5-Amino-1-(4-fluorophenyl)-1H-pyrazole-4-carboxylic acid

Synthesis

mmol) in a solvent mixture of methanol (200 mL). The reaction mixture was heated to reflux for 17 h, followed by cooling to room temperature and filtration. The filtrate was acidified with 2 N HCl solution to pH=7. The precipitated solid was collected by filtration and dried under reduced pressure to afford the target compound 5-amino-1-(4-fluorophenyl)-1H-pyrazole-4-carboxylic acid as a light yellow solid (18.64 g, 95% yield), which was used in subsequent reactions without further purification.

References

[1] Patent: WO2008/53136, 2008, A1. Location in patent: Page/Page column 36
[2] Bioorganic and Medicinal Chemistry Letters, 2016, vol. 26, # 20, p. 5032 - 5038
[3] Journal of Medicinal Chemistry, 2006, vol. 49, # 5, p. 1562 - 1575
[4] Patent: WO2008/74814, 2008, A1. Location in patent: Page/Page column 56
[5] Patent: WO2008/777, 2008, A2. Location in patent: Page/Page column 58-59