N-(5-Fluoro-2-nitrophenyl)-2-methylalanine → 6-Fluoro-3,3-dimethyl-3,4-dihydro-1H-quinoxalin-2-one

HRID 1736717Notes

Reaction equation

HRID 1736717 reaction equation
[F:1][C:2]1[CH:3]=[CH:4][C:5]([N+:15]([O-])=O)=[C:6]([NH:8][C:9]([CH3:14])([C:11](O)=[O:12])[CH3:10])[CH:7]=1>C(O)C.[Pd]>[CH3:10][C:9]1([CH3:14])[NH:8][C:6]2[C:5](=[CH:4][CH:3]=[C:2]([F:1])[CH:7]=2)[NH:15][C:11]1=[O:12]

Participants

4

Reactant 1

HCID 22912907N-(5-Fluoro-2-nitrophenyl)-2-methylalanine

Product 1

HCID 229128926-Fluoro-3,3-dimethyl-3,4-dihydro-1H-quinoxalin-2-one

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 702EthanolSolvent

Procedure

N-(5-Fluoro-2-nitrophenyl)-2-methylalanine is taken up in approximately 1 L of ethanol and divided into two lots for reduction. The reductions are done with 1.7-1.9 g of palladium on carbon (10%) under hydrogen at initial pressures of 41 and 43 psi. After 4 hr the reaction is judged complete and the catalyst is filtered off. The filtrates are combined after concentration (with heating) to about 100 ml, then further concentrated. The crude product is chromatographed on silica gel (900 ml) eluting with ethyl acetate/dichloromethane (20/80), the appropriate fractions are pooled and concentrated to give the title compound which is crystallized from methanol/dichloromethane/hexane, mp 146°-148°.

Workup

  1. filtrationthe catalyst is filtered off
  2. concentrationafter concentration (with heating) to about 100 ml
  3. concentrationfurther concentrated
  4. customThe crude product is chromatographed on silica gel (900 ml)
  5. washeluting with ethyl acetate/dichloromethane (20/80)
  6. concentrationconcentrated

Sources & evidence

ORD record
ord-7c0c67b50d1145c38dff61531c9a2825
Source dataset
uspto-grants-1996_07
Patent number
US05541324

Reaction notes

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