16034-46-1

White to yellow solid

1-Methyl-5-pyrazolecarboxylic acid is a biochemical reagent that can be used as a biological material or organic compound for life science related research.

ChEBI: 1-methyl-pyrazole-5-carboxylic acid is a member of the class of pyrazoles that is N-methylpyrazole substituted by a carboxy group substituents at position 5. It has a role as a metabolite. It is a member of pyrazoles and a monocarboxylic acid. It is functionally related to a N-methylpyrazole.

1-Methyl-1H-pyrazole (2.0 g, 24.4 mmol) was dissolved in tetrahydrofuran (THF, 30 mL) at room temperature. The reaction mixture was cooled to -78 °C under nitrogen protection, followed by slow dropwise addition of n-butyllithium (n-BuLi, 10.72 mL, 26.8 mmol). The reaction temperature of -78 °C was maintained and the reaction mixture was stirred for 2 h. Subsequently, it was gradually warmed up to room temperature and stirring was continued for 1 h. The reaction temperature was maintained at -78 °C. Under the condition of maintaining the reaction temperature, dry carbon dioxide gas was passed into the reaction solution for about 5 minutes. The reaction mixture continued to be stirred at room temperature for 1 hour. Subsequently, water (30 mL) was added to the reaction mixture to quench the reaction and dilute the mixture. The reaction mixture was extracted with dichloromethane. After precipitation of a large amount of solid from the acidic aqueous phase, the separation was carried out by filtration. The resulting filter cake was dried to give a final 1.5 g of white solid product 1-methyl-1H-pyrazole-5-carboxylic acid in 48.8% yield.

[1] ACS Medicinal Chemistry Letters, 2015, vol. 6, # 6, p. 650 - 654
[2] Patent: CN105384739, 2016, A. Location in patent: Paragraph 0345; 0346; 0347
[3] Patent: WO2009/71705, 2009, A1. Location in patent: Page/Page column 39
[4] Patent: WO2009/71706, 2009, A1. Location in patent: Page/Page column 48
[5] Patent: US2008/242661, 2008, A1. Location in patent: Page/Page column 25