Efficient synthesis of benzo[h]carbazol[3,2‐b][1,6]naphthyridines

The use of CuI as a promoter to examine amination in the reaction of aminocarbazole (1) and 2‐methyl‐4‐chloroquinoline (2) resulted in a functionalized series of substituted naphthylamino carbazole. After cyclization with polyphosphoric acid and benzoic acid/p‐toluic acid, new isomeric ellipticine derivatives of linear benzo[h]carbazol[3,2‐b][1,6]naphthyridines were obtained in high yield. The current method has the advantages of a straightforward methodology, a clean and mild reaction, a broad substrate range, and a high yield.