A new P1′ group for TACE inhibitors was identified by eliminating the oxygen atom in the linker of the original 4-(2-methylquinolin-4-ylmethoxy) phenyl P1′ group. Incorporation of this 4-(2-methylquinolin-4-ylmethyl) phenyl group onto different β-aminohydroxamic acid cores provided compound 18, which demonstrated potent porcine TACE (p-TACE) and human whole blood activity, excellent PK properties, and good selectivity against a variety ...