Abstract: Syntheses of unsymmetrical dicoumarol were carried out by reacting one equivalent of 4-hydroxycoumarin (5ac)
and one equivalent of an appropriate aromatic anhydride in ethanol solvent at a temperature of 80 oC for 45
minutes. The products (1a-f) were isolated as yellow compounds with poor yields (28 - 30%) due to competitive
dimer formation (1g). Their after, six equivalents of Hanzsch's ester (6a) were added to a solution of the
unsymmetrical dicoumarol (1a-f) in methanol solvent. In order to achieve complete conversion, the reaction
were left to stir overnight and this gave compound (2a- f) in a poor to moderate yields (20- 74%).The identities
of the compounds were confirmed using NMR, IR and mass spectrometry. Compounds (2a- f) were assayed in
the absence of BSA and their IC50 values show moderate inhibitory potency towards NQO1 enzyme.
Key words: synthesis, unsymmetrical dicoumarol, Hanzsch's ester, enzyme assay, NQO1
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