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.
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.