Synthesis of 4,5-diaryl-1H-pyrazole-3-ol derivatives as potential COX-2 inhibitors

J Org Chem. 2004 Oct 15;69(21):7058-65. doi: 10.1021/jo049264k.

Abstract

4,5-Diaryl-1H-pyrazole-3-ol was utilized as a versatile template to synthesize several classes of compounds such as pyrazolo-oxazines 7, pyrazolo-benzooxazines 9, pyrazolo-oxazoles 10, and its analogues 11a-c as potential COX-2 inhibitors. Compounds 11b,c were successfully synthesized with use of pyridinium p-toluenesulfonate mediated cyclization of the ketal intermediate. Diaryl-pyrazolo-benzooxazepine analogues were synthesized by using Cu-mediated cyclization of the O-alkylated arylbromide intermediate. Arylsulfonamides were synthesized efficiently on a large scale with 4-[4-(4-fluorophenyl)-5-hydroxy-2H-pyrazol-3-yl]benzenesulfonamide 31 template readily synthesized from commercially available 4-sulfamoyl benzoic acid 29. The structure of a representative compound from each class was confirmed by X-ray crystallography. Selected compounds tested for inhibitory activity against COX-1 and COX-2 enzymes showed good selectivity for COX-2 versus COX-1 enzyme.

MeSH terms

  • Crystallography, X-Ray
  • Cyclooxygenase 1
  • Cyclooxygenase 2
  • Cyclooxygenase 2 Inhibitors
  • Cyclooxygenase Inhibitors / chemical synthesis*
  • Cyclooxygenase Inhibitors / pharmacology*
  • Isoenzymes / antagonists & inhibitors*
  • Molecular Structure
  • Prostaglandin-Endoperoxide Synthases
  • Pyrazoles / chemical synthesis*
  • Pyrazoles / pharmacology*

Substances

  • Cyclooxygenase 2 Inhibitors
  • Cyclooxygenase Inhibitors
  • Isoenzymes
  • Pyrazoles
  • Cyclooxygenase 1
  • Cyclooxygenase 2
  • Prostaglandin-Endoperoxide Synthases