Synthesis, structure, antimicrobial and antioxidant investigations of dicoumarol and related compounds

Different substituted 3,3′-arylidenebis-4-hydroxycoumarins (1–7) and tetrakis-4-hydroxycoumarin derivative 8 are the final products when 4-hydroxycoumarin and aromatic aldehydes containing different groups in ortho, meta or para positions condense in boiling ethanol or acetic acid. Upon heating 3,3′-arylidenebis-4-hydroxycoumarins, and tetrakis-4-hydroxycoumarin derivative in anhydride acetic acid, the epoxydicoumarins (9–16) were formed. From a study of nuclear magnetic resonance and infrared spectra, intramolecularly hydrogen-bonded structures are proposed for the dicoumarols (1–8). A possible relationship between such hydrogen-bonded structures and the antimicrobial and the antioxidant activities of compounds 1–8 is suggested.

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