Ring Closure in Quinonoylmethane Dyes; On the Reactivity of the Cyclohexyl Moiety in 2-Chloro-3--1,4-naphthoquinone

Article abstract of DOI:10.1002/hlca.19820650706

The reactive title compound (1a, X= F, R¹= C6H11, R²= Cl) was obtained from the reaction of 1-cyclohexyl-6-fluoro-2,3-dimethylquinoxalinium perchlorate with 2,3-dichloro-1,4-naphyoquinone.Upon treatment with pyridine and acetic acid in acetone and separation of the desired naphtophenazinone 2a, an unexpected azepinoquinoxaline 4a was isolated.The structure of 4a was determined by its mass and 360-MHz-1H-NMR. spectra in connenction with decoupling experiments.