Glycine, N-(5-fluoro-2-nitrophenyl)-, ethyl ester → 6-fluoro-1,2,3,4-tetrahydroquinoxalin-2-one

HRID 1736672Notes

Reaction equation

HRID 1736672 reaction equation
C([O:3][C:4](=O)[CH2:5][NH:6][C:7]1[CH:12]=[C:11]([F:13])[CH:10]=[CH:9][C:8]=1[N+:14]([O-])=O)C.[H][H]>[Pd].CO>[F:13][C:11]1[CH:12]=[C:7]2[C:8](=[CH:9][CH:10]=1)[NH:14][C:4](=[O:3])[CH2:5][NH:6]2

Participants

5

Reactant 2

HCID 10331949Glycine, N-(5-fluoro-2-nitrophenyl)-, ethyl esterHCID 178418361HCID 178418361, compound

Product 1

HCID 101035036-fluoro-1,2,3,4-tetrahydroquinoxalin-2-one

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalyst2×HCID 887MethanolSolvent

Procedure

A mixture of N-(5-fluoro-2-nitrophenyl)glycine ethyl ester (XI, EXAMPLE 5, 28.60 g), palladium on carbon (10%, 1.01 g) and methanol (500 ml) is shaken under 45 psi of hydrogen on a Parr shaker. After 2 hr an additional 0.54 g of 10% palladium on carbon catalyst is added. The mixture is shaken for an hour at 42 psi and then the catalyst is removed by filtration. p-Toluenesulfonic acid (0.314 g) is added to the filtrate. The solution is concentrated under reduced pressure to a volume of about 250 ml and then stirred at 20°-25°. The reaction is then further concentrated and dichloromethane is added. The solid that formed is collected and chromatographed on 800 ml of silica gel (column) eluting with dichloromethane/methanol (98/2). The appropriate fractions are pooled and concentrated and triturated with a small amount of dichloromethane. The solid is collected, dried, and triturated a second time with dichloromethane and redried to give the title compound, mp 176.0°-177.5°; NMR (CDCl3) 3.95, 3.99, 6.42, 6.63 and 8.33 δ.

Workup

  1. customthe catalyst is removed by filtration
  2. additionp-Toluenesulfonic acid (0.314 g) is added to the filtrate
  3. concentrationThe solution is concentrated under reduced pressure to a volume of about 250 ml
  4. stirringstirred at 20°-25°
  5. concentrationThe reaction is then further concentrated
  6. additiondichloromethane is added
  7. customThe solid that formed
  8. customis collected
  9. customchromatographed on 800 ml of silica gel (column)
  10. washeluting with dichloromethane/methanol (98/2)
  11. concentrationconcentrated
  12. customtriturated with a small amount of dichloromethane
  13. customThe solid is collected
  14. customdried
  15. customtriturated a second time with dichloromethane
  16. customredried

Sources & evidence

ORD record
ord-f425aaa756ea42e58a097a4100d43738
Source dataset
uspto-grants-1996_07
Patent number
US05541324

Reaction notes

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