Reaktion #1109034

Reaktionsgleichung

189b

tert-Butyl 4-(5-Bromopyrazin-2-yl)piperazine-1-carboxylate

diphenylmethanimine

(R)-(+)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl

Cs2CO3

→

189c

Ausbeute 75.2%

tert-Butyl 4-(5-(Diphenylmethyleneamino)pyrazin-2-yl)piperazine-1-carboxylate

Ausbeute 75.2%

Lösungsmittel

1,4-dioxane

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeA 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser
2. 2
   SonstigeAfter three cycles of vacuum/argon flush
3. 3
   TemperaturIt was then cooled to room temperature
4. 4
   Filtrationfiltered
5. 5
   EinengenThe filtrate was concentrated under reduced pressure
6. 6
   Sonstigethe resulting residue was purified by silica-gel column chromatography
7. 7
   Wascheneluting with 5:1 petroleum ether/ethyl acetate

Vorschrift

A 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 189b (3.3 g, 9.6 mmol), diphenylmethanimine (1.74 g, 9.6 mmol), palladium diacetate (440 mg, 0.48 mmol), (R)-(+)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (598 mg, 0.96 mmol), Cs2CO3 (6.2 g, 19.2 mmol), and 1,4-dioxane (80 mL). After three cycles of vacuum/argon flush, the mixture was heated at 115° C. for 64 h. It was then cooled to room temperature and filtered. The filtrate was concentrated under reduced pressure and the resulting residue was purified by silica-gel column chromatography eluting with 5:1 petroleum ether/ethyl acetate to afford 189c as a yellow solid (3.2 g, 75%). MS: [M+H]+ 444.2.

Quelle