1H-Pyrazole-4-carboxaldehyde, 3,5-dimethyl-1-phenyl- → 4-(2-methoxy-vinyl)-3,5-dimethyl-1-phenyl-1H-pyrazole

Temperatur

0 °C

To an ice-cold suspension of methoxymethyltriphenylphosphonium chloride (26.2 g, 74.9 mmol) in 300 mL tetrahydrofuran was added n-butyllithium (31 mL, 2.5 M in hexane). The mixture was stirred at 0° C. for 15 minutes and treated with 3,5-dimethyl-1-phenyl-1H-pyrazole-4-carbaldehyde (7.5 g, 37.5 mmol, suspended in 150 mL tetrahydrofuran). The mixture was slowly warmed to room temperature over 2 hours and quenched by slow addition of a saturated aqueous sodium chloride solution. The resulting white precipitate was removed by filtration and the filtrate was extracted several times with ethyl acetate. The combined organic layers were dried over magnesium sulfate and concentrated in vacuo to an oil, which was purified via silica gel column chromatography (0-20% ethyl acetate in heptane) to provide the title compound as a yellow oil (7.09 g, 31.1 mmol, 83% yield) as a mixture of E:Z isomers.

1. temperatureThe mixture was slowly warmed to room temperature over 2 hours
2. customquenched by slow addition of a saturated aqueous sodium chloride solution
3. customThe resulting white precipitate was removed by filtration
4. extractionthe filtrate was extracted several times with ethyl acetate
5. dry with materialThe combined organic layers were dried over magnesium sulfate
6. concentrationconcentrated in vacuo to an oil, which
7. customwas purified via silica gel column chromatography (0-20% ethyl acetate in heptane)

ORD-Eintrag

ord-9d39607e47c940cc9d505e406a581900

Quelldatensatz

uspto-grants-2011_05

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07943652B2