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

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Reaction Steps

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.

Provenance & Evidence