An Eco-Friendly Improved Protocol for the Synthesis of Bis(3-indolyl)methanes Using Poly(4-vinylpyridinium)hydrogen Sulfate as Efficient, Heterogeneous, and Recyclable Solid Acid Catalyst
Scheme 2
Synthesis of bis(3-indolyl)phenylmethane catalyzed by P(4-VPH)HSO4.