Solvent effect on keto–enol tautomerism in a new β-diketone: a comparison between experimental data and different theoretical approaches

In vitro study on potential pharmacological activity of curcumin analogues and their copper complexes

“…DFT calculations on K2T31 were performed to predict a possible structure of [Cu (K2T31) 2 ] complex and to elucidate the antioxidant properties of metal complexes, in particular the ability to scavenge DPPH. The theoretical calculation confirms that in vacuo , the keto–enol tautomer is the most stable one as previously observed for curcumin and other substituted curcuminoids …”

“…Recently, our interest has been directed to the synthesis of curcumin derivatives showing greater chemical stability while maintaining almost unchanged the biological properties of the lead compound as a prelude to a good pharmacological activity. A wide variety of curcumin analogues were synthesized with structural modifications on both the aromatic rings and the diketonic group by the insertion of an alkyl substituent to the central carbon atom . Among these derivatives, those with a t ‐butyl ester on central carbon atom, namely K2T series, showed higher chemical stability under physiological condition with respect to curcumin and showed cytotoxicity against different tumorigenic cell lines, with IC 50 values similar to or in many cases lower than curcumin itself .…”

Tautomerism: Introduction, History, and Recent Developments in Experimental and Theoretical Methods

“…Since in fluorescence experiments no accumulation in the T state is observed, the back reaction to E is also considered fast, although no direct experiments have confirmed this so far. of the small free energy differences between the tautomeric forms [81,82]; the situation with calculations of barriers between the tautomeric forms is not much better. Even apart from the question of whether it is just the barrier heights that are needed to estimate the tunneling frequencies -this idea probably derives from Arrhenius and the transition-state theory, but in tunneling other parameters are also relevant -no consensus can be found between various methods to calculate these.…”

Tautomerism in o-hydroxyanilino-1,4-naphthoquinone derivatives: Structure, NMR, HPLC and density functional theoretic investigations

“…Isomerisation of prototrophic tautomers refers to the migration of proton from atom to another such as C, N, O or may be S. The migration of such proton involving carbon atom being sufficiently slow so that the corresponding tautomers could be separated easily in solution. Contrary to this the proton transfer involving nitrogen to oxygen or vice-versa are rapid and the separation of tautomers in solution [3,4] become far from straightforward. Tautomeric equillibria are dependent on the dielectric constant of the medium and the ability of solvents to hydrogen bond with each tautomer.…”