5-Chloro-1H-indazole-3-carboxylic acid

Application

5-Chloro-1H-indazole-3-carboxylic acid is an important pharmaceutical intermediate used to construct the core of active drug molecules.

Chemical Properties

Light yellow solid

Synthesis

1H-indazole-3-carboxylic acid was dissolved in anhydrous acetic acid in a three-necked flask, heated and stirred. After the substrate was dissolved and clarified, phosphorus oxychloride was dissolved in anhydrous acetic acid and slowly added dropwise. In an oil bath at 90°C, the mixture was condensed back into the chemical book and reacted for 14 hours. After the reaction was complete, a white precipitate was produced. It was cooled in an ice bath, vacuum filtered, and the solid was washed with ethyl acetate first and then with ether to obtain 5-Chloro-1H-indazole-3-carboxylic acid.

References

[1] Patent: WO2005/14554, 2005, A1. Location in patent: Page/Page column 60-61
[2] Patent: EP2565192, 2013, A1. Location in patent: Paragraph 0356
[3] Journal of Medicinal Chemistry, 2013, vol. 56, # 15, p. 6259 - 6272
[4] Patent: WO2015/103317, 2015, A1. Location in patent: Page/Page column 97