Polystyrene-Supported Aluminum Chloride as an Efficient and Reusable Catalyst for Condensation of Indole with Various Carbonyl Compounds

Crosslinked polystyrene-supported aluminum chloride (PS-AlCl3) is a stable, recyclable and environmental friendly heterogeneous catalyst for the condensation of indole with aldehydes and ketones to afford diindolylmethanes. In addition, PS-AlCl3 shows satisfactory selectivity in the reaction of mixtures of an aldehyde and a ketone with indole. Although AlCl3 is a water sensitive, corrosive and environmentally harmful compound, PS-AlCl3 is a stable and water-tolerant species. The mild reaction conditions, short reaction times, easy work-up, high to excellent yields, chemoselectivity, reuse of the catalyst for at least ten times without significant change in its catalytic activity, low cost, and easy preparation and handling of the polymeric catalyst are obvious advantages of the present method

Modified polyacrylamide supported chlorochromate as a new polymeric oxidizing agent

Modified polyacrylamide supported chlorochromate was synthesized and used as a versatile and efficient oxidizing agent for the oxidation of various organic compounds such as hydroxyl compounds, silylethers, oximes, thiols, and other compounds. Over oxidation of the products (aldehydes to carboxylic acids) was not observed with this oxidizing agent. The oxidant was insoluble in oxidation media and chromium (VI) ions remained firmly bound to the insoluble polymeric support after the oxidation reaction. The mild reaction condition, easy work-up, short reaction times, regenerability of the reagent and its easy preparation and handling are among the advantages of this new polymeric chlorochromate reagent

JSCS–3975 Original scientific paper

Polystyrene-supported aluminum chloride as an efficient and reusable catalyst for condensation of indole with various carbonyl compound