The reaction of 4-methyl-pyrrolidin-2-ones, chlorinated at the C (3) and C (6) positions, with n-propylamine constitutes a new method for the preparation of 5-propylimino-pyrrolidin-2- ones or 3-pyrrolin-2-ones in generally good yields. The transformation involves a series of eliminations, substitutions and double bond shifts. This constitutes a remarkable example of a functional rearrangement.