The Condensation of (Chlorocarbonyl)phenyl Ketene with Bisnucleophiles. Synthesis of 4-Hydroxy-5-phenylpyro-[2,3-c]pyrazol-6-ones and Formation of Pyrazolo[1,2-a]pyrazole-triones by Hydrogen Exchange in Unstable Mesoionic Compounds

Mehdi Abaszadeh; Hassan Sheibani; Kazem Saidi

doi:10.1071/CH09344

RESEARCH ARTICLE

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The Condensation of (Chlorocarbonyl)phenyl Ketene with Bisnucleophiles. Synthesis of 4-Hydroxy-5-phenylpyro-[2,3-c]pyrazol-6-ones and Formation of Pyrazolo[1,2-a]pyrazole-triones by Hydrogen Exchange in Unstable Mesoionic Compounds

Mehdi Abaszadeh ^A , Hassan Sheibani ^A ^B and Kazem Saidi ^A

+ Author Affiliations

- Author Affiliations

^A Department of Chemistry, Shahid Bahonar University of Kerman, Kerman 76169, Iran.

^B Corresponding author. Email: hsheibani@mail.uk.ac.ir

Australian Journal of Chemistry 63(1) 92-95 https://doi.org/10.1071/CH09344
Submitted: 18 June 2009 Accepted: 29 July 2009 Published: 8 January 2010

Abstract

The addition of (chlorocarbonyl)phenyl ketene 2 to 5-alkylpyrazol-3(4H)-ones 1 led to the formation of 3-hydroxypyrazolo[1,2-a]pyrazole-dione/pyrazolo[1,2-a]pyrazole-trione derivatives 3. This is ascribed to hydrogen exchange in initially formed unstable, mesoionic pyrazolo[1,2-a]pyrazol-4-ium-5-olates. In contrast, condensation of the same ketene with 3-alkyl-1-phenyl-2-pyrazolin-5-ones 4 afforded 4-hydroxy-3-alkyl-1,5-diphenylpyrano[2,3-c]pyrazol-6-one derivatives 5. The latter reaction provides a new and rapid route to 4-hydroxy-2-pyrones fused to pyrazole rings, in good to excellent yields.

Acknowledgements

The authors express appreciation to the Shahid Bahonar University of Kerman Faculty Research Committee for its support of this investigation.

References

The Condensation of (Chlorocarbonyl)phenyl Ketene with Bisnucleophiles. Synthesis of 4-Hydroxy-5-phenylpyro-[2,3-c]pyrazol-6-ones and Formation of Pyrazolo[1,2-a]pyrazole-triones by Hydrogen Exchange in Unstable Mesoionic Compounds

Abstract

Acknowledgements

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