Polarographic study of acridine and 9-chloroacridine and its derivatives in dimethylformamide

Polarographic data on the reduction of acridine (I) and its 9-chloro (II), 2-methoxy-9-chloro (III), 4-methoxy-9-chloro (IV), 2-methyl-9-chloro (V), 4-methyl-9-chloro (VI), 2,9-dichloro (VII), and 4,9-dichloro (VIII) derivatives and a mechanism for the reduction are presented. In dimethylformamide (DMF) the polarographic reduction of acridine I takes place in two steps with participation of one electron in each step and the intermediate formation of an anion radical. Acridine II is reduced in four steps: The second and fourth waves correspond to the reduction of the heteroring, while the first and third waves are associated with detachment of a chlorine atom. The addition of phenol as a proton donor facilitates the reduction but does not affect the number of electrons consumed by the depolarizer during its reduction. A linear correlation between E_1/2 and the corresponding constants of quinoline is observed for acridines II, III, V, and VII; this made it possible to calculate the previously unknown constants for acridines that contain a substituent in the 4 position. The E_1/2¹ values for acridine II and its derivatives correlate with the rate constants for chemical dehalogenation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1660–1665, December, 1978.