Chloropyrazine → Pyrazine, 2-phenyl-

HRID 482290

Reaktionsgleichung

Reaktionsgleichung von HRID 482290
Cl[C:2]1[CH:7]=[N:6][CH:5]=[CH:4][N:3]=1.[C:8]1([Mg]Br)[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1>C1COCC1.C1C=CC(P(C2C=CC=CC=2)CCP(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.Cl[Ni]Cl>[C:8]1([C:2]2[CH:7]=[N:6][CH:5]=[CH:4][N:3]=2)[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1

Komponenten

5

Edukt 2

HCID 73277ChloropyrazineHCID 178418255HCID 178418255, Verbindung

Produkt 1

HCID 642870Pyrazine, 2-phenyl-Ausbeute 39 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 2734542[1,2-Bis(diphenylphosphino)ethane]dichloronickel(II)KatalysatorHCID 8028TetrahydrofuranLösungsmittel

Versuchsvorschrift

Chloropyrazine (20.68 gram, 177 mmol) and [1,2-bis(diphenylphosphino)ethane]nickel(II) chloride (41.08 gram, 77.8 mmol) in dry THF (1.5 liter) were mixed and stirred for 80 minutes in a flask (cooled with a water bath) under nitrogen. A solution of phenylmagnesium bromide (3M in Et2O) (103 ml, 309 mmol) was added slowly through a dropping funnel into the cooled brick-red slurry at room temperature under nitrogen over 3.5 hours. After stirring at room temperature overnight, TLC showed that the reaction was complete. 3 N HCI (100 ml) was added slowly through a dropping funnel under nitrogen and the mixture was stirred for one hour. The THF layer was separated from the aqueous layer. The aqueous layer was adjusted to pH 12 with 6 N NaOH and extracted with EtOAc (100 ml, 3×). The organic fractions (THF and EtOAc) were combined and dried over MgSO4, filtered and concentrated to give a solid. The product was purified by flash chromatography on 300 g of flash grade silica gel in 2.5% EtOAc/CH2Cl2 to give 10.79 gram (69 mmol, 39%) of 2-phenylpyrazine, m.p. 69°-70° C.; FAB mass [M+1]+ 157;

Aufarbeitung

  1. temperature(cooled with a water bath) under nitrogen
  2. stirringAfter stirring at room temperature overnight
  3. addition3 N HCI (100 ml) was added slowly through a dropping funnel under nitrogen
  4. stirringthe mixture was stirred for one hour
  5. customThe THF layer was separated from the aqueous layer
  6. extractionextracted with EtOAc (100 ml, 3×)
  7. dry with materialdried over MgSO4
  8. filtrationfiltered
  9. concentrationconcentrated
  10. customto give a solid
  11. customThe product was purified by flash chromatography on 300 g of flash grade silica gel in 2.5% EtOAc/CH2Cl2

Quellen und Nachweise

ORD-Eintrag
ord-ba32755abd7c420a9096422057f19698
Quelldatensatz
uspto-grants-1998_08
Patentnummer
US05795894

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