ChemicalBook CAS DataBase List 6-Bromoindazole

6-Bromoindazole synthesis

5synthesis methods

Product Name:6-Bromoindazole
CAS Number:79762-54-2
Molecular formula:C7H5BrN2
Molecular Weight:197.03

57848-46-1

79762-54-2

General procedure for the synthesis of 6-bromo-1H-indazole from 4-bromo-2-fluorobenzaldehyde: Hydrazine hydrate (30 mL, 832 mmol) and 4-bromo-2-fluorobenzaldehyde (4.69 g, 23 mmol) were added to a 100 mL round bottom flask. The reaction mixture was stirred at 125 °C for 3 hours. Upon completion of the reaction, it was cooled to room temperature and the reaction solution was subsequently concentrated under reduced pressure. The concentrated reaction solution was quenched by pouring it into an ice-water mixture (100 mL) and then extracted with ethyl acetate (3 × 100 mL). The organic phases were combined, dried over anhydrous sodium sulfate, and filtered to remove the desiccant. The filtrate was concentrated to dryness under reduced pressure, and the resulting crude product was adsorbed on silica gel. The crude product was purified by column chromatography using a Redi-Sep pre-populated silica gel column (40 g) with hexane/ethyl acetate (0 to 100% gradient) as eluent to give the final 6-bromo-1H-indazole (4.6 g, 18 mmol, 76% yield). The product was detected by LCMS, [M + H]+ m/z 197.9 (calculated value C7H5BrN2 197.0).1H NMR (400 MHz, CD3OD): δ 8.03 (s, 1H), 7.67-7.72 (m, 2H), 7.24-7.26 (m, 1H).

57848-46-1
387 suppliers
$9.00/1g

79762-54-2
379 suppliers
$3.00/1g

Yield:79762-54-2 89.1%

Reaction Conditions:

with hydrazine hydrate for 20 h;Reflux;

Steps:

1.A Step A: 6-Bromoindazole
2-Fluoro-4-bromobenzaldehyde (20.0 g, 98.5 mmol) was suspended in hydrazine hydrate (100 mL) and heated under reflux for 20 hours. Cooling to room temperature to produce a large number of precipitates,The precipitate was collected by filtration and washed with water, and dried to give the title compound (17.3 g, 89.1%).

References:

Centaurus BioPharma Co., Ltd.;Liang, Zhi;Dai, Yusen;Wang, Juan;Liu, Bo;Chen, Yong;Kong, Fansheng;Luo, Hong;Xiao, Dengming;Han, Yongxin CN106146401, 2016, A Location in patent:Paragraph 0117; 0190; 0191

FullText

93777-26-5 Synthesis