(2,4-Dichlorophenyl)boronic acid → 8-(2,4-Dichlorophenyl)-2-ethylimidazo[1,2-a]pyrazine-3-carboxylic acid methyl ester

HRID 501011Notes

Reaction equation

HRID 501011 reaction equation
[CH3:1][O:2][C:3]([C:5]1[N:9]2[CH:10]=[CH:11][N:12]=[C:13](Cl)[C:8]2=[N:7][C:6]=1[CH2:15][CH3:16])=[O:4].[Cl:17][C:18]1[CH:23]=[C:22]([Cl:24])[CH:21]=[CH:20][C:19]=1B(O)O>C1(C)C=CC=CC=1.CO>[CH3:1][O:2][C:3]([C:5]1[N:9]2[CH:10]=[CH:11][N:12]=[C:13]([C:21]3[CH:20]=[CH:19][C:18]([Cl:17])=[CH:23][C:22]=3[Cl:24])[C:8]2=[N:7][C:6]=1[CH2:15][CH3:16])=[O:4]

Participants

5

Reactant 2

HCID 2734659(2,4-Dichlorophenyl)boronic acidHCID 865920598-Chloro-2-ethylimidazo[1,2-a]pyrazine-3-carboxylic Acid Methyl Ester

Product 1

HCID 684225218-(2,4-Dichlorophenyl)-2-ethylimidazo[1,2-a]pyrazine-3-carboxylic acid methyl esterYield 77.4%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 1140TolueneSolvent

Procedure

8-Chloro-2-ethylimidazo[1,2-a]pyrazine-3-carboxylic methyl ester (0.92 g, 3.8 mmol) synthesized in Reference Example 1 was dissolved in a mixed solvent of toluene (32 mL) and methanol (8 mL), then 2,4-dichlorobenzeneboronic acid (1.49 g, 7.8 mmol) and tetrakistriphenylphosphine palladium complex (230 mg, 0.2 mmol) were added thereto, and the mixture was heated under reflux for 2 hours under nitrogen atmosphere. The reaction mixture was allowed to cool, and purified by silica gel column chromatography (n-hexane:ethyl acetate=3:1) to give the title compound (1.03 g) as a pale yellow crystals.

Workup

  1. temperaturethe mixture was heated
  2. temperatureunder reflux for 2 hours under nitrogen atmosphere
  3. temperatureto cool
  4. custompurified by silica gel column chromatography (n-hexane:ethyl acetate=3:1)

Sources & evidence

ORD record
ord-b2009eccce304ab698363cc22e1a4a41
Source dataset
uspto-grants-2010_08
Patent number
US07772249B2

Reaction notes

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