Nitric Acid → 2-Bromo-1,3-difluoro-4-nitrobenzene

HRID 891848Notes

Reaction equation

HRID 891848 reaction equation
[F:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([F:8])[C:3]=1[Br:9].[N+:10]([O-])([OH:12])=[O:11]>S(=O)(=O)(O)O.O>[Br:9][C:3]1[C:2]([F:1])=[C:7]([N+:10]([O-:12])=[O:11])[CH:6]=[CH:5][C:4]=1[F:8]

Participants

5

Reactant 2

HCID 944Nitric AcidHCID 1235571-Bromo-2,6-difluorobenzene

Product 1

HCID 137327452-Bromo-1,3-difluoro-4-nitrobenzeneYield 94%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 1118Sulfuric AcidSolvent2×

Procedure

A mixture of 2,6-difluorobromobenzene (125.5 g, 650 mmol) in 98% sulphuric acid (250 ml) was cooled in an ice-water bath and then treated with a 1:1 mixture of 98% sulphuric acid and fuming nitric acid (100 ml) added at such a rate that the internal temperature never exceeded 35° C. Once addition was complete the reaction was stirred at ambient temperature for 3 h then poured onto ice. This mixture was diluted with water (final volume 5 l), the resulting solid collected by filtration, washed with water, then dried under vacuum over phosphorus pentoxide, to afford 2-bromo-1,3-difluoro-4-nitrobenzene as a cream-coloured solid (145 g, 94%): 1H NMR (360 MHz, CDCl3) δ 7.10–7.15 (1H, m), 8.09–8.16 (1H, m).

Workup

  1. temperaturewas cooled in an ice-water bath
  2. additionadded at such a rate that the internal temperature never exceeded 35° C
  3. additionOnce addition
  4. additionthen poured onto ice
  5. filtrationcollected by filtration
  6. washwashed with water
  7. dry with materialdried under vacuum over phosphorus pentoxide

Sources & evidence

ORD record
ord-eb2c2d030080436ba15d150f050a8619
Source dataset
uspto-grants-2006_02
Patent number
US07005431B2

Reaction notes

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