Syntheses of Benzo[d]Thiazol-2(3H)-One Derivatives and Their Antidepressant and Anticonvulsant Effects

Thirty-four new benzo[d]thiazol derivatives 2a–2i, 3a–3r, and 4a–4g were synthesized and investigated for their potential antidepressant and anticonvulsant effects. In a forced swimming test, 2c and 2d showed the highest antidepressant and anticonvulsant effects. 2c and 2d displayed a higher percentage decrease in immobility duration (89.96% and 89.62%, respectively) than that of fluoxetine (83.62%). In the maximal electroshock seizure test, 3n and 3q showed the highest anticonvulsant effect, with ED50 values of 46.1 and 64.3 mg kg−1, and protective indices of 6.34 and 4.11, respectively, which were similar to those of phenobarbital or valproate. We also found that the mechanism for the antidepressant activity of 2c and 2d may be via increasing the concentrations of serotonin and norepinephrine.