Surface Modified Zirconia as Chiral Stationary Phases

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DESCRIPTION (provided by applicant): Our phase I work addressed one of the major current trends in HPLC - the development of materials for improved chiral chromatography. In response, we prepared two new classes of chiral stationary phases (CSPs). We prepared 10 different examples of the class wherein the chiral selector is covalently bonded to the surface of carbon-clad zirconia. Additionally, we prepared 26 different variants of the second class of CSP wherein the chiral selectors is bonded to the surface of zirconia through a Lewis acid/base coordinate covalent anchor group. We found that the second class of phase generally has much better chiral selectivity than the first and was very comparable to commercial phases based on related chiral selectors. Given the very different surface chemistry of zirconia we believe that Bronsted surface acid-base reactions with aminated drugs will be much less serious issues with zirconia based phases compared to silica-based phases. For these reasons phase II work will center on exploiting the newly developed Lewis acid-base anchored CSPs. Our four principal aims in phase II are: to extend our phase I work on 3 micron analytical HPLC particles unto 5, 7,10 and 25-micron particles for semi-prep and prep-scale LC, to scale-up production to the larger batch sizes, to characterize these larger particles made in bigger batches for their critical chromatographic properties (chiral selectivity, loading capacity, efficiency) and last to synthesize a series of Whelk O 1-like and alpha-Burke 2 emulator phases that can be used for rapid chiral selector screening in new HPLC method development to quickly determine the most appropriate type of chiral selector. To accomplish these goals we will subcontract the synthetic efforts to Prof. Tom Hoye of the University of Minnesota an international expert in the area of natural products synthetic chemistry.