Br[C:2]1[CH:7]=[N:6][C:5]([CH3:8])=[CH:4][N:3]=1.[C:9]([O:13][C:14]([N:16]1[CH:20]=[CH:19][CH:18]=[C:17]1B(O)O)=[O:15])([CH3:12])([CH3:11])[CH3:10].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C(=O)([O-])[O-].[K+].[K+]>COCCOC.C([O-])(=O)C.[Pd+2].C([O-])(=O)C.C(OCC)(=O)C.O>[CH3:8][C:5]1[N:6]=[CH:7][C:2]([C:17]2[N:16]([C:14]([O:13][C:9]([CH3:12])([CH3:11])[CH3:10])=[O:15])[CH:20]=[CH:19][CH:18]=2)=[N:3][CH:4]=1Commercially available 2-bromo-5-methylpyrazine (260 mg, 1.50 mmol) and commercially available 1-(t-butoxycarbonyl)pyrrole-2-boronic acid (380 mg, 1.80 mmol) were dissolved in 1,2-dimethoxyethane (20 mL), and palladium (II) acetate (17.0 mg, 0.076 mmol), triphenylphosphine (79.0 mg, 0.301 mmol) and an aqueous potassium carbonate solution (1.5M, 2.0 mL, 3.00 mmol) were added, followed by stirring at 100° C. for 19 hours under nitrogen atmosphere. The reaction solution was cooled to room temperature, water (20 mL) and ethyl acetate (20 mL) were added, and the solution was separated. The organic layer was washed with saturated brine, and subsequently dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure, and the resulting residue was purified using silica gel column chromatography (elution solvent: ethyl acetate/hexane=5%-30%) to afford the desired compound (373 mg, yield 96%) as a yellow oil.
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