Abstract:
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 from substituents either
in the aromatic or the saturated ring; isomer pyridocarbazoles could not be isolated. Electrophilic
substitutions of pyridocarbazoles 6 under mild conditions took place exclusively at the 5-position
and gave pyridocarbazolediones 9-11 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
phosphorylchloride 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.
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