Dipole Interactions of Cyclic Peptide

Dipole Interactions of Cyclic Peptides wMi Aromatic Compounds... 

As mentioned above, dipole-dipole interactions such as hydrogen bonding and interactions with benzene are always involved in the conformational anatysis. In the following sections the conformational analysis wili be treated tc ether with weak interactions of cyclic peptides with low-molecular-weight substances such as dipole interactions. 

Conformation of Cyclic Peptides and Dipole-Dipole Interactions... 

On the other hand, the addition of benzene to the chloroform solution of Cyclo-(Sar2) and Cyclo-(Sar ly) caused upfield shifts of N-CH3 and resonance signals (77), although these cyclic peptides only have a cis peptide bond. The upfield shift implies the complex formation between the cyclic peptides and benzene. However, this complex may have been formed due to a dipole-induced dipole interaction, the latter being generated in benzene by the ac tiDn of a strong dipole of cyclic peptides. A/[tenzene], in which A represents the benzene-induced ft in ppm, was... 

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