Regioselective Synthesis of 1,3,5-Trisubstituted Pyrazoles Containing an Anthranilic Acid Motif

Viktor A. Savel’ev, Anna A. Kotova, Tatyana V. Rybalova, Elvira E. Shults

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

An effective method was developed for the synthesis of 1,3,5-trisubstituted pyrazoles by using acetylenic ketones, obtained from ethyl 5-ethynylanthranilate, in reactions with substituted hydrazines and hydrazides. It was shown that the cyclization of ethyl 5-(3-aryl-3-oxopropinyl)- anthranilates with arylhydrazines proceeded regioselectively and led to the formation of 1,3,5-trisubstituted pyrazoles containing an anthranilate moiety at the position C-3. Significant deterioration of regioselectivity was observed in the reactions of ethyl 5-(3-aryl-3-oxopropinyl)anthranilates with N-methyl- and N-tert-butylhydrazines. The initial products formed in reactions of ethyl 5-[3-(4-fluorophenyl)-3-oxopropinyl]anthranilate with benzoyl and isonicotinoyl hydrazides were 5-hydroxypyrazolines, which underwent dehydration in the presence of pyridine and thionyl chloride in benzene, giving the respective 1,3,5-trisubstituted pyrazoles.

Original languageEnglish
Pages (from-to)943-955
Number of pages13
JournalChemistry of Heterocyclic Compounds
Volume55
Issue number10
DOIs
Publication statusPublished - 1 Oct 2019

Keywords

  • alkynyl ketones
  • cyclization
  • ethynyl anthranilates
  • hydrazines
  • pyrazoles
  • X-ray structural analysis
  • CATALYSIS
  • DESIGN
  • PALLADIUM COMPLEXES
  • MODULATORS
  • PYRIMIDINES
  • CRYSTAL-STRUCTURES
  • PATHWAY
  • ACETYLENIC KETONES
  • DERIVATIVES

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