Synthesis and in vitro biological evaluation of new heterocycles based on the indole moiety

New compounds based on the indole moiety were synthesized via the reaction of indole-3-carbinal 1 with different nucleophiles such as 6-aryl-[4-(2-methoxybenzyl)pyridazin-3-yl] hydrazones 2a-c, benzidine, 3,3'-dimethoxybenzidine 4a,b and 2,6-diaminopyridine 6 to afford hydrazine derivatives 3a-c and three different classes of bis-Schiff bases. The structures of the new compounds were elucidated on the basis of their FTIR, H-1 NMR, C-13 NMR spectral data, GC/MS and elemental analysis. The antimicrobial activity of the new compounds was evaluated using a broth dilution technique in terms of minimal inhibitory concentration (MIC) against four pathogenic bacteria and two pathogenic fungi strains. Compound 14b showed excellent activity against Escherichia coli and Klebsiella pneumoniae. Some of the prepared compounds were tested for anti-cancer activity against human cell lines HCT116 (colon), MCF7 (breast) and HELA (cervix). From the results of the in vitro assays, compounds 3a,b, and 18a,c presented promising anti-cancer activity.