Discovery of triazole aminopyrazines as a highly potent and selective series of PI3Kδ inhibitors.

A novel class of potent PI3Kδ inhibitors with >1000-fold selectivity against other class I PI3K isoforms is described. Optimization of the substituents on a triazole aminopyrazine scaffold, emerging from an in-house PI3Kα program, turned moderately selective PI3Kδ compounds into highly potent and selective PI3Kδ inhibitors. These efforts resulted in a series of aminopyrazines with PI3Kδ IC50 ⩽1nM in the enzyme assay, some of the most selective PI3Kδ inhibitors published to date, with a cell potency in a JeKo-cell assay of 20-120nM.