Increasing metabolic stability via the deuterium kinetic isotope effect: An example from a proline-amide-urea aminothiazole series of phosphatidylinositol-3 kinase alpha inhibitors

Identification of NVP-CLR457 as an Orally Bioavailable Non-CNS-Penetrant pan-Class IA Phosphoinositol-3-Kinase Inhibitor

“…To determine the class IA PI3K activities, a set of mechanistic assays in a Rat1 rat fibroblast cell line was used to assess both potency and selectivity. The use of these assays as the primary on-target screen had been successfully validated in previous PI3K projects within Novartis, including the identification of the PI3Kα selective inhibitor alpelisib. − For each isoform, the p110 catalytic subunit is stably expressed in a constitutively activated form (myristylated), and PI3K activity is determined by the extent of Akt phosphorylation on Ser473 (S473P-Akt) using a reverse phase protein array (RPPA) readout . These Rat1-myr-p110 cell lines were additionally implanted into rodents to generate tumor xenograft models, and these mechanistic models were used to establish PK/PD/efficacy relationships as part of the optimization screening cascade .…”

“…1-(6-(6-Amino-4-(trifluoromethyl)pyridin-3-yl)-2-morpholinopyrimidin-4-yl)-1-(2-hydroxyethyl)-3-methylurea (26). A mixture of 1-(6-chloro-2-morpholinopyrimidin-4-yl)-1-(2-hydroxyethyl)-3-methylurea (120 mg, 304 μmol), 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2yl)-4-(trifluoromethyl)pyridin-2-amine (105 mg, 365 μmol), and Na 2 CO 3 (97 mg, 912 μmol) in dimethoxyethane (3 mL) and water (0.45 mL) was flushed with argon, and tetrakis(triphenylphosphine)palladium(0) (28 mg, 24 μmol) was added at rt.…”