Pyrolysis of enaminone derivatives of 1,2-ethylenediamine

Enaminones are applied as synthons in the preparation of heterocyclic compounds [1, 2]. Their properties depend essentially on the character of the amine fragment of the molecule. In this study we showed that the enaminones obtained from acetylacetone and monosubstituted 1,2-ethylenediamines at 200–250°С suffer a thermal cleavage to give acetone and N-substituted imidazolines. The reaction apparently proceeds along a mechanism similar to that of the ester cleavage of β-dicarbonyl compounds.