ORGN 28 |
| Tatyana Voloshchuk, Nicola Farina, Paul Haberfield, and Alexander Greer. Department of Chemistry and The Graduate Center, The City University of New York (CUNY), Brooklyn College, Brooklyn, NY 11210 |
| This talk presents a new concept in the study of Nature that connects aspects of physical-organic chemistry to factors related to the biogenesis of natural substances. Approximately 7% of natural products possess bilateral symmetry, but the complexity of the molecules and their abundance across a range of structures has hampered the emergence of an understanding that connects phenomena that may be related. Whether bilateral symmetry is viewed as a structure concept or a property concept, a key aspect is the idea that this symmetry applies to a manifold of natural products tied to the building blocks from whence they arise. The coupling of aryl rings to give biaryl is an example of this construction. Theoretical calculations indicate that dimers evolve more energy per connecting bond than the corresponding trimers or tetramers would. This we propose is a guiding parameter that adjusts molecule growth. The corresponding trimers, tetramers, or high oligomers appear to represent "missing" compounds in Nature. By analogy, work in organic synthesis has recognized the usefulness of connecting two identical halves to simplify molecule synthesis. Aside from the fundamental interest in the biogenesis of natural substances, it is of special significance that bilateral symmetry is common among enzyme inhibitors. Recognition frequency may relate to a disparity to capture of molecules possessing bilateral vs unilateral symmetry with a special entropic advantage of the former. Of all the methods used to relate bioactivity, small molecule bilateral symmetry has received little attention. We anticipate the findings from this study will be useful to chemical creativity and guide in understanding Nature’s production of dimers and the role for potential manipulation of their biochemical properties. What remains to be done is to further understand the relationship between bilateral symmetry and the molecule’s potential to initiate a biological reaction. Evaluating borderline molecules, such as tubocurarine, is a next step to explore the possibility that bilaterally symmetrical molecules subsequently evolved to produce more specialized activity, by losing exact bilateral symmetry. It is also possible that bilateral symmetry in small molecules has functions analogous to the palindromic sequences found in some RNAs and DNAs. |
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Physical Organic Chemistry: Calculations, Mechanisms, Photochemistry and High Energy Species
8:00 AM-12:00 PM, Sunday, September 7, 2003 Sheraton New York -- Royal Ballroom A, Oral
Division of Organic Chemistry |