cyclopropane-1,2-diamine

To a solution of NaN3 (163 g, 2.5 mol) in 300 mL water, 5 in 200 mL anhydrous acetone was added at 0°C in ice bathwith mechanic stirring. After the addition completed, thereaction mixture was kept at 0~5°C for another 3 hours.Then the mixture was poured into 750 mL ice water andstirred for half an hour, extracted with ether (400 mL3), anddried over MgSO4. After removal of solvent by vacuum, crude 6 was obtained. Without further purification, 500 mLtoluene was added and the mixture was slowly heated to refluxand maintained that temperature for another two hours.Then cooled to room temperature, the solution was slowlyadded to 400 mL concentrated hydrochloric acid in ice bath, and stirred at that temperature for half an hour and furtherheated to 60°C for another 2 hours. After removal of the waterby water knockout trap and toluene in vacuum respectively, the solid mass was recrystallized from absolute ethanoltwice (150 mL2), and a slight violet crystal was obtained(88 g, 61percent for 3 steps). 192°C decomposed (Lit. [21]190°C). 1H-NMR(300 MHz, D2O). 2.95-3.00 (2H, m), 1.50-1.59 (1H, m), 1.28- 1.35 (1H, m).