Studies on the syntheses of condensed indole-4,7-dione derivatives. I. Syntheses of benz[f]indole-4,9-diones starting from 2,3-dichloronaphthoquinone (author's transl)

Abstract

2, 3-Dichloronaphthoquinone (3) easily reacted with active methylene compounds such as dimethyl malonate, ethyl acetoacetate, diethyl oxalacetate and a Schiff base, prepared from dimethyl β-ketoglutarate and aminoacetal, in the presence of potassium succinimidate to give the corresponding substituted monochloroquinones (5a-c and 17, respectively). The chloroquinone (5a) was converted to N-substituted 2-hydroxy-3-methoxycarbonylbenz [f] indole-4, 9-diones (9a-e) by the reaction with ammonia or various primary amines, and 5b was converted to N-substituted 3-ethoxycarbonyl-2-methylbenz [f] indole-4, 9-diones (11a-c) in the same manner.