Synthesis of azulenic compounds substituted in the 1-position with heterocycles

Abstract

The review proposes an overview of the important general routes for the achievement of 1-heteroarylazulenes using both azulene substitution by heterocycles and azulenic cyclic construction pathways. With strong electrophilic heterocyclic derivatives, the electrophilic substitution takes place while concerted route is adopted for medium and low reactive heterocyclic substrates. Particular attention has been paid to the heterocycles construction from the functional groups attached to azulenic 1-position.