(2,4-Dichlorophenyl)boronic acid → 8-(2,4-Dichlorophenyl)-2-ethyl-6-methylimidazo[1,2-a]pyrazine-3-carboxylic Acid Methyl Ester

HRID 501016Notes

Reaction equation

HRID 501016 reaction equation
[CH3:1][O:2][C:3]([C:5]1[N:9]2[CH:10]=[C:11]([CH3:15])[N:12]=[C:13](Br)[C:8]2=[N:7][C:6]=1[CH2:16][CH3:17])=[O:4].[Cl:18][C:19]1[CH:24]=[C:23]([Cl:25])[CH:22]=[CH:21][C:20]=1B(O)O>C1(C)C=CC=CC=1.CO>[CH3:1][O:2][C:3]([C:5]1[N:9]2[CH:10]=[C:11]([CH3:15])[N:12]=[C:13]([C:22]3[CH:21]=[CH:20][C:19]([Cl:18])=[CH:24][C:23]=3[Cl:25])[C:8]2=[N:7][C:6]=1[CH2:16][CH3:17])=[O:4]

Participants

5

Reactant 2

HCID 2734659(2,4-Dichlorophenyl)boronic acidHCID 865920608-Bromo-2-ethyl-6-methylimidazo[1,2-a]pyrazine-3-carboxylic Acid Methyl Ester

Product 1

HCID 684231488-(2,4-Dichlorophenyl)-2-ethyl-6-methylimidazo[1,2-a]pyrazine-3-carboxylic Acid Methyl EsterYield 107.4%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 1140TolueneSolvent

Procedure

8-Bromo-2-ethyl-6-methylimidazo[1,2-a]pyrazine-3-carboxylic acid methyl ester (0.30 g, 1.0 mmol) was dissolved in a mixed solvent of toluene (5.6 mL) and methanol (1.4 mL). Then 2,4-dichlorobenzeneboronic acid (0.382 g, 2.0 mmol) and tetrakistriphenylphosphine palladium complex (116 mg, 0.1 mmol) were added thereto, and the mixture was heated under reflux for 4 hours under nitrogen atmosphere. After the reaction mixture was allowed to cool, the solvent was removed. Then the residue was purified by silica gel column chromatography (n-hexane:ethyl acetate=5:1) to give the title compound (391 mg) as white crystals.

Workup

  1. temperaturethe mixture was heated
  2. temperatureunder reflux for 4 hours under nitrogen atmosphere
  3. temperatureto cool
  4. customthe solvent was removed
  5. customThen the residue was purified by silica gel column chromatography (n-hexane:ethyl acetate=5:1)

Sources & evidence

ORD record
ord-ec4d458f4e8543cd9de5858ab3d9785d
Source dataset
uspto-grants-2010_08
Patent number
US07772249B2

Reaction notes

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