Kurinovich, Mary Ann published the artcileThe acidity of uracil and uracil analogs in the gas phase: four surprisingly acidic sites and biological implications, Recommanded Product: 3-Methylpyrimidine-2,4(1H,3H)-dione, the publication is Journal of the American Society for Mass Spectrometry (2002), 13(8), 985-995, database is CAplus and MEDLINE.
The gas phase acidities of a series of uracil derivatives (1-methyluracil, 3-methyluracil, 6-methyluracil, 5,6-dimethyluracil, and 1,3-dimethyluracil) have been bracketed to provide an understanding of the intrinsic reactivity of uracil. The experiments indicate that in the gas phase, uracil has four sites more acidic than water. Among the uracil analogs, the N1-H sites have ΔHacid values of 331-333 kcal mol-1; the acidity of the N3 sites fall between 347-352 kcal mol-1. The vinylic C6 in 1-methyluracil and 3-methyluracil brackets to 363 kcal mol-1, and 369 kcal mol-1 in 1,3-dimethyluracil; the C5 of 1,3-dimethyluracil brackets to 384 kcal mol-1. Calculations conducted at B3LYP/6-31+G are in agreement with the exptl. values. The bracketing of several of these sites involved utilization of an FTMS protocol to measure the less acidic site in a mol. that has more than one acidic site, establishing the generality of this method. In mols. with multiple acidic sites, only the two most acidic sites were bracketable, which is attributable to a kinetic effect. The measured acidities are in direct contrast to solution acidities, where the two most acidic sites of uracil (N1 and N3) are cannot be differentiated. The vinylic C6 site is also particularly acidic, compared to acrolein and pyridine. The biol. implications of these results particularly with respect to enzymes for which uracil is a substrate are discussed.
Journal of the American Society for Mass Spectrometry published new progress about 608-34-4. 608-34-4 belongs to pyrimidines, auxiliary class Pyrimidine,Amide, name is 3-Methylpyrimidine-2,4(1H,3H)-dione, and the molecular formula is C5H6N2O2, Recommanded Product: 3-Methylpyrimidine-2,4(1H,3H)-dione.
Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia