Aluminium lithium hydride → HCID 86662720, Verbindung

A solution (10 mL) of ethyl 1-(4-methoxyphenyl)-4-methyl-1H-pyrazole-3-carboxylate (2.7 g) synthesized in the above-mentioned (1) in tetrahydrofuran was added to an ice-cooled solution (20 mL) of lithium aluminum hydride (0.40 g) in tetrahydrofuran. The ice bath was removed, and the reaction mixture was stirred at room temperature for 1 hr. The mixture was ice-cooled again, and water (1.0 mL), 1N aqueous sodium hydroxide solution (5.0 mL) and water (1.0 mL) were successively added dropwise to quench the reaction. The residue was filtered through celite, and the filtrate was concentrated under reduced pressure to give a crude product (1.38 g) of 1-(4-methoxyphenyl)-4-methyl-1H-pyrazole-3-methanol as a pale-yellow oil. This was dissolved in toluene (30 mL), manganese dioxide (2.0 g) was added, and the mixture was heated under reflux with a Dean-Stark trap for 1 hr. The reaction mixture was allowed to cool to room temperature, and manganese dioxide was collected by filtration. The solvent was evaporated under reduced pressure to give the title object compound (0.96 g, 43%) as a yellow solid.

1. customThe ice bath was removed
2. temperaturecooled again
3. additionwater (1.0 mL), 1N aqueous sodium hydroxide solution (5.0 mL) and water (1.0 mL) were successively added dropwise
4. customto quench
5. customthe reaction
6. filtrationThe residue was filtered through celite
7. concentrationthe filtrate was concentrated under reduced pressure
8. customto give a crude product (1.38 g) of 1-(4-methoxyphenyl)-4-methyl-1H-pyrazole-3-methanol as a pale-yellow oil
9. temperaturethe mixture was heated
10. temperatureunder reflux with a Dean-Stark trap for 1 hr
11. temperatureto cool to room temperature
12. filtrationmanganese dioxide was collected by filtration
13. customThe solvent was evaporated under reduced pressure

ORD-Eintrag

ord-cb2c3928720841dab893d96758db6aee

Quelldatensatz

uspto-grants-2013_05

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08436043B2