New investigation of the reaction of 2-amino-2-oxazolines with isocyanates and isothiocyanates. Evidence of a transposition during the second step

The reaction of some 2-amino-2-oxazolines with isocyanates and arylisothiocyanates yields 3-monosubstituted or 2,3-disubstituted 2-iminooxazolidines depending on the experimental conditions and on the nature of the electrophile reactants. The structures of a mono- and a disubstituted derivative were established by X-ray analysis. The chemical behaviour of the compounds was investigated by molecular and quantum mechanics calculations. An intramolecular transposition during the second step of the reaction was found.