ORGN 681 |
| Tetra hydroxy-prolinylmethyl derivatives of a tetra-sulfonated calix[4]resorcarene are effective chiral NMR solvating agents for water-soluble compounds with phenol, pyridyl, or naphthyl rings. The aromatic compounds form host-guest complexes with the calix[4]resorcarenes in water. Complexation of substrates with the calix[4]resorcarenes are likely promoted by hydrophobic effects. Aromatic resonances of the substrates show substantial upfield shifts because of shielding from the aromatic rings of the calix[4]resorcarene, and several resonances in the H-1 NMR spectra typically exhibit enantiomeric discrimination. The extent of enantiomeric discrimination depends in part on interactions of the substituent groups of the substrates with the hydroxy-prolinylmethyl groups of the calix[4]resorcarenes. The effectiveness of a calix[4]resorcarene prepared from cis-4-hydroxy-D-proline, cis-4-hydroxy-L-proline and trans-4-hydroxy-L-proline as a chiral NMR discriminating agents are compared to the L-prolinylmethyl derivative. |
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Asymmetric Reactions, Combinatorial Chemistry, Molecular Recognition and Self-Assembly, Proteins, Peptides, Amino Acids and Enzyme Inhibitors
8:00 PM-10:00 PM, Wednesday, March 28, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Organic Chemistry |