Hydrogen Bromide → 2-Bromo-3-nitrophenol

HRID 1632017Notes

Reaction equation

HRID 1632017 reaction equation
N[C:2]1[C:7]([N+:8]([O-:10])=[O:9])=[CH:6][CH:5]=[CH:4][C:3]=1[OH:11].[BrH:12].N([O-])=O.[Na+]>O.O1CCOCC1>[Br:12][C:2]1[C:7]([N+:8]([O-:10])=[O:9])=[CH:6][CH:5]=[CH:4][C:3]=1[OH:11]

Participants

6

Reactant 3

HCID 260Hydrogen BromideHCID 41154952-Amino-3-NitrophenolHCID 23668193Sodium Nitrite

Product 1

HCID 81672542-Bromo-3-nitrophenolYield 50%

Reagents, catalysts & solvents 2

HCID 962WaterSolvent2×HCID 312751,4-DioxaneSolvent

Conditions

Temperature
2.5 °C

Procedure

(Prepared by a modification of reported procedure, J. Org. Chem. 1988, 53, pp 1170-1176). To 2-amino-3-nitro-phenol (24.9 mmol, 1.0 eq.) in 24 mL of water and 12 mL of 1,4-dioxane at reflux, was added 13 mL of HBr (48% aq.) over 10 minutes. The resulting solution was refluxed for an additional 15 minutes, and cooled 0-5° C. A solution of sodium nitrite (24.4 mmol, 0.98 eq.) in 20 mL of water was added over 10 minutes, and stirred for 15 minutes. The reaction mixture was then heated to 60° C. for 15 minutes, and allowed to cool naturally to room temperature, and stirred for 16 hours. The reaction mixture was then extracted with two portions of diethyl ether, and the combined ethereal layers washed with brine, dried over magnesium sulfate, filtered through a layer of celite and concentrated. The residue was diluted with dichloromethane (with ˜0.1% MeOH), and purified via silica gel plug filtration with dichloromethane to yield 2-bromo-3-nitro-phenol (I-8, X═Br) as a pale orange-brown solid. Yield: 50%. 1H NMR (400 MHz; CDCl3): 6.07 (s, 1H), 7.25 (dd, J=8.4, 1.2 Hz, 1H), 7.37 (t, J=8.0 Hz, 1H), 7.48 (dd, J=8.0, 1.6 Hz, 1H) ppm.

Workup

  1. custom(Prepared by a modification of reported procedure, J
  2. temperatureThe resulting solution was refluxed for an additional 15 minutes
  3. temperatureThe reaction mixture was then heated to 60° C. for 15 minutes
  4. temperatureto cool naturally to room temperature
  5. stirringstirred for 16 hours
  6. extractionThe reaction mixture was then extracted with two portions of diethyl ether
  7. washthe combined ethereal layers washed with brine
  8. dry with materialdried over magnesium sulfate
  9. filtrationfiltered through a layer of celite and
  10. concentrationconcentrated
  11. additionThe residue was diluted with dichloromethane (with ˜0.1% MeOH)
  12. filtrationpurified via silica gel plug filtration with dichloromethane

Sources & evidence

ORD record
ord-ae2b53ebe66d402593ef7f20aaaf9adc
Source dataset
uspto-grants-2014_07
Patent number
US08791267B2

Reaction notes

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