Synlett 2005(4): 643-645  
DOI: 10.1055/s-2005-863708
LETTER
© Georg Thieme Verlag Stuttgart · New York

Dyotropic Rearrangements of Tetraazafulvalenes - A New Approach to ­Aminosubstituted 1,4,5,8-Tetraazanaphthalenes

Frances Stöcknera, Christian Käpplingera, Rainer Beckert*a, Helmar Görlsb
a Institut für Organische und Makromolekulare Chemie, Friedrich-Schiller-Universität, 07743 Jena, Germany
Fax: +49(3641)948212; e-Mail: c6bera@uni-jena.de;
b Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität, 07743 Jena, Germany
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Publication History

Received 16 December 2004
Publication Date:
22 February 2005 (online)

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Abstract

Tetraazafulvalenes 1 rearrange in the presence of Montmorillonite-clay to give strongly fluorescent 1,4,5,8-tetraazanaphthalenes of type 2. This observation agrees with that reported for the cross-conjugated systeme of indigo, thus indicating a dyotropic rearrangement has taken place. Inclusion of the extended π-electron-systeme of 1 should facilitate this symmetry forbidden [σ22]-process. Based on these results, some reactions of heterofulvalenes and -fulvenes reported in the literature can now be explained by dyotropic rearrangements. The easy rearrangement of 1 in the presence of K10 and DMF opens the way for the synthesis of hard to obtain ring-fused pyrazines of type 2.