An efficient synthesis of 3-indolyl-3-hydroxy oxindoles and 3,3-di(indolyl)indolin-2-ones catalyzed by sulfonated β-CD as a supramolecular catalyst in water

Abstract

Please cite this article as: Tayade, Y.A., Patil, D.R., Wagh, Y.B., Jangle, A.D., Dalal, D.S., An efficient synthesis of 3-indolyl-3-hydroxy oxindoles and 3,3-di(indolyl)indolin-2-ones catalyzed by sulfonated β-CD as a supramolecular catalyst in water, Tetrahedron Letters (2014), doi: http://dx.

β‐Cyclodextrin: A Green and Efficient Supramolecular Catalyst for Organic Transformations

“…In view of the above importance, the development of a generally applicable and environmentally benign methodology for the synthesis of 3‐indolyl‐3‐hydroxy oxindoles 37 a – f and 3,3‐di(indolyl)indolin‐2‐ones 38 a – o derivatives from various indoles 35 and isatin 36 are highly desirable. In search for an alternative practical route for the facile and ecofriendly synthesis of 3‐indolyl‐3‐hydroxy oxindoles and 3,3‐di(indolyl)indolin‐2‐ones, our group design a convenient and highly efficient protocol for this useful organic transformation for a variety of structurally diverse isatins (1 mmol) and indoles (1 mmol) using supramolecular catalyst sulfonated‐β‐cyclodextrin (β‐CD−SO 3 H) (0.1 mmol) in aqueous medium (Figure , Scheme ) …”

Iron‐containing ionic liquid as an efficient and recyclable catalyst for the synthesis of C3‐substituted indole derivatives

“…Therefore, various methods have been reported for preparing this class of compounds . The most straightforward method to obtain the heterocycle involves the condensation of indoles with different carbonyl compounds (aldehydes or ketones), which was often promoted by homo‐ and heterogeneous catalysts such as acid catalysts, nano catalysts, supported catalysts, metal catalysts, ion exchange resin, and enzymes . Although these reported protocols have made some certain merits, many of them still have notable disadvantages such as harsh reaction conditions, long reaction times, limited substrate scope, using expensive Lewis acids and solvents, high catalyst loading and generation of large amounts of harmful wastes.…”

MCM-41-Accelerated PWA Catalysis of Friedel-Crafts Reaction of Indoles and Isatins

“…Some literature sources revealed that the synthesis of 3,3-diaryloxindole skeleton can be achieved by coupling of indoles and isatins with acid [9,10], I 2 [11], metal salts [12], ionic liquids [13], CAN [14], -CD [15], Amberlyst-15 [16], and nanomaterials [17]. Despite these important contributions, developing and searching for a highly effective catalytic system is still challenging.…”