Abstract
magnified image Tetrahydrocarbazoles 4 obtained from phenylhydrazines and cyclohexanones gave by cyclocondensation with 2‐substituted malonates 5 in all cases 4‐hydroxy‐8,9,10,11‐tetrahydropyrido[3,2,1‐jk]carbazol‐6‐ones 6 by attack at the nitrogen and the aromatic ring of tetrahydrocarbazoles 4; the direction of the cyclization was not dependent on substituents either in the aromatic or the saturated ring; isomeric pyridocarbazoles could not be isolated. Electrophilic substitutions of pyridocarbazoles 6 under mild conditions took place exclusively at the 5‐position and gave pyridocarbazolediones 9, 10, 11 with 5‐nitro‐, 5‐hydroxy or 5‐chloro‐substituents. Exchange of the chloro substituent in 11 gave 5‐azido‐ and 5‐amino products 12, 14 or 16. Reactions at the aromatic ring were not observed. Chlorination of 4‐hydroxypyridocarbazoles 6 with phosphoryl chloride by nucleophilic substitution took place exclusively at the 4‐position and gave 4‐chloropyridocarbazolones 17, which were further reacted to azides and amines 18, 19. J. Heterocyclic Chem., (2010).