N-bromobutanimide → 1-Bromo-4-chloroimidazo[1,2-A]quinoxaline

HRID 1025476Notes

Reaction equation

HRID 1025476 reaction equation
[Cl:1][C:2]1[C:3]2[N:4]([CH:12]=[CH:13][N:14]=2)[C:5]2[C:10]([N:11]=1)=[CH:9][CH:8]=[CH:7][CH:6]=2.C1C(=O)N([Br:22])C(=O)C1>C1COCC1.CN1C(=O)CCC1>[Br:22][C:12]1[N:4]2[C:5]3[C:10]([N:11]=[C:2]([Cl:1])[C:3]2=[N:14][CH:13]=1)=[CH:9][CH:8]=[CH:7][CH:6]=3

Participants

4

Reactant 2

HCID 67184N-bromobutanimide2×HCID 107745254-chloroimidazo[1,2-a]quinoxaline

Product 1

HCID 717416391-Bromo-4-chloroimidazo[1,2-A]quinoxalineYield 87.4%

Reagents, catalysts & solvents 1

HCID 22156051tetrahydrofuran N-methylpyrrolidinoneSolvent

Procedure

To a stirred suspension of 4-chloro-imidazo[1,2-a]quinoxaline (28.9 g, 141.8 mmol) in THF/NMP 2:1 (300 mL) was added NBS (25.2 g, 141.8 mmol) in one portion at rt. After 18 h stirring, additional 12.6 g (70.9 mmol) NBS were added and the mixture was stirred for additional 2 h at rt. After removal of the THF portion of the organic phase by vacuum evaporation, water was added (500 mL). The precipitate was filtered and the residue was washed with water and dried to give 1-bromo-4-chloro-imidazo[1,2-a]quinoxaline as an off-white solid (35 g, 78.6%): 1H-NMR (300 MHz, d6-DMSO): δ=12.42 (1H, s), 8.19 (1H, s), 7.75 (1H, d), 7.44 (2H, m) ppm. UPLC-MS: RT=1.14 min; m/z 284.6 [MH+]; required MW=283.5.

Workup

  1. stirringthe mixture was stirred for additional 2 h at rt
  2. customAfter removal of the THF portion of the organic phase
  3. customby vacuum evaporation, water
  4. additionwas added (500 mL)
  5. filtrationThe precipitate was filtered
  6. washthe residue was washed with water
  7. customdried

Sources & evidence

ORD record
ord-b48d2f538d4c4589b156128307271d15
Source dataset
uspto-grants-2014_05
Patent number
US08729082B2

Reaction notes

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