Synthesis and biological effects evaluation of benzoconduritols C and D from oxabenzonorbornadiene

The effective synthesis of benzoconduritols C and D is reported. Oxidation of oxabenzonorbornadiene followed by acetylation with Ac2O/pyridine or AcCl/CH2Cl2 gave the corresponding exo-diacetate compound stereoselectively. Acid-catalyzed ring opening of the bridged ether bond (the 1,4-anhydo bond) with Ac2O in the oxabenzonorbornadiene system to produce benzoconduritol tetraacetates followed by ammonolysis furnished the desired benzoconduritols C and D, respectively. The novel benzoconduritols (9, 10, 15, 16, and 17) were evaluated for the first time in terms of their potential antioxidant, anti-inflammatory, and enzyme inhibition activities. Most of the complexes exhibited moderate activity. Especially 15 (IC50 = 0.374 mM) and 10 (IC50 = 0.450 mM) have better anti-inflammatory effect when compared to ibuprofen (IC50 = 0.437 mM). Furthermore, the benzoconduritol C 9 has better alpha-glucosidase inhibition potential with the IC50 value of 0.437 mM than acarbose (IC50 = 0.445 mM). The results of this study point out that most of these molecules have the potential to provide an alternative for the clinical control of inflammation and diabetes due to their anti-inflammatory and anti-glucosidase activities. Graphic abstract