The general procedure for the synthesis of 1,3-dimethylimidazolidine-2-imine hydrochloride from 1,3-dimethyl-2-imidazolidinone was as follows: a mixture of 1,3-dimethyl-2-imidazolidinone (20.7 g, 0.18 mol) with triphosgene (15.14 g, 0.051 mol) in 50 mL of carbon tetrachloride was stirred for 5 hours at room temperature. Upon completion of the reaction, the precipitate was collected by filtration, washed with hexane and subsequently dried under vacuum. Ammonia (5 mL) was added to the resulting product in two portions at -50°C until the ammonia was completely evaporated. The final product was obtained as 4.4 g in 12% yield. The results of elemental analysis were as follows (calculated values correspond to C5H13N3Cl-NH4Cl, molecular weight 204.12): C, 29.42%; H, 8.39%; N, 27.45%; Cl, 34.74%. Measured values: C, 28.98%; H, 9.28%; N, 27.74%; Cl, 35.40%.
