Studies on the Synthesis of Diphenylene Dioxide (Dibenzo-p-dioxin) Derivatives. XXIII.

Syntheses of Phenylenedioxyquinolines (Benzo-p-dioxinoquinolines). (Supplement 1)

Abstract

The Ullmann reaction of 7, 8-dibromoquinoline and pyrocatechol did not afford the desired benzo[7, 8]-p-dioxino[2, 3-h]quinoline (II) but the same reaction with 7-bromo-8-hydroxyquinoline and o-bromophenol successfully gave (II). The same reaction of 6-hydroxy-7-bromoquinoline and o-bromophenol afforded benzo[6, 7]-p-dioxino[2, 3-g]quinoline (IV). The Ullmann reaction of 7-hydroxy-8-bromoquinoline alone yielded a minute amount of a substance assumed to be the objective pyrido [2, 3-α]pyrido[2, 3-h]dibenzo-p-dioxine (II) but could not be identified. An attempt to obtain pyrido[2, 3-h]pyrido[2, 3-i]dibenzo-p-dioxine (V) by the same reaction on 6-hydroxy-7-bromoquinoline did not materialize, nor the Ullmann reaction of 7-bromo-8-hydroxyquinoline.