Publication detail

Kinetic study of the formation of 1,4-diaryl pyrazoles via 1,3-dipolar cycloaddition from N-arylsydnones

Authors: Hladíková Veronika | Kammel Richard | Hanusek Jiří

Year: 2016

Type of publication: ostatní - přednáška nebo poster

Page from-to: nestránkováno

Titles:

Language	Name	Abstract	Keywords
eng	Kinetic study of the formation of 1,4-diaryl pyrazoles via 1,3-dipolar cycloaddition from N-arylsydnones	Sydnones belong to a group of mesoionic aromatic compounds displaying many important properties. Recently Kolodych et al. reported copper-catalyzed sydnone-alkyne regioselective cycloaddition under milder conditions providing higher yield. Several pyrazoles have been prepared using this protocol, but no kinetic study on their formation has appeared until now. We performed preliminary HPLC kinetic study of Cu-mediated cycloaddition of N-phenylsydnones with terminal alkynes (CuSAC) giving exclusively 1,4-diarylpyrazoles. The reaction rate was measured under various conditions. It was found that kinetic rate is dependent on starting concentration of sydnone but independent on the starting concentration of phenylacetylene. A dramatic acceleration of reaction rate was observed after the addition of 5 equivalents of sydnone and under these conditions reaction occurred within 8 hour with complete conversion. The kinetic curve is of zero-order to the sydnone.

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