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.

Synthesis and Anticonvulsant Activity of α-Amino Acid Amide Derivatives

Background: Epilepsy is a disease of the central nervous system that affects approximately 50 million individuals worldwide. Although several new drugs have been marketed in the last 25 years, almost one-third of patients are not protected. In many cases, currently available drugs produce undesirable side effects. As a result, a need exists for novel anticonvulsants with unique mechanisms of action and minimal side effects. Methods: A mixed anhydride coupling procedure and standard deprotection procedures were utilized to prepare 36 α-amino acid amides. All final products were evaluated in mice and rats utilizing a standard battery of anticonvulsant tests. Results: α-Amino acids containing a 2,6-dimethylanilide group exhibited anticonvulsant activity in the maximal electroshock seizure test and 6 Hz test in mice and rats. A small, branched-chain on the α- carbon generally maintained or enhanced anticonvulsant activity in the maximal electroshock seizure test. The (R)-α-amino acid amides were typically more potent and slightly more neurotoxic than the corresponding (S)-enantiomers. The valine dimethylanilide (R)-42 was highly active in the MES test in mice (ED50 = 3.6mg/kg) and rats (ED50 = 3.8 mg/kg). (R)-42 also demonstrated excellent anticonvulsant activity in the 6 Hz, picrotoxin, and corneal kindled mouse tests. Furthermore, (R)-42 did not lower seizure threshold when evaluated in the intravenous metrazol seizure test. Conclusion: α-Amino acid 2,6-dimethylanilides exhibited potent activity in a variety of anticonvulsant tests in mice and rats. The valine derivative (R)-42 represents a promising compound for potential use in complex partial seizures.