Design, synthesis and anticonvulsant evaluation of N-(benzo[d]thiazol-2-ylcarbamoyl)-2-methyl-4-oxoquinazoline-3(4H)-carbothioamide derivatives: A hybrid pharmacophore approach

Assessing the Effects of Thiazole-Carboxamide Derivatives on the Biophysical Properties of AMPA Receptor Complexes as a Potential Neuroprotective Agent

An optimal balance between excitatory and inhibitory transmission in the central nervous system provides essential neurotransmission for good functioning of the neurons. In the neurology field, a disturbed balance can lead to neurological diseases like epilepsy, Alzheimer's, and Autism. One of the critical agents mediating excitatory neurotransmission is α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors, which are concerned with synaptic plasticity, memory, and learning. An imbalance in neurotransmission finally results in excitotoxicity and neurological pathologies that should be corrected through specific compounds. Hence, the current study will prove to be an evaluation of new thiazole-carboxamide derivatives concerning AMPAR-modulating activity and extended medicinal potential. In the current project, five previously synthesized thiazole-carboxamide derivatives, i.e., TC-1 to TC-5, were used to interact with the AMPARs expressed in HEK293T cells, which overexpress different subunits of the AMPAR. Patch-clamp analysis was carried out while the effect of the drugs on AMPAR-mediated currents was followed with a particular emphasis on the kinetics of inhibition, desensitization, and deactivation. All tested TC compounds, at all subunits, showed potent inhibition of AMPAR-mediated currents, with TC-2 being the most powerful for all subunits. These compounds shifted the receptor kinetics efficiently, mainly enhancing the deactivation rates, and hence acted as a surrogate for their neuroprotective potentials. Additionally, recently published structure-activity relationship studies identified particular substituent groups as necessary for improving the pharmacologic profiles of these compounds. In this regard, thiazole-carboxamide derivatives, particularly those classified as TC-2, have become essential negative allosteric modulators of AMPAR function and potential therapeutics in neurological disturbances underlain by the dysregulation of excitatory neurotransmission. Given their therapeutic effectiveness and safety profiles, these in vivo studies need to be further validated, although computational modeling can be further developed for drug design and selectivity. This will open possibilities for new drug-like AMPAR negative allosteric modulators with applications at the clinical level toward neurology.

Frentizole, a Nontoxic Immunosuppressive Drug, and Its Analogs Display Antitumor Activity via Tubulin Inhibition

Antimitotic agents are one of the more successful types of anticancer drugs, but they suffer from toxicity and resistance. The application of approved drugs to new indications (i.e., drug repurposing) is a promising strategy for the development of new drugs. It relies on finding pattern similarities: drug effects to other drugs or conditions, similar toxicities, or structural similarity. Here, we recursively searched a database of approved drugs for structural similarity to several antimitotic agents binding to a specific site of tubulin, with the expectation of finding structures that could fit in it. These searches repeatedly retrieved frentizole, an approved nontoxic anti-inflammatory drug, thus indicating that it might behave as an antimitotic drug devoid of the undesired toxic effects. We also show that the usual repurposing approach to searching for targets of frentizole failed in most cases to find such a relationship. We synthesized frentizole and a series of analogs to assay them as antimitotic agents and found antiproliferative activity against HeLa tumor cells, inhibition of microtubule formation within cells, and arrest at the G2/M phases of the cell cycle, phenotypes that agree with binding to tubulin as the mechanism of action. The docking studies suggest binding at the colchicine site in different modes. These results support the repurposing of frentizole for cancer treatment, especially for glioblastoma.

Design, Synthesis and Biological Activities of (Thio)Urea Benzothiazole Derivatives

(Thio)ureas ((T)Us) and benzothiazoles (BTs) each have demonstrated to have a great variety of biological activities. When these groups come together, the 2-(thio)ureabenzothizoles [(T)UBTs] are formed, improving the physicochemical as well as the biological properties, making these compounds very interesting in medicinal chemistry. Frentizole, bentaluron and methabenzthiazuron are examples of UBTs used for treatment of rheumatoid arthritis and as wood preservatives and herbicides in winter corn crops, respectively. With this antecedent, we recently reported a bibliographic review about the synthesis of this class of compounds, from the reaction of substituted 2-aminobenzothiazoles (ABTs) with iso(thio)cyanates, (thio)phosgenes, (thio)carbamoyl chlorides, 1,1'-(thio)carbonyldiimidazoles, and carbon disulfide. Herein, we prepared a bibliographic review about those features of design, chemical synthesis, and biological activities relating to (T)UBTs as potential therapeutic agents. This review is about synthetic methodologies generated from 1968 to the present day, highlighting the focus to transform (T)UBTs to compounds containing a range substituents, as illustrated with 37 schemes and 11 figures and concluded with 148 references. In this topic, the scientists dedicated to medicinal chemistry and pharmaceutical industry will find useful information for the design and synthesis of this interesting group of compounds with the aim of repurposing these compounds.

Elemental Sulfur-Promoted Benzoxazole/Benzothiazole Formation Using a C═C Double Bond as a One-Carbon Donator

An efficient method to assemble diverse benzoxazoles/benzothiazoles in good yields was developed via oxidative cyclization with 2-aminothiophenols or 2-iodoanilines as raw materials. In this protocol, elemental sulfur was used as the effective oxidant and C atoms on the C═C double bond were introduced as a one-carbon donator.

Recent Development in Substituted Benzothiazole as an Anticonvulsant Agent

Heterocyclic compounds and their derivatives gained more attention due to their valuable biological and pharmacological properties. Benzothiazole is a heterocyclic structure containing a bicyclic ring system with a large panel of applications. The benzothiazole is present in many new products undergoing research hoping that it possesses various biological activities. Epilepsy is a diverse group of diseases marked by neuronal excitability and hypersynchronous neuronal activity of motor, sensory or autonomic events with or without loss of consciousness. Presently, many antiepileptic drugs like lamotrigine, stiripentol tiagabine, pregabalin, felbamate, and topiramate are available and effective towards 60-80% of patients only, along with undesirable side effects, such as hepatotoxicity, gastrointestinal disturbance, drowsiness, gingival hyperplasia, and hirsutism. Thus, many attempts are still on-going to develop antiepileptic drugs with a safer profile. This review is mainly focused on the compilation of reported scientific literature data in the recent one-decade on the anticonvulsant activity of benzothiazole compounds.

Recent advancement in the discovery and development of anti-epileptic biomolecules: An insight into structure activity relationship and Docking

Although there have been many advancements in scientific research and development, the cause of epilepsy still remains an open challenge. In spite of high throughput research in the field of anti-epileptic drugs, efficacy void is still prevalent before the researchers. Researchers have persistently been exploring all the possibilities to curb undesirable side effects of the anti-epileptic drugs or looking for a more substantial approach to diminish or cure epilepsy. The drug development has shown a hope to medicinal chemists and researchers to carry further research by going through a substantial literature survey. This review article attempts to describe the recent developments in the anti-epileptic agents, pertaining to different molecular scaffolds considering their structure-activity relationship, docking studies and their mechanism of actions.

Recent advances in the pharmacological diversification of quinazoline/quinazolinone hybrids

Due to the pharmacological activities of quinazoline and quinazolinone scaffolds, it has aroused great interest in medicinal chemists for the development of new drugs or drug candidates. The pharmacological activities of quinazoline and its related scaffolds include anti-cancer, anti-microbial, anti-convulsant, and antihyperlipidaemia. Recently, molecular hybridization technology is used for the development of hybrid analogues with improved potency by combining two or more pharmacophores of bioactive scaffolds. The molecular hybridization of various biologically active pharmacophores with quinazoline derivatives resulted in lead compounds with multi-faceted biological activity wherein specific as well as multiple targets were involved. The present review summarizes the advances in lead compounds of quinazoline hybrids and their related heterocycles in medicinal chemistry. Moreover, the review also helps to intensify the drug development process by providing an understanding of the potential role of these hybridized pharmacophoric features in exhibiting various pharmacological activities.

Recent advances in quinazoline/quinazolinone hybrid heterocycles in medicinal chemistry and their pharmacological diversification.

Chagas Disease Drug Discovery: Multiparametric Lead Optimization against Trypanosoma cruzi in Acylaminobenzothiazole Series

Acylaminobenzothiazole hits were identified as potential inhibitors of Trypanosoma cruzi replication, a parasite responsible for Chagas disease. We selected compound 1 for lead optimization, aiming to improve in parallel its anti-T. cruzi activity (IC₅₀ = 0.63 μM) and its human metabolic stability (human clearance = 9.57 mL/min/g). A total of 39 analogues of 1 were synthesized and tested in vitro. We established a multiparametric structure-activity relationship, allowing optimization of antiparasite activity, physicochemical parameters, and ADME properties. We identified compound 50 as an advanced lead with an improved anti-T. cruzi activity in vitro (IC₅₀ = 0.079 μM) and an enhanced metabolic stability (human clearance = 0.41 mL/min/g) and opportunity for the oral route of administration. After tolerability assessment, 50 demonstrated a promising in vivo efficacy.

Facile Synthesis of a Series of Non-Symmetric Thioethers Including a Benzothiazole Moiety and Their Use as Efficient In Vitro anti-Trypanosoma cruzi Agents

A series of 2-benzylsulfanyl benzothiazole (BTA) derivatives were synthesized and fully characterized and in vitro tested against two strains of T. cruzi (NINOA and INC-5), exhibiting good activities at low concentrations.

Design and synthesis of leucine-linked quinazoline-4(3H)-one-sulphonamide molecules distorting malarial reductase activity in the folate pathway

Optimization of a modified Grimmel's method for N-heterocyclization of a leucine-linked sulfonamide side-arm at position 2 leading to 2,3-disustituted-4-quinazolin-(3H)-ones was accomplished. Further, 22 hybrid quinazolinone motifs (4a-v) were synthesized by N-heterocyclization reaction under microwave irradiation using the ionic liquid [Bmim][BF₄ ]-H₂ O as green solvent as well as the catalyst. The in vitro screening of the hybrid entities against the malarial species Plasmodium falciparum yielded five potent molecules 4l, 4n, 4o, 4t, and 4u owning antimalarial activity comparable to those of the reference drugs. In continuation, an in silico study was carried out to obtain a pharmacophoric model and quantitative structure-activity relationship. We also built a 3D-QSAR model to procure more information that could be applied to design new molecules with more potent Pf-DHFR inhibitory activity. The designed pharmacophore was recognized to be more potent for the selected molecules, exhibiting five pharmacophoric features. The active scaffolds were further evaluated for enzyme inhibition efficacy against alleged receptor Pf-DHFR computationally and in vitro, proving their candidature as lead dihydrofolate reductase inhibitors, and the selectivity of the test candidates was ascertained by toxicity study against Vero cells. Good oral bioavailability was also proved by studying pharmacokinetic properties.

Green synthesis, biological evaluation, molecular docking studies and 3D-QSAR analysis of novel phenylalanine linked quinazoline-4(3H)-one-sulphonamide hybrid entities distorting the malarial reductase activity in folate pathway

A modified Grimmel's method for N-heterocyclization of phenylalanine linked sulphonamide side arm at position-2 was optimized leading to 2,3-disustituted-4-quinazolin-(3H)-ones. Further, [Bmim][BF₄]-H2O (IL) was used as green solvent as well as catalyst for the synthesis of twenty two hybrid quinazolinone motifs (4a-4v) by N-heterocyclization reaction using microwave irradiation technique. The in vitro screening of the hybrid entities against the malarial species Plasmodium falciparum yielded five potent molecules 4l, 4n, 4r, 4t & 4u owing comparable antimalarial activity to the reference drugs. In continuation, anin silicostudy was carried out to obtain a pharmacophoric model and quantitative structure activity relationship. We also built a 3D-QSAR model to procure more information that could be applied to design new molecules with more potent Pf-DHFR inhibitory activity. The designed pharmacophore was recognized to be more potent for the selected molecules, exhibiting five pharmacophoric features. The active scaffolds were further evaluated for enzyme inhibition efficacy against alleged receptor Pf-DHFR computationally and in vitro, proving their candidature as lead dihydrofolate reductase inhibitors as well as the selectivity of the test candidates was ascertained by toxicity study against vero cells. The perception of good oral bioavailability was also proved by study of pharmacokinetic properties.

Synthesis, in vivo and in silico evaluation of novel 2,3-dihydroquinazolin-4(1H)-one derivatives as potential anticonvulsant agents

In light of the pharmacophoric structural requirements for achieving anticonvulsant activity, a series of N-(1-methyl-4-oxo-2-un/substituted-1,2-dihydroquinazolin-3[4H]-yl)benzamide (4a-g) and N-(1-methyl-4-oxo-2-un/substituted-1,2-dihydroquinazolin-3[4H]-yl)-2-phenylacetamide (4h-n) derivatives were synthesized in two steps starting from the reaction of N-methyl isatoic anhydride with the appropriate hydrazide and followed by condensation with the appropriate aldehyde. The anticonvulsant activities of the synthesized compounds were evaluated according to the anticonvulsant drug development (ADD) programme protocol. Among the synthesized compounds, 4n showed promising activity in both the maximal electroshock (MES) and pentylenetetrazole (PTZ) tests with median effective dose (ED₅₀ ) values of 40.7 and 6 mg/kg, respectively. The six most promising derivatives, 4b, 4a, 4c, 4f, 4j, and 4i, showed very low ED₅₀ values in the PTZ test (3.1, 4.96, 8.68, 9.89, 12, and 13.53 mg/kg, respectively). All the tested compounds showed no to low neurotoxicity in the rotarod test with a wide therapeutic index. Docking studies of compound 4n suggested that GABA_A binding could be the mechanism of action of these derivatives. The in silico drug likeliness parameters indicated that none of the designed compounds violate Lipinski's rule of five and that they are able to cross the blood-brain barrier. Hit, Lead & Candidate Discovery.

Therapeutic advancement of benzothiazole derivatives in the last decennial period

Benzothiazole, a fused heterocyclic moiety, has attracted synthetic and medicinal chemists for good reasons. It is a valuable scaffold that possesses diverse biological activities, such as anticancer, anti-inflammatory, antimicrobial, antiviral, antimalarial, and anticonvulsant effects. This review mainly focusses on the recent research work on the different biological activities of benzothiazole-based compounds.

Cinnamamide pharmacophore for anticonvulsant activity: evidence from crystallographic studies

A number of cinnamamide derivatives possess anticonvulsant activity due to the presence of a number of important pharmacophore elements in their structures. In order to study the correlations between anticonvulsant activity and molecular structure, the crystal structures of three new cinnamamide derivatives with proven anticonvulsant activity were determined by X-ray diffraction, namely (R,S)-(2E)-N-(2-hydroxybutyl)-3-phenylprop-2-enamide-water (3/1), C₁₃H₁₇NO₂·0.33H₂O, (1), (2E)-N-(1-hydroxy-2-methylpropan-2-yl)-3-phenylprop-2-enamide, C₁₃H₁₇NO₂, (2), and (R,S)-(2E)-N-(1-hydroxy-3-methyl-butan-2-yl)-3-phenylprop-2-enamide, C₁₄H₁₉NO₂, (3). Compound (1) crystallizes in the space group P-1 with three molecules in the asymmetric unit, whereas compounds (2) and (3) crystallize in the space group P2₁/c with one and two molecules, respectively, in their asymmetric units. The carbonyl group of (2) is engaged in an intramolecular hydrogen bond with the hydroxy group. This type of interaction is observed for the first time in these kinds of derivatives. A disorder of the substituent at the N atom occurs in the crystal structures of (2) and (3). The crystal packing of all three structures is dominated by a network of O-H...O and N-H...O hydrogen bonds, and leads to the formation of chains and/or rings. Furthermore, the crystal structures are stabilized by numerous C-H...O contacts. We analyzed the molecular structures and intermolecular interactions in order to propose a pharmacophore model for cinnamamide derivatives.

Rhodium-catalyzed C–H bond activation alkylation and cyclization of 2-arylquinazolin-4-ones

An efficient method for the synthesis of isoquinolino[1,2-b]quinazolin-8-one derivatives and 12-methyl-12H-isoindolo[1,2-b]quinazoline-10-one derivatives is described herein.

Synthesis and Determination of Lipophilicity, Anticonvulsant Activity, and Preliminary Safety of 3-Substituted and 3-Unsubstituted N-[(4-Arylpiperazin-1-yl)alkyl]pyrrolidine-2,5-dione Derivatives

A new series of 1,3-substituted pyrrolidine-2,5-dione derivatives as potential anticonvulsant agents are described. Initial pharmacological screening of these compounds was performed by using acute models of seizures (MES and scPTZ tests) in mice after intraperitoneal administration. Quantitative pharmacological research revealed that the most promising compounds were N-[{4-(3-trifluoromethylphenyl)piperazin-1-yl}propyl]-3-benzhydrylpyrrolidine-2,5-dione monohydrochloride (11) with a ED₅₀ value of 75.9 mg kg^-1 (MES test) and N-[{4-(3,4-dichlorophenyl)piperazin-1-yl}ethyl]-3-methylpyrrolidine-2,5-dione monohydrochloride (18) with ED₅₀ =88.2 mg kg^-1 (MES test) and ED₅₀ =65.7 kg mg^-1 (scPTZ test). These compounds displayed a more beneficial protective index than well-known antiepileptic drugs. A plausible mechanism of action of compounds 11 and 18 [molecule 11 blocked the sodium channel (site 2) and 18 blocked both the sodium (site 2) and L-type calcium channels] and their preliminary safety in vitro were evaluated. Besides, the lipophilicity of all synthesized compounds was determined by using UPLC-MS.

Design, synthesis, anticonvulsant evaluation and docking study of 2-[(6-substituted benzo[d]thiazol-2-ylcarbamoyl)methyl]-1-(4-substituted phenyl)isothioureas

In this paper, we report the synthesis of 2-[(6-substituted benzo[d]thiazol-2-ylcarbamoyl)methyl]-1-(4-substituted phenyl)isothiourea derivatives (4a-y) carrying active pharmacophores essential for anticonvulsant activity. The anticonvulsant activity was evaluated in vivo by maximal electroshock (MES) test and subcutaneous pentylenetetrazole (scPTZ) test in mice. Most of the compounds showed promising anticonvulsant activity. The most active compounds 4b and 4q were found active in both MES and scPTZ models, without signs of neurotoxicity. Compound 4b showed the moderate change in SGOT and alkaline phosphatase level as compared to control. Compounds 4b and 4w were also found to elevate GABA levels in the olfactory lobe, mid brain, medulla oblongata and cerebellum regions of rat brain. In molecular docking study, the title compounds exhibited good binding properties with epilepsy molecular targets such as GABA-A. Structure-activity relationships are also elaborated along with the analysis of lipophilicity. The results suggested that compound 4b is likely to have varied mechanisms of action including voltage-gated ion channel inhibition and modulating GABAergic action.

EFFECTS OF 4-THIAZOLIDINONE DERIVATIVES LES-2658 AND LES-1205 ON SLEEP - WAKEFULNESS CYCLE IN KINDLED RATS

The research is dedicated to in-depth study of neurotrophic and antiepileptic properties of original potential anticonvulsant agents from 4-thiazolidinones – LES-2658 (5-(3-nitro-benzylidene)-2-(thiazol-2-ylimino)-thiazolidin-4-one) and LES-1205 ([2,4-dioxo-5-(thiazol-2-ylcarbamoylmethyl)-thiazolidin-3-yl]-acetic acid ethyl ester), synthesized at the Department of Pharmaceutical, Organic and Bioorganic Chemistry of Danylo Halytsky Lviv National Medical University, Ukraine. Studying of sleep - wakefulness cycle characteristics in animals with chronic epileptic syndrome in conditions of 4-thiazolidinones derivatives LES-2658 and LES-1205 use was performed. The kindling syndrome was induced in Wistar rats via daily pentylenetetrazol (PTZ) (30 mg/kg, i.p.) administrations during three weeks and sleep - wakefulness cycle was studied under conditions of LES-2658 and LES-1205 administrations at doses 25.0and 100.0 mg/kg i.p.. Total wakefulness, non - rapid eye movement sleep, rapid eye movement sleep, falling asleep latency, REM - onset latency and also number of REM sleep episodes have been determined by behavioral characteristics of experimental animals. It was established that 4-thiazolidinone derivatives Les-1205 and Les-2658 reduce REM sleep fragmentation and increase its duration in PTZ-kindled rats. Les-1205 compound at dose 100.0 mg/kg show a clear correcting influence on kindling - induced sleep disturbances.

Crystal structure of N-(adamantan-1-yl)-4-phenylpiperazine-1-carbothioamide, C21H29N3S

C21H29N3S, orthorhombic, Pbca (No. 61), a = 9.8658(7) Å, b = 11.7298(9) Å, c = 31.960(2) Å, V = 3698.5(5) Å3, Z = 8, R gt (F) = 0.0644, wR ref (F 2) = 0.1684, T = 100 K.

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.

Crystal structure of (E)-4-(acetoxyimino)-N-allyl-3-isopropyl-2,6-diphenylpiperidine-1-carbothioamide

The title compound, C₂₆H₃₁N₃O₂S, crystallizes with two mol­ecules (A and B) in the asymmetric unit. In each case, the piperidine ring exists in a twist-boat conformation. The dihedral angle between the phenyl rings is 46.16 (12)° in mol­ecule A and 44.95 (12)° in mol­ecule B. In both mol­ecules, the allyl side chain is disordered over two orientations in a 0.649 (9):0.351 (9) ratio for mol­ecule A and 0.826 (10):0.174 (10) ratio for mol­ecule B. In the crystal, neither mol­ecule forms a hydrogen bond from its N—H group, presumably due to steric hindrance. A+A and B+B inversion dimers are formed, linked by pairs of weak C—H⋯O hydrogen bonds enclosing R₂²(22) ring motifs.

Synthesis of quinazolines and quinazolinones via palladium-mediated approach

Quinazoline derivatives have drawn attention in the field of heterocyclic chemistry because of their unique skeleton and interesting biological applications. This review summarizes the recent palladium-catalyzed reactions used to construct quinazoline and its related 4(3H)-quinazolinone analogues. The mechanisms of some Pd-catalyzed reactions are also discussed.

Synthesis, Antimicrobial and Hypoglycemic Activities of Novel N-(1-Adamantyl)carbothioamide Derivatives

The reaction of 1-adamantyl isothiocyanate 4 with the various cyclic secondary amines yielded the corresponding N-(1-adamantyl)carbothioamides 5a–e, 6, 7, 8a–c and 9. Similarly, the reaction of 4 with piperazine and trans-2,5-dimethylpiperazine in 2:1 molar ratio yielded the corresponding N,N'-bis(1-adamantyl)piperazine-1,4-dicarbothioamides 10a and 10b, respectively. The reaction of N-(1-adamantyl)-4-ethoxycarbonylpiperidine-1-carbothioamide 8c with excess hydrazine hydrate yielded the target carbohydrazide 11, in addition to 4-(1-adamantyl)thiosemicarbazide 12 as a minor product. The reaction of the carbohydrazide 11 with methyl or phenyl isothiocyanate followed by heating in aqueous sodium hydroxide yielded the 1,2,4-triazole analogues 14a and 14b. The reaction of the carbohydrazide 11 with various aromatic aldehydes yielded the corresponding N'-arylideneamino derivatives 15a–g. The compounds 5a–e, 6, 7, 8a–c, 9, 10a, 10b, 14a, 14b and 15a–g were tested for in vitro antimicrobial activity against certain strains of pathogenic Gram-positive and Gram-negative bacteria and the yeast-like fungus Candida albicans. The compounds 5c, 5d, 5e, 6, 7, 10a, 10b, 15a, 15f and 15g showed potent antibacterial activity against one or more of the tested microorganisms. The oral hypoglycemic activity of compounds 5c, 6, 8b, 9, 14a and 15b was determined in streptozotocin (STZ)-induced diabetic rats. Compound 5c produced significant reduction of serum glucose levels, compared to gliclazide.

Synthesis of 5-alkoxythieno[2,3-e][1,2,4]triazolo[4,3-c]pyrimidine derivatives and evaluation of their anticonvulsant activities

This work concerns the design and synthesis of novel, substituted 5-alkoxythieno[2,3-e][1,2,4]triazolo[4,3-c]pyrimidine derivatives 5a-p prepared from 3-amino-2-thiophenecarboxylic acid methyl ester. The final compounds were screened for their in vivo anticonvulsant activity using maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) tests. Neurotoxicity (NT) was tested using a rotarod test. The structure-anticonvulsant activity relationship analysis revealed that the most effective structural motif involves a substituted phenol, especially when substituted with a single chlorine, fluorine or trifluoromethyl group (at the meta-position), or two chlorine atoms. These molecules possessed high activity according to the MES and scPTZ models. Quantitative assessment of the compounds after intraperitoneal administration in mice showed that the most active compound was 5-[3-(trifluoromethyl)phenoxy]thieno[2,3-e] [1,2,4]triazolo[4,3-c]pyrimidine (5o) with ED50 values of 11.5 mg/kg (MES) and 58.9 mg/kg (scPTZ). Furthermore, compound 5o was more effective in the MES and scPTZ tests than the well-known anticonvulsant drugs carbamazepine and ethosuximide.

Recent advances in the chemistry and biology of benzothiazoles

Benzothiazole is a privileged heterocyclic scaffold having a benzene ring fused with a five-membered thiazole ring. This moiety has attracted considerable attention because of its wide range of pharmacological activities such as antitubercular, antimicrobial, antimalarial, anticonvulsant, anthelmintic, analgesic, anti-inflammatory, antidiabetic, antitumor activity, etc. In the last few years, some novel benzothiazoles have been developed with varied biological activities. To access this scaffold in high yield and to introduce diversity, a variety of new synthetic methods have been invented. In this review, we highlight the development of novel benzothiazoles for various biological activities along with the best synthetic protocols for their synthesis.

Thiazole: a promising heterocycle for the development of potent CNS active agents

Thiazole is a valuable scaffold in the field of medicinal chemistry and has accounted to display a variety of biological activities. Thiazole and its derivatives have attracted continuing interest to design various novel CNS active agents. In the past few decades, thiazoles have been widely used to develop a variety of therapeutic agents against numerous CNS targets. Thiazole containing drug molecules are currently being used in treatment of various CNS disorders and a number of thiazole derivatives are also presently in clinical trials. A lot of research has been carried out on thiazole and their analogues, which has proved their efficacy to overcome several CNS disorders in rodent as well as primate models. The aim of present review is to highlights diverse CNS activities displayed by thiazole and their derivatives. SAR of this nucleus has also been well discussed. This review covers the recent updates present in literature and will surely provide a greater insight for the designing and development of potent thiazole based CNS active agents in future.

A comprehensive review in current developments of benzothiazole-based molecules in medicinal chemistry

Benzothiazole (BTA) and its derivatives are the most important heterocyclic compounds, which are common and integral feature of a variety of natural products and pharmaceutical agents. BTA shows a variety of pharmacological properties, and its analogs offer a high degree of structural diversity that has proven useful for the search of new therapeutic agents. The broad spectrum of pharmacological activity in individual BTA derivative indicates that, this series of compounds is of an undoubted interest. The related research and developments in BTA-based medicinal chemistry have become a rapidly developing and increasingly active topic. Particularly, numerous BTA-based compounds as clinical drugs have been extensively used in practice to treat various types of diseases with high therapeutic potency. This work systematically gives a comprehensive review in current developments of BTA-based compounds in the whole range of medicinal chemistry as anticancer, antibacterial, antifungal, antiinflammatory, analgesic, anti-HIV, antioxidant, anticonvulsant, antitubercular, antidiabetic, antileishmanial, antihistaminic, antimalarial and other medicinal agents. It is believed that, this review article is helpful for new thoughts in the quest for rational designs of more active and less toxic BTA-based drugs, as well as more effective diagnostic agents and pathologic probes.