Triethylamine → 4-Methylbenzo[f]quinoxaline-2,3(1H,4H)-dione

HRID 1494337Notes

Reaction equation

HRID 1494337 reaction equation
Br[C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[C:8]([N+:12]([O-])=O)=[C:7]([NH:15][CH3:16])[CH:6]=[CH:5]2.C(N(CC)CC)C.Cl.NC1C=CC2C(=CC=CC=2)C=1N.O.O.[C:39]([OH:44])(=O)[C:40](O)=[O:41]>C(O)C.Cl.[Pd]>[CH3:16][N:15]1[C:7]2[CH:6]=[CH:5][C:4]3[CH:3]=[CH:2][CH:11]=[CH:10][C:9]=3[C:8]=2[NH:12][C:40](=[O:41])[C:39]1=[O:44]

Participants

8

Reactant 4

HCID 8471TriethylamineHCID 61373Oxalic acid dihydrateHCID 12224794Naphthalene-1,2-diamine hydrochlorideHCID 198278026-Bromo-2-methylamino-1-nitronaphthalene

Product 1

HCID 198277974-Methylbenzo[f]quinoxaline-2,3(1H,4H)-dioneYield 92%

Reagents, catalysts & solvents 3

HCID 23938PalladiumCatalystHCID 313Hydrochloric AcidSolventHCID 702EthanolSolvent

Procedure

A suspension of 6-bromo-2-methylamino-1-nitronaphthalene (2.81 g, 10 mmol) and triethylamine (1.40 ml, 10 mmol) in 150 ml of 96% ethanol was hydrogenated at room temperature and atmospheric pressure in the presence of 5% palladium-on-carbon (500 mg) for 1 h. The solution was filtered directly into 50 ml of 4M hydrochloric acid under a nitrogen atmosphere. The acidic filtrate was evaporated to dryness and the solid diaminonaphthalene hydrochloride was refluxed with oxalic acid dihydrate (1.5 g, 11.9 mmol) in 25 ml of 4M hydrochloric acid without further purification. After reflux for 2 h the mixture was cooled, and the solid product was isolated by filtration and washed with water, ethanol and ether to give 2.07 g (92%) of the title compound. M.p. 332.7° C. (ethanol); IR (KBr): 1685 cm-1 ; 1H-NMR (DMSO-d6): 3.60 (s, 3H, CH3), 7.33-7.93 (m, 5H, ArH), 8.37-8.60 (m, 1H, ArH), 12.13 (broad s, 1H, NH); MS m/z: 226 (M+, 100%).

Workup

  1. customwas hydrogenated at room temperature
  2. filtrationThe solution was filtered directly into 50 ml of 4M hydrochloric acid under a nitrogen atmosphere
  3. customThe acidic filtrate was evaporated to dryness
  4. temperatureAfter reflux for 2 h the mixture
  5. temperaturewas cooled
  6. customthe solid product was isolated by filtration
  7. washwashed with water, ethanol and ether

Sources & evidence

ORD record
ord-162a0898f0834b4f9daaab29956707e0
Source dataset
uspto-grants-1991_06
Patent number
US05026704

Reaction notes

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