Abstract: A new synthesis of the indole system has been achieved by cyclodehydrogenation of amino phenylmalonate heterocycles.
Thus, the 4-amino coumarins 1a,b or the 4-amino-2-quinolones 1c-g are converted to
the indoles 2 with palladium on charcoal in boiling diphenyl ether. The reaction
of the aminocompounds 1 with diphenyl carbonate yields the fused polycyclic isoquinolines 4.
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