Abstract
The preparation and some nucleophilic substitution reactions of 2-alkoxycycloheptimidazole derivatives were examined. Reaction of 2-methoxytropone derivatives with O-ethylisourea gave 2-ethoxycycloheptimidazoles (II, VIII to XIV) listed in Table I. The reaction of 2-methoxytroponeimine (V) with O-ethylisourea gave 2-aminocycloheptimidazole (VI) and 2-phenylcycloheptimidazole (VIII), besides 2-ethoxycycloheptimidazole (II). Reactions of II with sodium butoxide, aqueous ammonia, and dimethylamine gave 2-butoxy-(XXIX), 2-amino-(VI), and 2-dimethylaminocycloheptimidazole (XXX), respectively. Reaction of 4- and 6-bromo-2-ethoxycycloheptimidazole (VIII and IX) with dimethylamine resulted in displacement of the bromine atom on the seven-membered ring giving 4- and 6-dimethylamino-2-ethoxycycloheptimidazole (XXXI and XXXII), respectively. 2-Ethoxy-6-nitrocycloheptimidazole (XII) and IX gave 2, 6-diethoxycycloheptimidazole (XXXIII) by their reaction with sodium ethoxide. Acid hydrolysis of 2-ethoxycycloheptimidazoles (VIII to XIV) gave cycloheptimidazol-2 (1H)-ones (XXXV to XLIII) listed in Table II, whose substituents on the seven-membered ring remained unchanged. On the other hand, acid hydrolysis of XXXIII occurred preferentially at C-6 and 2-ethoxycycloheptimidazol-6 (1H)-one (XLIV) was obtained.
