C–C RECYCLIZATIONS OF SOME 2,7-DISUBSTITUTED 6-ETHOXYCARBONYLPYRAZOLO[1,5-<i>a</i>]PYRIMIDINES

Authors

  • Г. Г. Данагулян Russian-Armenian (Slavonic) State University, Institute of Organic Chemistry, Scientific-Technological Center of Organic and Pharmaceutical Chemistry of the National Academy of Sciences of the Republic of Armenia
  • А. П. Бояхчян Institute of Organic Chemistry, Scientific-Technological Center of Organic and Pharmaceutical Chemistry of the National Academy of Sciences of the Republic of Armenia
  • А. Г. Данагулян Institute of Organic Chemistry, Scientific-Technological Center of Organic and Pharmaceutical Chemistry of the National Academy of Sciences of the Republic of Armenia
  • Г. А. Паносян Molecular Structure Research Center, Scientific-Technological Center of Organic and Pharmaceutical Chemistry of the National Academy of Sciences of the Republic of Armenia

DOI:

https://doi.org/10.1007/2104

Keywords:

pyrazolo[1, 5-a]pyrimidine, 1, 2, 4-triazolo[1, rearrangement, recyclization

Abstract

Condensation of ethyl ethoxymethyleneacetoacetate and ethyl ethoxymethylenecyanoacetate in ethanol with 3-substituted 3-aminopyrazoles and 5-amino-1,2,4-triazole gave the 2-substituted 6-ethoxy-carbonyl-7-methyl- and 7-amino-6-ethoxycarbonylpyrazolo[1,5-a]pyrimidines as well as 7-amino-6-ethoxycarbonyl-1,2,4-triazolo[1,5-a]pyrimidine. In the presence of alkali these rearranged to 2-substituted 6-acetyl-7-hydroxy- and 6-carbamoyl-7-hydroxypyrazolo[1,5-a]pyrimidines respectively and also to 6-carbamoyl-7-hydroxy-1,2,4-triazolo[1,5-a]pyrimidine. According to 1H (including NOESY) NMR spectroscopic data there were formed, along with the cyclization products, noncyclic condensation adducts (as cyano derivatives) from ethyl ethoxymethylenecyanoacetate with 5-aminopyrazoles. In the presence of alcoholic alkaline solution these were also transformed in high yield to 6-carbamoyl-7-hydroxypyrazolopyrimidines. When refluxed for a longer time in 12% aqueous alcoholic alkaline solution the 6-ethoxycarbonyl-2,7-dimethylpyrazolo[1,5-a]pyrimidine and 6-acetyl-7-hydroxy-2-methylpyrazolo[1,5-a]pyrimidine recyclize to give 6-carboxy-2,7-dimethyl- and 2,7-di-methylpyrazolo[1,5-a]pyrimidines.

How to Cite
Danagulyan, G. G.; Boyakhchyan, A. P.; Danagulyan, A. G.; Panosyan, H. A. Chem. Heterocycl. Compd. 2011, 47(3), 321. [Khim. Geterotsikl. Soedin. 2011, 393.]

For this article in the English edition see DOI 10.1007/s10593-011-0760-x

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Published

2014-12-01

Issue

No. 3 (2011)

Section

Original Papers