3-(alphaR)-alpha-((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-hydroxybenzyl)-N-alkyl-N-arylbenzamides: potent, non-peptidic agonists of both the micro and delta opioid receptors

J Med Chem. 2003 Feb 13;46(4):623-33. doi: 10.1021/jm020395s.

Abstract

Opioid analgesics with both micro and delta opioid receptor activation represent a new approach to the treatment of severe pain with an improved safety profile. Compounds with this profile may exhibit strong analgesic properties due to micro agonism, with a reduced side effect profile resulting from delta agonism. Replacing the p-diethylamide of the known potent delta opioid receptor selective agonist BW373U86 with a m-diethylamide resulted in a compound with agonist activity at both the micro and delta opioid receptors. Modifying the amide to an N-methyl-N-phenylamide increased agonist potency at both receptors. A series of 3-(alphaR)-alpha-((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-hydroxybenzyl)-N-alkyl-N-arylbenzamides have been made to explore the structure-activity relationship (SAR) around the N-methyl-N-phenylamide. Several potent agonists of both the micro and delta opioid receptors have been identified, including (+)-3-((alphaR)-alpha-((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-hydroxybenzyl)-N-(4-fluorophenyl)-N-methylbenzamide (23), which has EC50 values of 0.67 and 1.1 nM at the micro (guinea pig ileum assay) and delta (mouse vas deferens assay) opioid receptors, respectively.

MeSH terms

  • Animals
  • Benzamides / chemical synthesis*
  • Benzamides / chemistry
  • Benzamides / pharmacology
  • Guinea Pigs
  • Ileum / drug effects
  • Ileum / physiology
  • In Vitro Techniques
  • Male
  • Mice
  • Muscle Contraction / drug effects
  • Muscle, Smooth / drug effects
  • Muscle, Smooth / physiology
  • Piperazines / chemical synthesis*
  • Piperazines / chemistry
  • Piperazines / pharmacology
  • Receptors, Opioid, delta / agonists*
  • Receptors, Opioid, mu / agonists*
  • Stereoisomerism
  • Structure-Activity Relationship
  • Vas Deferens / drug effects
  • Vas Deferens / physiology

Substances

  • 3-(alpha-(4-allyl-2,5-dimethyl-1-piperazinyl)-3-hydroxybenzyl)-N-(4-fluorophenyl)-N-methylbenzamide
  • Benzamides
  • Piperazines
  • Receptors, Opioid, delta
  • Receptors, Opioid, mu