4-Hydroxy-pyrido[3,2,1-jk]carbazol-6-ones (3) which contain two biologically interesting structures, the indole and the 4-hydroxypyridone moiety, are obtained easily by cyclocondensation of carbazoles 1 (R' = H, OH) and monosubstituted malonates 2 . Nucleophilic substitution of the hydroxy group resulted in a number of reactive products such as 4-amino, 4-halogeno, 4-tosyloxy, 4-cyano or 4-azido compounds 4, which could be cyclized e.g. to indolo derivatives 5 or quinolino derivatives 6. Electrophilic substitution took place at the enolized CH-acidic 1,3-dicarbonyl function of 3 to give 5,5-disubstituted pyrido[3,2,1-jk]carbazole-4,6-diones 7 with alkyl, aryl, amino, azido, halogeno, hydroxy or nitro substituents in position 5. The oxo function in position 4 could be exchanged against a carbon function such as alkyl or alkylidene substituents (e.g. 6-oxo-pyrido[3,2,1-jk]carbazol-4-ylideneacetate 8).
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