Tetrathiafulvalenes Acting as Leaving Groups:A Route to Bithiazoles

摘要

The five-membered heterocyclic 1,3-thiazole ring system is found in many natural products,and alkylbithiazole oligomers have also been tested for organic electronic applications.Here,we consider the extension of monocyclic heterocycles to bicyclic systems.The annulation of a benzene ring to a heterocycle generally results in change of properties,depending on the annulation topology.Specifically,in the case of thiazoles,the annulation of a benzene ring by means of the established cyclocondensation of ortho-aminothiophenols with carboxylic acids or aldehydes yields benzo[d]thiazoles.Two notable examples of thiazoles fused at face d (at the 4,5 bond) are thiazole orange,a powerful intercalator dye with base-stacking ability,and luciferin,which causes biolumi-nescence in insects.In contrast,however,there are few reports on thiazoles fused at face c (at the 3,4 bond),and there are,to our knowledge,no structural reports of the thiazolo[3,4-a]pyridinium ring system.