Chemistry of Heterocyclic Compounds

, Volume 7, Issue 7, pp 892–893 | Cite as

Preparation of the simplest Δ1-pyrazolines by isomerization of Δ2-pyrazolines

  • B. V. Ioffe
  • N. B. Burmanova


Δ2-Pyrazolines that do not have substituants in the 1- and 3-positions are not capable of isomerization to 3-substituted pyrazolines and can be converted to Δ1-pyrazolines by slow distillation in the presence of bases. This method, which is completely analogous to the synthesis of azo compounds from alkylhydrazones, gives good results when applied to 4-alkyl- and 5,5-dialkyl-Δ2-pyrazolines and makes it possible to obtain the corresponding Δ1-pyrazolines in yields of 40–70%. 4-Ethyl-, 5-methyl-5-ethyl-, and 5,5-diethyl-Δ1-pyrazolines are described for the first time.


Organic Chemistry Pyrazolines 
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Copyright information

© Consultants Bureau, a division of Plenum Publishing Corporation 1974

Authors and Affiliations

  • B. V. Ioffe
    • 1
  • N. B. Burmanova
    • 1
  1. 1.A. A. Zhdanov Leningrad State UniversityUSSR

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