Synthesis and human monoamine oxidase inhibitory activity of novel C2-, C3- and C4-substituted phthalonitriles

Development of new selective reversible monoamine oxidase (MAO) B inhibitors is still essential for the treatment of Alzheimer's and Parkinson's disease. Phthalonitrile compounds have been shown to display MAO inhibitory activity with MAO-B selectivity. In this study, we synthesized and evaluated the inhibitory activities of a new series of phthalonitrile compounds. Compound 3, 4 and 5 presented selective MAO-B inhibition, compound 5 being the most selective (75.16-fold). Additionally, molecular docking simulations were carried out. Investigation of binding modes of each compound with both isoforms were carried out to elaborate structure-activity relationships. Druglikeness was calculated for each compound, revealing that the lipophilicity of compound 5 (logP = 3.37) is optimal to cross membranes.