On January 11, 2018, Ilyina, Margarita G.; Khamitov, Edward M.; Ivanov, Sergey P.; Mustafin, Akhat G.; Khursan, Sergey L. published an article.Recommanded Product: 6-Methylpyrimidine-2,4(1H,3H)-dione The title of the article was Theoretical Models for Quantitative Description of the Acid-Base Equilibria of the 5,6-Substituted Uracils. And the article contained the following:
The acidities of 18 5,6-substituted uracils have been numerically estimated as pKa values in terms of three theor. models. The first scheme includes the calculation of the gas-phase acidity of uracil with the G3MP2B3 method and taking into account the solvent effect using the polarizable continuum approximation PCM(SMD)-TPSS/aug-cc-pVTZ. The second model is one-step and implies calculating of the free Gibbs energies of the hydrate complex of uracil (and its anion) with 5 water mols. by the TPSS/aug-cc-pVTZ method. This model accounts the solvent effect corresponding to both specific and nonspecific solvation. The third scheme required high time and computational resources and includes the strong features of the two previous schemes. Here, the theor. estimation of pKa is performed by the CBS-QB3 composite method. As in the second approach, both specific (as pentahydrate) and nonspecific solvent effects are accounted. We have analyzed the advantages and model restrictions of the considered schemes for the pKa calculations All models have the systematic errors, which have been corrected with the linear empirical regression relations. Herewith, the absolute mean deviations of the pKa values of uracils dissociating via the N1-H bonds diminish to 0.25, 0.28 and 0.23 pKa units (resp., for I, II, and III models) that corresponds to ∼0.3 kcal/mol on the energy scale. The applicability of our computational schemes to uracils dissociating via N3-H, O-H (orotic acids) and C-H bonds is discussed. The experimental process involved the reaction of 6-Methylpyrimidine-2,4(1H,3H)-dione(cas: 626-48-2).Recommanded Product: 6-Methylpyrimidine-2,4(1H,3H)-dione
The Article related to acid base equilibrium acidity uracil derivative water solution, Phase Equilibriums, Chemical Equilibriums, and Solutions: Acid-Base Equilibriums, Complex Formation and other aspects.Recommanded Product: 6-Methylpyrimidine-2,4(1H,3H)-dione
Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia