ZurFischer-Indol-Umlagerung sterisch gehinderter Systeme, 6. Mitt.: Reaktionen mit cyclischen Oxalylverbindungen, 22. Mitt.

The N,N-diphenylhydrazones1 and7 combine with oxalyl chloride yielding the corresponding 2,3-dihydropyrrole-2,3-diones (2), the indeno1,2—b]pyrrol-2,3-dion derivative8 a and the 1-diphenylamino-4,5-tetrahydrobenzg]indol-2,3-dione (8 b).2 can be rearranged into the pyrrolo2,3—b]indole systems3 by thermolysis in decaline. Heating of3 a gives ethyl 1,2-diphenyl-indole-3-carboxylate5, while3 b under the same conditions is converted into the (indolyl-)glyoxylic acid derivative4. The diaza-propellanes9 are synthesized by thermolysis of8 in decaline. Oxidative hydrolysis of9 leads to the indole derivatives10, which on the other hand are made byFischer indole synthesis starting with7.