2-Ethylbutyraldehyde → 1-[1-(Benzyloxy)-1H-pyrazol-5-yl]-2-ethylbutan-1-ol

Temperature

-78 °C

To 1-benzyloxy-1H-pyrazole (prepared as described in JOC 60:4996 1995) dissolved in THF (20 mL) and cooled to −78° C. under a nitrogen atmosphere was added a solution of n-butyllithium (1.6 M in hexane, 2.0 mL, 3.2 mmol) via syringe over 10 min. After stirring at the above temperature for 1.25 h, 2-ethyl-butyraldehyde (0.42 mL, 3.4 mmol) was added dropwise. The mixture was then stirred at −78° C. for 1.5 h and quenched by dropwise addition of saturated aqueous ammonium chloride solution (3 mL). The mixture was warmed to ambient temperature and diluted with EtOAc, washed with saturated aqueous NaCl and the organic phase was dried over MgSO4. Filtration and evaporation of the organic extract produced an oil that was purified on a Biotage column (hexane/EtOAc, 6:1) to give the product as a clear colorless oil (0.565 g, 72%).

1. stirringThe mixture was then stirred at −78° C. for 1.5 h
2. customquenched by dropwise addition of saturated aqueous ammonium chloride solution (3 mL)
3. temperatureThe mixture was warmed to ambient temperature
4. additiondiluted with EtOAc
5. washwashed with saturated aqueous NaCl
6. dry with materialthe organic phase was dried over MgSO4
7. filtrationFiltration and evaporation of the
8. extractionorganic extract
9. customproduced an oil that
10. customwas purified on a Biotage column (hexane/EtOAc, 6:1)

ORD record

ord-e4b8caaf70e24e7abd981bde71fb79a5

Source dataset

uspto-grants-2008_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07399778B2