Structure-Activity Relationship Study of Subtype-Selective Positive Modulators of KCa2 Channels

J Med Chem. 2022 Jan 13;65(1):303-322. doi: 10.1021/acs.jmedchem.1c01473. Epub 2021 Dec 28.

Abstract

A series of modified N-cyclohexyl-2-(3,5-dimethyl-1H-pyrazol-1-yl)-6-methylpyrimidin-4-amine (CyPPA) analogues were synthesized by replacing the cyclohexane moiety with different 4-substituted cyclohexane rings, tyrosine analogues, or mono- and dihalophenyl rings and were subsequently studied for their potentiation of KCa2 channel activity. Among the N-benzene-N-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-4-pyrimidinamine derivatives, halogen decoration at positions 2 and 5 of benzene-substituted 4-pyrimidineamine in compound 2q conferred a ∼10-fold higher potency, while halogen substitution at positions 3 and 4 of benzene-substituted 4-pyrimidineamine in compound 2o conferred a ∼7-fold higher potency on potentiating KCa2.2a channels, compared to that of the parent template CyPPA. Both compounds retained the KCa2.2a/KCa2.3 subtype selectivity. Based on the initial evaluation, compounds 2o and 2q were selected for testing in an electrophysiological model of spinocerebellar ataxia type 2 (SCA2). Both compounds were able to normalize the abnormal firing of Purkinje cells in cerebellar slices from SCA2 mice, suggesting the potential therapeutic usefulness of these compounds for treating symptoms of ataxia.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cerebellum* / drug effects
  • Disease Models, Animal
  • Female
  • Ion Channel Gating
  • Male
  • Membrane Transport Modulators* / chemistry
  • Membrane Transport Modulators* / pharmacology
  • Mice
  • Potassium Channels, Calcium-Activated* / agonists
  • Potassium Channels, Calcium-Activated* / metabolism
  • Purkinje Cells* / drug effects
  • Pyrimidines* / chemistry
  • Spinocerebellar Ataxias* / drug therapy
  • Spinocerebellar Ataxias* / metabolism
  • Spinocerebellar Ataxias* / pathology
  • Structure-Activity Relationship

Substances

  • Membrane Transport Modulators
  • Potassium Channels, Calcium-Activated
  • Pyrimidines
  • N-(5-Chloro-2-fluorophenyl)-2-(3,5-dimethyl-1H-pyrazol-1-yl)-6-methylpyrimidin-4-amine