Three new analogues of moclobemide are synthesized. Antidepressant activity of compounds assayed by the Porsolt method reveals that the morpholine ring in moclobemide is one of the key structural parts necessary for antidepressant activity. Superimposition of norepinephrine and gauche forms of serotonin and moclobemide suggest that the phenyl ring, electronegative group attached to the aromatic ring and the amine terminal group ...