Br[C:2]1[C:11]([CH3:12])=[CH:10][C:5]2[C:6]([CH3:9])=[N:7][O:8][C:4]=2[CH:3]=1.[NH2:13][C:14]1[CH:19]=[N:18][C:17](B2OC(C)(C)C(C)(C)O2)=[CH:16][N:15]=1.[O-]P([O-])([O-])=O.[K+].[K+].[K+].CC(=O)OCC>C(#N)C.O1CCOCC1.O>[CH3:9][C:6]1[C:5]2[CH:10]=[C:11]([CH3:12])[C:2]([C:17]3[N:18]=[CH:19][C:14]([NH2:13])=[N:15][CH:16]=3)=[CH:3][C:4]=2[O:8][N:7]=1A mixture of 6-bromo-3,5-dimethylbenz[d]isoxazole (104) (54 mg, 0.24 mmol), 2-aminopyrazine-5-boronic acid pinacol ester (14) (79 mg, 0.358 mmol), bis(ditertbutyl(4-dimethylaminophenyl)phosphine)dichloropalladium (II) (25 mg, 10% mol) and K3PO4 (76 mg) in 1 ml ACN, 1 ml dioxane, 0.5 ml H2O was bubbled with argon before heated at 85° C. for 3 h. After cooling down to r.t., the reaction mixture was taken up in EA, washed with aq. NaHCO3 and brine. Org. phase was dried over Na2SO4, concentrated and then subjected to silica gel flash column chromatography (0-100% B, A: hexane; B: EA) to give 5-(3,5-dimethylbenz[d]isoxazol-6-yl)pyrazine-2-ylamine (109) (15 mg, yield: 26.1%, purity>95%) as light yellow solid.
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