A green alternative approach for the preparation of bis-indolyl, tris-indolyl and di(bis-indolyl methanes) in aqueous media

A facile, efficient and green synthesis of bis-indolyl methanes, tris-indolyl methanes and di(bis-indolyl methanes) has been developed by one-pot condensation of indole with structurally diverse aldehydes and ketones in the presence of Me-SO3H in water medium as homogeneous and efficient catalyst at room temperature.