Br[C:2]1[CH:7]=[N:6][C:5]([Br:8])=[CH:4][N:3]=1.[C:9]([O:13][CH2:14][CH3:15])(=[O:12])[CH:10]=[CH2:11].C1(C)C=CC=CC=1P(C1C=CC=CC=1C)C1C=CC=CC=1C>CN(C=O)C.C(N(C(C)C)CC)(C)C.C([O-])(=O)C.[Pd+2].C([O-])(=O)C>[Br:8][C:5]1[N:6]=[CH:7][C:2](/[CH:11]=[CH:10]/[C:9]([O:13][CH2:14][CH3:15])=[O:12])=[N:3][CH:4]=1A solution of 2,5-dibromopyrazine (238.0 mg, 1.0 mmol), ethyl acrylate (174.0 μL, 1.6 mmol), palladium(II) acetate (3.4 mg, 0.015 mmol), and tri(o-tolyl)phosphine (36.5 mg, 0.12 mmol) in DMF (1.4 mL) and diisopropylethylamine (0.7 mL) was heated at reflux (115° C. oil bath) for 4.4 h, cooled to room temperature, and then quenched with H2O. The suspension was extracted with EtOAc (300 mL). The extract was washed (brine) and dried. After solvent removal at reduced pressure, the residue was purified on silica gel (11% EtOAc/hexane) to give 22 mg (8.5%) of ethyl(E)-3-(5-bromo-2-pyrazinyl)-2-propenoate as a cream solid.
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