Nitric Acid → 3,4-dihydro-1,3,3-trimethyl-6-nitroquinoxalin-2(1H)-one

HRID 990962Notes

Reaction equation

HRID 990962 reaction equation
[CH3:1][N:2]1[C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[NH:5][C:4]([CH3:13])([CH3:12])[C:3]1=[O:14].[N+:15]([O-])([OH:17])=[O:16].[OH-].[Na+]>OS(O)(=O)=O>[CH3:1][N:2]1[C:11]2[C:6](=[CH:7][C:8]([N+:15]([O-:17])=[O:16])=[CH:9][CH:10]=2)[NH:5][C:4]([CH3:12])([CH3:13])[C:3]1=[O:14]

Participants

5

Reactant 3

HCID 944Nitric AcidHCID 14798Sodium HydroxideHCID 31313661,3,3-Trimethyl-1,2,3,4-tetrahydroquinoxalin-2-one

Product 1

HCID 184161633,4-dihydro-1,3,3-trimethyl-6-nitroquinoxalin-2(1H)-oneYield 94%

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent2×

Conditions

Temperature
-15 °C

Procedure

In a 50-mL r.b. flask, a solution of 3,4-dihydro-1,3,3-trimethylquinoxalin-2(1H)-one (830 mg, 4.36 mmol) in 20 mL of conc. H2SO4 was cooled to −15° C. A solution of HNO3 (336 mg, 4.80 mmnol, 1.1 equiv) dissolved in conc. H2SO4 (1 mL) was then added dropwise via syringe in order to maintain a temperature below −5° C. After complete addition the reaction was allowed to stir at −15° C. for 15 min, warmed to rt, poured over NaOH (15 g) pellets and ice. After complete solution of the NaOH pellets, the red precipitate was filtered, redissolved in EtOAc (150 mL), washed with H2O (20 mL), brine (20 mL), dried (MgSO4), filtered, and concentrated to give a orange solid. No further purification is required to obtain 960 mg (94%) of 3,4-dihydro-1,3,3-trimethyl-6-nitroquinoxalin-2(1H)-one as an orange solid. Data for 3,4-dihydro-1,3,3-trimethyl-6-nitroquinoxalin-2 (1H)-one: 1H NMR (400 MHz, CDCl3) δ 7.76 (dd, J=8.8, 2.5, 1H), 7.55 (d, J=2.4, 1H), 6.96 (d, J=8.9, 1H), 4.04 (bs, 1H), 3.42 (s, 3H), 1.41 (s, 6H).

Workup

  1. additionwas then added dropwise via syringe in order
  2. temperatureto maintain a temperature below −5° C
  3. additionAfter complete addition the reaction
  4. temperaturewarmed to rt
  5. filtrationAfter complete solution of the NaOH pellets, the red precipitate was filtered
  6. dissolutionredissolved in EtOAc (150 mL)
  7. washwashed with H2O (20 mL), brine (20 mL)
  8. dry with materialdried (MgSO4)
  9. filtrationfiltered
  10. concentrationconcentrated
  11. customto give a orange solid
  12. customNo further purification

Sources & evidence

ORD record
ord-cfb0318d5a5342e9890d18fac40b3eba
Source dataset
uspto-grants-2002_10
Patent number
US06462038B1

Reaction notes

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