New Azacycles by One-Pot Three-Component Hantzsch-Like Synthesis of Tetra(hexa)azacyclopenta[a]anthracenes, Tetraazaindeno[5,4-b]fluorenes, and Oxatetraazacyclopenta[m]tetraphenes

Abstract

Multicomponent reactions (MCRs) are envisaged as an entry point for the synthesis of heterocyclic compounds with interesting biological activities. An efficient approach to annelated tetra(hexa)azacyclopenta[a]anthracenes, tetraazaindeno[5,4-b]fluorenes, and oxatetraazacyclopenta[m]tetraphene was accomplished using a three-component reaction involving 7-amino-2-methyl-3-phenylpyrazolo[1,5-a]pyrimidin-5-one with aromatic aldehydes and the corresponding active 1,3-dicarbonyl compounds (namely, dimedone, 1,3-dimethylbarbituric acid, 1,3-indanedione, and 4-hydroxycoumarine). The reactions were conducted in glacial acetic acid at reflux for 5 h to give the desired products in good yields (62–83 %). The chemical constitutions of all new products were confirmed spectroscopically.