ChemInform Abstract: Electrophilic Substitution Reactions of Indole. Part 20. Use of Montmorillonite Clay K‐10.

It is observed that using Montmorillonite Clay K-10 electrophilic substitution of indole with ketones generally stop at the diindolyl methane stage unlike mineral and Lewis acids where the predominant electrophiles are obtained from aldol condensation products. Using four different electrophiles, acetone, an alpha,beta -unsaturated ketone (mesityl oxide), a diketone system (acetyl acetone) and cyclohexanone, indole in the presence of montmorillonite Clay K-10 affords compounds 1-4.