Potassium Carbonate → Ethyl 8-(benzyloxy)-2,6-dimethylimidazo[1,2-a]pyridine-3-carboxylate

HRID 1624105Notes

Reaction equation

HRID 1624105 reaction equation
[CH2:1]([O:8][C:9]1[C:10]2[N:11]([C:16]([C:20]([O:22][CH2:23][CH3:24])=[O:21])=[C:17]([CH3:19])[N:18]=2)[CH:12]=[C:13](Br)[CH:14]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[CH3:25]B1OB(C)OB(C)O1.C(=O)([O-])[O-].[K+].[K+]>O1CCOCC1.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>[CH2:1]([O:8][C:9]1[C:10]2[N:11]([C:16]([C:20]([O:22][CH2:23][CH3:24])=[O:21])=[C:17]([CH3:19])[N:18]=2)[CH:12]=[C:13]([CH3:25])[CH:14]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

6

Reactant 3

HCID 11430Potassium CarbonateHCID 574072TrimethylboroxineHCID 86717925Ethyl 8-(benzyloxy)-6-bromo-2-methylimidazo[1,2-a]pyridine-3-carboxylate

Product 1

HCID 86717926Ethyl 8-(benzyloxy)-2,6-dimethylimidazo[1,2-a]pyridine-3-carboxylate

Reagents, catalysts & solvents 2

HCID 178418397HCID 178418397, compoundCatalystHCID 312751,4-DioxaneSolvent

Procedure

Under argon, 105 g (270 mmol) of ethyl 8-(benzyloxy)-6-bromo-2-methylimidazo[1,2-a]pyridine-3-carboxylate Example 85A were suspended in 4.2 l of 1,4-dioxane, 135.4 g (539 mmol, purity 50%) of trimethylboroxine, 31.2 g (27 mmol) of tetrakis(triphenylphosphine)palladium(0) and 78.3 g (566 mmol) of potassium carbonate were added in succession and the mixture was stirred under reflux for 8 h. The reaction mixture was cooled to RT, the precipitate was filtered off over silica gel and the filtrate was concentrated. The residue was dissolved in dichloromethane and purified by silica gel chromatography (dichloromethane:ethyl acetate=9:1). This gave 74 g (84.6% of theory; purity 100%) of the target compound.

Workup

  1. temperatureunder reflux for 8 h
  2. filtrationthe precipitate was filtered off over silica gel
  3. concentrationthe filtrate was concentrated
  4. dissolutionThe residue was dissolved in dichloromethane
  5. custompurified by silica gel chromatography (dichloromethane:ethyl acetate=9:1)

Sources & evidence

ORD record
ord-8b844ded5e9b4bf6928c43f8fcc96075
Source dataset
uspto-grants-2014_07
Patent number
US08778964B2

Reaction notes

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