Lithium Chloride → 2-Ethyl-3-(4-pyridyl)-imidazo[1,2-a]pyridine

HRID 2303651Notes

Reaction equation

HRID 2303651 reaction equation
Br[C:2]1[N:6]2[CH:7]=[CH:8][CH:9]=[CH:10][C:5]2=[N:4][C:3]=1[CH2:11][CH3:12].C([Sn](CCCC)(CCCC)[C:18]1[CH:23]=[CH:22][N:21]=[CH:20][CH:19]=1)CCC.[Cl-].[Li+]>C1(C)C=CC=CC=1.[Pd]>[CH2:11]([C:3]1[N:4]=[C:5]2[CH:10]=[CH:9][CH:8]=[CH:7][N:6]2[C:2]=1[C:18]1[CH:23]=[CH:22][N:21]=[CH:20][CH:19]=1)[CH3:12]

Participants

6

Reactant 3

HCID 433294Lithium ChlorideHCID 27373184-(Tri-n-butylstannyl)pyridineHCID 219127413-Bromo-2-ethyl-imidazo[1,2-a]pyridine

Product 1

HCID 219127892-Ethyl-3-(4-pyridyl)-imidazo[1,2-a]pyridineYield 38.7%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 1140TolueneSolvent

Procedure

To a solution of 3-bromo-2-ethyl-imidazo[1,2-a]pyridine (1.4 g, 6.28 mmol), 4-tributylstannylpyridine (2.31 g, 6.28 mmol) and Pd (II) (Ph3P)2Cl2 (442 mg, 0.63 mmol) in toluene (5 mL) was added lithium chloride (26.7 mg, 0.63). After refluxing for 18 h, the mixture was partitioned between ethyl acetate and aqueous sodium bicarbonate. The aqueous layer was extracted with ethyl acetate (3×). Combined organic phase was washed with brine and dried over anhydrous magnesium sulfate. Concentration followed by flash chromatography eluting with 100% ethyl acetate, then 10% methanol in methylene chloride afforded the title compound (543 mg) as a viscous oil.

Workup

  1. temperatureAfter refluxing for 18 h
  2. customthe mixture was partitioned between ethyl acetate and aqueous sodium bicarbonate
  3. extractionThe aqueous layer was extracted with ethyl acetate (3×)
  4. washCombined organic phase was washed with brine
  5. dry with materialdried over anhydrous magnesium sulfate
  6. concentrationConcentration
  7. washeluting with 100% ethyl acetate

Sources & evidence

ORD record
ord-1d062d17217641bea8c4651229d84109
Source dataset
uspto-grants-2002_08
Patent number
US06432981B1

Reaction notes

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