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Synlett 2014; 25(18): 2585-2590
DOI: 10.1055/s-0034-1379083
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© Georg Thieme Verlag Stuttgart · New York

Synthesis of Azepino[4,5-b]indolones by an Intramolecular Cyclization of ­Unsaturated Tryptamides

John Eugene Nidhiry
Department of Organic Chemistry, Indian Institute of Science, Sir C. V. Raman Avenue, Bangalore 560012, India   Fax: +91(80)23600529   Email: prasad@orgchem.iisc.ernet.in
,
Kavirayani R. Prasad*
Department of Organic Chemistry, Indian Institute of Science, Sir C. V. Raman Avenue, Bangalore 560012, India   Fax: +91(80)23600529   Email: prasad@orgchem.iisc.ernet.in
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Publication History

Received: 03 July 2014

Accepted after revision: 15 August 2014

Publication Date:
02 October 2014 (online)

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Dedicated to Prof. H. Ila, an outstanding organic chemist from India, on the occasion of her 70th birthday

Abstract

A facile general route for the synthesis of azepino[4,5-b]indolones is presented. The strategy involves a Brønsted acid assisted intramolecular cyclization of unsaturated tryptamides. The methodology developed has been applied to the synthesis of the ABCD tetracyclic core of the natural product tronocarpine.

Key words

alkaloids - azepino[4,5-b]indolone - tronocarpine - tryptamide - ethyl lactate

Supporting Information

    for this article is available online at http://www.thieme-connect.com/products/ejournals/journal/ 10.1055/s-00000083.
  • Supporting Information
 

  • References and Notes

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  • 19 The experimental procedures for the preparation of compounds 11c–m are described in the Supporting Information.
  • 20 The structure of E-isomer was elucidated by single crystal X-ray diffraction analysis. For an ORTEP diagram, see the Supporting Information. The crystal structure data have been deposited with the Cambridge Crystallographic Data Centre (CCDC No. 980704).
  • 21 The crystal structure data have been deposited with the Cambridge Crystallographic Data Centre (CCDC No. 995842).
  • 22 For an ORTEP diagram of 18, see the Supporting Information. The crystal structure data have been deposited with the Cambridge Crystallographic Data Centre (CCDC No. 980703).

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