Methylglyoxal → 6-Bromo-2-methylquinoxaline

HRID 551546Notes

Reaction equation

HRID 551546 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([NH2:9])[C:5]([NH2:8])=[CH:6][CH:7]=1.[CH3:10][C:11]([CH:13]=O)=O>C(#N)C>[Br:1][C:2]1[CH:3]=[C:4]2[C:5](=[CH:6][CH:7]=1)[N:8]=[C:11]([CH3:13])[CH:10]=[N:9]2

Participants

4

Reactant 2

HCID 880MethylglyoxalHCID 3235934-Bromobenzene-1,2-diamine

Product 1

HCID 6142876-Bromo-2-methylquinoxaline

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

The product from Example 61A (9.4 g, 50 mmol) in acetonitrile (100 mL) was treated with 40% aqueous pyruvic aldehyde (11.0 mL, 60 mmol) dropwise. After stirring at room temperature for 2 hours, the mixture was concentrated and the residue was suspended in IPAc (100 mL) and filtered. The filtrate was washed with 20% brine, dried with Na2SO4, filtered, and the filtrate was concentrated. The residue was purified by silica gel column chromatography eluting with heptane:EtOH:MeOH (8:2:1) to provide the title compounds. MS 224 (M+H)+; 1H NMR (400 MHz, CDCl3) δ 8.73 (s, 1H), 8.72 (s, 1H), 8.23 (d, J=2.2 Hz, 1H), 8.18 (d, J=2.1 Hz, 1H), 7.75-7.93 (m, 4H), 2.78 (s, 3H), 2.76 (s, 3H); 13C NMR (400 MHz, CDCl3) δ 154.32, 153.73, 146.34, 145.83, 142.28, 141.17, 140.45, 139.34, 133.17, 132.15, 131.15, 130.75, 130.16, 129.71, 123.66, 122.38, 22.89.

Workup

  1. concentrationthe mixture was concentrated
  2. filtrationfiltered
  3. washThe filtrate was washed with 20% brine
  4. dry with materialdried with Na2SO4
  5. filtrationfiltered
  6. concentrationthe filtrate was concentrated
  7. customThe residue was purified by silica gel column chromatography
  8. washeluting with heptane:EtOH:MeOH (8:2:1)

Sources & evidence

ORD record
ord-5e512423b29245e58185ac150ba5630c
Source dataset
uspto-grants-2011_05
Patent number
US07947711B2

Reaction notes

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