Unusual formation of imidazooxazolone in the reaction of 1-[(2-Acetylamino)ethyl]imidazolone with KSCN in the presence of AcOH

1-[(2-Acetylamino)ethyl]imidazolone was introduced for the first time in the condensation with KSCN in the presence of AcOH and imidazooxazolone was unexpectedly obtained. This result was possible only because of the unique character of 1-((2-Acetylamino)ethyl)imidazolone, which has an intramolecular N-H...O-H hydrogen bond and, therefore, reacts with the NCS anion to give only imidazooxazolone.