4-Nitropyrazole (cas:2075-46-9)

Uses 4-Nitropyrazole is a pharmaceutical and pesticide intermediate, and also an important intermediate for the synthesis of nitropyrazole-type energetic compounds. Synthesis method (1) Preparation of nitrosulfuric acid Mixture Take 19.3 mL (0.30 mol) of 20% fuming sulfuric acid and add it to a 100 mL four-necked flask. While stirring under an ice-water bath, slowly add 6.3 mL (0.15 mol) of fuming nitric acid to the four-necked flask using a dropping funnel, and control the temperature at 0-10℃. (2) Preparation of 4-Nitropyrazole Step 1: At room temperature, add 11 mL (0.21 mol) of concentrated sulfuric acid and 6.8 g (0.1 mol) of pyrazole to a 100 mL four-necked flask equipped with a stirrer and thermometer. After the addition is completed, stir at room temperature for 30 min. Step 2: Add 25 mL of nitrosulfuric acid mixture dropwise to the four-necked flask under an ice-water bath. After the addition is completed, raise the temperature to 50℃ and react for 1.5 h. The reaction solution was poured into 200 mL of ice water, and a large amount of white solid precipitated. After filtration, washing with ice water, and vacuum drying, the product 4-nitropyrazole was given by recrystallization from diethyl ether/hexane in 85% yield. Storage and Safety: 4-Nitropyrazole should be stored in a sealed container in a cool, dry place. Contact with oxidants should be avoided; its decomposition products include carbon monoxide, carbon dioxide, and nitrogen oxides.