Conformational Studies on Tocinamide and Deaminotocinamide by 220 MHz Nuclear Magnetic Resonance Spectroscopy

AUTOR(ES)

Brewster, Anne I.

RESUMO

The 220 MHz spectra of tocinamide and deaminotocinamide, the ring moieties of oxytocin and of deamino-oxytocin, respectively, were investigated in [U-2H]dimethylsulfoxide solution. Extensive decoupling and exchange experiments allow complete spectral assignment and determination of many coupling constants. Circular dichroism spectra assigned a right-hand screw sense to the C-S-S-C group. The conformations of tocinamide and deaminotocinamide are different from each other and from those suggested for the ring portions of oxytocin and deamino-oxytocin. The relationship of this difference to biological activity is commented upon. The importance of the interaction of the side chain with the ring in oxytocin and deamino-oxytocin is emphasized.

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