Synthesis of 2, 4-disubstituted-1H-benzo[b][1,4]diazepine derivatives as promising anticancer agents

A novel series of 1H-benzo[b][1,4]diazepine derivatives bearing different substitutions at positions 2 and 4 was designed, synthesized, and tested as anticancer agents.

The reaction of chalcone derivatives 5a-h with o-phenylenediamine (OPDA) in ethanol and the presence of acetic acid as a catalyst afforded the targeted 1H-benzo[b][1,4]diazepine derivatives (6a-h). The structures of the newly synthesized compounds were confirmed via spectral data and elemental analyses. These compounds were tested as in vitro anti-cancer agents against MCF7, PC3 cancer cells and BJ normal cells.

Compound 6h showed the best efficacy with IC50 of 29.1 and 50.7 µM on MCF7 and PC3, respectively, compared to the reference drug with IC50 of 32.36 and 47.96 µM, respectively. 6h was tested on the BJ to investigate its selectivity on the tested cancer cells, and the selectivity index of 6h was 2.25 and 1.30 on MCF7 and PC3, respectively. It is important to note that compound 6h has strong selectivity, especially on MCF7, and moderate selectivity on PC3, both being more than that found in the reference drug. Moreover, 6h was investigated for further studies to explore its mechanism of action using DNA fragmentation, DNA damage, and gene expression techniques.