3-BROMO-1H-PYRAZOLE synthesis

Yield:14521-80-3 12.20 g

Reaction Conditions:

with potassium dichromate;hydrogen bromide at 5 - 15;

Steps:

2.1.2 Example 2
(1) 6.81 g (0.1 mol) of pyrazole was dissolved in 50.0% of hydrobromic acid (161.80 g, containing 1.0 mol of hydrogen bromide).Under stirring, the temperature is controlled at 5-15° C., and a 25.0% solution of potassium dichromate 47.07 g is added dropwise.After completion of the dropwise addition, the reaction temperature was controlled at 5-15° C. to allow the reaction system to undergo a bromination reaction. During the reaction, samples were taken at regular intervals and detected by high performance liquid chromatography.When it was detected that the mass of 3-bromopyrazole in the reaction system accounted for 93.0% of the total mass of organic matter in the reaction system, 4.31 g (0.06 mol) of ferrous oxide was added to terminate the reaction to obtain a feed liquid containing 3-bromopyrazole; (2) Add 73.5 g of chlorobenzene to the feed solution, stir and extract for 2 hours, let stand for 1 hour, take the organic phase and allow it to cool down to -15°C to -5°C,The solids were analyzed by elution from the organic phase. The resulting 12.20 g of solid was 3-bromopyrazole. The yield was calculated to be 83%. After the determination, the main content was 98.5%.

References:

Shandong Tianxin Chemical Co., Ltd.;Ju Youguo;Zhao Benteng;Wang Zewu;Yang Hanhua;Zhang Zhaoyuan;Liu Jian;Gong Fangxin CN107954913, 2018, A Location in patent:Paragraph 0017

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