4-Phenoxybutoxy-substituted heterocycles--a structure-activity relationship study of blockers of the lymphocyte potassium channel Kv1.3

Eur J Med Chem. 2009 May;44(5):1838-52. doi: 10.1016/j.ejmech.2008.10.033. Epub 2008 Nov 5.


The voltage-gated potassium channel Kv1.3 constitutes an attractive pharmacological target for the treatment of effector memory T cell-mediated autoimmune diseases such as multiple sclerosis and psoriasis. Using 5-methoxypsoralen (5-MOP, 1), a compound isolated from Ruta graveolens, as a template we previously synthesized 5-(4-phenoxybutoxy)psoralen (PAP-1, 2) which inhibits Kv1.3 with an IC(50) of 2nM. Since PAP-1 is more than 1000-fold more potent than 5-MOP, we here investigated whether attaching a 4-phenoxybutoxy side chain to other heterocyclic systems would also produce potent Kv1.3 blockers. While 4-phenoxybutoxy-substituted quinolines, quinazolines and phenanthrenes were inactive, 4-phenoxybutoxy-substituted quinolinones, furoquinolines, coumarins or furochromones inhibited Kv1.3 with IC(50)s of 150 nM to 10 microM in whole-cell patch-clamp experiments. Our most potent new compound is 4-(4-phenoxybutoxy)-7H-furo[3,2-g]chromene-7-thione (73, IC(50) 17 nM), in which the carbonyl oxygen of PAP-1 is replaced by sulfur. Taken together, our results demonstrate that the psoralen system is a crucial part of the pharmacophore of phenoxyalkoxypsoralen-type Kv1.3 blockers.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 5-Methoxypsoralen
  • Autoimmune Diseases / drug therapy
  • Ficusin / chemistry
  • Ficusin / pharmacology
  • Heterocyclic Compounds / chemistry
  • Heterocyclic Compounds / pharmacology*
  • Humans
  • Kv1.3 Potassium Channel / antagonists & inhibitors*
  • Lymphocytes* / chemistry
  • Lymphocytes* / drug effects
  • Methoxsalen / analogs & derivatives
  • Pancreatitis-Associated Proteins
  • Ruta
  • Structure-Activity Relationship
  • T-Lymphocytes / immunology


  • Heterocyclic Compounds
  • Kv1.3 Potassium Channel
  • Pancreatitis-Associated Proteins
  • REG3A protein, human
  • 5-Methoxypsoralen
  • Ficusin
  • Methoxsalen