quinoxaline

noun

qui·​nox·​a·​line kwi-ˈnäk-sə-ˌlēn  -ˌlīn 

: a weakly basic bicyclic compound C₈H₆N₂ made by condensing the ortho form of phenylenediamine with glyoxal and having fused benzene and pyrazine rings

also : any of various derivatives of quinoxaline having antibiotic properties