Phosphorus tribromide → 5-Bromo-4-(bromomethyl)-1-(tert-butyl)-1H-pyrazole
Reaktionsgleichung
[Br:1][C:2]1[N:6]([C:7]([CH3:10])([CH3:9])[CH3:8])[N:5]=[CH:4][C:3]=1[CH2:11]O.P(Br)(Br)[Br:14]>ClCCl>[Br:1][C:2]1[N:6]([C:7]([CH3:10])([CH3:9])[CH3:8])[N:5]=[CH:4][C:3]=1[CH2:11][Br:14]Komponenten
4
Edukt 2
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Reaktionsbedingungen
- Temperatur
- 0 °C
Versuchsvorschrift
A solution of (5-bromo-1-tert-butyl-1H-pyrazol-4-yl)methanol (460 mg, 1.97 mmol) in dichloromethane (25 mL) was cooled to 0° C. and then treated with phosphorus(III)bromide (0.37 mL, 3.46 mmol), dropwise, over 5 minutes. The mixture was stirred 30 minutes at 0° C. and then 1 hour at room temp. The mixture was quenched slowly with water (50 mL), stirred 30 minutes, and then extracted with ethyl acetate (2×50 mL). The organic phase was washed with saturated aqueous sodium bicarbonate (50 mL), dried over sodium sulfate, filtered and concentrated to yield 362 mg of 5-bromo-4-(bromomethyl)-1-tert-butyl-1H-pyrazole as a clear oil. 1H NMR (400 MHz, CDCl3, δ): 7.54 (s, 1H), 4.39 (s, 2H), 1.74 (s, 9H).