A 18 Acid-base properties and prototropic tautomerism of isomeric 1,2,4-triazin-3- and -5-ones [Electronic resource] / I. V. Khabibulina, R. E. Trifonov, A.P. Volovodenko, M. S. Eremenkova, O. N. Chupakhin, V. L. Rusinov, G. V. Zyryanov, V. A. Ostrovskii // Russian Journal of Organic Chemistry (Translation of Zhurnal Organicheskoi Khimii). - 2004. - Vol. 40, № 3. - P426-430. - Bibliogr. : p. 430 (40 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ACID -- BASE -- TRIAZINE DERIVATIVE -- AQUEOUS SOLUTION Аннотация: The acidity and basicity constants of isomeric phenyl(aryl)-1,2,4-triazin- 3- and -5-ones in aqueous solution were determined by spectrophotometry: pK a = 7.3-6.2; pKBH+ = 0.1 to -2.2. 1,2,4-Triazin-3-ones are weaker bases than the corresponding 1,2,4-triazin-5-ones. According to the AM1 calculations, the most thermodynamically favorable tautomer in the gas phase is the oxo form: namely, 2H-tautomers of the neutral bases and 2,4-H,H +-tautomers of the conjugate acids. \\\\Expert2\\nbo\\Russian Journal of Organic Chemistry\\2004, 40 (3), 426.pdf |