Synthesizing isomeric methoxy derivatives of 6-nitro-9-chlordacridine and 6-nitroacridone
Condensation of 2-chloro-4-nitrobenzoic acid with o, m, and p-anisidines under the conditions of the Ullmann reaction gives the corresponding 2′-, 3′-, or 4′-methoxy derivatives of 5-nitrodiphenylamine-2-carboxylic acid. Phosphorus oxychloride cyclizes the latter to the corresponding methoxy-substituted 6-nitro-9-chloroacridines, and the latter, when treated with dilute hydrochloric acid, give good yields of methoxy derivatives of 6-nitroacridones.