| preparation | synthetic N-Boc-cyclopropylhydrazine: cyclopropylamine (59.3g,1.04mol,10eq.), dichloromethane (180mL) and N-methylmorpholine (NMM,11.5g,0.114mol,1.1eq.) are sequentially added to a 500mL three-mouth flask, the ice salt bath was cooled to -5~0 ℃, and solid N-Boc-O-p-toluenesulfonyl hydroxylamine (BocHNOTs,29.8g,0.104mol,1.0eq.) was added in batches. After adding, the reaction was maintained at 0 ℃ for 2 hours, and the reaction endpoint was monitored overnight at room temperature (below 20 ℃). Stop the reaction, concentrate and dry, add dichloromethane and water to the crude product, after stratification, collect the organic phase, then extract the water layer twice with dichloromethane, combine the organic phase, dry, filter, concentrate to obtain crude product (21g, theoretical value 16.4g), crude product is beaten with petroleum ether to obtain light yellow solid (11g,67% yield), melting point 105.4~106.2 ℃. Preparation of cyclopropylhydrazine hydrochloride: add N-Boc-cyclopropylhydrazine (5g,29mmoL,1.0eq.) to a 100mL three-mouth flask, and drip concentrated hydrochloric acid (10mL) under ice water bath. After dropping, the reaction was carried out overnight at room temperature (20~25 ℃) (17~20 hours),TLC tracking and monitoring the reaction was completed, activated carbon was added to the reaction solution to decolorization, filtration, concentration of water phase to obtain 10g crude product, recrystallized with ethanol to obtain white crystal (2.4g,76% yield), melting point 131.6~132.6 ℃. |
