ORGN 624 |
| Carbinolamides are a vital functionality in a variety of biological processes, most notably as an intermediate in the biosyntheses of mammalian peptide hormones. The studies presented here show the effects of electron-donating and electron-withdrawing groups on the hydroxide-dependent reaction of N-(hydroxymethyl)benzamide. It has been established, that when electron-withdrawing groups are attached to the aromatic ring the reaction proceeds through a specific-base catalyzed deprotonation of the hydroxyl group, followed by rate-limiting breakdown to the acyl amide anion and formaldehyde. Both a Ka and a rate for the breakdown of the deprotonated carbinolamide (k1) can be determined and a plot of log (k1X/k1H), when X is an electron-withdrawing group, leads to a linear correlation. However, when electron-donationg are placed on the aromatic ring the k1 values obtained from the fit of kobsd vs. [HO-] no longer fit on the same correlation. The results of the kinetic investigations and the reasons for this non-linear Hammett correlation will be discussed. |
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Physical Organic Chemistry: Calculations, Mechanisms, Photochemistry, and High-Energy Species
8:00 AM-12:00 PM, Thursday, 30 March 2006 Georgia World Congress Center -- C303, Oral
Division of Organic Chemistry |