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Synthesis of some 1H-1,5-benzodiazepine Series Containing Chromene Ring from α,β-Unsaturated Ketones of 6-Acetyl-5-Hydroxy-4-Methylcoumarin

Author(s):

Duong Ngoc Toan*, Nguyen Dinh Thanh, Mai Xuan Truong and Nguyen Minh Thao   Pages 1 - 7 ( 7 )

Abstract:


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 were precursors for synthesis of 2,3-dihydro1H-1,5-benzodiazepines through its reaction with o-phenylenediamine.

Method: 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. 2ʹ,3ʹ-Dihydro-1H-1ʹ,5ʹ-benzodiazepines were synthesized by using the reaction of these enones with o-phenylenediamine in absolute ethanol in the presence of with glacial acetic acid as a catalyst. Their biological activities were evaluated using disk diffusion method.

Results: Seven new 2ʹ,3ʹ-dihydro-1H-1ʹ,5ʹ-benzodiazepines were obtained and their structures were confirmed by thin layer chromatography, IR, NMR and MS spectra. Some synthesized benzodiazepines had antibacterial and antifungal activities againsts 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 the similar yields. The formation of 2ʹ,3ʹ-dihydro-1H-1ʹ,5ʹbenzodiazepine structure from the aforementioned enones and o-phenylenediamine.

Keywords:

Benzodiazepines, chromene, ethyl acetoacetate, 3-acetylcoumarin, o-phenylenediamine, α, β-unsaturated ketones.

Affiliation:

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



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