Ringschlüsse an Chinonylmethanfarbstoffen und analogen Merocyaninen. 6. Mitteilung. Über die Reaktivität des Cyclohexylrestes in 2-Chlor-3-[(1-cyclohexyl-6-fluor-3-methyl-1H-chinoxalin-2-yliden)methyl]-1,4-naphthochinon

Ring Closure in Quinonylmethane Dyes On the Reactivity of the Cyciohexyl Moiety in 2-Chloro-3-[(1-cyclohexyl-6-fluoro-3-methyl-1H-quinoxalin-2-ylidene)niethyl]-1,4-naphthoquinonc The reactive title compound ( 1a , X = F , R ¹ = C⁶H¹¹, R ²=Cl) was obtained from the reaction of 1-cyclohexyl-6-fluoro-2,3-dimethylquinoxalinium perchlorate with 2,3-dichloro-1,4-naphthoquinone. Upon treatment with pyridine and acetic acid in acetone and separation of the desired naphthophenazinone 2a , an unexpected azepinoquinoxaline 4a was isolated. The structure of 4a was determined by its mass and 360-MHz-¹H-NMR. spectra in connection with decoupling experiments.