Regioselective N-Methylation of 6-Chloroindolo[3,2-c]quinolines and Their Amination Reactivity at the C-6 Position

The treatment of 6-chloroindolo[3,2-c]quinoline 6 with NaH-MeI led to methylation at N-11, forming 8, while the reaction of 6 with MeI with heating gave the corresponding 5-methylated quinolinium salt whose SNAr with water smoothly proceeded to form 5-methylindolo[3,2-c]quinolin-6-one 3b. The amination reactivity at the C-6 was assigned in the order of 6 > 11-methylated 8.