Ethanol → Ethyl 1H-pyrazole-3-carboxylate

Temperature

80 °C

To 1H-pyrazole-5-carboxylic acid (8.21 g, 73.2 mmol) in EtOH (100 mL) was added concentrated sulfuric acid (21.6 g, 220 mmol). The reaction mixture was heated to 80° C. for 16 hours. The mixture was cooled to ambient temperature and concentrated under reduced pressure. The residue was diluted with EtOAc (200 mL) and 2N NaOH aqueous solution was added until pH=8. The phases were separated and the organic phase was washed with saturated NaHCO3 aqueous solution (50 mL) and brine (20 mL), dried (Na2SO4), and concentrated to give the product (6.36 g).

1. temperatureThe mixture was cooled to ambient temperature
2. concentrationconcentrated under reduced pressure
3. additionThe residue was diluted with EtOAc (200 mL) and 2N NaOH aqueous solution
4. additionwas added until pH=8
5. customThe phases were separated
6. washthe organic phase was washed with saturated NaHCO3 aqueous solution (50 mL) and brine (20 mL)
7. dry with materialdried (Na2SO4)
8. concentrationconcentrated

ORD record

ord-8c90ee69889d441dad802834e733ce69

Source dataset

uspto-grants-2014_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08841455B2