The alkylation of 5,5-pentamethylenehydantoin (I) with 1-bromo-2-chloroethane (II) by means of KOH in refluxing ethanol gives 3-(2-chloroethyl)-5,5-pentamethylenehydantoin (II), which is condensed with diethanolamine (IV) by means of NaI in hot DMF yielding 3-[2-[bis(2 hydroxyethyl)amino]ethyl] 5,5-pentamethylenehydantoin (V) Finally, this compound is treated with hot POCl3.