Discovery of potent liver-selective stearoyl-CoA desaturase-1 (SCD1) inhibitors, thiazole-4-acetic acid derivatives, for the treatment of diabetes, hepatic steatosis, and obesity.

SCD1 is a rate-limiting enzyme in the conversion of saturated fatty acids to monounsaturated fatty acids. SCD1 inhibitors have potential effects on obesity, diabetes, acne, and cancer, but the adverse effects associated with SCD1 inhibition in the skin and eyelids are impediments to clinical development. To avoid mechanism-based adverse effects, we explored the compounds that selectively inhibit SCD1 in the liver in an ex vivo assay. Starting from a systemically active lead compound, we focused on the physicochemical properties tPSA and cLogP to minimize exposure in the off-target tissues. This effort led to the discovery of thiazole-4-acetic acid analog 48 as a potent and liver-selective SCD1 inhibitor. Compound 48 exhibited significant effects in rodent models of diabetes, hepatic steatosis, and obesity, with sufficient safety margins in a rat toxicology study with repeated dosing.