Synthesis of 5,6-, 5,8- and 7,8-Isoquinolinediones from the Corresponding Isoquinolinois and Di-methoxyisoquinolines

Abstract

5,8-Isoquinolinediones (12,18, 25), 7,8-isoquinolinediones (14,19) and 5,6-isoquinolinediones (26) were synthesized by oxidative demethylation of the corresponding dimethoxyisoquinolines with cerium(IV) ammonium nitrate or silver-(II) oxide. 8-Dialkylamino-5,6-isoquinolinediones (31) and 3,5-bis(dialkylamino)-7,8-isoquinolinediones (33) were prepared by copper(II)-catalyzed oxidation of the corresponding isoquinolinols with secondary amines. 5,8-Iso-quinolinediones (29, 34, 40) were also prepared. © 1991, The Pharmaceutical Society of Japan. All rights reserved.