Synthesis 2011(2): 199-206  
DOI: 10.1055/s-0030-1258373
PSP
© Georg Thieme Verlag Stuttgart ˙ New York

2,4-Disubstituted Thiazoles by Regioselective Cross-Coupling or Bromine-Magnesium Exchange Reactions of 2,4-Dibromothiazole

Stefan Gross, Stefan Heuser, Carolin Ammer, Golo Heckmann, Thorsten Bach*
Lehrstuhl für Organische Chemie I, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany
Fax: +49(89)28913315; e-Mail: thorsten.bach@ch.tum.de;
Further Information

Publication History

Received 25 November 2010
Publication Date:
20 December 2010 (online)

Abstract

Cross-coupling reactions occur on 2,4-dibromothiazole preferentially at the more electron-deficient 2-position. This fact can be favorably used to prepare 2-substituted 4-bromothiazoles, which serve as precursors for 2,4-disubstituted thiazoles. Protocols for regioselective Negishi and Stille cross-coupling reactions are provided. Alternatively, the title compound can be metalated in 2-position by a halogen-metal exchange reaction. As a supplement to the well-established bromine-lithium exchange, the regioselective bromine-magnesium exchange reaction is presented.

1

Current address: Georg-Simon-Ohm Hochschule, Fakultät für Angewandte Chemie, Prinzregentenufer 47, 90489 Nürnberg, Germany.

2

Current address: Pharmazell GmbH, Rosenheimer Straße 43, 83064 Raubling, Germany.

3

Current address: Boehringer Ingelheim Pharma GmbH & Co. KG, Binger Straße 173, 55216 Ingelheim, Germany.