Benzophenone derivatives and related compounds as potent histamine H3-receptor antagonists and potential PET/SPECT ligands

Arch Pharm (Weinheim). 2001 Feb;334(2):45-52. doi: 10.1002/1521-4184(200102)334:2<45::aid-ardp45>3.0.co;2-2.

Abstract

Para-substituted aromatic ethers with benzophenone or related structural elements and a 3-(1H-imidazol-4-yl)propyloxy moiety were prepared by Mitsunobu-type ether synthesis or SNAr reaction. Most of the title compounds possess high antagonist potency in histamine H3-receptor assays in vitro as well as in vivo in mouse CNS following oral administration. After defining 4-(3-(1H-imidazol-4-yl)propyloxy)phenyl phenyl methanone as a new lead, structure-activity relationships were investigated for this new class of compounds. Substitution of the meta'-position of the benzophenone moiety with halogen atoms (e.g., iodine, fluorine) led to compounds with high antagonist potency in vitro as well as in vivo (Ki = 9.3 and 4.3 nM, ED50 = 0.7 and 0.47 mg/kg p.o., 18 and 12, respectively). A receptor profile of several functional in vitro assays for several biogenic amine receptors for the meta'-iodinated derivative demonstrated high selectivity toward the histamine H3 receptor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Benzophenones / chemical synthesis*
  • Benzophenones / chemistry
  • Benzophenones / pharmacology*
  • Cerebral Cortex / drug effects
  • Guinea Pigs
  • Histamine Antagonists / chemical synthesis*
  • Histamine Antagonists / chemistry
  • Histamine Antagonists / pharmacology*
  • Ligands
  • Male
  • Mice
  • Muscle, Smooth / drug effects
  • Rats
  • Receptors, Histamine H3 / drug effects*
  • Structure-Activity Relationship
  • Tomography, Emission-Computed*
  • Tomography, Emission-Computed, Single-Photon*

Substances

  • Benzophenones
  • Histamine Antagonists
  • Ligands
  • Receptors, Histamine H3