Centrally acting serotonergic agents. Synthesis and structure-activity relationships of C-1- or C-3-substituted derivatives of 8-hydroxy-2-(di-n-propylamino)tetralin

J Med Chem. 1993 Mar 19;36(6):671-82. doi: 10.1021/jm00058a003.

Abstract

The synthesis and structure-activity relationships (SAR) of C-1- or C-3-substituted derivatives of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) are described. These analogs were synthesized via alkylation of the tetralone derivatives followed by reductive amination. All of the analogs were inactive at the dopamine D2 receptor. Among the 8-OMe or 8-OH C-1,N-disubstituted analogs synthesized, the cis analogs were more potent in the 5-HT1A binding assay than the corresponding trans analogs. However, in the case of 1-(cyclopropylmethyl)-N-n-propyl analogs, the trans isomer has a slightly higher 5-HT1A affinity than its cis counterpart. The order of binding potency for C-1 substitution was found to be allyl > hydroxymethyl > n-propyl > cyclopropylmethyl >> carbomethoxy. Interestingly, the 5-OMe analogs were found to be inactive in both the 5-HT1A and dopamine D2 binding assays. In the C-3 allyl-substituted analogs, 5-HT1A agonist activity was found to be considerably lower. In these examples, the trans analogs showed weak 5-HT1A binding activity whereas the cis analogs were inactive. Analogs with C-1,N,N-trisubstitution also showed a marked decrease in 5-HT1A binding affinity. Overall, the SAR study showed that cis C-1 substitution maintains the 5-HT1A agonist activity of 8-OH-DPAT whereas trans C-1 substitution displays somewhat diminished activity. On the other hand, the trans C-3 substitution shows modest agonist activity whereas cis C-3 substitution removes the activity completely.

MeSH terms

  • 8-Hydroxy-2-(di-n-propylamino)tetralin / analogs & derivatives*
  • Animals
  • Behavior, Animal / drug effects
  • Binding Sites
  • Brain / drug effects
  • Brain / metabolism
  • Cats
  • Cattle
  • Male
  • Mice
  • Rats
  • Receptors, Serotonin / metabolism
  • Serotonin Receptor Agonists / chemical synthesis*
  • Serotonin Receptor Agonists / metabolism
  • Serotonin Receptor Agonists / pharmacology
  • Stereoisomerism
  • Structure-Activity Relationship

Substances

  • Receptors, Serotonin
  • Serotonin Receptor Agonists
  • 8-Hydroxy-2-(di-n-propylamino)tetralin