A parallel synthesis demonstration library of tri-substituted indazoles containing new antimutagenic/antioxidant hits related to benzydamine

Comb Chem High Throughput Screen. 2003 Aug;6(5):471-80. doi: 10.2174/138620703106298644.

Abstract

A solution phase strategy for the multiple parallel synthesis of a demonstration library of indazoles is described by which regio-selectivity problems inherent to previous syntheses of this nucleus are largely overcome. Synthesis of selected components proceeded satisfactorily indicating that a fully realized library of indazole analogs could readily be produced using this methodology. Simple modifications of the basic nucleophilic aromatic substitution route unambiguously produce a range of N-1 substitutions (alkyl, aryl and aralkyl) in 50-75% yields. Next a range of substituents was introduced at the C-3 position in 50-80% yields by O-alkylation. Careful choice of reagents and reaction conditions were required to prevent by-product formation due to competing alkylation at N-2 (trace to 15% yields). When present, these contaminants were readily removed by chromofiltration. A third diversity site was sketched in at C-5 in 75-90% yield by reductive alkylation or acylation. Screening of some of the demonstration library members in vitro revealed highly active antioxidants suggesting that producing a full library would be worthwhile.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Antimutagenic Agents / chemistry*
  • Antioxidants / chemistry*
  • Combinatorial Chemistry Techniques
  • Indazoles / chemical synthesis*
  • Indazoles / chemistry
  • Magnetic Resonance Spectroscopy
  • Spectrometry, Mass, Electrospray Ionization

Substances

  • Antimutagenic Agents
  • Antioxidants
  • Indazoles