n-Dodecylbenzene Sulfonic Acid (DBSA) as a Novel Brønsted Acid Catalyst for the Synthesis of Bis(indolyl)methanes and Bis(4-hydroxycoumarin-3-yl)methanes in Water

Abstract

N-Dodecylbenzene sulfonic acid (DBSA) was used as a novel, biodegradable and efficient Bronsted acid catalyst for the condensation of indole/4-hydroxycoumarin with aryl aldehydes to obtain bis(indolyl)methanes I [R = H, 4-Cl, 4-Me, 2-Br, etc.] and bis(4-hydroxycoumarin-3-yl)methanes II resp. DBSA catalyst exhibited remarkable activity and tolerated a wide variety of functional groups providing desired products in good to excellent yield (70%-96%) in water. This procedure has the advantages of mild reaction conditions, short reaction time, high yields of products and simple exptl. technique. [on SciFinder(R)]