A New Synthetic Framework for 11‐Demethylellipticine

A new synthetic route for the synthesis of 5-methyl-6H-pyrido[4,3-b]carbazole (8), so-called 11-demethylellipticine, was described. Construction of the tetracyclic structure hexahydro-1H-pyrido[4,3-b]carbazol-5(6H)-one skeleton (6) was also achieved by nucleophilic substitution reaction in the synthetic route. Also new tetrahydrocarbazole derivatives (2, 3, 4, and 5) were synthesized. Several ellipticine analogs and octahydropyridocarbazole-based G-protein coupled receptors inhibitors can also be synthesized from tetracyclic structure (6) because of carbonyl functionality at position 5.