Synthesis of BMS-309403-related compounds, including [ ¹⁴C]BMS- 309403, a radioligand for adipocyte fatty acid binding protein

Adipocyte fatty acid binding protein (A-FABP; FABP4), which is predominantly expressed in macrophages and adipose tissue, regulates fatty acid storage and lipolysis, and is also an important mediator of inflammation. Here, we report a synthesis of ¹⁴C-labeled 2-[2′-(5-ethyl-3,4- diphenyl-1H-pyrazol-1-yl)biphenyl- 3-yloxy]acetic acid (BMS309403), a potent and selective small-molecular FABP4 inhibitor, as a chemical tool for investigating the roles of FABP4 in inflammatory and metabolic disorders. The structure-activity relationship of several BMS derivatives for inhibition of FABP4 is also reported.