Here, we describe the synthesis and anticonvulsant activity of thiazole-bearing hybrids based on 2-imino-4-thiazolidinone and 2,4-dioxothiazolidine-5-carboxylic acid cores. The structure of target compounds was based on the following: (i) A combination of two thiazole cores; (ii) similarity to ralitolin’s structure; (iii) the compliance with structural requirements for the new anticonvulsants. Target compounds were synthesized via known approaches based on Knoenavegel reaction, alkylation reaction, and one-pot three-component reaction. Anticonvulsant properties of compounds were evaluated in two different models—pentylenetetrazole-induced seizures and maximal electroshock seizure tests. Among the tested compounds 5Z-(3-nitrobenzylidene)-2-(thiazol-2-ylimino)-thiazolidin-4-one Ib, 2-[2,4-dioxo-5-(thiazol-2- ylcarbamoylmethyl)-thiazolidin-3-yl]-N-(2-trifluoromethylphenyl)acetamide IId and (2,4-dioxo-5- (thiazol-2-ylcarbamoylmethylene)-thiazolidin-3-yl)acetic acid ethyl ester IIj showed excellent anticonvulsant activity in both models. The directions of compounds modification based on SAR aspects were discussed. The results of the study provide a basis for further study of the anticonvulsant properties of selected thiazole-thiazolidinones.

Neuroinflammation is an integral part of epilepsy pathogenesis and other convulsive conditions, and non-steroidal anti-inflammatory drugs (NSAIDs) present a potent tool for the contemporary search and design of novel anticonvulsants. In the present paper, evaluation of the anticonvulsant activity of the potential NSAID dual COX-2/5-LOX inhibitor darbufelone methanesulfonate using an scPTZ model in mice in dose 100 mg/kg is reported. Darbufelone possesses anticonvulsant properties in the scPTZ model and presents interest for in-depth studies as a possible anticonvulsant multi-target agent with anti-inflammatory activity. The series of 4-thiazolidinone derivatives have been synthesized following the analogue-based drug design and hybrid-pharmacophore approach using a darbufelone matrix. The synthesized derivatives showed a significant protection level for animals in the scPTZ model and are promising compounds for the design of potential anticonvulsants with satisfactory drug-like parameters.

It was determined that the studied 5-[(Z)-(4-nitrobenzylidene)]-2-(thiazol-2-ylimino)-4-thiazolidinone (Les-6222) affects the cyclooxygenase pathway of the arachidonic acid cascade, the markers of damage to neurons on models of PTZ kindling. In the model of chronic epileptogenesis in mice (pentylenetetrazole kindling), a 4-thiazolidinone derivative showed high anticonvulsant activity, which is weaker than the effect of sodium valproate and higher than Celecoxib. The mentioned compound has a pronounced anti-inflammatory effect in the brain on the background of the PTZ kindling, reliably inhibiting COX-1 and COX-2. The predominant inhibition of COX-2 by 44.5% indicates this enzyme’s high selectivity of Les-6222. According to the molecular docking study results, the studied compound revealed the properties of COX-1/COX-2 inhibitor and especially 5-LOX/FLAP. The decreasing content of 8-isoprostane in the brain of mice of the Les-6222 group indicates a beneficial effect on cell membranes in the background of oxidative stress during the long-term administration of PTZ. In addition, Les-6222 significantly decreased the content of neuron-specific enolase, indicating neuroprotective properties in the background of chronic epileptogenesis. The obtained results experimentally substantiate the feasibility of further developing Les-6222 as a promising anticonvulsant agent.

Aim. To synthesize 5-ene-4-thiazolidinones containing heterocyclic rings in the molecule as potential anticonvulsants, and screen their anticonvulsant activity on a model of pentylenetetrazole (PTZ) seizures.Results and discussion. A straightforward and convenient synthesis of novel 5-ene-derivatives of thiazol/oxazole-bearing 4-thiazolidinones as possible anticonvulsant agents was performed. Compounds were characterized using methods of spectral analysis (1H NMR and LC-MS). 5-Chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde underwent the aminolysis on a chlorine atom by a molecule of monoethanolamine (MEA) in the Knoevenagel reaction with thiazole/oxazole-bearing 4-thiazolidinones. The preliminary screening of the anticonvulsant activity was performed for the compounds synthesized on the model of PTZ-induced seizures, and active derivatives were identified.Experimental part. Commercially available 2-aminothiazole and 5-methylisoxazol-3-amine were used as starting compounds for the synthesis of 2-chloro-N-(hetaryl)acetamides. The latter were transformed into thiazole/oxazole-bearing 4-thiazolidinones by the treatment with ammonium isothiocyanate. Modification at C5 position of the heterocycles synthesized was performed by the Knoevenagel reaction with aromatic/heteroaromatic aldehydes and MEA as a catalyst (either equimolar or 0.1 mol% amount) in the ethanol medium. The structure of novel derivatives was confirmed by 1H NMR and LC-MS spectra. The anticonvulsant activity of all derivatives synthesized was studied in vivo on the model of PTZ-induced seizures. Latency of the seizures, the number of clonic-tonic seizures in one mouse, the percent of animals with clonic and tonic seizures, the duration of the seizure period, and the lifetime of the animals before death were evaluated and calculated.Conclusions. The results obtained are promising for further design of potential anticonvulsants among oxazole-bearing 4-thiazolidones with the possible mechanism of the anticonvulsant action through the GABA-ergic impact and inhibition of the prostaglandin and leukotriene synthesis.

Aim. To study the range of psychotropic properties of a new original compound of 5-[(Z)-(4-nitrobenzylidene)]-2-(thiazol-2-ylimino)-4 thiazolidinone with the anticonvulsant activity. Materials and methods. Adult nonlinear white mice of both sexes weighing 20-27 g were used in the experiments. The locomotor, exploratory, emotional activities were studied in the open field test. The elevated plus maze was used to study anxiety. The effect of the compound on depressive behavior was studied by the tail suspension test. The passive avoidance test was used to study memory. The influence of the compound on the skeletal muscle tone and coordination was studied in the rotarod test. Actoprotective properties were studied in a swimming test with a load of 10 % by weight of the animal. Results and discussion. In the previous studies, 5-[(Z)-(4-nitrobenzylidene)]-2-(thiazol-2-ylimino)-4-thiazolidinone showed a pronounced anticonvulsant effect in seizure models with different pathogenesis. In this study the related psychotropic effects of the test compound were studied. It was found that in intact mice 5-[(Z)-(4-nitrobenzylidene)]-2-(thiazol-2-ylimino)-4-thiazolidinone in the dose of 100 mg/kg by intragastrical administration did not affect the locomotor, exploratory, emotional activity and its vegetative support, anxiety, depressive activity (in contrast to the reference drug – a classic anticonvulsant sodium valproate, which showed depressive properties), and memory. The test compound did not have a negative effect on the skeletal muscle tone and coordination, but statistically significantly increased the physical endurance of animals, being only slightly inferior to the classic CNS stimulant caffeine. Conclusions. Thus, 5-[(Z)-(4-nitrobenzylidene)]-2-(thiazol-2-ylimino)-4-thiazolidinone in the dose of 100 mg/kg can be considered as a potential anticonvulsant without related psychotropic effects and with actoprotective properties.

The participation of arachidonic acid metabolism products – prostaglandins and leukotrienes – in the process of inflammation is a common pathogenetic link of cold injury and epilepsy. Montelukast is widely used for the treatment of bronchial asthma and allergic rhinitis as a leukotriene receptor blocker. However, the mechanism of action of the drug suggests a wider range of its pharmacological properties and the corresponding scope of application. This study is aimed to determine the effectiveness of montelukast as a potential frigoprotective and anticonvulsant drug. Experiments were performed on 73 white mice weighing 20-22 g on models of acute general cooling and pentylenetetrazol convulsions. Frigoprotective properties were studied at a temperature of –18°C, recording the lifetime. Montelukast ("Singular", 2 mg/kg), acetylsalicylic acid ("Aspirin", 50 mg/kg), celecoxib ("Celebrex", 74 mg/kg), diclofenac sodium ("Voltaren", 14 mg/kg) were administered intragastrically as a suspension in a prophylactic mode, 30 minutes before the cold injury. In the study of anti­convulsant activity, montelukast ("Singular", 4 mg/kg) and sodium valproate ("Depakin", 300 mg/kg) were admi­nistered intragastrically 30 minutes before stimulating convulsions by subcutaneous administration of pentylene­tetrazole (90 mg/kg). The latent period of convulsions, the number of convulsions per 1 animal, % of mice with clonic and tonic paroxysms, the severity of convulsions in points, the duration of the convulsive period, the lifetime of animals and lethality were recorded for an hour. On the model of acute general cooling, montelukast showed a dose-dependent frigoprotective effect at a dose of 2 mg/kg surpassing drugs with proven frigoprotective properties – acetylsalicylic acid and celecoxib. On the model of pentylenetetrazole-induced convulsions, montelukast statistically significantly reduced the integral indicator of anticonvulsant activity – lethality – by 2.57 times. Thus, the experiment proved the significant role of leukotrienes in the pathogenesis of cold injury and epilepsy and justified the feasibility of further study of the frigoprotective and anticonvulsant properties of montelukast – leukotriene receptor blocker a drug as for adjuvant therapy, especially when these pathologies are combined with bronchial asthma and allergic rhinitis.