A rapid, efficient and versatile green synthesis of 3,3′-diindolylmethanes

Abstract

The natural product 3,3′-diindolylmethane (DIM) exhibits anti-cancer and immunostimulatory properties. We report an operationally simple, efficient and versatile synthesis of DIM derivatives by reaction of indoles with aldehydes in the presence of sulfuric acid in water. Short reaction times of only 5 min, simple work-up procedure, avoidance of hazardous organic solvents, and excellent yields are apparent advantages of this method. The synthetic protocol tolerates a broad range of functional groups allowing fast and straightforward access to a large variety of DIM derivatives, including 20 new compounds not previously described in literature, which have potential as anti-cancer drugs.