Thermodynamic prediction of proton and hydrogen atom abstraction in dehydroascorbic acid and its bicyclic form

Conformation analysis of dehydroascorbic acid and its bicyclic form was performed using the density functional theory. For the energetically preferred conformations, ionization potentials (IP) and bond dissociation enthalpies (BDE) were calculated using the B3LYP functional and 6-311++G** basis set. The effects of aqueous solution were estimated using the solvation model based on density (SMD) and the polarizable continuum model (IEF-PCM). The obtained results were compared with available experimental data for reference L-ascorbic acid (vitamin C). Our calculations indicate that the investigated bicyclic metabolic product of vitamin C can also exhibit limited radical scavenging ability due to the thermodynamically preferred dissociation of tertiary —CH bonds.