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Chemistry of Heterocyclic Compounds

, Volume 15, Issue 5, pp 501–507 | Cite as

Strong base-catalyzed thermal rearrangements of azines of benzyl alkyl ketones

  • I. I. Grandberg
  • L. B. Dmitriev
  • V. I. Sorokin
  • Yu. A. Larshin
Article
  • 48 Downloads

Abstract

Azines of benzyl alkyl ketones undergo cyclization in the presence of strong basic catalysts to give mixtures of compounds of the pyrrole and pyrazole series. The formation of pyrazole products probably proceeds via the scheme of the Fischer reaction taking into account the concept of a [3,3] sigmatropic shift. However, the presence of nitriles and hydrocarbons among the products of the reaction of pyrazole derivatives indicates the ambiguous character of the proposed scheme. The rearrangement of azines to pyrazole compounds probably proceeds through a step involving the formation of a carbanion, while the formation of nitriles and hydrocarbons can be explained by radical processes. The dependence of the ratio of the pyrolysis products (pyrrole/pyrazole) on the amount of catalyst and its basicity (LiH, NaH, KH, NaOH, KOH, PhOK, and CH3OK) makes it possible to assume that the occurrence of the reaction through a step involving a [3,3] shift is realized thermally and that small amounts of the catalyst promote the realization of this reaction pathway; however, a high percentage of the catalyst and the use of the most basic catalysts lead to an increase in the yields of the pyrazole products.

Keywords

Hydrocarbon Pyrolysis Nitrile Benzyl Pyrrole 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Plenum Publishing Corporation 1979

Authors and Affiliations

  • I. I. Grandberg
    • 1
  • L. B. Dmitriev
    • 1
  • V. I. Sorokin
    • 1
  • Yu. A. Larshin
    • 1
  1. 1.K. A. Timiryazev Moscow Agricultural AcademyMoscow

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