Synthesis and anticonvulsant activity of 2(3H)-benzoxazolone and 2(3H)-benzothiazolone derivatives

Comparing the Developmental Toxicity Delay and Neurotoxicity of Benzothiazole and Its Derivatives (BTHs) in Juvenile Zebrafish

In this study, a semi-static water exposure method was employed to investigate the early developmental and neurotoxic effects of four benzothiazole substances (BTHs), namely benzothiazole (BTH), 2-mercaptobenzothiazole (MBT), 2-hydroxybenzothiazole (BTON), and 2-aminobenzothiazole (2-ABTH), on zebrafish at an equimolar concentration of 10 μM. The findings revealed that all four BTHs exerted certain impacts on early development in zebrafish. MBT stimulated spontaneous movement in juvenile zebrafish, whereas BTON inhibited such movements. Moreover, all four BTHs hindered the hatching process of zebrafish larvae, with MBT exhibiting the strongest inhibition at 24 h post-fertilization (hpf). Notably, MBT acted as a melanin inhibitor by suppressing melanin production in juvenile zebrafish eyes and weakening phototaxis. Additionally, both BTH and BTON exhibited significantly lower speeds than the control group and other test groups under conditions without bright field stimulation; however, their speeds increased to average levels after percussion stimulation, indicating no significant alteration in motor ability among experimental zebrafish groups. Short-term exposure to these four types of BTHs induced oxidative damage in zebrafish larvae; specifically, BTH-, MBT-, and BTON-exposed groups displayed abnormal expression patterns of genes related to oxidative damage. Exposure to both BTH and MBT led to reduced fluorescence intensity in transgenic zebrafish labeled with central nervous system markers, suggesting inhibition of central nervous system development. Furthermore, real-time quantitative PCR results demonstrated abnormal gene expression associated with neural development. However, no significant changes were observed in 2-ABTH gene expression at this concentration. Overall findings indicate that short-term exposure to BTHs stimulates neurodevelopmental gene expression accompanied by oxidative damage.

Novel Thiazolidine-2,4-dione-trimethoxybenzene-thiazole Hybrids as Human Topoisomerases Inhibitors

Cancer is a complex and heterogeneous disease and is still one of the leading causes of morbidity and mortality worldwide, mostly as the population ages. Despite the encouraging advances made over the years in chemotherapy, the development of new compounds for cancer treatments is an urgent priority. In recent years, the design and chemical synthesis of several innovative hybrid molecules, which bring different pharmacophores on the same scaffold, have attracted the interest of many researchers. Following this strategy, we designed and synthetized a series of new hybrid compounds that contain three pharmacophores, namely trimethoxybenzene, thiazolidinedione and thiazole, and tested their anticancer properties on two breast cancer (MCF-7 and MDA-MB-231) cell lines and one melanoma (A2058) cell line. The most active compounds were particularly effective against the MCF-7 cells and did not affect the viability of the normal MCF-10A cells. Docking simulations indicated the human Topoisomerases I and II (hTopos I and II) as possible targets of these compounds, the inhibitory activity of which was demonstrated by the mean of direct enzymatic assays. Particularly, compound 7e was proved to inhibit both the hTopo I and II, whereas compounds 7c,d blocked only the hTopo II. Finally, compound 7e was responsible for MCF-7 cell death by apoptosis. The reported results are promising for the further design and synthesis of other analogues potentially active as anticancer tools.

Targeting the kinetics mechanism of AMPA receptor inhibition by 2-oxo-3H-benzoxazole derivatives

Ionotropic glutamate receptors are ligand-gated ion channels found in most excitatory synapses in the brain that allow for rapid information transfer. Due to their quick excitatory processes, α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid-type glutamate (AMPA) receptors have been linked to various neurodegenerative disorders, including epilepsy and Parkinson's disease. It has been critical to develop new neuroprotective compounds that inhibit AMPA-sensitive glutamate-controlled channels allosterically, and many classes of AMPA receptor-inhibiting compounds have been synthesized and evaluated. The current study focuses on thirteen 2-oxo-3H-benzoxazole derivatives (COBs) as potential AMPA receptor modulators. The whole-cell patch-clamp technique was used to assess the effects of COBs on AMPA receptor subunits (i.e., GluA1, GluA2, GluA1/2, and GluA2/3) amplitudes in the human embryonic kidney (HEK293) cells and the rates of desensitization and deactivation before and after COBs delivery. According to our findings, the COBs bind AMPA receptors allosterically and alter AMPAR characteristics in various ways. COB-1, COB-2, and COB-13 were the most effective in decreasing AMPAR currents by around 10-12 folds compared to the other COBs. Furthermore, the COBs significantly impacted AMPA receptor deactivation and desensitization rates. Of the examined homomeric and heteromeric AMPAR subunits, GluA2 was the most impacted. COB compounds appear to be a viable candidate for future study and development in regulating neurological diseases involving AMPA receptors.

Synthesis and Evaluation of α-Asaronol Esters with LDH and GABAA Receptor Modulation as Anticonvulsant Agents

Background:

Our previous studies showed that α-asaronol was a potential antiepileptic candidate. Here, twelve O-terminus modified ester derivatives of α-asaronol were designed, synthesized and evaluated their anticonvulsant activity.

Methods:

All synthetic compounds were subjected to three animal models of seizure (MES, scPTZ and sc3-MP models) combined with neurotoxicity test, as well as the LDH inhibitory test. Furthermore, GABAA Receptor modulation and pharmacokinetic evaluation of compound 4k were also performed.

Results:

Five compounds (4a, 4b, 4d, 4e and 4k) showed significant anticonvulsant properties at the dose of 30-300 mg/kg in MES and scPTZ test, but weak activity in sc3-MP model. Meanwhile, 4a, 4b, 4d and 4k showed good LDH inhibitory activity in vitro. Specifically, 4k was the best compound in above evaluation, and better than that of α-asaronol and reference compound (stiripentol). In addition, 4k could increase chloride ion influx by modulating GABAA receptor α1β2γ2 subtype with EC50 of 48.65 ± 10.31 μM and showed good PK profiles in rats with moderate oral bioavailability (51.5%).

Conclusion:

These results suggested 4k possesses potential effectiveness in treatment of therapyresistant seizures and is expected to be developed as a novel molecule for safer and efficient anticonvulsants having neuroprotective effects as well as low toxicity.

Structural Activity Relationship and Importance of Benzothiazole Derivatives in Medicinal Chemistry: A Comprehensive Review

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Benzothiazole (1, 3-benzothiazole) is one of the heterocyclic compounds, which is a weak base having varied biological activities. The unique methine center present in the thiazole ring makes benzothiazole as the most important heterocyclic compound. It is a common and integral structure of many natural and synthetic bioactive molecules. Benzothiazole derivatives show a variety of activities, with less toxic effects and their derivatives showed enhanced activities, which has proven Benzothiazole scaffold as one of the important moieties in medicinal chemistry. Benzothiazole ring containing compounds possess various pharmacological activities such as anti-viral, anti-microbial, antiallergic, anti-diabetic, anti-tumor, anti-inflammatory, anthelmitic and anti-cancer, which makes benzothiazole a rapidly developing and interesting compound in the medicinal chemistry. This review briefly explains the importance, common methods of synthesis of the benzothiazole scaffold and also explains the popular benzothiazole molecules which have applications in various fields of chemistry. A review has been carried out based on various pharmacological activities containing benzothiazole moieties and rationalize the activities based on the structural variations. Literature on benzothiazole derivatives reveals that substitution on the C-2 carbon atom and C-6 are the reasons for a variety of biological activities.

Thiazole-containing compounds as therapeutic targets for cancer therapy

In the last few decades, considerable progress has been made in anticancer agents development, and several new anticancer agents of natural and synthetic origin have been produced. Among heterocyclic compounds, thiazole, a 5-membered unique heterocyclic motif containing sulphur and nitrogen atoms, serves as an essential core scaffold in several medicinally important compounds. Thiazole nucleus is a fundamental part of some clinically applied anticancer drugs, such as dasatinib, dabrafenib, ixabepilone, patellamide A, and epothilone. Recently, thiazole-containing compounds have been successfully developed as possible inhibitors of several biological targets, including enzyme-linked receptor(s) located on the cell membrane, (i.e., polymerase inhibitors) and the cell cycle (i.e., microtubular inhibitors). Moreover, these compounds have been proven to exhibit high effectiveness, potent anticancer activity, and less toxicity. This review presents current research on thiazoles and elucidates their biological importance in anticancer drug discovery. The findings may aid researchers in the rational design of more potent and bio-target specific anticancer drug molecules.

Synthesis and some novel reactions of 8-chloro-2H-[1,2,4]triazino[3,4-b] [1,3]benzothiazole-3,4-dione and 6-chloro-2-hydrazino-1,3-benzothiazole

3,8-Dichloro-4H-[1,2,4]triazino[3,4-b][1,3]benzothiazole-4-one on reaction independently with sodium hydroxide solution and sodium azide undergo novel ring contraction reactions to give 7-chloro[1,2,4]triazolo[3,4-b][1,3] benzothiazole and 8-chloro tetrazolo[1′,5′:1,5][1,2,4]triazolo[3,4-b][1,3]benzothiazole respectively.

Benzo[d]thiazol-2(3H)-ones as new potent selective CB2 agonists with anti-inflammatory properties

The high distribution of CB₂ receptors in immune cells suggests their important role in the control of inflammation. Growing evidence offers this receptor as an attractive therapeutic target: selective CB₂ agonists are able to modulate inflammation without triggering psychotropic effects. In this work, we report a new series of selective CB₂ agonists based on a benzo[d]thiazol-2(3H)-one scaffold. This drug design project led to the discovery of compound 9, as a very potent CB₂ agonist (K_i = 13.5 nM) with a good selectivity versus CB₁. This compound showed no cytotoxicity, acceptable ADME-Tox parameters and demonstrates the ability to counteract colon inflammatory process in vivo.

Benzothiazole analogs as potential anti-TB agents: computational input and molecular dynamics

Biotin is very important for the survival of Mycobacterium tuberculosis. 7,8-Diamino pelargonic acid aminotransaminase (DAPA) is a transaminase enzyme involved in the biosynthesis of biotin. The benzothiazole title compounds were investigated for their in vitro anti-tubercular activity against two tubercular strains: H37Rv (ATCC 25,177) and MDR-MTB (multidrug-resistant M. tuberculosis, resistant to isoniazid, rifampicin, and ethambutol) by an agar incorporation method. The possible binding mode and predicted affinity were computed using a molecular docking study. Among the synthesized compounds in the series, the title compound {2-(benzo[d]thiazol-2-yl-methoxy)-5-fluorophenyl}-(4-chlorophenyl)-methanone was found to exhibit significant activity with minimum inhibitory concentrations of 1 μg/mL and 2 μg/mL against H37Rv and MDR-MTB, respectively; this compound showed the highest binding affinity (-24.75 kcal/mol) as well.

Crystal structure and theoretical study of N,N-bis-[(5-chloro-2-oxo-2,3-di-hydro-benzo[d]oxazol-3-yl)meth-yl]-2-phenyl-ethanamine

One of the nine-membered 2,3-di­hydro-1,3-benzoxazole rings and the phenyl ring are almost parallel to each other, making a dihedral angle of 5.30 (18)°. These rings are almost normal to the mean plane of the other nine-membered 2,3-di­hydro-1,3-benzoxazole ring. The crystal structure features C—H⋯O hydrogen bonds and π–π stacking inter­actions.

In the mol­ecular structure of the title compound, C₂₄H₁₉Cl₂N₃O₄, the three C atoms of the central N,N-di­methyl­methanamine moiety are bonded to the N atoms of the two 5-chloro-1,3-benzoxazol-2(3H)-one groups and to the methyl C atom of the methyl­benzene group. One of the nine-membered 2,3-di­hydro-1,3-benzoxazole rings and the phenyl ring are almost parallel to each other, making a dihedral angle of 5.30 (18)°, but they are almost normal to the mean plane of the other nine-membered 2,3-di­hydro-1,3-benzoxazole ring, subtending dihedral angles of 89.29 (16) and 85.41 (18)°, respectively. The crystal structure features C—H⋯O hydrogen bonds and π–π stacking inter­actions [centroid-to-centroid distances = 3.5788 (19) Å, slippage = 0.438 and 3.7773 (16) Å, and slippage = 0.716 Å].

Carbon dioxide-based facile synthesis of cyclic carbamates from amino alcohols

We report herein a straightforward general method for the synthesis of cyclic carbamates from amino alcohols and carbon dioxide in the presence of an external base and a hydroxyl group activating reagent. Utilizing p-toluenesulfonyl chloride (TsCl), the reaction proceeds under mild conditions, and the approach is fully applicable to the preparation of various high value-added 5- and 6-membered rings as well as bicyclic fused ring carbamates. DFT calculations and experimental results indicate a S_N2-type reaction mechanism with high regio-, chemo-, and stereoselectivity.

N-alkyl-[1,1'-biphenyl]-2-sulfonamide derivatives as novel broad spectrum anti-epileptic drugs with efficacy equivalent to that of sodium valproate

In order to develop phenyl sulfonamides as a novel class of anti-epileptic drugs (AED) for both general and partial seizure, we initiated in vivo screening of our chemical library in the mice MES and sc-PTZ models and found compounds 1 and 2 as lead compounds. Optimization of 1 and 2 led to the discovery of compound 21, which showed potent anticonvulsant effect in MES, scPTZ and rat amygdala kindling models. These findings indicate that compound 21 could be a useful new broad spectrum AED like sodium valproate and provide an opportunity to struggle current therapy-resistant epilepsy.

Simple N,N-dimethyl phenylsulfonamides show potent anticonvulsant effect in two standard epilepsy models

Optimization of the previously reported benzothiazine analogue A led to the identification of compound 1, which showed anti-convulsant activity in two golden standard animal models of seizure, the MES and scPTZ models. Structure-activity relationship investigation of compound 1 revealed compounds 2, 6 and 19 as attractive anti-epileptic drug (AED) candidates with potent anticonvulsant effect in both the MES and scPTZ models. As these compounds are structurally different from existing AEDs, determination of their mechanism of actions could provide clues to understanding current therapy-resistant seizures. Moreover, these simple phenylsulfoneamide compounds could be good starting points for searching broad spectrum AEDs by such in vivo screening.

Discovery of benzothiazine derivatives as novel, orally-active anti-epileptic drug candidates with broad anticonvulsant effect

In order to develop novel anti-epileptic drugs that are effective for both general and partial seizure, we conducted in vivo screening of our chemical library in the mice MES and sc-PTZ models and found the benzothiazine 1 as lead compound. Optimization of this compound led to the discovery of compound 7b, which showed potent anticonvulsant effect in the MES, scPTZ and rat amygdala kindling models. Since the chemical structure of 7b is different from that of any existing AED, it is suggested that 7b may have unique mechanism of action for relieving both partial and generalized epilepsy.

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.

Pharmacological investigation of 2-aminobenzothiazolium-4-methylbenzenesulphonate: Synthesis, spectral characterization and structural elucidation

An organic charge transfer complex, 2-aminobenzothiazolium-4-methylbenzenesulphonate (ABPTS) was synthesized and single crystals grown by slow solvent evaporation solution growth technique at ambient temperature. The single crystal X-ray diffraction analysis was carried out to establish the molecular structure of the title crystal. FT-IR spectral study was carried out to identify the various functional groups present in the crystal. The (1)H and (13)C spectra were recorded to further confirm the molecular structure of the CT complex. The TG/DTA analyses were carried out to establish the thermal stability of the complex. The antibacterial and antifungal activities of synthesized complex were examined against various bacteria and fungi strains, to identify the antibacterial and antifungal activity. The DNA binding profile of the complex has been investigated through absorption spectroscopy and complex has intrinsic binding constant 3.6 × 10(4) M(-1). A gel electrophoresis assay demonstrated the ability of the complex to cleave the pBR322 DNA. The free radical scavenging activity of the complex has been determined against DPPH, OH and ABTS radicals.

TDAE strategy in the benzoxazolone series: synthesis and reactivity of a new benzoxazolinonic anion

We describe an original pathway to produce new 5-substituted 3-methyl-6-nitro-benzoxazolones by the reaction of aromatic carbonyl and α-carbonyl ester derivatives with a benzoxazolinonic anion formed exclusively via the TDAE strategy.

Anticonvulsant profiles of certain new 6-aryl-9-substituted-6,9-diazaspiro-[4.5]decane-8,10-diones and 1-aryl-4-substituted-1,4-diazaspiro[5.5]undecane-3,5-diones

Synthesis and anticonvulsant potential of certain new 6-aryl-9-substituted-6,9-diazaspiro[4.5]decane-8,10-diones (6a–l) and 1-aryl-4-substituted-1,4-diazaspiro[5.5]undecane-3,5-diones (6m–x) are reported. The intermediates 1-[(aryl)(cyanomethyl)amino]cycloalkanecarboxamides (3a–f) were prepared via adopting Strecker synthesis on the proper cycloalkanone followed by partial hydrolysis of the obtained nitrile functionality and subsequent N-cyanomethylation. Compounds 3a–f were subjected to complete nitrile hydrolysis to give the respective carboxylic acid derivatives 4a–f which were cyclized under mild conditions to give the spiro compounds 5a–f. Ultimately, compounds 5a–f were alkylated or aralkylated to give the target compounds 6a–i and 6m–u. On the other hand, compounds 6j–l and 6v–x were synthesized from the intermediates 5a–f through alkylation, dehydration and finally tetrazole ring formation. Anticonvulsant screening of the target compounds 6a–x revealed that compound 6g showed an ED₅₀ of 0.0043 mmol/kg in the scPTZ screen, being about 14 and 214 fold more potent than the reference drugs, Phenobarbital (ED₅₀ = 0.06 mmol/kg) and Ethosuximide (ED₅₀ = 0.92 mmol/kg), respectively. Compound 6e exhibited an ED₅₀ of 0.019 mmol/kg, being about 1.8 fold more potent than that of the reference drug, Diphenylhydantoin (ED₅₀ = 0.034 mmol/kg) in the MES screen. Interestingly, all the test compounds 6a–x did not show any minimal motor impairment at the maximum administered dose in the neurotoxicity screen.

Synthesis and anticonvulsant activity of ethyl 2,2-dimethyl-1-(2-substitutedhydrazinecarboxamido) cyclopropanecarboxylate derivatives

In this study on the development of new anticonvulsants, fourteen ethyl 2,2-dimethyl-1-(2-substitutedhydrazinecarboxamido) cyclopropanecarboxylate derivatives were synthesized and tested for anticonvulsant activity using the maximal electroshock, subcutaneous pentylenetetrazole screens, which are the most widely employed seizure models for early identification of candidate anticonvulsants. Their neurotoxicity was determined applying the rotorod test. Two compounds 6f and 6k showed promising anticonvulsant activities in both models employed for anticonvulsant evaluation. The most active compound 6k showed the maximal electroshock-induced seizures with ED50 value of 9.2 mg/kg and TD50 value of 387.5 mg/kg after intraperitoneally injection to mice, which provided compound 6k with a protective index (TD50/ED50 ) of 42.1 in the maximal electroshock test.

General and efficient synthesis of benzoxazol-2(3H)-ones: evolution of their anti-cancer and anti-mycobacterial activities

A novel class of benzo[d]oxazol-2(3H)-one derivatives has been synthesized and their in vitro cytotoxicity against human pancreatic adenocarcinoma and human non-small cell lung carcinoma cancer cell lines was evaluated.

Synthesis of 3-alkylbenzoxazolones from N-alkyl-N-arylhydroxylamines by contiguous O-trichloroacetylation, trichloroacetoxy ortho-shift, and cyclization sequence

Benzoxazolone pharmacophore is present in clinical pharmaceuticals, drug candidates, and many compounds having a wide spectrum of biological activities. The methods available for the synthesis of benzoxazolones have limited diversity due to problems in accessibility and air-sensitivity of diversely substituted o-aminophenols from which they are generally prepared by cyclocarbonylation with phosgene or its equivalents. The present paper describes a mild method for the synthesis of 3-alkylbenzoxazolones from easily accessible and air-stable nitroarenes. Nitroarenes were converted to N-alkyl-N-arylhydroxylamines in two steps involving partial reduction to arylhydroxylamines followed by selective N-alkylation. Treatment of N-alkyl-N-arylhydroxylamines with trichloroacetyl chloride and triethylamine afforded 3-alkylbenzoxazolones generally in good yields through an uninterrupted three-step sequence involving O-trichloroacetylation, N→C(ortho) trichloroacetoxy shift, and cyclization in a single pot at ambient temperatures. The present method is mild, wide in scope, economical, and regioselective. Many sensitive groups like alkyl and aryl esters, amide, cyano, and the carbon-carbon double bond survive the reaction.

Synthesis and hepatoprotective properties of Acanthus ilicifolius alkaloid A and its derivatives

Acanthus ilicifolius alkaloid A (4-hydroxy-2(3H)benzoxazolone, HBOA) is a naturally occurring compound that has been separated from Acanthus ilicifolius. Previous studies have reported the beneficial effects of HBOA on HSC-T6 cells. This study was undertaken in order to synthesize HBOA and two of its derivatives, specifically, 4-acetoxy-2(3H)-benzoxazolone (AcO-BOA) and 3-acetyl-4-acetoxy-2-benzoxazolone (TC-3), and to investigate the hepatoprotective potentials of these three compounds on CCl₄-induced liver injury in mice. HBOA was prepared from 2-nitroresorcinol by a 'one pot' reduction and subsequent cyclization with urea. The acyl derivatives, AcO-BOA and TC-3, were prepared from HBOA using a substitution reaction. The compounds were synthesized with good yields (63.08-68.22%). An acute liver injury model was established by administering CCl₄ intraperitoneally to Kunming mice. The mice were then intragastrically administered bifendate (150 mg/kg) or the synthesized compounds at three different doses (200, 100 and 50 mg/kg). The treatment with CCl₄ was observed to increase the levels of aminotransferase (ALT), aspartate aminotransferase (AST), lactic dehydrogenase (LDH) and malondialdehyde (MDA) and decrease the levels of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and glutathione peroxidase (Gpx) in the liver tissues of the mice. Furthermore, treatment with CCl₄ elevated the expression level of the proinflammatory mediator TNF-α. However, HBOA and its derivatives attenuated the changes induced by CCl₄. Furthermore, CCl₄-induced histopathological changes were reduced by treatment with these compounds. These results suggest that HBOA and its acyl derivatives are able to significantly alleviate the hepatotoxicity induced by CCl₄ in mice.