Oxopyrido[2,3‑<i>d</i>]pyrimidines as Covalent L858R/T790M Mutant Selective Epidermal Growth Factor Receptor (EGFR) Inhibitors

In nonsmall cell lung cancer (NSCLC), the threonine⁷⁹⁰–methionine⁷⁹⁰ (T790M) point mutation of EGFR kinase is one of the leading causes of acquired resistance to the first generation tyrosine kinase inhibitors (TKIs), such as gefitinib and erlotinib. Herein, we describe the optimization of a series of 7-oxopyrido­[2,3-<i>d</i>]­pyrimidinyl-derived irreversible inhibitors of EGFR kinase. This led to the discovery of compound <b>24</b> which potently inhibits gefitinib-resistant EGFR^L858R,T790M with 100-fold selectivity over wild-type EGFR. Compound <b>24</b> displays strong antiproliferative activity against the H1975 nonsmall cell lung cancer cell line, the first line mutant HCC827 cell line, and promising antitumor activity in an EGFR^L858R,T790M driven H1975 xenograft model sparing the side effects associated with the inhibition of wild-type EGFR