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 for receptor labelling.
