In the chemical reaction process, reaction time, type of solvent, can easily affect the result of the reaction, thereby determining the yield and properties of the reaction product. An updated downstream synthesis route of 2075-45-8 as follows. name: 4-Bromo-1H-pyrazole
Step 1 : 4-(Methylthio)-1H-pyrazole A suspension of 4-bromopyrazole (4 g, 27 mmol) in tetrahydrofuran (68 mL) was cooled to 0C and n-butyllithium (2.5 M in hexanes, 35.9 mL, 90 mmol) was added dropwise over a period of 20 min. The reaction mixture was stirred at room temperature for 1 h and then was cooled to 0C. 1 ,2-Dimethyldisulfide (2.66 mL, 30.0 mmol) was added dropwise. The reaction mixture was stirred at 0C for 1.5 h. The reaction mixture was poured into water (150 mL) and then it was acidified to pH~8 with a saturated aqueous solution of ammonium chloride and a solution of aqueous hydrochloric acid (1 N). The mixture was extracted with ethyl acetate (150 mL x 3) and the combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure to afford 4-(methylthio)-1 H-pyrazole (3300 mg). 1H NMR (500 MHz, CDCI3) delta 2.36 (s, 3H), 7.63 (s, 2H).
According to the analysis of related databases, 2075-45-8, the application of this compound in the production field has become more and more popular.
Reference:
Patent; PFIZER INC.; AHN, Kay; BOEHM, Markus; CABRAL, Shawn; CARPINO, Philip A.; FUTATSUGI, Kentaro; HEPWORTH, David; KUNG, Daniel W.; ORR, Suvi; WANG, Jian; WO2013/150416; (2013); A1;,
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