2,6-Dibromopyridine → 2-Bromo-6-cyclopentylpyridine

HRID 1796020Notes

Reaction equation

HRID 1796020 reaction equation
Br[C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([Br:8])[N:3]=1.[Br-].[CH:10]1([Zn+])[CH2:14][CH2:13][CH2:12][CH2:11]1>C(OCC)(=O)C.C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1>[Br:8][C:4]1[CH:5]=[CH:6][CH:7]=[C:2]([CH:10]2[CH2:14][CH2:13][CH2:12][CH2:11]2)[N:3]=1

Participants

5

Reactant 2

HCID 122742,6-DibromopyridineHCID 178419768HCID 178419768, compound

Product 1

HCID 221807702-Bromo-6-cyclopentylpyridine

Reagents, catalysts & solvents 2

HCID 178418397HCID 178418397, compoundCatalystHCID 8857Ethyl AcetateSolvent

Procedure

To 2,6-dibromopyridine (5.9 g, 25 mmol) and tetrakis(triphenylphosphine)palladium(0) (1.4 g, 1.2 mmol) was added cyclopentylzinc bromide (50 ml, 0.5 M solution in tetrahydrofuran) and the mixture heated at reflux for 18 h. The reaction was diluted with ethyl acetate and washed with water. The organic phase was separated, dried over magnesium sulfate, filtered and evaporated in vacuo to give an oil. The crude product was chromatographed on silica, eluting on a gradient from 1 to 5% methanol in dichloromethane, to give 2-bromo-6-cyclopentylpyridine (3.25 g) as a white solid: δH (400 MHz, CDCl3) 1.60-1.90 (6H, m), 2.09 (2H, m), 3.17 (1H, m), 7.12 (1H, d, J 7.4), 7.28 (1H, d, J 7.4), 7.44 (1H, t, J 7.2); m/z (ES+) 226:228 (1:1) (M++H).

Workup

  1. temperaturethe mixture heated
  2. temperatureat reflux for 18 h
  3. washwashed with water
  4. customThe organic phase was separated
  5. dry with materialdried over magnesium sulfate
  6. filtrationfiltered
  7. customevaporated in vacuo
  8. customto give an oil
  9. customThe crude product was chromatographed on silica
  10. washeluting on a gradient from 1 to 5% methanol in dichloromethane

Sources & evidence

ORD record
ord-a25407265d444a9bb3742ca2e2d2d71a
Source dataset
uspto-grants-2006_04
Patent number
US07030128B2

Reaction notes

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