DFT study of tautomerism in aklavinone

Aklavinone has an anthraquinone-based chromophore and its backbone highly resembles the kernel of some anthracycline antibiotics that possess anticancer activity, e.g., daunomycin. Since aklavinone s structure possesses many --OH groups and 2 keto groups, it is quite probable that certain tautomeric equilibria may occur. Presently, aklavinone prototropic tautomers possessing embedded anthraquinone moiety have been investigated quantum chemically by using density functional theory at the levels of RB3LYP/6-31G(d) and RB3LYP/6-31G(d,p). Additionally, IR spectra of the tautomers were calculated. Moreover, the phenolate ions obtained from the most stable tautomer in water were considered, and the protonation of this tautomer at various possible sites was investigated quantum chemically.