Synthesis of novel oxazol-based cyclic pseudopeptides as scaffolds for artificial receptors

ORGN 706

Áron Pintér, Pinter_Aron@web.de and Gebhard Haberhauer, gebhard.haberhauer@urz.uni-heidelberg.de. Organisch-Chemisches Institut, Ruprecht-Karls Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
Since the the early 90`s a variety of unusual macrocyclic peptide alkaloids have been isolated from marine sources. The Lissoclinum cyclopeptides incorporate three or four amino acids containing five membered heterocyclic rings in their backbones, which result from intramolecular condensation of serine, threonine or cysteine side chains. The conformationally constrained structure of these cyclic peptides suggested us to utilize them as platforms for artificial receptors. In our research work we turned our attention to the functionalization of similar cyclohexapeptides in the position 5 of the three oxazole rings. Our attempt led to a versatile scaffold suited for further transformation to variable C3-symmetrical artificial receptors, conical or cylindrical shaped macrocyclic cavitands. Advantages of this platform are the greater distance between receptor arm bridgeheads and the property that it is recyclable in case of benzyl-type side chains.