5,8-ISOQUINOLINEDIONES .2. CHEMICAL AND ELECTROCHEMICAL BEHAVIOR OF 5,8-ISOQUINOLINEDIONE SYSTEM

We have devised two general synthetic schemes to 5,8‐isoquinolinediones and have investigated the chemical and electrochemical behavior of these compounds. The 1,4‐addition reactions of these quinones with amines was shown to occur at the 7‐position and a number of 7‐amino‐5,8‐isoquinolinediones. were synthesized. The 1,4‐addition of hydrogen bromide was also studied. The ethylenic double bond of the 5,8‐quinone system underwent Diels‐Alder additions to yield the oxidized forms of the adducts. The nucleophilic displacement of the methoxy group in 7‐methoxy‐5,8‐isoquinoline was accomplished with both potassium hydroxide and morpholine. A Polarographic study of the half‐wave potentials of substituted 5,8‐isoquinolinediones showed a linear correlation between the change in the half‐wave potential of the quinone system (ΔE° 1/2) resulting from the introduction of different substituents, and the substituent constants (σp‐x). Copyright © 1969 Journal of Heterocyclic Chemistry