Novel iminium-type coupling agents containing proton acceptors in their iminium moiety, which can be used beneficially as coupling agents in various chemical polypeptide and/or polynucleotide syntheses, and are particularly useful as yield enhancing and racemization suppressing coupling agents for use in peptide syntheses, are disclosed. Further disclosed are a process of preparing such iminium-type coupling agents and their use in the preparation of polypeptides and/or polynucleotides.
The present invention provides 3-heterocyclyl[(heterocyclylmethoxy)imino]methyl}-oxadiazolinone derivatives of formula (I)
wherein A, T and X
1
to X
3
represent various substituents.