Ester derivatives of annulated tetrahydroazocines: a new class of selective acetylcholinesterase inhibitors

Bioorg Med Chem. 2006 Nov 1;14(21):7205-12. doi: 10.1016/j.bmc.2006.06.055. Epub 2006 Jul 14.

Abstract

A series of ester derivatives of annulated tetrahydroazocines, namely 2,3,6,11-tetrahydro-1H-azocino[4,5-b]indoles (5-10), 2,3,6,7-tetrahydro-1H-azocino[5,4-b]indoles (11-14), and 4,7,8,9-tetrahydro-1H-pyrrolo[2,3-d]azocines (15-18), synthesized through an efficient 6-->8 membered ring expansion procedure, were investigated for their acetylcholinesterase (AChE) inhibitory activities. Most of the compounds acted as AChE inhibitors in vitro, with IC(50) values ranging from 5 to 40 microM. The most potent compounds 11 and 15, both as racemic mixtures, proved selective toward AChE, exhibiting selectivity ratios versus butyrylcholinesterase (BuChE) of ca. 15 and more than 20, respectively. Structure-activity studies highlighted, among other factors, lipophilicity as a property modulating the AChE inhibition potency, as shown by a reasonable parabolic correlation between pIC(50) and experimental 1-octanol/water partition coefficient (logP), which described the prevailing behavior of the examined compounds (r(2)=0.665). Molecular docking simulations using the X-ray crystal structure of AChE from Torpedo californica suggested possible binding modes of the tetrahydroazocine ester derivatives 11 and 15.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholinesterase / drug effects*
  • Animals
  • Azocines / chemistry
  • Azocines / pharmacology*
  • Cattle
  • Cholinesterase Inhibitors / chemistry
  • Cholinesterase Inhibitors / pharmacology*
  • Erythrocytes / drug effects
  • Erythrocytes / enzymology
  • Esters
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Spectrometry, Mass, Electrospray Ionization
  • Structure-Activity Relationship

Substances

  • Azocines
  • Cholinesterase Inhibitors
  • Esters
  • Acetylcholinesterase