ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The 1H-nmr spectra (270 MHz) of cyclic di- and tri-L-azatidine-2-carboxylic acid [cy-clo(L-Aze)2 and cyclo(L-Aze)3] were determined in CDCl3 and D2O and computer simulated. The spectral results were compared with those obtained with cyclo (L-Pro)2 and cyclo (L,-Pro)3. In CDCl3 and D2O solution, the four membered ring of cyclo (L-Aze)2 is puckered with the α-proton in a pseudo-axial position, and the φ angle is smaller in absolute value than -60°, as found for cyclo (L-Pro)2,. The puckering of the four-membered ring of cyclo(L,-Aze)3 in CDCl3 has the α-proton in a pseudo-equatorial position and φ angle larger in absolute value than -60°, in agreement with cyclo(L-Pro)3. In D2O, cyclo(L-Aze)3 was found to interconvert rapidly between different conformers. In the azetidine cyclic peptides studied, the range of values found for the φ angles was smaller than in the related proline cyclic peptides, indicating greater rigidity in the four-membered ring.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.1978.360171009
