Discovery of (S) -N-2-1- (3-Ethoxy-4-methoxyphenyl) -2-methanesulfonylethyl-1, 3-dioxo-2, 3-dihydro-1H-isoindol-4-ylacetamide (Apremilast), a Potent and Orally Active Phosphodiesterase 4 and Tumor Necrosis Factor-α Inhibitor

In this communication, we report the discovery of 1S (apremilast), a novel potent and orally active phosphodiesterase 4 (PDE4) and tumor necrosis factor-alpha inhibitor. The optimization of previously reported 3-(1,3-dioxo-1,3-dihydroisoindol-2-yl)-3-(3,4-dimethoxyphenyl)propionic acid PDE4 inhibitors led to this series of sulfone analogues. Evaluation of the structure-activity relationship of substitutions on the phthalimide group led to the discovery of an acetylamino analogue 1S, which is currently in clinical trials.