On January 10, 2013, Notario, Rafael; Emel’yanenko, Vladimir N.; Roux, Maria Victoria; Ros, Francisco; Verevkin, Sergey P.; Chickos, James S.; Liebman, Joel F. published an article.Name: 6-Methylpyrimidine-2,4(1H,3H)-dione The title of the article was Thermochemistry of Uracils. Experimental and Computational Enthalpies of Formation of 5,6-Dimethyl-, 1,3,5-Trimethyl-, and 1,3,5,6-Tetramethyluracils. And the article contained the following:
An exptl. and computational study of three methylated uracils, in particular, the 5,6-dimethyl-, 1,3,5-trimethyl-, and 1,3,5,6-tetra-Me derivatives are presented. The values of the standard (p0 = 0.1 MPa) molar enthalpies of formation in the gas phase at T = 298.15 K have been determined The energies of combustion were measured by static bomb combustion calorimetry, and from the results obtained, the standard molar enthalpies of formation in the crystalline state at T = 298.15 K were calculated The enthalpies of sublimation were determined using the transpiration method in a saturated N2 stream. Values of -(376.2 ± 2.6), -(355.9 ± 3.0), and -(381.7 ± 2.8) kJ·mol-1 for the gas-phase enthalpies of formation at T = 298.15 K of 5,6-dimethyluracil, 1,3,5-trimethyluracil, and 1,3,5,6-tetramethyluracil, resp., were obtained from the exptl. thermochem. study. An extended theor. study with the G3 and the G4 quantum-chem. methods has been carried out for all the possible methylated uracils. There is very good agreement between exptl. and calculated enthalpies of formation for the three derivatives studied. A Free-Wilson anal. on G4-calculated enthalpies of formation has been carried out, and the contribution of methylation in the different positions of the uracil ring has been estimated The experimental process involved the reaction of 6-Methylpyrimidine-2,4(1H,3H)-dione(cas: 626-48-2).Name: 6-Methylpyrimidine-2,4(1H,3H)-dione
The Article related to enthalpy combustion sublimation formation methyluracil exptl theory, Thermodynamics, Thermochemistry, and Thermal Properties: Thermochemical Properties and other aspects.Name: 6-Methylpyrimidine-2,4(1H,3H)-dione
Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia