Anwendung der Azirin/Oxazolon-Methode in der Peptid-Chemie: Synthese von Modell-Tripeptiden

Abstract

The Azirine/Oxazolone Method in Peptide Chemistry: Synthesis of Tripeptide Models
Tripeptides 5, containing an alpha,alpha-disubstituted alpha-amino acid and ethyl p-aminobenzoate, were synthesized in high yield by application of the azirine/oxazolone method (Table 2). In this versatile approach for the incorporation of disubstituted residues into the peptide chain, N-protected peptides or amino acids are coupled with 2,2-dialkyl-3-amino-2H-azirines and, after the selective hydrolysis of the newly formed C-terminal amide bond, further condensed with amino components via in situ generated oxazole-5(4H)-ones in the presence of additives (Scheme 1). A comparison with conventional procedures clearly demonstrates the advantages of this new method that works equally well with beta-branched, cyclic, or acyclic disubstituted amino acids.