ORGN 163 |
| It is well known that Nb-alkyl tryptophan alkyl esters undergo the Pictet-Spengler reaction with aldehydes to furnish both cis- and trans-1,2,3,4-tetrahydro-β-carbolines, with the trans isomer predominating. Epimerization at C-1 takes place under acidic conditions to produce, exclusively, the thermodynamically more stable trans diastereomer, potentially through a carbocationic intermediate. The epimerization rate has been shown to be sensitive to electronic effects directed toward the C-1 position. In order to determine if the carbocationic intermediate does indeed exist, rate data was obtained for a series of tri-substituted 1-phenyl-1,2,3,4-tetrahydro-β-carbolines. This rate data was applied to the Hammett relationship and σ and σ+ values were compared. |
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Physical Organic Chemistry, Combinatorial and Process Chemistry, New Reactions and Methodology, Peptides, Proteins and Amino Acids
8:00 PM-10:00 PM, Sunday, April 6, 2008 Morial Convention Center -- Hall A, Poster
Division of Organic Chemistry |