Phosphorus oxychloride → 8-Bromo-2-chloroquinoxaline

HRID 1056030Notes

Reaction equation

HRID 1056030 reaction equation
[Br:1][C:2]1[CH:3]=[CH:4][CH:5]=[C:6]2[C:11]=1[NH:10][C:9](=O)[CH:8]=[N:7]2.P(Cl)(Cl)([Cl:15])=O>>[Br:1][C:2]1[CH:3]=[CH:4][CH:5]=[C:6]2[C:11]=1[N:10]=[C:9]([Cl:15])[CH:8]=[N:7]2

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 593927088-Bromoquinoxalin-2(1H)-one

Product 1

HCID 593926708-Bromo-2-chloroquinoxalineYield 55%

Conditions

Temperature
50 °C

Procedure

A mixture of 8-bromoquinoxalin-2(1H)-one (483 mg, 2.146 mmol) in phosphoryl trichloride (100 mL) was heated to 50° C. for 2 h. The crude material was concentrated to remove the POCl3, diluted with EtOAc (150 ml), added to a separatory funnel, and washed with water (2×100 ml) and saturated aq. NaHCO3 (100 ml) before the organic layer was separated, dried over Na2SO4, and concentrated. The mixture and was adsorbed onto silica and was purified via automated flash chromatography (silica gel) with 100% hexanes to 5% EtOAc/hexanes to give 8-bromo-2-chloroquinoxaline (210e, 55% yield) as an off-white solid. MS (ESI, pos. ion) m/z: 243.0/245 (M+1).

Workup

  1. concentrationThe crude material was concentrated
  2. customto remove the POCl3
  3. additiondiluted with EtOAc (150 ml)
  4. additionadded to a separatory funnel
  5. washwashed with water (2×100 ml) and saturated aq. NaHCO3 (100 ml) before the organic layer
  6. customwas separated
  7. dry with materialdried over Na2SO4
  8. concentrationconcentrated
  9. customwas purified

Sources & evidence

ORD record
ord-9a3a22c803ad469cb284cc8756df4919
Source dataset
uspto-grants-2016_07
Patent number
US09394297B2

Reaction notes

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