Intramolecular cyclization of the N - (2 - chloroethylcarbamoyl) derivatives of glycine, valine and phenylalanine give imidazolidone, oxazoline and hydantoin derivatives. The imidazolidone and oxazoline derivatives possess alkylating activity toward NBP. but the hydantoins do not. N - (2 - Chloroethylcarbamoyl)glycine reacts with the mercapto group of cysteine; thus, this alkylating group may be useful