Synthesis of natural product derivatives containing 2,4-concatenated oxazoles

Herein is described the synthesis of several oxazole-containing derivatives of IB-01211. The macrocyclization reaction of peptide 14 containing a concatenated triazole was successful and afforded 3 by amide bond formation. However, for those compounds containing quaterazoles or quinqueazoles, the oxazole ring had to be formed during macrocyclization. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).