Iodine → 2-fluoroquinoxaline

HRID 342889

Reaktionsgleichung

Reaktionsgleichung von HRID 342889
[N:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[N:4]=[CH:3][CH:2]=1.II.[F:13]F.C(=O)(O)[O-].[Na+]>S(S([O-])=O)([O-])(=O)=O.[Na+].[Na+]>[F:13][C:2]1[CH:3]=[N:4][C:5]2[C:10](=[CH:9][CH:8]=[CH:7][CH:6]=2)[N:1]=1

Komponenten

6

Edukt 4

HCID 807IodineHCID 7045QuinoxalineHCID 24524Fluorine2×HCID 516892Sodium Bicarbonate

Produkt 1

HCID 109425992-fluoroquinoxaline

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 656671Sodium PyrosulfiteLösungsmittel

Versuchsvorschrift

A solution containing quinoxaline (15.6 g), 120 mmol) and iodine (30.5 g, 120 mmol) in CF2ClCFCl2 (150 ml) was placed in a fluorination apparatus fitted with a drying tube filled with soda lime. Elemental fluorine (165 mmol) as a 10% mixture in nitrogen was then passed through the stirred solution using narrow bore PTFE tubing at ca. 40 ml/min. After the fluorine had been added the solution was poured into 10% aqueous sodium metabisulfite solution (300 ml), neutralised with sodium bicarbonate and continuously extracted with dichloromethane for 24 hours. The organic extracts were dried and evaporated to an oil (13.6 g). GC/MS analysis showed a 49% conversion of quinoxaline. The oil was purified by column chromatography on silica gel using dichloromethane as eluant to give pure 2-fluoroquinoxaline as a pale yellow oil (5.30 g, 62% based on 49% conversion); RF 0.53; δH (200 MHz; CDCl3 ; Me4Si) 7.7 ppm (2H, m), 7.9 (1H, m), 8.1 (1H, m), 8.67 (1H, d, JH,F 7.9, H-3); δF (250 MHZ; CDCl3 ; Me4Si) -75.1 ppm (s); δC (50.3 MHz, CDC13, Me4Si) 128.4 ppm (d, 4JC,F 1.6, C-8), 129.4 (s, C-7), 129.45 (s, C-6), 131.6 (s, C-5), 136.5 (d, 2JC,F 42.6, C-3), 139.72 (d, 3JC,F 10.9, C-8a), 141.52 (d 4JC,F 1.8, C-4a), 156.74 (d, 1JC-F 256.0, C-2); m/z (E1+) 148 (M+, 100), 129 (20), 121 (12), 103 (17), 76 (24), 50 (17); and 2,3-difluoroquinoxaline (0.27 g, 3%) as a pale yellow solid; RF 0.75; δH (400 MHz, CDCl3, Me4Si) 7.79 ppm (2H, m, Ar-H), 7.99 (2H, m, Ar-H); δC (50 MHz, CDCl3, Me4Si) 127.8 (s, C-8), 130.4 (s, C-7), 130.4 (s, C-7), 138.4 (d d, 3JC-F 5.4, C-4a), 146.1 (d d, 1JC-F 261.3,2JC-F 39.5, C-2); δF (235 MHz, CDCl3, CFCl3) -82.8 ppm (s); m/z (E1+) 166 (M+, 100%), 139 (11).

Aufarbeitung

  1. customfitted with a drying tube
  2. extractioncontinuously extracted with dichloromethane for 24 hours
  3. customThe organic extracts were dried
  4. customevaporated to an oil (13.6 g)
  5. customThe oil was purified by column chromatography on silica gel

Quellen und Nachweise

ORD-Eintrag
ord-078b5e1a60634932a34ef14427040a33
Quelldatensatz
uspto-grants-1999_01
Patentnummer
US05859255

Verknüpfte Notizen

Wird geladen…