10.1021/jo00828a075
The study investigates the intramolecular condensation reactions of 1,1,3,3-tetrakis(2-chloroethyl)urea (Ia). The researchers prepared Ia by reacting bis(2-chloroethyl)carbamoyl chloride with bis(2-chloroethyl)amine in refluxing benzene. Upon distillation, Ia unexpectedly transformed into 1,3-bis(2-chloroethyl)-2-imidazolidinone (IIa), indicating a rearrangement from a tetrasubstituted urea to an imidazolidinone structure. This transformation was further explored through alternative syntheses and reactions with other reagents. For instance, bis(2-chloroethyl)carbamoyl chloride was reacted with diethylamine to produce 1-(2-chloroethyl)-3-ethyl-2-imidazolidinone (IIc), and with pyrrolidine to yield 1-(4-chlorobutyl)-3-(2-chloroethyl)-2-imidazolidinone (IId). Additionally, the study examined the behavior of Ia in aqueous solution, where it underwent hydrolysis to form bis(2-[(2-chloroethyl)amino]ethyl) carbonate (V). The study provides insights into the reactivity and transformation pathways of these chloroethyl-containing ureas and imidazolidinones under different conditions.