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, Nguyen Minh Thao

Journal Name: Current Organic Synthesis

Volume 17 , Issue 5 , 2020

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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 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.

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

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Article Details

VOLUME: 17
ISSUE: 5
Year: 2020
Page: [404 - 410]
Pages: 7
DOI: 10.2174/1570179417666200415152105
Price: $65

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