Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The formation of peptides upon 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide (EDC)‐promoted activation of <jats:italic>N</jats:italic>‐carbamoylamino acids (CAA), was considered in the scope of our recent works on carbodiimide promoted C‐terminus elongation of peptides in a prebiotic context. Thus EDC promoted activation of CAA derivatives of Tyr(Me) or Ala in dilute aqueous medium pH 5.5–6.5 in the presence of excess of AA, resulted in peptide formation by C‐terminus activation/elongation. Kinetic results similar to those of EDC‐mediated activation of <jats:italic>N</jats:italic>‐acyl‐AA lead us to postulate the formation of a 2‐amino‐5(4<jats:italic>H</jats:italic>)‐oxazolone intermediate by cyclization of the activated CAA, in spite of the absence of epimerization occurred at CAA residues. Thus, in a prebiotic context, CAA may have played a similar role as <jats:italic>N</jats:italic>‐acyl‐AA in the initiation of C‐terminus peptide elongation.</jats:p>