Advances in the synthesis of imidazo[1,5-a]- and imidazo[1,2-a]quinoxalines

This review is intended to generalize and systematize available information on the synthesis of imidazo[1,5-a]- and imidazo[1,2-a]quinoxalines. Relevant studies published in the last 10-15 years, as well as earlier studies less familiar to the broad chemical community, are surveyed. Major methods of formation of the imidazoquinoxaline system from substituted quinoxalines and imidazoles according to the type of bond being formed are presented. Special focus is placed on the radically new methods that enable the synthesis of various derivatives of these heterocyclic systems from available and inexpensive reagents. The mechanisms of formation of these compounds are discussed. Information on the biological activity of imidazo[1,5-a]- and imidazo[1,2-a]quinoxalines and examples of pharmaceuticals based on them are reported. The bibliography includes 179 references.