Design, synthesis of 8-alkoxy-5,6-dihydro-[1,2,4]triazino[4,3-a]quinolin-1-ones with anticonvulsant activity

Ruthenium-Catalyzed Intramolecular Arene C(sp2)-H Amidation for Synthesis of 3,4-Dihydroquinolin-2(1H)-ones

We report the [Ru(p-cymene)(l-proline)Cl] ([Ru1])-catalyzed cyclization of 1,4,2-dioxazol-5-ones to form dihydroquinoline-2-ones in excellent yields with excellent regioselectivity via a formal intramolecular arene C(sp²)-H amidation. The reactions of the 2- and 4-substituted aryl dioxazolones proceeds initially through spirolactamization via electrophilic amidation at the arene site, which is para or ortho to the substituent. A Hammett correlation study showed that the spirolactamization is likely to occur by electrophilic nitrenoid attack at the arene, which is characterized by a negative ρ value of -0.73.

Synthesis and Evaluation of Antidepressant Activities of 5-Aryl-4,5-dihydrotetrazolo [1,5-a]thieno[2,3-e]pyridine Derivatives

In this study, we synthetized a series of 5-aryl-4,5-dihydrotetrazolo[1,5-a]thieno[2,3-e]pyridine derivatives containing tetrazole and other heterocycle substituents, i.e., triazole, methyltriazole, and triazolone. The forced swim test (FST) and tail suspension test (TST) were used to evaluate the antidepressant activity of the target compounds. The compound 5-[4-(trifluoromethyl)phenyl]-4,5-dihydrotetrazolo[1,5-a]thieno[2,3-e]pyridine (4i) showed the highest antidepressant activity, with a reduced immobility time of 55.33% when compared with the control group. Using an open-field test, compound 4i was shown to not affect spontaneous activity of mice. The determination of in vivo 5-hydroxytryptamine (5-HT) concentration showed that compound 4i may have an effect in the mouse brain. The biological activities of all synthetized compounds were verified by molecular docking studies. Compound 4i showed significant interactions with residues of the 5-HT1A receptor homology model.

Current Research on Antiepileptic Compounds

Epilepsy affects about 1% of the world’s population. Due to the fact all antiepileptic drugs (AEDs) have some undesirable side effects and about 30% of epileptic patients are not seizure-free with the existing AEDs, there is still an urgent need for the development of more effective and safer AEDs. Based on our research work on antiepileptic compounds and other references in recent years, this review covers the reported work on antiepileptic compounds which are classified according to their structures. This review summarized 244 significant anticonvulsant compounds which are classified by functional groups according to the animal model data, although there are some limitations in the data. This review highlights the properties of new compounds endowed with promising antiepileptic properties, which may be proven to be more effective and selective, and possibly free of unwanted side effects. The reviewed compounds represent an interesting possibility to overcome refractory seizures and to reduce the percentage of patients with a poor response to drug therapy.

Synthesis and Pharmacological Evaluation of Novel Benzenesulfonamide Derivatives as Potential Anticonvulsant Agents

A novel series of benzenesulfonamide derivatives containing 4-aminobenzenesul-fonamide and α-amides branched valproic acid or 2,2-dimethylcyclopropanecarboxylic acid moieties were synthesized and screened for their anticonvulsant activities in mice maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ) test. The activity experimental study showed that 2,2-dipropyl-N¹-(4-sulfamoylphenyl)malonamide (18b) had the lowest median effective dose (ED50) of 16.36 mg/kg in MES test, and 2,2-dimethyl-N-(4-sulfamoylphenyl)cyclopropane-1,1-dicarboxamide (12c) had the lowest ED50 of 22.50 mg/kg in scPTZ test, which resulted in the protective indexe (PI) of 24.8 and 20.4, respectively. These promising data suggest the new compounds have good potential as new class of anticonvulsant agents with high effectiveness and low toxicity for the treatment of epilepsy.

Synthesis of novel thiadiazolotriazin-4-ones and study of their mosquito-larvicidal and antibacterial properties

A series of novel 3-tert-butyl-7-(aryloxymethyl)-4H-[1,3,4]thiadiazolo[2,3-c][1,2,4]triazin-4-ones (5a-5n) were synthesized by refluxing 3,3-dimethyl-2-oxobutanoic acid (trimethyl pyruvic acid) (1) and thiocarbohydrazide (2) in ethanol as solvent for 12 h, to yield 3-mercapto-4-amino-6-tert-butyl-1,2,4-triazine-5(4H)-one (3) (Scheme 1), then the compound (3) was condensed with different substituted aryloxyacetic acids (4) in POCl3 at 90 °C for 8 h (Scheme 2). The structures of the newly synthesized compounds were confirmed by IR, (1)H NMR, (13)C NMR, elemental analyses and mass spectroscopic studies. Few of the synthesized compounds exhibited moderate mosquito-larvicidal and antibacterial activities. Among the novel derivatives, the compound (5f) showed relatively high larvicidal activity against a malaria vector. Compounds (5i) and (5m) exhibited a broad spectrum antibacterial activity against Gram positive and Gram negative species and hence they may be considered as drug candidates for bacterial pathogens.

In vitro stability and in vivo anti-inflammatory efficacy of synthetic jasmonates

A chlorinated methyl jasmonate analog (J7) was elaborated as an in vitro anti-inflammatory lead. However, its in vitro efficacy profile was not reproduced in a subsequent in vivo evaluation, presumably due to its rapid enzymatic hydrolysis in a biological system. In an attempt to improve the metabolic stability of the lead J7 by replacement of its labile methyl ester with reasonable ester groups, several analogs resistant to enzymatic hydrolysis were synthesized. In vivo evaluation of the stability-improved analogs showed that these compounds displayed higher efficacy than the lead J7, suggesting that these new jasmonate analogs may serve as potential anti-inflammatory leads.

Synthesis and anticonvulsant activity of 8-alkoxy-5,6-dihydro-4H-[1,2,4]triazolo[4,3-a][1]benzazepin-1-one derivatives

A series of novel 8-alkoxy-5,6-dihydro-4H-[1,2,4]triazolo[4,3-a][1]benzazepin-1-one derivatives were synthesized and screened for their anticonvulsant activities by the maximal electroshock (MES) test, subcutaneous pentylenetetrazol (scPTZ) test, and their neurotoxicity was evaluated by the rotarod neurotoxicity test (Tox). The results of these tests demonstrated that 8-heptyloxy-5,6-dihydro-4H-[1,2,4]triazolo[4,3-a][1]benzazepin-1-one (3f) and 8-hexyloxy -5,6-dihydro-4H-[1,2,4]triazolo[4,3-a][1]benzazepin-1-one (3e) were the most promising compounds, with median effective dose (ED(50)) of 17.6 and 17.9 mg/kg, and protective index (PI) of greater than 63.4 and 62.4 in the MES test, respectively. These PI values were higher than the PI value of the prototype antiepileptic drug carbamazepine. The scPTZ test showed that 8-pentyloxy-5,6-dihydro-4H-[1,2,4]triazolo[4,3-a][1]benzazepin-1-one (3d) was the most potent with ED(50) value of 38.0 mg/kg and PI value of greater than 29.4, which is much safer than marketed drug carbamazepine. The possible structure-activity relationship was discussed.

Synthesis and anticonvulsant activity of 1-formamide-triazolo[4,3-a]quinoline derivatives

Using 6-hydroxy-3,4-dihydro-2(1H)-quinolone as the starting material, a series of 1-formamide-triazolo[4, 3-a]quinoline derivatives (6a-6n) was synthesized, the anticonvulsant effect and neurotoxicity of the compounds was calculated with maximal electroshock test and rotarod tests with intraperitoneally injected in KunMing mice. The results demonstrated that compound 7-(hexyloxy)-4,5-dihydro-[1,2,4] triazolo[4,3-a]quinoline-1-carboxamide (6d) was the most active one and also had the lowest toxicity. In the anti-maximal electroshock potency test, it showed median effective dose (ED(50)) of 30.1 mg/kg, median toxicity dose (TD(50)) of 286 mg/kg, and the protective index of 9.5 which is greater than the reference drug carbamazepine with the protective index value of 6.0.