Synthesis and evaluation of 4-fluoro-8-substituted-2,3,4,5-tetrahydro-1H-2-benzazapines as selective inhibitors of phenylethanolamine N-methyltransferase versus the alpha(2)-adrenoceptor

J Med Chem. 2001 Aug 16;44(17):2849-56. doi: 10.1021/jm010147g.

Abstract

A small series of 4-fluoro-8-substituted-2,3,4,5-tetrahydro-1H-2-benzazapines (4-fluoro-THBAs; 12-15) were synthesized and evaluated as inhibitors of phenylethanolamine N-methyltransferase (PNMT; EC 2.1.1.28) and as inhibitors of the binding of clonidine at the alpha(2)-adrenoceptor. 4-Fluoro-THBAs 13-15 displayed selectivity ratios (alpha(2) K(i)/PNMT K(i)) greater than 75 and 4-fluoro-8-nitro-THBA (13) was found to be one of the most selective inhibitors of PNMT known, with a selectivity ratio of greater than 900. These compounds are also quite lipophilic and according to previous results from this laboratory should be able to penetrate the blood-brain barrier. These 4-fluoro-THBAs represent important leads in the development of new, more selective, CNS-active inhibitors of PNMT.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adrenergic alpha-Antagonists / chemical synthesis*
  • Adrenergic alpha-Antagonists / chemistry
  • Adrenergic alpha-Antagonists / pharmacology
  • Animals
  • Benzazepines / chemical synthesis*
  • Benzazepines / chemistry
  • Benzazepines / pharmacology
  • Cerebral Cortex / metabolism
  • Clonidine / metabolism
  • Enzyme Inhibitors / chemical synthesis*
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology
  • In Vitro Techniques
  • Male
  • Models, Molecular
  • Phentolamine / metabolism
  • Phenylethanolamine N-Methyltransferase / antagonists & inhibitors*
  • Radioligand Assay
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Adrenergic, alpha-2 / drug effects*
  • Receptors, Adrenergic, alpha-2 / metabolism
  • Structure-Activity Relationship

Substances

  • Adrenergic alpha-Antagonists
  • Benzazepines
  • Enzyme Inhibitors
  • Receptors, Adrenergic, alpha-2
  • Phenylethanolamine N-Methyltransferase
  • Clonidine
  • Phentolamine