Design, synthesis and pharmacological evaluation of novel tetrasubstituted thiophene analogues as anti-inflammatory agents

J Enzyme Inhib Med Chem. 2008 Dec;23(6):819-28. doi: 10.1080/14756360701608692.

Abstract

A new series of tetrasubstituted thiophene analogues (4a-4f, 5a-5f and 8a-8i) were designed incorporating the pharmacophoric features of COX-1 (as in fenamates), 5-LOX and the p38 MAP kinase inhibitors. The designed series was synthesized by nucleophilic addition of aryl/aroylisothiocyanate and enamine (2) yielding the addition product l-(alpha-Carbomethoxy-beta-aminothiocrotonoyl)-aryl/aroyl amines (3/7); which on reaction with substituted phenacyl bromides gave the targeted tetrasubstituted thiophene esters (4a-4f / 8a-8i). The tetrasubstituted thiophenes esters (4a-4f ) on hydrolysis with one equivalent of potassium hydroxide solution in methanol at room temperature gave corresponding acids (5a-5f ). All the targeted compounds were evaluated for their anti-inflammatory activity in carrageenin-induced rat hind paw oedema model at the doses of 10, 20 and 40 mg/kg body weight using standard drugs mefanamic acid and ibuprofen. The compounds (4c, 4e, 4f, 5f, 8a- 8i) which gave reasonable protection to the inflamed paw, eliciting good or moderate comparable anti-inflammatory activity were selected for investigating their analgesic activity using acetic acid induced writhing response test in albino mice at 10 mg/kg dose using standard drug ibuprofen and in order to arrive at possible mechanism of their anti-inflammatory activity, in vitro antioxidant nitric oxide radical scavenging assay at the concentrations of 5, 10, 15, 20, 25, 30 and 35 microg/mL were performed using standard drug ascorbic acid.

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / chemical synthesis*
  • Anti-Inflammatory Agents / chemistry
  • Anti-Inflammatory Agents / pharmacology
  • Anti-Inflammatory Agents / therapeutic use*
  • Antioxidants / chemical synthesis
  • Antioxidants / chemistry
  • Antioxidants / pharmacology
  • Drug Design*
  • Edema / chemically induced
  • Edema / drug therapy
  • Female
  • Male
  • Molecular Structure
  • Rats
  • Structure-Activity Relationship
  • Thiophenes / chemical synthesis*
  • Thiophenes / chemistry
  • Thiophenes / pharmacology
  • Thiophenes / therapeutic use*

Substances

  • Anti-Inflammatory Agents
  • Antioxidants
  • Thiophenes