Solvent‐Assistant Purification for the Synthesis of Indole Derivatives Catalyzed by Solid Acid

Abstract

Traditional methods of isolating product from reaction mixture via chromatography or recrystallization suffer disadvantages of generation of waste like silica gels and toxic organic solvents, time‐ and labor‐consuming procedure. To solve the problem, a product purification strategy has been developed based on the solubility control of the products in water‐containing solvents, with the use of hydrophobic solid acid as catalyst. The method provides up to 99% LC‐purity for 34 indole derivatives in the Michael addition and condensation reaction. The formation of the agglomeration between products and hydrophobic solid catalyst plays important role.