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


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.


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


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    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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