Potent and selective inhibitors of PI3Kδ: Obtaining isoform selectivity from the affinity pocket and tryptophan shelf

A potent inhibitor of PI3Kδ that is ⩾200 fold selective for the remaining three Class I PI3K isoforms and additional kinases is described. The hypothesis for selectivity is illustrated through structure activity relationships and crystal structures of compounds bound to a K802T mutant of PI3Kγ. Pharmacokinetic data in rats and mice support the use of 3 as a useful tool compound to use for in vivo studies.