Identification of the 4-Position of 3-Alkynyl and 3-Heteroaromatic Substituted Pyridine Methanamines as a Key Modification Site Eliciting Increased Potency and Enhanced Selectivity for Cytochrome P-450 2A6 Inhibition

J Med Chem. 2018 Aug 23;61(16):7065-7086. doi: 10.1021/acs.jmedchem.8b00084. Epub 2018 Aug 1.

Abstract

Cigarette smoking causes nearly one in every five deaths in the United States. The development of a specific inhibitor of cytochrome P450 2A6 (CYP2A6), the major nicotine-metabolizing enzyme in humans, which could be prescribed for the cessation of cigarette smoking, has been undertaken. To further refine the structure activity relationship of CYP2A6, previously synthesized 3-alkynyl and 3-heteroaromatic substituted pyridine methanamines were used as lead compounds. Isosteric pyridine replacement and appendage of all available positions around the pyridine ring with a methyl group was performed to identify a modification that would increase CYP2A6 inhibition potency, which led to 4g (IC50 = 0.055 mM) as a primary analogue. Potent compounds were evaluated for CYP selectivity, human liver microsomal half-life, and compliance with the rules of five. Top compounds (i.e., 6i, IC50 = 0.017 mM, >120 min half-life) are poised for further development as treatments for smoking and tobacco use cessation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cytochrome P-450 CYP2A6 / antagonists & inhibitors*
  • Cytochrome P-450 CYP2A6 / metabolism
  • Enzyme Inhibitors / chemical synthesis
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Humans
  • Methylamines / chemical synthesis
  • Methylamines / chemistry
  • Methylamines / pharmacology*
  • Microsomes, Liver / drug effects*
  • Microsomes, Liver / enzymology
  • Molecular Structure
  • Pyridines / chemical synthesis
  • Pyridines / chemistry
  • Pyridines / pharmacology*
  • Smoking / drug therapy
  • Tobacco Use Cessation

Substances

  • Enzyme Inhibitors
  • Methylamines
  • Pyridines
  • Cytochrome P-450 CYP2A6