Highly Efficient Povidone-Phosphotungstic Acid Catalyst for the Tandem Acetalization of Aldehydes to Bis- and Tris(indolyl)methanes.
- Resource Type
- Academic Journal
- Authors
- Kamble SB; Chemical Engineering and Process Development Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008 (India), Fax: (+91) 2590-2620.; Swami RK; Chemical Engineering and Process Development Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008 (India), Fax: (+91) 2590-2620.; Sakate SS; Chemical Engineering and Process Development Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008 (India), Fax: (+91) 2590-2620.; Rode CV; Chemical Engineering and Process Development Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008 (India), Fax: (+91) 2590-2620.
- Source
- Publisher: Wiley-VCH Country of Publication: Germany NLM ID: 101580948 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 2192-6506 (Electronic) Linking ISSN: 21926506 NLM ISO Abbreviation: Chempluschem Subsets: PubMed not MEDLINE; MEDLINE
- Subject
- Language
- English
A novel, nonleachable hybrid of heteropoly acid and polyvinylpyrrolidone (or povidone) catalyzes the acetalization of aldehydes in methanol at room temperature followed by reaction with indole to give bis(indolyl)methanes (BIMs) and tris(indolyl)methanes (TIMs) in quantitative yields (90-97 %). The catalyst was shown by pyridine FTIR spectroscopy to possess Brønsted acidity, and the hybrid formation was confirmed by XRD and 31 P NMR studies. Friedel-Crafts alkylation of indole as well as the tandem synthesis of BIMs and TIMs were established with several types of carbonyl and indole substrates to give the corresponding products quantitatively. The catalyst was recycled efficiently for three successive runs without losing its original activity.
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