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

HRID 2275846Notes

Reaction equation

HRID 2275846 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 from Example 237A 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, cooled to RT, was filtered off from the precipitate 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. filtrationwas filtered off from the precipitate 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-91a3c64ee29d4cad8f5169641387ad16
Source dataset
uspto-grants-2015_09
Patent number
US09126998B2

Reaction notes

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