Conformational studies of N-acetyl-N′-methylamide derivatives of α-aminobutyric acid,norvaline, and valine. I. Preferred conformations in solution as studied by 1H-nmr spectroscopy |
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Authors: | Toshimasa Yamazaki Akihiro Abe |
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Abstract: | The 1H-nmr studies were extensively carried out to elucidate preferred conformations of dipeptides CH3C*O—X—NHCH3, with X = Abu, nVal, and Val in various solvents. The vicinal 1H—1H coupling constants for the NH—CαH moiety and those around the Cα—Cβ bond in the articulated side chain provided the information regarding the average conformation of these molecules. The results indicate that transformation of skeletal conformations takes place in solution among conformers having similar dihedral angles, θ , in the Karplus expression. |
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