Synthesis of some 1H-1,5-benzodiazepine series containing chromene ring from alpha,beta-unsaturated ketones of 6-acetyl-5-hydroxy-4-methylcoumarin.

BACKGROUND: Reaction of alpha,beta-unsaturated ketones with o-phenylenediamine afforded corresponding 2,3-dihydro-1H-1,5- benzodiazepines. OBJECTIVE: alpha,beta-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. 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 with glacial acetic acid as a catalyst. Their biological activities were evaluated using 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 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 2',3'-dihydro-1H-1',5'benzodiazepine structure from the aforementioned enones and o-phenylenediamine.