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Chemistry of Heterocyclic Compounds

, Volume 46, Issue 9, pp 1144–1145 | Cite as

Synthesis of mesoionic 1,2,4-triazolo[4,3-a]pyrimidin-5-ones and subsituted formamidines from diethyl (5-1-r-1h-1,2,4-triazol -3-yl)aminomethylenemalonates

  • A. V. Astakhov
  • V. M. ChernyshevEmail author
Article

Introduction

Hetaryl-substituted aminomethylenemalonates obtained by the condensation of aminoazoles with 2-alkoxymethylenemalonates are commonly used for the synthesis of biologically active azolopyrimidines [1, 2]. However, cyclization of hetaryl-substituted aminomethylenemalonates to give azolopyrimidines often proceeds only at high temperature or under upon microwave activation [1] or by using special reagents [2]. In the present work, we found that brief heating of diethyl aminomethylenemalonates 1a and 1b in ethanol in the presence of sodium ethylate leads to the formation of mesoionic 1,2,4-triazolo[4,3-a]pyrimidin-5-ones 2a or 2b in high yield. This reaction does not occur upon heating aminomethylenemalonates 1a or 1b with tertiary aliphatic amines in ethanol at reflux. However, heating esters 1 with primary or secondary amines in ethanol or acetonitrile at reflux leads to nucleophilic substitution of the malonate ester and formation of amidines 3a-c in high yield.

Keywords

amidines aminomethylenemalonates mesoionic 1,2,4-triazolo[4,3-a]pyrimidin-5-ones cyclization 

References

  1. 1.
    G. Bratulescu, Synthesis, 2833 (2005).Google Scholar
  2. 2.
    N. M. Ahmad and K. Jones, Tetrahedron Lett., 51, 3263 (2010).CrossRefGoogle Scholar
  3. 3.
    V. M. Chernyshev, A. A. Astakhov, and Z. A. Starikova, Tetrahedron, 66, 3301 (2010).CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, Inc. 2010

Authors and Affiliations

  1. 1.South Russian State Technical UniversityNovocherkasskRussia

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