During our screening of a combinatorial library, we identified aryloxyacetamides (eg, 1 and 2) as highly potent κ-agonists. 11 Based on these lead compounds, we recently reported the design and synthesis of two novel series of constrained aryloxyacetamides 3. 12 In this communication, we report a novel series of phenylamino acetamide derivatives with the general structure I, which are bioisosteres of aryloxyacetamides with the replacement of oxygen ...