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Synthesis 2005(16): 2751-2757  
DOI: 10.1055/s-2005-872165
PAPER
© Georg Thieme Verlag Stuttgart · New York

The Hemetsberger-Knittel Synthesis of Substituted 5-, 6-, and 7-Azaindoles

Patrick J. Roy*, Claude Dufresne, Nicolas Lachance, Jean-Philippe Leclerc, Michel Boisvert, Zhaoyin Wang, Yves Leblanc
Merck Frosst Centre for Therapeutic Research, C.P. 1005, Pointe Claire-Dorval, Québec H9R 4P8, Canada
Fax: +1(514)4284900; e-Mail: patrick_roy@merck.com;
Further Information

Publication History

Received 3 May 2005
Publication Date:
12 August 2005 (online)

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Abstract

A series of substituted 5-, 6-, and 7-azaindoles were prepared via the Hemetsberger-Knittel reaction. In general, better yields were obtained at higher temperatures and shorter reaction times than required for the formation of the analogous indoles, and in some cases, only decomposition occurred below a minimum temperature. The resulting templates offer up to five sites for subsequent functionalization to allow a wide range of chemical diversity.

Key words

Hemetsberger-Knittel reaction - azaindoles - thermolysis - cyclization - template

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Azidopyridine acrylate 12b was isolated by extraction with EtOAc-hexane (1:1) since it is an oil.