The synthesis of the decaendothiopeptide BOC-Trp-Ile-Ala-Aib-Ile-ValΨ [CSNH] Aib-Leu-Aib- Pro-OMe is described. The introduction of the thioamide group next to the bulky Aib occurred via a variation of the 'azirine/oxazolone method'without epimerisation. The structure of the decaendothiopeptide was etablished by single-crystal X-ray crystallography, thereby two types of helices could be observed.
