[Br:1][C:2]1[CH:11]=[C:10]2[C:5]([N:6]=[CH:7][C:8](Cl)=[N:9]2)=[CH:4][CH:3]=1.[CH3:13][N:14]1[CH:18]=[C:17](B2OC(C)(C)C(C)(C)O2)[CH:16]=[N:15]1.C(=O)([O-])[O-].[Na+].[Na+].COCCOC>O.C([O-])(=O)C.[Pd+2].C([O-])(=O)C.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>[Br:1][C:2]1[CH:11]=[C:10]2[C:5]([N:6]=[CH:7][C:8]([C:17]3[CH:16]=[N:15][N:14]([CH3:13])[CH:18]=3)=[N:9]2)=[CH:4][CH:3]=17-bromo-2-chloro-quinoxaline (502 g; 2.06 mol), 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (450.42 g; 2.16 mol), triphenylphosphine (10.82 g; 0.041 mol) and palladium(II)acetate were added to a mixture of sodium carbonate (240.37 g; 2.267 mol), 1,2-dimethoxyethane (5.48 L) and water (1.13 L). The reaction mixture was stirred at reflux for 20 hours, then 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (42.9 g; 0.206 mol) was added and the reaction mixture refluxed until complete conversion (4 hours). The reaction mixture was poured out in water, stirred for 2 hours at room temperature, filtered and the precipitate was washed with water. The precipitate was then triturated in methanol and filtered. The precipitate was washed with methanol and dried to give 532.2 g (89%) of 7-Bromo-2-(1-methyl-1H-pyrazol-4-yl)-quinoxaline (off-white powder).
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