PROTOLYTIC EQUILIBRIUM OF CERTAIN ANNELATED AZOLOAZINES

Authors

  • А. П. Воловоденко St. Petersburg State Technological Institute
  • P. E. Трифонов St. Petersburg State Technological Institute
  • П. B. Плеханов Institute of Organic Synthesis, Urals Branch, Russian Academy of Sciences (RAN), Ekaterinburg
  • Г. Л. Русинов Institute of Organic Synthesis, Urals Branch, Russian Academy of Sciences (RAN), Ekaterinburg
  • Д. Г. Береснев Institute of Organic Synthesis, Urals Branch, Russian Academy of Sciences (RAN), Ekaterinburg
  • В. А. Островский Санкт-Петербургский государственный технологический институт

DOI:

https://doi.org/10.1007/243

Keywords:

annelated azoloazines, basicity, protonation, prototropic tautomerism

Abstract

The first and second protonations of annelated azoloazines have been investigated quantitatively in aqueous solution. Compounds investigated were pyrazolo[1,5-a]pyrimidine (pKBH+ 0.03±0.02, pKBH2+ ‑7.87±0.30), 1,2,4-triazolo[4,3-b]-1,2,4-triazine (pKBH+ -0.04±0.02, pKBH2+ -8.00±0.10), 1,2,4‑triazolo[1,5-a]pyrimidine (pKBH+ 0.21±0.03, pKBH2+ -9.00±0.09) and its 6R derivatives (R = NO2, Br, Cl). The annelated azoloazines studied are weaker bases than their unannelated analogs. According to quantum chemical calculations (AM1), protonation of these heterocycles may occur both at the azole and the azine fragments of the molecule.

Authors: A. P. Volovodenko, R. E. Trifonov, P. V. Plekhanov, G. L. Rusinov, D. G. Beresnev, and V. A. Ostrovskii.

English Translation in Chemistry of Heterocyclic Compounds, 2000, 36 (6), pp 714-721

http://link.springer.com/article/10.1007/BF02297681

Author Biography

В. А. Островский, Санкт-Петербургский государственный технологический институт

St. Petersburg State Technological Institute

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Published

2013-02-04

Issue

No. 6 (2000)

Section

Original Papers