A CONVENIENT FORMATION OF HIGHLY FUNCTIONALIZED 5-BROMO-1,3-THIAZOLES.

A CONVENIENT FORMATION OF HIGHLY FUNCTIONALIZED 5-BROMO-1,3-THIAZOLES Eduard Dolusic, Sara Modaffari, Johan Wouters, Bernard Masereel and Raphaël Frédérick NAmur MEDIcine Center (NAMEDIC), NARILIS, 61 rue de Bruxelles, 5000 Namur, Belgium In the framework of our research program, we were interested in the synthesis of substituted thiazole N-oxides. However, treatment of starting thiazoles with mCPBA1 did not afford the desired products. Spectral analyses proved that corresponding 5-bromothiazoles were formed instead in very good yields. This can be explained by the fact that the starting compounds were, in fact, hydrobromide salts. Oxidative bromination mediated by mCPBA then occurred in the 5-position of the thiazole ring. Various 5-bromo-1,3-thiazoles bearing alkyl and aryl substituents (containing both electron withdrawing and electron donating groups) in the 2- and 4-positions very easily prepared in this way. These products formed rapidly, in an one-pot operation from simple starting materials, using mild conditions (room temperature) and avoiding the use of catalysts or hazardous reagents like elemental bromine. This convenient procedure allows simple and quick access to a range of highly functionalized thiazoles, which can be further elaborated by known chemical methods. References: 1. e. g. Campeau, L.-C, et al, J. Am. Chem. Soc. 2009, 131, 3291-3306 ; Campeau, L.-C, et al, J. Am. Chem. Soc. 2008, 130, 3276-3277. This work is supported by the FNRS and the Walloon Region (BioWin project CANTOL: Convention n° 5678).