Azacyclohexadienyl radical

Formation of pentacycle 55 was consistent with the radical addition-quinoline rearomatization-overoxidation sequence depicted below. Thus, the initially formed acyl radical L undergoes regioselective cyclization upon the 4-position of the quinoline ring to give the azacyclohexadienyl radical M, which is probably oxidized by hydrogen abstraction at the hands of the initiator AIBN <04AGE95>. A new hydrogen abstraction at the doubly... 

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