Conformational restriction through C3.0.CO;2-L/asset/equation/tex2gif-stack-1.gif?v=1&t=h5leb2yp&s=05f921c59c194fd223b94576c188aaf9338e6350" class="inlineGraphic"> ↔ C3.0.CO;2-L/asset/equation/tex2gif-stack-2.gif?v=1&t=h5leb2yp&s=ea458a66d72597739a309b78f89c3f87f71a63fe" class="inlineGraphic"> cyclization: Ac12c, the largest cycloaliphatic Cα,α- disubstituted glycine known

✍ Scribed by Michele Saviano; Rosa Iacovino; Valeria Menchise; Ettore Benedetti; Gian Maria Bonora; Maddalena Gatos; Laura Graci; Fernando Formaggio; Marco Crisma; Claudio Toniolo

• Publisher: Wiley (John Wiley & Sons)
• Year: 2000
• Tongue: English
• Weight: 184 KB
• Volume: 53
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/(sici)1097-0282(200002)53:2<200::aid-bip10>3.0.co;2-l

✦ Synopsis

Two complete series of N-protected, monodispersed oligopeptide esters to the pentamer level from 1-aminocyclododecane-1-carboxylic acid (Ac 12 c), an ␣-amino acid conformationally constrained through C i ␣ 7 C i ␣ cyclization, and either L-Ala or Aib residues, along with the N-protected Ac 12 c homopeptide alkylamide series from monomer to trimer, have been synthesized by solution methods and fully characterized. The solution-preferred conformations of these peptides have been assessed by Fourier transform ir absorption and 1 H-nmr techniques. Moreover, the molecular structures of one derivative (Z-Ac 12 c-OH) and three peptides [the tripeptide ester Z-L-Ala-Ac 12 c-L-Ala-OMe, the tripeptide alkylamide Z-(Ac 12 c) 3 -NHiPr, and the tetrapeptide ester Z-(Aib) 2 -Ac 12 c-Aib-OtBu (Aib, ␣-aminoisobutyric acid)] have been determined in the crystal state by x-ray diffraction. The results obtained point to the conclusion that ␤-bends and 3 10 -helices are preferentially adopted by peptides based on Ac 12 c, the largest cycloaliphatic C-disubstituted glycine