100665-27-8Relevant academic research and scientific papers
ENDOANNULAR INTERACTIONS IN CYSTEINE-CONTAINING CYCLOTRIPEPTIDES: ONE-STEP SYNTHESIS AND CRYSTAL STRUCTURE OF A TETRACYCLIC AZA-CYCLOL
Zanotti, Giancarlo,Pinnen, Francesco,Lucente, Gino,Cerrini, Silvio,Gavuzzo, Enrico
, p. 2647 - 2652 (2007/10/02)
Mild unmasking of the thiol group of the linear tripeptide N-chloroacetyl-S-t-butylthio-L-cysteinyl-L-phenylalanyl-L-proline p-nitrophenyl ester (8) with tributylphosphine in aqueous solution at room temperature gave, in one step, the tetrahedral adduct (aza-cyclol) (13).The same adduct was obtained starting from (R)-5-oxothiomorpholin-3-ylcarbonyl-L-phenylalanyl-L-proline p-nitrophenyl ester (12).The conformationally rigid polycyclic skeleton stabilizes the structure of the aza-cyclol (13) which is an example of a tetrahedral adduct derived from amide-amide interaction.Relevant conformational details, as revealed by an X-ray crystallographic analysis, are: the proline ring adopts a Cs-Cβendo conformation; the phenylalanine side-chain is extended towards its nitrogen; the proline Hα and hydroxylic hydrogen atom are in the characteristic planar W conformation.
