3-Bromo-2-chloro-5-nitropyridine → 3-Bromo-2-fluoro-5-nitropyridine

HRID 367098Notes

Reaction equation

HRID 367098 reaction equation
[Br:1][C:2]1[C:3](Cl)=[N:4][CH:5]=[C:6]([N+:8]([O-:10])=[O:9])[CH:7]=1.[F-:12].[K+]>[Br-].C1([P+](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C(#N)C>[Br:1][C:2]1[C:3]([F:12])=[N:4][CH:5]=[C:6]([N+:8]([O-:10])=[O:9])[CH:7]=1

Participants

5

Reactant 2

HCID 2308893-Bromo-2-chloro-5-nitropyridineHCID 522689Potassium Fluoride

Product 1

HCID 3451243-Bromo-2-fluoro-5-nitropyridineYield 56.8%

Reagents, catalysts & solvents 2

HCID 2724163Tetraphenylphosphonium BromideCatalystHCID 6342AcetonitrileSolvent

Procedure

3-Bromo-2-chloro-5-nitropyridine (119 g, 0.500 mol, prepared according to V. Koch and S. Schnatterer, Synthesis, 1990, 497-498), potassium fluoride (79.5 g, 1.37 mol), and tetraphenylphosphonium bromide (109 g, 0.260 mol) were combined in acetonitrile (1.5 L) and heated at reflux for 4 days until GLC indicated complete consumption of the 3-bromo-2-chloro-5-nitropyridine. The volume of the mixture was reduced to 750 mL in vacuo, then the residual liquid was diluted with 2 L of ether. The mixture was filtered and the filtrate concentrated. The residue was triturated with hot hexane, and the combined hexane extracts were concentrated to give 62.8 g (54%) of the title compound: 1H NMR (DMSO-d6 300 MHz) δ 9.14 (m, 2H).

Workup

  1. temperatureheated
  2. temperatureat reflux for 4 days until GLC
  3. customconsumption of the 3-bromo-2-chloro-5-nitropyridine
  4. additionthe residual liquid was diluted with 2 L of ether
  5. filtrationThe mixture was filtered
  6. concentrationthe filtrate concentrated
  7. customThe residue was triturated with hot hexane
  8. concentrationthe combined hexane extracts were concentrated

Sources & evidence

ORD record
ord-c8cdb94c0e694dd3ae4ebddffadb6662
Source dataset
uspto-grants-2000_10
Patent number
US06133253

Reaction notes

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