[CH:1]([Sn](CCCC)(CCCC)CCCC)=[C:2]([CH3:4])[CH3:3].[NH2:18][C:19]1[CH:24]=[N:23][C:22](Br)=[CH:21][N:20]=1.C(N(CC)C(C)C)(C)C.[Cl-].[Li+]>CN(C)C=O.C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1>[NH2:18][C:19]1[CH:24]=[N:23][C:22]([CH:1]=[C:2]([CH3:4])[CH3:3])=[CH:21][N:20]=1
A mixture of the crude isobutenyltri-n-butyltin (6.90 g, 58 purity), 2-amino-5-bromopyrazine (1.92 g, 11 mmol), and N,N-diisopropylethylamine (5 mL) in N,N-dimethylformamide (50 mL) was treated with lithium chloride (2.0 g) and tetrakis(triphenylphosphine)palladium(0) (381 mg, 0.33 mmol). The mixture was stirred at 130° C. for 4 h, at which time, thin layer chromatography indicated complete consumption of the starting material. The mixture was concentrated in vacuo. The residue was treated with a saturated aqueous potassium fluoride solution and then extracted with ethyl acetate. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over sodium sulfate, filtered, and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230–400 mesh, 1.5/1 hexanes/ethyl acetate) afforded 2-amino-5-(2,2-dimethylvinyl)-pyrazine (420 mg, 26%).
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