Discovery and SAR of Novel 2,3-Dihydroimidazo[1,2-c]quinazoline PI3K Inhibitors: Identification of Copanlisib (BAY 80-6946)

ChemMedChem. 2016 Jul 19;11(14):1517-30. doi: 10.1002/cmdc.201600148. Epub 2016 Jun 16.


The phosphoinositide 3-kinase (PI3K) pathway is aberrantly activated in many disease states, including tumor cells, either by growth factor receptor tyrosine kinases or by the genetic mutation and amplification of key pathway components. A variety of PI3K isoforms play differential roles in cancers. As such, the development of PI3K inhibitors from novel compound classes should lead to differential pharmacological and pharmacokinetic profiles and allow exploration in various indications, combinations, and dosing regimens. A screening effort aimed at the identification of PI3Kγ inhibitors for the treatment of inflammatory diseases led to the discovery of the novel 2,3-dihydroimidazo[1,2-c]quinazoline class of PI3K inhibitors. A subsequent lead optimization program targeting cancer therapy focused on inhibition of PI3Kα and PI3Kβ. Herein, initial structure-activity relationship findings for this class and the optimization that led to the identification of copanlisib (BAY 80-6946) as a clinical candidate for the treatment of solid and hematological tumors are described.

Keywords: PI3K inhibitors; X-ray crystallography; copanlisib; lipid kinases; phosphoinositide 3-kinase.

MeSH terms

  • Antineoplastic Agents / chemical synthesis
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology
  • Binding Sites
  • Cell Line, Tumor
  • Class I Phosphatidylinositol 3-Kinases / antagonists & inhibitors
  • Class Ib Phosphatidylinositol 3-Kinase / chemistry
  • Drug Discovery
  • Humans
  • Hydrogen Bonding
  • Imidazoles / chemical synthesis
  • Imidazoles / chemistry
  • Imidazoles / pharmacology*
  • Molecular Docking Simulation
  • Phosphoinositide-3 Kinase Inhibitors
  • Protein Kinase Inhibitors / chemical synthesis
  • Protein Kinase Inhibitors / chemistry
  • Protein Kinase Inhibitors / pharmacology*
  • Pyrimidines / chemical synthesis
  • Pyrimidines / chemistry
  • Pyrimidines / pharmacology*
  • Quinazolines / chemical synthesis
  • Quinazolines / chemistry
  • Quinazolines / pharmacology*
  • Structure-Activity Relationship


  • Antineoplastic Agents
  • Imidazoles
  • Phosphoinositide-3 Kinase Inhibitors
  • Protein Kinase Inhibitors
  • Pyrimidines
  • Quinazolines
  • Class I Phosphatidylinositol 3-Kinases
  • Class Ib Phosphatidylinositol 3-Kinase
  • PIK3CA protein, human
  • PIK3CB protein, human
  • PIK3CD protein, human
  • PIK3CG protein, human
  • copanlisib