Modified chemotactic peptides: synthesis and activity of an azaTic-containing fMLP-OMe analogue

The synthesis and the biological activity of a pseudopeptide analogue of the chemotactic N-formyltripeptide fMLP-OMe, containing the azaTic (3,4-dihydro-2(1H)-phthalazinecarboxylic acid) residue replacing the native phenylalanine, is described. Whereas pseudopeptides containing linear alpha-azaamino acids are currently studied, data on the new group of analogues containing cyclic alpha-aza residues capable of limiting the rotameric distribution of the side chains (topological control) are just emerging in the literature. At our best knowledge, the here described [azaTic3]fMLP-OMe represents the first example of the introduction of this new type of alpha-aza residue into a natural bioactive peptide.