Regioselective synthesis of 4- and 7-alkoxyindoles from 2,3-dihalophenols: application to the preparation of indole inhibitors of phospholipase A2

J Org Chem. 2007 Jul 6;72(14):5113-8. doi: 10.1021/jo070643y. Epub 2007 Jun 9.

Abstract

An efficient and regioselective synthesis of 4- and 7-alkoxyindoles has been developed from commercially available starting materials such as 3-halophenols and 3-chloroanisole. Directed ortho-metalation followed by two palladium-catalyzed processes, a Sonogashira coupling and a tandem amination/cyclization reaction, allows the synthesis of regiochemically pure 4- and 7-substituted indoles. This strategy has been successfully applied to the preparation of 2-[3-(2-amino-2-oxoacetyl)-1-benzyl-2-ethyl-1H-indol-4-yloxy]acetic acid (LY315920), a known inhibitor of phospholipase A2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkanes / chemical synthesis*
  • Alkylation
  • Anisoles / chemistry*
  • Enzyme Inhibitors / chemical synthesis*
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology
  • Ethers / chemistry
  • Indoles / chemical synthesis*
  • Indoles / chemistry
  • Molecular Structure
  • Oxygen / chemistry
  • Phenols / chemistry*
  • Phospholipases A / antagonists & inhibitors*
  • Phospholipases A / metabolism
  • Phospholipases A2
  • Stereoisomerism

Substances

  • 3-chloroanisole
  • Alkanes
  • Anisoles
  • Enzyme Inhibitors
  • Ethers
  • Indoles
  • Phenols
  • indole
  • Phospholipases A
  • Phospholipases A2
  • Oxygen