Hydrochloric Acid → 3-ethyl-7-fluoro-3,4-dihydroquinoxalin-2(1H)-one

HRID 1019818

Reaktionsgleichung

Reaktionsgleichung von HRID 1019818
[F:1][C:2]1[CH:7]=[CH:6][C:5]([NH:8][CH:9]([CH2:13][CH3:14])[C:10](O)=[O:11])=[C:4]([N+:15]([O-])=O)[CH:3]=1.Cl.C(O)C.O.O.[Sn](Cl)Cl>>[CH2:13]([CH:9]1[NH:8][C:5]2[C:4](=[CH:3][C:2]([F:1])=[CH:7][CH:6]=2)[NH:15][C:10]1=[O:11])[CH3:14]

Komponenten

5

Edukt 4

HCID 313Hydrochloric AcidHCID 702EthanolHCID 61436Stannous chloride dihydrateHCID 197943402-(4-Fluoro-2-nitrophenylamino)butanoic acid

Produkt 1

HCID 776236013-ethyl-7-fluoro-3,4-dihydroquinoxalin-2(1H)-oneAusbeute 41,8 %

Reaktionsbedingungen

Temperatur
78 °C

Versuchsvorschrift

The heterogeneous mixture of 2-(4-fluoro-2-nitrophenylamino)butanoic acid (181.7 g, 750.0 mmol), 3 N aq. HCl (750.0 ml, 2250 mmol), and ethanol (1923 ml, 750.0 mmol) in 5-L three neck round bottom flask was added Tin(II) chloride dihydrate (507.7 g, 2250 mmol) and the organe mixture was heated at 78° C. with stirring using an overhead stirrer for 4 h ([Note 1]: The orange heterogeneous mixture became an orange homogeneous mixture and the orange color changed to a red color over ˜2 hour). After 4 h, the mixture was cooled to rt and concentrated under reduced pressure to remove ethanol, and left at rt for 48 h. The resulting yellow precipitate was collected by filtration and washed with water (500 mL). The yellow solid was suspended in ice water (1 L) and the mixture was adjusted ˜pH 13 with KOH (˜250 g). The heterogeneous mixture was extracted with DCM (1 L×3). The combined organic layers were washed with water (1 L×1) and brine (1 L×1), dried over Na2SO4, filtered, and concentrated under reduced pressure to give 3-ethyl-7-fluoro-3,4-dihydroquinoxalin-2(1H)-one (60.92 g, 41.8% yield) as a light yellow solid. 1H NMR (400 MHz, DMSO-d6) δ ppm 10.26 (s, 1H), 6.68 (dd, J=8.6, 5.5 Hz, 1H), 6.47-6.61 (m, 2H), 5.95 (d, J=1.2 Hz, 1H), 3.62 (ddd, J=6.7, 5.0, 2.0 Hz, 1H), 1.50-1.72 (m, 2H), 0.92 (t, J=7.4 Hz, 3H), Mass Spectrum (ESI) m/e=195.1 (M+1).

Aufarbeitung

  1. customfor 4 h
  2. waitAfter 4 h
  3. temperaturethe mixture was cooled to rt
  4. concentrationconcentrated under reduced pressure
  5. customto remove ethanol
  6. waitleft at rt for 48 h
  7. filtrationThe resulting yellow precipitate was collected by filtration
  8. washwashed with water (500 mL)
  9. extractionThe heterogeneous mixture was extracted with DCM (1 L×3)
  10. washThe combined organic layers were washed with water (1 L×1) and brine (1 L×1)
  11. dry with materialdried over Na2SO4
  12. filtrationfiltered
  13. concentrationconcentrated under reduced pressure

Quellen und Nachweise

ORD-Eintrag
ord-5fc14cf1eaa243888e50cc4810c98670
Quelldatensatz
uspto-grants-2014_05
Patentnummer
US08716290B2

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