A short synthesis of pyrazolylcarbazoles from 9-alkylcarbazoles in three steps is
reported. The acetylcarbazoles prepared by the acetylation of carbazoles with acetic
anhydride catalyzed by BiCl3 were converted into chloroaldehydes with Vilsmeier reagent. Condensation of chloroaldehydes
with hydrazine followed by cyclization yield the pyrazolylcarbazoles. Carbazolyl chalcones
were prepared by the condensation of carbazole-3-aldehyde with o-aminoacetophenone and cyclized to carbazolylquinolone using several catalysts. Cyclization
of carbazolyl chalcones with the Vilsmeier reagent yields a mixture of carbazolylquinoline
carbaldehydes.
carbazoles - heterocycles - aldehydes - ring closure - condensation
