Introduction of substituents into 5‐membered aza‐heteroaromatics

Abstract

Abstract With emphasis on mono‐ and regio‐selectively, methods for introduction of substituents at nitrogen and carbon atoms of 5‐membered aza‐heteroaromatics have been developed. The methods involve application of activation and of assistant groups for direction and protection. Activation has been achieved by the use of quaternary azolium ions and azol‐N‐oxides as reactive intermediates. If necessary, the N‐oxides were further activated by alkylation or acylation.