%0 Journal Article %T Discovery of Novel Pyrido-pyridazinone Derivatives as FER Tyrosine Kinase Inhibitors with Antitumor Activity %J - %D 2019 %R https://doi.org/10.1021/acsmedchemlett.8b00631 %X To obtain a new anticancer drug, we focused on FER tyrosine kinase. Starting with high-throughput screening with our in-house chemical library, compound 1, which has a pyridine moiety, was found. Referring to their X-ray crystal structure with FES proto-oncogene tyrosine kinase, as a surrogate of FER followed by chemical modification including scaffold hopping of the pyridine template, we discovered pyrido-pyridazinone derivatives with potent FER kinase inhibitory activity. Here, we disclose the structure¨Cactivity relationship on the scaffold and representative compound 21 (DS21360717), which showed in vivo antitumor efficacy in a subcutaneous tumor model %U https://pubs.acs.org/doi/10.1021/acsmedchemlett.8b00631