31230-17-8

1118-61-2

31230-17-8

General procedure for the synthesis of 3-amino-5-methyl-1H-pyrazole from 3-aminobut-2-enenenitrile: 10 g of 3-aminobut-2-enenitrile and 5 L of ethanol were added to a 10 L reaction flask and stirred until completely dissolved. Subsequently, 2500 g of 80% hydrazine hydrate was added. After stirring at room temperature for 10-20 minutes, the reaction was slowly heated to reflux, keeping the reaction temperature between 85-95 °C. Note: A large amount of gas is generated during the reaction. When the reaction has been carried out for 1.5-2.5 hours, confirm the complete reaction of the feedstock by TLC monitoring. Upon completion of the reaction, the reaction solution is concentrated under reduced pressure at 50-60°C to 20-30% of the original volume. Finally, a light yellow liquid (converted to a light yellow solid after cooling) was obtained by oil pump distillation in a yield of 2230 g with 94.2% yield. The purity of 3-amino-5-methyl-1H-pyrazole was higher than 98% and the content of single impurity was lower than 0.5% by GC and HPLC analysis.