Water → 7-bromo-1H-quinoxalin-2-one

HRID 524369Notes

Reaction equation

HRID 524369 reaction equation
[NH:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[N:4]=[CH:3][C:2]1=[O:11].[Br:12]Br.O>C(O)(=O)C>[Br:12][C:8]1[CH:9]=[C:10]2[C:5]([N:4]=[CH:3][C:2](=[O:11])[NH:1]2)=[CH:6][CH:7]=1

Participants

5

Reactant 3

HCID 962WaterHCID 145262(1H)-QuinoxalinoneHCID 24408Bromine

Product 1

HCID 49132647-bromo-1H-quinoxalin-2-oneYield 66.2%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

To a stirred solution of 1H-quinoxalin-2-one (50 g, 342.5 mmol) in glacial acetic acid (2500 mL) was added bromine (54.7 g, 342.5 mmol in 120 mL acetic acid) over a period of 1.5 h at rt. After 18 h stirring, the mixture was slowly poured into 2000 mL water and stirred for 1 h at rt. The precipitate was filtered and the residue was washed with water and dried to give 7-bromo-1H-quinoxalin-2-one as an off-white solid (51 g, 66%): 1H-NMR (300 MHz, d6-DMSO): δ=12.42 (1H, s), 8.19 (1H, s), 7.75 (1H, d), 7.44 (2H, m) ppm.

Workup

  1. stirringstirred for 1 h at rt
  2. filtrationThe precipitate was filtered
  3. washthe residue was washed with water
  4. customdried

Sources & evidence

ORD record
ord-a0a102626e494a438b56e96fc3657bfa
Source dataset
uspto-grants-2016_05
Patent number
US09340528B2

Reaction notes

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