Pyridone Dipeptides – Synthesis of a Novel Peptide Chromophore

Abstract Sequential elimination of two water molecules transfers the diols 2 and 3 into the pyridone dipeptide 1 . Both dehydration steps become part of the peptide synthesis under appropriate reaction conditions. A straightforward strategy for the incorporation of 1 in oligopeptide sequences is presented here. As part of the oligopeptide backbone, 1 has a local rigidifying effect which was studied in the cyclic octapeptides 16 and 25 . Both cyclopeptides exhibit conformational averaging although a fixed conformation was identified for the 1 ‐Phe tripeptide fragment of octapeptide 25 . The pyridone dipeptide 1 serves also as a fluorescence label and the UV/Vis‐spectroscopic properties of tetrapeptide 13 are investigated here. The peptide backbones of the two cyclic octapeptides 16 and 25 arrange a pair of chromophores 1 in close vicinity of each other. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)