Design, synthesis and evaluation of novel monoamine oxidase B (MAO-B) inhibitors with improved pharmacokinetic properties for Parkinson?s disease

A series of novel ((benzofuran-5-yl)methyl)pyrrolidine-2-carboxamide derivatives were designed, synthesized and evaluated as MAO-B inhibitors. SAR studies indicated that cyclizing benzyl ether into benzofuran ring resulted in the most potent MAO-B inhibitor (IC50 = 0.037 mu M), (2S,4S)-4-fluoro-1-((2-(4-fluorophenyl) benzofuran-5-yl)methyl)pyrrolidine-2-carboxamide (C14). PK properties of C14 in rats and mice were significantly improved compared to our previous candidate and safinamide, indicating that benzofuran moiety is essential for improving PK properties. Moreover, C14 displayed good metabolic stability and brain-blood barrier permeability, as well as favorable in vitro properties. Finally, C14 significantly inhibited MAO-B in the mouse brain. C14 exhibited a potential efficacy for DA deficits in the MPTP-induced mouse model and significantly increased DA concentration in the striatum. Thus, we identified that C14 may be a promising drug candidate for PD treatment.