Synthesis and antimicrobial activities of 9H-carbazole derivatives

AbstractIn this work 9H-carbazole was utilized as a precursor to prepare new heterocyclic derivatives. Treatment of carbazole 1 with ethyl acetoacetate gave ethyl 9H-carbazol-9-ylacetate 2. The acetate ester derivative 2 was transformed into the 2-(9H-carbazol-9-yl)acetohydrazide 3 through treatment with hydrazine hydrate. Reaction of compound 3 with sodium nitrite/HCl afforded [(9H-carbazol-9-ylacetyl)amino]diazonium chloride 4. Compounds 3-[3-(9H-carbazol-9-ylacetyl)triazanylidene]pentane-2,4-dione 5 and ethyl 2-[3-(9H-carbazol-9-ylacetyl)triazanylidene]-3-oxobutnoate 6 were obtained by reaction of compound 4 with acetylacetone and ethyl acetoacetate, respectively. Treatment of compounds 5 and 6 with urea and phenylhydrazine afforded 5-[3-(9H-carbazol-9-ylacetyl)triazanylidene]-4,6-dimethyl pyrimidin-2(5H)-one 7 and 4-[3-(9H-carbazol-9-yl acetyl)triazanylidene]-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one 8, respectively. The structures of the synthesized compounds were characterized by IR, 1H NMR, 13C NMR and elemental analysis. All synthesized products were tested and evaluated as antimicrobial agents