Regorafenib iMpurity

The impurity 1-(4-chloro-3-(trifluoromethyl)phenyl)-3-(3-fluoro-4-hydroxyphenyl)urea is an impurity with the structure shown below that is generated during the production of regorafenib. Regorafenib is a novel multi-kinase inhibitor developed by Bayer AG. It targets tumorigenesis, tumor angiogenesis, and the maintenance of tumor microenvironment signaling by inhibiting multiple tumor-promoting protein kinases.