[Mg:1].Br[CH2:3][CH3:4].[NH:5]1[C:13]2[C:8](=[CH:9][CH:10]=[CH:11][N:12]=2)[CH:7]=[CH:6]1.[CH3:14][N:15]1[C:19](=[O:20])[C:18]([Br:21])=[C:17]([Br:22])[C:16]1=[O:23].[Cl-].[NH4+]>C1(C)C=CC=CC=1.ClCCl.O1CCCC1>[CH2:3]([Mg:1][Br:21])[CH3:4].[Br:22][C:17]1[C:16](=[O:23])[N:15]([CH3:14])[C:19](=[O:20])[C:18]=1[C:7]1[C:8]2[C:13](=[N:12][CH:11]=[CH:10][CH:9]=2)[NH:5][CH:6]=1
A solution of ethylmagnesium bromide is prepared, starting from magnesium (12.7 mmol) suspended in bromoethane (12.7 mmol) and dry tetrahydrofuran (5 ml). The solution is stirred at ambient temperature for 1 hour and then 7-azaindole (12.7 mmol), dissolved in 40 ml of anhydrous toluene, is added dropwise. After stirring at ambient temperature for 1 hour 30 minutes, a solution of N-methyl-2,3-dibromomaleimide (3.53 mmol) in 40 ml of anhydrous toluene is added dropwise. After 20 minutes, 60 ml of dry dichloromethane are added; the reaction mixture is then stirred at 40° C. for 75 hours and hydrolysed with saturated aqueous ammonium chloride solution. The organic product is extracted with ethyl acetate, and the organic phases are then combined, dried over magnesium sulphate and filtered. After evaporating off the solvent and purifying the residue by chromatography on silica gel (cyclohexane/ethyl acetate: 3/2), the expected product is isolated.
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