc. in Ridgefield, CT.  Prior to this, he worked for sixteen years in the Analytical Department at Merck Research Laboratories in Rahway, NJ, where he was a Senior Research Fellow.  He has authored and coauthored over 90 publications, including articles and book chapters.  He is currently on the editorial board of the Journal of Liquid Chromatography and Related Techniques and is a Co-editor of the Advances in Chromatography series. He is also the President of Connecticut Separation Science Council, and he was the Course Director for a Short Course on Separation of Enantiomers at the Eastern Analytical Symposium and member of the Board of Directors of the Society of Small Molecule Science.  Dr. Grinberg obtained his Ph.D. in Chemistry from the Technical University of lasi in Romania. He conducted post­doctoral research with Professor Barry Karger at Northeastern University and with Professor E. Gil-Av at The Weizmann Institute of Science in Rehovot, Israel.

95 Gathering Place
865 North Colony Road
Wallingford, CT 06492
(203) 265-1552

Last Updated:  05/22/2008 11:08 PM