Syntheses and N-methyl-D-aspartate receptor antagonist pharmacology of fluorinated arylcycloheptylamines

Med Chem. 2014;10(8):843-52. doi: 10.2174/1573406410666140428104444.

Abstract

Selective uncompetitive antagonists of the phencyclidine (PCP) binding site of the N-methyl-D-aspartate receptor (NMDAR) are known to have therapeutic potential as anticonvulsants and neuroprotective agents. Several fluorinated molecules with each containing a cycloheptane ring were designed to probe the PCP pharmacophore and test the influence of fluorine substitution on NMDAR binding and in vivo efficacy. Syntheses and analyses of six novel compounds, 1-(4- fluorophenyl)cycloheptanamine (3), 1-(1-(4-fluorophenyl)cycloheptyl)piperidine (4), 1-(1-(4-fluorophenyl)cycloheptyl) pyrrolidine (5), 1-(3-fluorophenyl)cycloheptanamine (6), 1-(1-(3-fluorophenyl)cycloheptyl)piperidine (7), 1-(1-(3-fluorophenyl) cycloheptyl)pyrrolidine (8) and several related reference arylcyloalkylamines are described. Receptor binding was performed at the PCP site of NMDAR for each compound using [(3)H]-(+)-MK-801 displacement. Unexpectedly, the 3- fluoro- primary amine 6 had the greatest affinity of the series and these binding results support a different structure activity relationship (SAR) profile for arylcycloheptylamines when compared to arylcyclohexylamines like PCP. Five of the novel compounds have affinity (Ki) in the hundred nM (10(-7)) range. In addition, compounds 3, 5, 6, 7 and 8 were evaluated and found to exhibit neuroprotective effects from NMDA induced toxicity in vitro and compounds 6, 7 and 8 exhibited anticonvulsant activities in rats. An ED50 of 13.84 mg/kg was found for compound 6 in rat maximal electroshock (MES) test with a protective index (PI) of 3.66 against ataxia. These results support further investigation of the arylcycloheptylamine class.

Publication types

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

MeSH terms

  • Amines / chemical synthesis*
  • Amines / chemistry
  • Amines / pharmacology
  • Animals
  • Anticonvulsants / chemical synthesis*
  • Anticonvulsants / chemistry
  • Anticonvulsants / pharmacology
  • Ataxia / drug therapy*
  • Ataxia / metabolism
  • Ataxia / physiopathology
  • Binding Sites
  • Binding, Competitive
  • Cycloheptanes / chemical synthesis*
  • Cycloheptanes / chemistry
  • Cycloheptanes / pharmacology
  • Dizocilpine Maleate / metabolism
  • Dizocilpine Maleate / pharmacology
  • Electroshock
  • Halogenation
  • Hippocampus / cytology
  • Hippocampus / drug effects
  • Hippocampus / metabolism
  • Neurons / cytology
  • Neurons / drug effects
  • Neurons / metabolism
  • Neuroprotective Agents / chemical synthesis*
  • Neuroprotective Agents / chemistry
  • Neuroprotective Agents / pharmacology
  • Phencyclidine / metabolism
  • Phencyclidine / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors*
  • Receptors, N-Methyl-D-Aspartate / chemistry
  • Receptors, N-Methyl-D-Aspartate / metabolism
  • Structure-Activity Relationship
  • Tissue Culture Techniques
  • Tritium

Substances

  • Amines
  • Anticonvulsants
  • Cycloheptanes
  • Neuroprotective Agents
  • Receptors, N-Methyl-D-Aspartate
  • Tritium
  • Dizocilpine Maleate
  • Phencyclidine