Synthesis 2002(9): 1163-1170
DOI: 10.1055/s-2002-32527
PAPER
© Georg Thieme Verlag Stuttgart · New York

Syntheses of Phenothiazinylboronic Acid Derivatives - Suitable Starting Points for the Construction of Redox Active Materials

Christa S. Krämer, Thomas J. Zimmermann, Markus Sailer, Thomas J. J. Müller*
Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13 (Haus F), 81377 München, Germany
Fax: +49(6221)544205; e-Mail: Thomas_J.J.Mueller@urz.uni-heidelberg.de;
Further Information

Publication History

Received 6 March 2002
Publication Date:
28 June 2002 (online)

Abstract

Phenothiazinylboronic acid derivatives 3,7 and 9, useful building blocks for the construction of oligophenothiazines, are readily synthesized in good yield from brominated phenothiazines 5 and 6 by bromine-lithium exchange followed by trapping with trialkylborate (route A) or by palladium-catalyzed borylation with tetramethyl dioxoborolane (8) (route B). The novel class of tetrakis(phenothiazinylphenyl)methanes 11, showing remarkably large Stokes shifts and a reversible low oxidation potential, can be prepared in good yield by Suzuki coupling of tetrakis(p-bromophenyl)methane (10) with 3a.

1

New Address: Organisch-Chemisches Institut der Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.