Indene-based scaffolds. Design and synthesis of novel serotonin 5-HT6 receptor ligands

Org Biomol Chem. 2008 Oct 21;6(20):3795-810. doi: 10.1039/b808641a. Epub 2008 Aug 11.

Abstract

A series of novel indene derivatives designed by a scaffold selection gave access to several examples of (Z)-arylmethylideneindenes and indenylsulfonamides that acted as serotonin 5-HT(6) receptor ligands. Different synthetic multistep routes could be applied to these target compounds, each with their own complexity and limitations. A reasonable route involved the (3-indenyl)acetic acids as the key intermediates, and two alternatives were also examined. The first protocol used was a two-step sequence employing a modified Horner-Wadsworth-Emmons reaction, but better results were obtained with a procedure based on the condensation of indanones with the lithium salt of ethyl acetate, followed immediately by dehydration with acid and hydrolysis/isomerization under basic catalysis. (3-Indenyl)acetic acids were transformed to the corresponding acetamides, which were effectively reduced to indenylsulfonamides using an optimized procedure with AlH(3)-NMe(2)Et. The binding at the 5-HT(6) receptor was with moderate affinity (K(i) = 216.5 nM) for the (Z)-benzylideneindenylsulfonamide and enhanced affinity for the simple indenylsulfonamide counterpart (K(i) = 50.6 nM). Selected indenylsulfonamides were then tested, showing K(i) values as low as 20.2 nM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Drug Design*
  • Humans
  • Indenes / chemical synthesis*
  • Indenes / chemistry
  • Indenes / metabolism*
  • Ligands
  • Protein Binding
  • Receptors, Serotonin / metabolism*

Substances

  • Indenes
  • Ligands
  • Receptors, Serotonin
  • serotonin 6 receptor
  • indene