Volume 55, Issue 43 pp. 13514-13518
Communication

Direct and Versatile Synthesis of Red-Shifted Azobenzenes

Mickel J. Hansen

Mickel J. Hansen

Centre for Systems Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands

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Michael M. Lerch

Michael M. Lerch

Centre for Systems Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands

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Dr. Wiktor Szymanski

Corresponding Author

Dr. Wiktor Szymanski

Centre for Systems Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands

Department of Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands

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Prof. Dr. Ben L. Feringa

Corresponding Author

Prof. Dr. Ben L. Feringa

Centre for Systems Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands

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First published: 26 September 2016
Citations: 149

Graphical Abstract

Red-shifted tetra-ortho-substituted azobenzenes were synthesized in a rapid manner with high functional group tolerance (see picture). The privileged tetra-ortho-methoxy, -chloro, and -fluoro azobenzenes become readily accessible, which paves the way for future applications of red-shifted azobenzenes in material and biological sciences.

Abstract

A straightforward synthesis of azobenzenes with bathochromically-shifted absorption bands is presented. It employs an ortho-lithiation of aromatic substrates, followed by a coupling reaction with aryldiazonium salts. The products are obtained with good to excellent yields after simple purification. Moreover, with the presented methodology, a structurally diverse panel of different azobenzenes, including unsymmetric tetra-ortho-substituted ones, can be readily obtained, which paves the way for future development of red-light-addressable azobenzene derivatives for in vivo application.

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