Reaktion #88512

Reaktionsgleichung

5-bromo-2-chloro-3-fluoropyridine

tert-butyl carbamate

cesium carbonate

→

title compound

Ausbeute 86.0%

(6-Chloro-5-fluoropyridin-3-yl)-carbamic acid tert-butyl ester

Ausbeute 86.0%

Lösungsmittel

dioxane

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction mixture was cooled to ambient temperature
2. 2
   Sonstigethe resultant solid was removed by filtration
3. 3
   WaschenThe resultant solid was washed with ethyl acetate
4. 4
   Einengenconcentrated in-vacuo
5. 5
   Sonstigeto afford a residue that
6. 6
   Sonstigewas purified by flash chromatography (silica: cyclohexane to 25% ethyl acetate/cyclohexane)

Vorschrift

A degassed mixture of 5-bromo-2-chloro-3-fluoropyridine (22.5 g, 107 mmol), tert-butyl carbamate (13.8 g, 117.5 mmol), tris(dibenzylideneacetone) dipalladium(0) (2.95 g, 3.2 mmol), XantPhos (2.48 g, 4.28 mmol) and cesium carbonate (69.7 g, 214 mmol) in dioxane (340 mL) was heated at 85° C. for 24 hours. The reaction mixture was cooled to ambient temperature and the resultant solid was removed by filtration. The resultant solid was washed with ethyl acetate followed by dichloromethane and the filtrate was combined and concentrated in-vacuo to afford a residue that was purified by flash chromatography (silica: cyclohexane to 25% ethyl acetate/cyclohexane) to afford the title compound as a pale yellow solid (22.6 g, 86%). 1H NMR (300 MHz, CDCl3): 8.04 (dd, J=10.1, 2.4 Hz, 1H), 7.98 (d, J=2.4 Hz, 1H), 6.62 (s, 1H), 1.53 (s, 9H).

Quelle