Synthesis
To a 250 mL round bottom flask was added 4-(1H-pyrazol-1-yl)benzonitrile (2 g, 11.82 mmol), ethanol (40 mL), water (40 mL) and sodium hydroxide (705 mg, 17.63 mmol). The reaction mixture was stirred at 105 °C for 16 h and subsequently concentrated under reduced pressure. The residue was diluted with distilled water (30 mL) and extracted with ethyl acetate (50 mL). The pH of the aqueous phase was adjusted to 5 with 6.0 M hydrochloric acid.The precipitated solid was collected by filtration, washed with distilled water (10 mL) and dried in an oven to afford 4-(1H-pyrazol-1-yl)benzoic acid as a light yellow solid (1 g, 45% yield).LCMS (ESI): m/z 189 [M + H]+.
References
[1] Patent: US2016/185785, 2016, A1. Location in patent: Paragraph 2106; 2108
[2] Patent: US2016/185786, 2016, A1. Location in patent: Paragraph 0630