Reaktion #793798

Reaktionsgleichung

cesium carbonate

2-chloro-4-fluoropyridine

tert-butyl carbamate

cesium carbonate

→

tert-butyl 4-fluoropyridin-2-ylcarbamate

Ausbeute 70.1%

Lösungsmittel

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThis mixture was refluxed under nitrogen for 7 hours
2. 2
   Sonstigereaction to completion
3. 3
   Filtrationfiltered through Celite
4. 4
   Waschenthe Celite was washed with ethyl acetate
5. 5
   SonstigeThe filtrate was partitioned between saturated sodium bicarbonate and ethyl acetate
6. 6
   WaschenThe aqueous layer was washed with ethyl acetate twice
7. 7
   WaschenThe combined organics were washed with brine
8. 8
   Trocknendried with sodium sulfate
9. 9
   Einengenconcentrated under vacuum
10. 10
    Sonstigepurified by column chromatography

Vorschrift

A flask was charged with 2-chloro-4-fluoropyridine (20 g, 152 mmol), tert-butyl carbamate (89 g, 760 mmol), tris(dibenzylideneacetone)dipalladium (1.39 g, 1.52 mmol), X-PHOS (1.48 g, 3.10 mmol), cesium carbonate (99 g, 588 mmol), and tetrahydrofuran (500 mL) under an atmosphere of dry nitrogen. This mixture was refluxed under nitrogen for 7 hours. An additional equivalent of cesium carbonate was added to drive reaction to completion. The mixture was cooled to ambient temperature and filtered through Celite, and the Celite was washed with ethyl acetate. The filtrate was partitioned between saturated sodium bicarbonate and ethyl acetate. The aqueous layer was washed with ethyl acetate twice. The combined organics were washed with brine and dried with sodium sulfate, concentrated under vacuum, and purified by column chromatography to give tert-butyl 4-fluoropyridin-2-ylcarbamate as a pale yellow solid (22.6 g).

Quelle