Reactions of tropylium ions having a fused heterocyclic system with various amines were examined. Reaction of 2-phenyloxazolotropylium monomethylsulfate (I) and 2-phenylthiazotropylium chloride (XXIV) with dimethylamine produced 2-phenyl-6-dimethylamino-6H-cycloheptoxazole (II) and 6-dimethylamino-2-phenyl-6H-cycloheptathiazole (XXV), respectively. Regarding the reaction with p-toluidine, both I and 1-p-tolyl-2-phenylimidazolotropylium chloride (XXVI) gave 1-p-tolyl-2-phenyl-1, 6-dihydrocycloheptimidazole (VI) and 1-p-tolyl-2-phenyl-6-p-tolylimino-1, 6-dihydrocycloheptimidazole (VII). Reaction of I with N-methylaniline produced 2-phenyl-6-p-methylaminophenyl-6H-cycloheptoxazole (XIX) and 2-phenyl-4-p-methylaminophenyl-4H-cycloheptoxazole (XX). From these results, it is concluded that the tropylium ions condensing a heterocycle has a priority for amination at C-6.
