Synthesis, characterization and biological screening of some newer carbazole conjugates

A novel series of novel 5-[(9H-carbazol-9-yl)methyl]-N-[(substituted phenyl)(piperazin-1-yl)methyl]-1,3,4-oxadiazol-2-amines (4a—o) products were synthesized from starting material of carbazole, which were on reacted with ethyl chloro-acetate yielded to form ethyl 2-(9H-carbazole-9-yl)acetate (1). Compound 1 on reacted with semicarbazide followed by cyclisation by sulphuric acid to give 5-((9H-carbazole-9-yl)-1,3,4-oxadiazol-2-amine (3), which through Mannich condensation with piperazine and a variety of aromatic aldehydes in the occurrence of acetic acid to form titled compounds (4a—o). The structures of compounds were characterized by UV, FT-IR, ¹H-NMR and MS spectral studies, and by elemental analysis.