Instability of Amide Bond Comprising the 2-Aminotropone Moiety: Cleavable under Mild Acidic Conditions

An unusual hydrolysis/solvolysis of the classical acyclic amide bond, derived from N-troponylaminoethylglycine (Traeg) and α-amino acids, is described under mild acidic conditions. The reactivity of this amide bond is possibly owed to the protonation of the troponyl carbonyl functional group. The results suggest that the Traeg amino acid is a potential candidate for protecting and caging of the amine functional group of bioactive molecules via a cleavable amide bond.