The Synthesis of Conformationally Constrained Peptides and <i>Pseudo</i>-Peptides Incorporating an <i>Endo</i>-(2<i>S</i>,3<i>R</i>)-2-Amino-3-Carboxy-Norborn-5-ene Residue
作者:Iwan Jones、Wyn Jones、Michael North
DOI:10.1055/s-1997-706
日期:——
Methodology has been developed to carry out a Curtius rearrangement on enantiomerically pure amido-acids derived from (S)-proline esters. The resulting isocyanates were used to prepare conformationally constrained peptides incorporating and endo-(2S,3R)-2-amino-3-carboxy-norborn-5-ene residue.
Synthesis of Peptides and Pseudopeptides Incorporating an <i>endo-</i>(2<i>S</i>,3<i>R</i>)-Norborn-5-ene Residue as a Turn Inducer
作者:David E. Hibbs、Michael B. Hursthouse、Iwan G. Jones、Wyn Jones、K. M. Abdul Malik、Michael North
DOI:10.1021/jo9717651
日期:1998.3.1
The desymmetrization of endo-norborn-5-ene-2,3-dicarboxylic anhydride (5) by proline derivatives is used to prepare peptides and pseudopeptides incorporating an endo-(2S,3R)-2-amino-3-carboxynorborn-5-ene (1) residue. The peptides contain a single conformationally constrained beta-amino acid residue, while the pseudopeptides also contain a urea linkage and two peptide chains running in parallel directions. The key step in the synthesis is a Curtius rearrangement on the amido acids 6a,b to generate an isocyanate that is then directly reacted with suitably protected amino acids and peptides to give the peptides and pseudopeptides. The synthesis of the peptide analogue 4 is also described; in this compound, the two peptide chains run parallel to one another, and the stereochemistry of the norbornene unit within compound 4 was determined by X-ray analysis of the related peptide analogue 23.