2-substituted 5-acetyl-4-thiazolyl triflates as useful building blocks forthe preparation of functionalized thiazoles

The readily available 2-substituted 5-acetyl-4-thiazolyl triflates 2 are us eful building blocks for the preparation of functionalised thiazoles by mea ns of palladium-catalysed cross-coupling reactions with organometallic reag ents and alkoxycarbonylation and deoxygenation reactions. The combination o f palladium-catalysed coupling of 2 together with 1-alkynes/6-endo-dig annu lation reactions in the presence of ammonia leads to functionalised pyrido[ 3,4-c]thiazoles in satisfactory yields. The utilisation of uncatalysed disp lacement reactions of the triflate group represents a very simple method fo r the synthesis of 4-N-,4-O-, and 4-S-substituted thiazoles.