Appropriate aryl aldehyde (16 mmol) was added dropwise to a stirred solution of 3-methylindole (4.20 g, 32.0 mmol) in 30 mL of ethanol. Concentrated sulfuric CP-466722 (10 drops) was added and the reaction solution stirred at room temperature and in the N2 atmosphere. The resulting precipitate was isolated by filtration and washed with cold ethanol when the reaction was finished. Recrystallization from hot ethanol afforded compounds 1–4.
Phenyl bis(3-methylindole-2-yl)methane (compound 1)