MAO-B-IN-4 (Compound 26) is an orally active and reversible MAO-B inhibitor with an IC 50 of 9 nM. MAO-B-IN-4 has good metabolic stability, safety profile and brain permeability. MAO-B-IN-4 shows antidepressant activity in rats and mice. MAO-B-IN-4 can be used in studies related to Alzheimer's disease.