Heterocyclic analogs of 5,12-naphthacenequinone 9. Study of the synthesis and reactivity of 4,11-dimethoxynaphtho[2,3-f]isatin-5,10-diones

A preparative method has been developed for N-alkyl 4,11-dimethoxynaphtho[2,3- f ]isatin-5,10-diones. Condensation reactions with several N- and C-nucleophiles have been carried out to give the corresponding derivatives at position 3. An efficient method has been discovered for the demethylation of the N-alkyl-4,11-dimethoxynaphtho[2,3- f ]isatin-5,10-diones to give a high yield of N-substituted 4,11-dihydroxynaphtho[2,3- f ]isatin-5,10-diones. Successive halogenation using phosphorus penta-chloride and acylation of tert-butylamine by the intermediate 2-chloro derivative converted 4,11-di-methoxynaphtho[2,3- f ]isatin-5,10-dione to the 2-amino-3H-naphtho[2,3-f]indole-3,5,10-trione derivative.