Synthesis, spectroscopic characterisation and X-ray analysis of regioisomeric 1,3,5-trisubstituted pyrazoles

Uzma Yunus, Rukhsana Kauser, Moazzam H. Bhatti, Muhammad Zia-Ul-Haq, Wai Yeung Wong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

2 Citations (Scopus)

Abstract

A new series of regioisomeric 1,3,5-trisubstituted pyrazoles 7-9(a,b) have been synthesized by the reaction of β-diketones (4-6) with methyl hydrazine in ethanol. All the compounds are characterised by the FT-IR,1H,13C NMR and mass spectrometry. The crystal structure of compounds 7a, 7b and minor isomer 8b have been determined by X-ray single crystal analysis which showed either of the substituted groups attached to pyrazole ring are essentially non-planar to the central pyrazole ring. Addition of trace amounts of acetic acid during the synthesis of compound 8 resulted in an unexpected compound 10 which is characterised by the X-ray single crystal analysis and is essentially planar. However, crystal structure of 10 is already reported. All structures are further stabilized by the classic and non-classic inter- and intramolecular hydrogen bonding.
Original languageEnglish
Pages (from-to)173-180
Number of pages8
JournalJournal of Molecular Structure
Volume995
Issue number1-3
DOIs
Publication statusPublished - 31 May 2011
Externally publishedYes

Keywords

  • β-diketones
  • Methyl hydrazine
  • Pyrazoles
  • X-ray analysis

ASJC Scopus subject areas

  • Analytical Chemistry
  • Spectroscopy
  • Organic Chemistry
  • Inorganic Chemistry

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