Sodium Hydroxide → 1-Methyl-1H-pyrazole-4-carboxylic acid

Temperature

25 °C

A solution of 1-methyl-1H-pyrazole-4-carboxylic acid ethyl ester (480 mg, 3.1 mmol) in ethanol cooled to 0° C. was treated with a 1N aqueous sodium hydroxide solution (9.3 mL, 9.3 mmol). The reaction was stirred at 25° C. for 18 h. At this time, the reaction was concentrated in vacuo and then acidified to pH=2 with a 1N aqueous hydrochloric acid solution. The product was extracted into ethyl acetate (2×50 mL). The organics were washed with a saturated aqueous sodium chloride solution (1×25 mL), dried over magnesium sulfate, filtered, and dried in vacuo to afford 1-methyl-1H-pyrazole-4-carboxylic acid (293 mg, 74.6%) as a white solid: EI-HRMS m/e calcd for C5H6N2O2 (M+) 126.0429, found 126.0429.

1. concentrationAt this time, the reaction was concentrated in vacuo
2. extractionThe product was extracted into ethyl acetate (2×50 mL)
3. washThe organics were washed with a saturated aqueous sodium chloride solution (1×25 mL)
4. dry with materialdried over magnesium sulfate
5. filtrationfiltered
6. customdried in vacuo

ORD record

ord-0db9bced1e5e4e528485cc140976f32e

Source dataset

uspto-grants-2006_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07135475B2