N-Bridgehead pyrrolodiazines (1998–2023)

This chapter presents the most important recent advances in the chemistry of pyrrolo fused N-bridgehead diazines which include pyrrolo[1,2-b]pyridazine, pyrolo[1,2-a]pyrimidine, pyrolo[1,2-c]pyrimidine and pyrolo[1,2-a]pyrazine. These compounds have been under constant increased interest in recent years due to their proven value in medicinal chemistry as bioactive molecules, in materials science owing to their interesting physico-chemical properties, or in catalysis. All these frameworks are present in naturally occurring compounds with one exception, pyrrolo[1,2-b]pyridazine which still has not been found in a natural product. However pyrrolo[1,2-b]pyridazine together with pyrolo[1,2-a]pyrimidine and pyrolo[1,2-c]pyrimidine have important physicochemical properties which are suitable for advanced or smart materials. The pyrrolo[1,2-a]pyrazine core is present in a tremendous number of natural compounds and this is due to its biosynthesis from simple aminoacids as building blocks. This chapter covers the synthetic methodologies to the aforementioned pyrrolo-fused diazines and also gives insights into their chemical properties and applications reported between 1998 and 2023 years.