Duong Ngoc Toan*, Nguyen Dinh Thanh*, Mai Xuan Truong and Nguyen Minh Thao Pages 404 - 410 ( 7 )
Background: Reaction of α,β-unsaturated ketones with o-phenylenediamine afforded corresponding 2,3-dihydro-1H-1,5-benzodiazepines.
Objective: α,β-Unsaturated ketones of 6-acetyl-5-hydroxy-4-methylcoumarin are precursors for synthesis of 2,3-dihydro-1H-1,5-benzodiazepines by a reaction with o-phenylenediamine.
Methods: Enones of 6-acetyl-5-hydroxy-4-methylcoumarin were prepared from this ketone and (un)substituted benzaldehydes in the presence of piperidine, triethylamine, or pyridine as a catalyst in absolute ethanol with 1:1 molar ratios, respectively. 2',3'-Dihydro-1H-1',5'-benzodiazepines were synthesized by using the reaction of these enones with o-phenylenediamine in absolute ethanol in the presence of glacial acetic acid as a catalyst. Their biological activities were evaluated using the disk diffusion method.
Results: Seven new 2',3'-dihydro-1H-1',5'-benzodiazepines were obtained and their structures were confirmed by thin-layer chromatography, IR, NMR and MS spectra. Some synthesized benzodiazepines showed antibacterial and antifungal activities against Escherichia coli (Gram-(−) bacterium), Staphylococus epidermidis (Gram-(+) bacterium). Candida albicans (fungus).
Conclusion: The formation of enones from 6-acetyl-5-hydroxy-4-methylcoumarin and (un)substituted benzaldehydes could be catalyzed by piperidine, triethylamine, pyridine to afford similar yields. 2',3'-dihydro-1H- 1',5'-benzodiazepines have been synthesized from the aforementioned enones and o-phenylenediamine.
Benzodiazepines, chromene, ethyl acetoacetate, 3-acetylcoumarin, o-phenylenediamine, α, β-unsaturated ketones.
Faculty of Chemistry, Thai Nguyen University of Education, 20 Luong Ngoc Quyen, Thai Nguyen, Faculty of Chemistry, VNU University of Science (Vietnam National University, Ha Noi), 19 Le Thanh Tong, Hoan Kiem, Ha Noi, Faculty of Chemistry, Thai Nguyen University of Education, 20 Luong Ngoc Quyen, Thai Nguyen, Faculty of Chemistry, VNU University of Science (Vietnam National University, Ha Noi), 19 Le Thanh Tong, Hoan Kiem, Ha Noi