ORGN 483 |
| James E. Johnson, Houquan Dai, and Diana C. Canseco. Department of Chemistry and Physics, Texas Woman's University, P.O.Box 425859, Denton, TX 76204 |
| The acid-catalyzed Z/E isomerization of methyl O-methylbenzohydroximate [PhC(OCH3)=NOCH3] has been studied in acetonitrile using HCl and a variety of other acids. A plot of pkisomerization vs. pKa gives a straight line for the five weakest acids studied. The rates of Z/E isomerization with the two strongest acids (CF3SO3H and FSO3H) are identical. The rate of isomerization in HCl is 220 times faster than the rate of isomerization with an acid of comparable acidity that has a weakly nucleophilic counterion (CCl3COOH). This study has allowed us to calculate the % isomerization of the hydroximate by nucleophilic catalysis when HCl is the catalyst. We have also been able to calculate the pKa's of the conjugate acids of the Z and E hydroximates. |
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Heterocycles, Aromatics, Metal-Mediated Reactions, Physical Organic, Materials
9:00 AM-11:00 AM, Wednesday, March 26, 2003 Convention Center -- Hall I-1, Poster
Division of Organic Chemistry |