Insights into the synthesis of hexaaminobenzene hydrochloride: An entry to hexaazatriphenylenes

Abstract

Polycyclic N-heteroaromatic systems and particularly, the dipyrazino[2,3-f:2′,3′-h]quinoxaline also known as 1,4,5,8,9,12-hexaazatriphenylene (HAT) displays very useful optoelectronic properties. Its synthesis through condensation of functionalized 1,2-diketones and hexaaminobenzene is often applied on laboratory scale. Hexaaminobenzene could be prepared from 4-nitroaniline but, despite its many applications, the experimental protocol is not trivial and should by carefully controlled in each step. In this work, we presented an efficient and reproducible 4 steps synthesis of hexaaminobenzene hydrochloride and a comprehensive analysis of reactions conditions and products formed in all synthetic steps. As evidence, this aromatic polyamine was effectively condensed with 1,2-di(4-bromophenyl)-1,2-ethanedione affording a synthetically versatile HAT derivative for the application in the design of organic materials.