Benzothiazole Moiety Research Articles

Exploration of the Antimicrobial Effects of Benzothiazolylthiazolidin-4-One and In Silico Mechanistic Investigation.

Background: Infectious diseases still affect large populations causing significant morbidity and mortality. Bacterial and fungal infections for centuries were the main factors of death and disability of millions of humans. Despite the progress in the control of infectious diseases, the appearance of resistance of microbes to existing drugs creates the need for the development of new effective antimicrobial agents. In an attempt to improve the antibacterial activity of previously synthesized compounds modifications to their structures were performed. Methods: Nineteen thiazolidinone derivatives with 6-Cl, 4-OMe, 6-CN, 6-adamantan, 4-Me, 6-adamantan substituents at benzothiazole ring were synthesized and evaluated against panel of four bacterial strains S. aureus, L. monocytogenes, E. coli and S. typhimirium and three resistant strains MRSA, E. coli and P. aeruginosa in order to improve activity of previously evaluated 6-OCF3-benzothiazole-based thiazolidinones. The evaluation of minimum inhibitory and minimum bactericidal concentration was determined by microdilution method. As reference compounds ampicillin and streptomycin were used. Results: All compounds showed antibacterial activity with MIC in range of 0.12–0.75 mg/mL and MBC at 0.25–>1.00 mg/mL The most active compound among all tested appeared to be compound 18, with MIC at 0.10 mg/mL and MBC at 0.12 mg/mL against P. aeruginosa. as well as against resistant strain P. aeruginosa with MIC at 0.06 mg/mL and MBC at 0.12 mg/mL almost equipotent with streptomycin and better than ampicillin. Docking studies predicted that the inhibition of LD-carboxypeptidase is probably the possible mechanism of antibacterial activity of tested compounds. Conclusion: The best improvement of antibacterial activity after modifications was achieved by replacement of 6-OCF3 substituent in benzothiazole moiety by 6-Cl against S. aureus, MRSA and resistant strain of E. coli by 2.5 folds, while against L. monocytogenes and S. typhimirium from 4 to 5 folds.

Synthesis of Novel Heterocycles Comprising Benzothiazole Moiety and Their Antimicrobial Evaluations

Various benzothiazole derivatives were synthesized by allowing 2-cyanomethylbenzothiazole (1) or its arylidene derivatives to react with diverse reagents under different simple and efficient reaction conditions. The chemical structures of novel synthesized benzothiazole derivatives were affirmed by elemental analysis and different spectral data. The newly synthesized compounds were assessed as antibacterial agents against Staphylococcus aureus and Escherichia coli bacteria.

Synthesis of Hetaryl-Substituted Asymmetric Porphyrins and Their Affinity to SARS-CoV-2 Helicase.

Novel porphyrin compounds containing benzothiazole, benzoxazole, and benzimidazole moieties have been prepared and their structures have been confirmed. Molecular docking of non-symmetric hetaryl-substituted porphyrins and chlorin e6 with SARS-CoV-2 helicase has been carried out. The affinity of hetaryl-substituted porphyrins to this protein has been found significantly higher than that of the drugs approved by the FDA and chlorin e6. The structure of the complexes of SARS-CoV-2 helicase with the considered macroheterocyclic compounds has been analyzed. Possible ways to inhibit and photoinactivate SARS-CoV helicase have been suggested basing on the localization of porphyrins and chlorin e6 in the helicase domains.

A Novel Calix[4]arene Thiourea Decorated with 2‐(2‐Aminophenyl)benzothiazole Moiety as Highly Selective Chemical Gas Sensor for Dichloromethane Vapor

AbstractA newly synthesized calix[4]arene thiourea derivative decorated with 2‐(2‐aminophenyl)benzothiazole unit is selected to take part important role in host‐guest interactions of the macrocyclic molecules. p‐tert‐butylcalix[4]arene dithiourea (C[4]‐DT) Langmuir‐Blodgett (LB) thin films are prepared and characterized to develop a new sensing element for the detection of seven different organic vapors (dichloromethane, chloroform, acetone, benzene, carbon tetrachloride, toluene and m‐xylene). The preparation of C[4]‐DT‐based thin films onto the different substrates was successfully and uniformly achieved with linear regressions of 0.9971 and 0.9954 for coating onto quartz glass and quartz crystal, respectively. The frequency shift (61.01 Hz) and the mass deposited onto quartz crystal (969.80 ng) were calculated for each layer. The swelling dynamics of C[4]‐DT QCM chemical sensor was also illuminated by developing the early time Fick's diffusion equation. The sensing measurements can be concluded that owing to its high sensitivity (6.63 Hz/ppm), fast response and low detection limit (0.45 ppm), this proposed C[4]‐DT LB coated sensor is expected to be promising alternative chemical sensor for detection of DCM vapor.

Synthesis and characterization of a novel benzothiazole functionalized chitosan and its use for effective adsorption of Cu(II)

Contamination of water with the copper(II) ions leads to serious diseases such as liver damage and cancer. This deadly effect prompted us to target the synthesis of a novel functionalized chitosan (Cs-BT) to be used as an adsorbent for removing the copper(II) ions from the aqueous solution. The functionalization was done by introducing benzothiazole moiety into the chitosan (Cs) chain and confirmed by the full disappearance of the NH2 band in the FT-IR spectrum of the adsorbent. The TGA-DTG analysis revealed that the functionalization reduced the thermal stability of the adsorbent (Cs-BT) as compared with pure chitosan. The adsorption was evidenced by SEM and EDX analysis. The adsorption study demonstrated that the optimal adsorption conditions were 120 min contact time, pH = 6, and initial Cu(II) concentration 200 mg/L. At these conditions, the Cs-BT achieved a maximum copper adsorption capacity of 1439.7 mg/g. Consequently, Cs-BT could be a promising and efficient Cu adsorbent in water treatment. Study the adsorption kinetics and isotherms manifested that the pseudo-first-order was better than pseudo-second-order and Temkin isotherm was better than Langmuir, Freundlich, and Dubinin–Radushkevich for explaining the adsorption process. The calculated thermodynamic parameters implied the spontaneity and the endothermic nature of the adsorption process.

Novel dibenzofuran and biphenyl phytoalexins from Sorbus pohuashanensis suspension cell and their antimicrobial activities

Two novel sulfur-containing dibenzofurans, sorbusins A (1) and B (2), two unprecedented biphenyl glycosides, 2′-hydroxyaucuparin 2′-O-ɑ-L-rhamnoside (3) and noraucuparin 5-O-ɑ-L-rhamnoside (4), and four known analogues (5–8), were isolated from Sorbus pohuashanensis suspension cell induced by yeast extract. Their structures were elucidated based on spectroscopic analyses and quantum calculation of 13C NMR data. Structurally, compound 1 possessed a rare naturally occurring benzothiazole moiety and represents the first example of thiazole fused dibenzofuran. A plausible biosynthetic pathway for the sulfur-containing dibenzofurans is proposed. These dibenzofuran and biphenyl phytoalexins were evaluated for their antimicrobial activities against pathogenic fungi and drug-resistant bacteria. Compound 7 exhibited significant antibacterial activity against methicinllin-resistant Staphylococcus aureus with an MIC value of 3.13 μg/mL.

Synthesis and Antibacterial Evaluation of 1,3-Benzoxazepine-1,5-diones bearing Benzothiazole Moiety

Azo-aldehyde derivative (2) was prepared through reaction of 2-hydroxybenzaldehyde with diazonium ion generated from 2-aminobenzothiazole (1). The producing aldehyde (2) was then treated with some anilines consisting (4-nitroaniline, 3-nitroaniline, 4-aminophenol, 4-methoxyaniline, 4-bromoaniline, 4-chloroaniline and 2,4-dichloroaniline) by (MW) method to give seven Schiff bases (3a-g). Cyloaddition reactions of Schiff bases (3a-g) and phthalic anhydride utilizing (MW) means in dry benzene yielded seven new 1,3-benzoxazepine-1,5-diones (4a-g) carrying the unit of benzothiazole. Determination of verves of final benoxazepines athwart bacteria done on Staphylococcus aurous (Gram-positive) and Escherichia coli (Gram-negative). The outputs showed that all benzoxazepine compounds exhibited greater activity to standard antibiotic (gentamycin) athwart Staphylococcus aurous. Moreover, the benzoxazepines (4a, 4b, 4c, 4d, 4e and 4g) appeared best activity athwart Escherichia coli comparably with that of standard antibiotic.

Carbazole-hydrazinobenzothiazole a selective turn-on fluorescent sensor for Hg2+ions – Its protein binding and electrochemical application studies

The sensor 2-(benzothiazol-2-yl)-1-((9-ethyl-9H-carbazol-6-yl)methylene)hydrazine (CBT-1) is successfully synthesized. The sensor CBT-1 showed selective detection of Hg2+ ions in pool of different metal ions through colorimetric and fluorimetric color changes. The sensing mechanism involves Intramolecular charge transfer process between carbazole unit and benzothiazole moiety on interaction with Hg2+ ions. The binding nature of CBT-1 and Hg2+ ion is understood with help of varied analytical techniques such as UV–vis, fluorescence, Mass IR spectral analysis and computational studies. The protein binding studies of CBT-1 and CBT-1+Hg2+ ensemble with protein (Bovine Serum Albumin, BSA) is carried out through one- and three-dimensional fluorescence spectral studies. The cyclic voltammetric analysis of the sensor CBT-1 with distinct metal ions has also been carried out to investigate its potential ability in electrochemical sensing of Hg2+ ions.

Modern Approaches to the Synthesis and Transformations of Practically Valuable Benzothiazole Derivatives.

The review is devoted to modern trends in the chemistry of 2-amino and 2-mercapto substituted benzothiazoles covering the literature since 2015. The reviewed heterocycles belong to biologically active and industrially demanded compounds. Newly developed synthesis methods can be divided into conventional multistep processes and one-pot, atom economy procedures, realized using green chemistry principles and simple reagents. The easy functionalization of the 2-NH2 and 2-SH groups and the benzene ring of the benzothiazole moiety allows considering them as highly reactive building blocks for organic and organoelement synthesis, including the synthesis of pharmacologically active heterocycles. The review provides a summary of findings, which may be useful for developing new drugs and materials and new synthetic approaches and patterns of reactivity.

Inhibitors of heat shock protein 70 (Hsp70) with enhanced metabolic stability reduce tau levels

The molecular chaperone, Heat Shock Protein 70 (Hsp70), is an emerging drug target for neurodegenerative diseases, because of its ability to promote degradation of microtubule-associated protein tau (MAPT/tau). Recently, we reported YM-08 as a brain penetrant, allosteric Hsp70 inhibitor, which reduces tau levels. However, the benzothiazole moiety of YM-08 is vulnerable to metabolism by CYP3A4, limiting its further application as a chemical probe. In this manuscript, we designed and synthesized seventeen YM-08 derivatives by systematically introducing halogen atoms to the benzothiazole ring and shifting the position of the heteroatom in a distal pyridine. In microsome assays, we found that compound JG-23 has 12-fold better metabolic stability and it retained the ability to reduce tau levels in two cell-based models. These chemical probes of Hsp70 are expected to be useful tools for studying tau homeostasis.

A New Compound for Sequential Sensing of Picric Acid and Aliphatic Amines: Physicochemical Details and Construction of Molecular Logic Gates.

Picric acid (PA) at low concentration is a serious water pollutant. Alongside, aliphatic amines (AAs) add to the queue to pollute surface water. Plenty of reports are available to sense PA with an ultralow limit of detection (LOD). However, only a handful of works are testified to detect AAs. A new fluorescent donor-acceptor compound has been synthesized with inherent intramolecular charge transfer (ICT) character that enables selective and sensitive colorimetric quantitative detection of PA and AAs with low LODs in non-aqueous as well as aqueous solutions. The synthesized compound is based on a hemicyanine skeleton containing two pyridenylmethylamino groups at the donor and a benzothiazole moiety at the acceptor ends. The detailed mechanisms and reaction dynamics are explained spectroscopically along with computational support. The fluorescence property of the detecting compound changes due to protonation of its pyridinyl centers by PA leading to quenching of fluorescence and subsequently de-protonation by AAs to revive the signal. We have further designed logic circuits from the acquired optical responses by sequential interactions.

An effective colorimetric sensor for detecting Cu2+ based on benzothiazole moiety

AbstractAn effective colorimetric chemosensor, 2,4‐dichloro‐6‐((E)‐(((Z)‐3‐methylbenzo[d]thiazol‐2(3H)‐ylidene)hydrazono)methyl)phenol (HMD), was synthesised for Cu2+ detection. HMD with benzothiazole moiety showed a large bathochromic shift (153 nm) and a definite colour change for Cu2+. HMD could detect Cu2+ down to 0.47 μmol/L in the solution phase and could clearly distinguish it from other metal ions, even in the test strip. The binding mode between HMD and Cu2+ was determined to be 1:1 using Job plot and electrospray ionisation mass spectrometry. The sensing mechanism of HMD for Cu2+ was illustrated as the combination of metal‐to‐ligand charge transfer and intramolecular charge transfer via theoretical calculation.

Light-induced energy transfer followed by electron transfer in axially co-ordinated benzothiazole tethered zinc porphyrin-fullero[C60/C70]pyrrolidine triads

Benzothiazole (BTZ)-zinc porphyrin (ZnP) dyads, Dyad-1 and Dyad-2 connected together with two different spacers, ester and ethoxy esters, were synthesized and light induced energy and electron transfer events were investigated. Within these dyads, due to the spectral overlap of the BTZ emission with the ZnP absorption, a selective photoexcitation of BTZ at 325 nm resulted in the photo-induced energy transfer (PEnT) from 1BTZ* to ZnP displaying the quenching of the BTZ emission followed by the concurrent appearance of the ZnP emission at 600 and 650 nm suggesting the formation of the 1ZnP* [Formula: see text]. 1BTZ*-ZnP [Formula: see text] BTZ-1ZnP*. When the dyads are titrated with imidazole appended fullero[C[Formula: see text]/C[Formula: see text]]pyrrolidines, four supramolecular triads, involving the axial co-ordination of the imidazole to the zinc center of the ZnP, were formed and the assembly formation was systematically monitored by the optical absorption technique. Cyclic voltammetry and the density functional theory calculations have revealed that, in these triads, the zinc porphyrin acts as an electron donor and fullerene moiety as the electron acceptor. Steady state fluorescence studies revealed that, upon selective excitation of the ZnP moiety at 550 nm, the emission of ZnP at 600 and 650 nm was quenched revealing the occurrence of photo-induced electron transfer (PET) from 1ZnP* to fullerene moiety leading to the formation of charge separated state [Formula: see text]. BTZ-1ZnP* : (ImC[Formula: see text] BTZ-ZnP[Formula: see text]:(ImC[Formula: see text]. More importantly, when the supramolecular triads were excited at 325 nm, the wavelength at which the BTZ absorbs predominantly, the emission of the BTZ moiety which was quenched due to PEnT from 1BTZ* to ZnP followed by the PET from 1ZnP* to fullerene indicates the probability of occurrence of 1BTZ*-ZnP:(ImC[Formula: see text] [Formula: see text] BTZ-1ZnP*[Formula: see text]: (ImC[Formula: see text] BTZ-ZnP[Formula: see text]:(ImC[Formula: see text].

Quinoline Functionalized Schiff Base Silver (I) Complexes: Interactions with Biomolecules and In Vitro Cytotoxicity, Antioxidant and Antimicrobial Activities.

A series of fifteen silver (I) quinoline complexes Q1–Q15 have been synthesized and studied for their biological activities. Q1–Q15 were synthesized from the reactions of quinolinyl Schiff base derivatives L1–L5 (obtained by condensing 2-quinolinecarboxaldehyde with various aniline derivatives) with AgNO3, AgClO4 and AgCF3SO3. Q1–Q15 were characterized by various spectroscopic techniques and the structures of [Ag(L1)2]NO3 Q1, [Ag(L1)2]ClO4 Q6, [Ag(L2)2]ClO4 Q7, [Ag(L2)2]CF3SO3 Q12 and [Ag(L4)2]CF3SO3 Q14 were unequivocally determined by single crystal X-ray diffraction analysis. In vitro antimicrobial tests against Gram-positive and Gram-negative bacteria revealed the influence of structure and anion on the complexes′ moderate to excellent antibacterial activity. In vitro antioxidant activities of the complexes showed their good radical scavenging activity in ferric reducing antioxidant power (FRAP). Complexes with the fluorine substituent or the thiophene or benzothiazole moieties are more potent with IC50 between 0.95 and 2.22 mg/mL than the standard used, ascorbic acid (2.68 mg/mL). The compounds showed a strong binding affinity with calf thymus-DNA via an intercalation mode and protein through a static quenching mechanism. Cytotoxicity activity was examined against three carcinoma cell lines (HELA, MDA-MB231, and SHSY5Y). [Ag(L2)2]ClO4 Q7 with a benzothiazole moiety and [Ag(L4)2]ClO4 Q9 with a methyl substituent had excellent cytotoxicity against HELA cells.

Investigation of phenol-formaldehyde resins as corrosion impeding agent in acid solution

The advent of organic molecules as inhibitors in the field of corrosion monitoring has been exponentially expanding in the past few years which enhanced the scope for innovation in polymers as potential corrosion inhibitors. The current research focused on the development of azomethine functionalised benzothiazole moiety containing four phenol-formaldehyde resins designated as PF1, PF2, PF3, and PF4; with the aim to combat impending degradations due to corrosion of low carbon containing steel in corrosive acid medium. The present work comprises empirical gravimetric and electrochemical techniques for analysing corrosion inhibition behavior of the developed resins, followed by subsequent surface characterization employing different analytical procedures. The synthesized polymeric resins performed as efficient corrosion inhibiting additives. Its anti-corrosion performance was found in the order: PF4 > PF2 > PF1 > PF3, established from all the experimental findings. It is revealed that the substitution in the benzene unit of benzothiazole moiety played crucial role in corrosion inhibiting mechanism. The activation energy steadily increased after addition of resins into the corrosive medium suggested that this elevated barrier is required to be crossed for the occurrence of corrosion phenomenon, which leads towards declining of corrosion rate. The application of phenol-formaldehyde resins in acid media substantially prevented carbon steel from deterioration due to corrosion. This is attributed to the corrosion inhibiting nature of the adsorbed resin, whereas, the adsorption of resins was confirmed by surface analysing techniques like SEM-EDX, AFM and XPS. Furthermore, these wet-chemical experimental outcomes are well complemented from results analysed from ab initio DFT study and MD simulation. Additionally, MD simulation outcomes helped in visualization of the adsorbed configuration of the modeled resins in presence of different corrosive components.

Arene ruthenium, rhodium and iridium complexes containing benzamide derivative ligands: Study of interesting bonding modes, antibacterial, antioxidant and DNA binding studies

The benzamide derivative ligands of benzothiazole (L1) and benzimidazole (L2) upon reaction with halide bridged metal precursors of platinum group yielded a series of complexes (1-6) formulated as [(arene)M(κ1(N)-L)Cl2], where, L = L1 and L2, M = Ru, Rh and Ir, arene = Cp*, p-cymene. Structural studies revealed the bonding of the ligands to the metal centers takes through the nitrogen donor atom of the benzothiazole and benzimidazole moiety in a monodentate fashion. Further reaction of rhodium and iridium complexes with NaN3 in methanol yielded di-azido κ1(N3) monodentate complexes by substituting two chlorides. In the case of ruthenium, azido complexes could not be isolated. Additional treatment of the di-azido complexes with diethyl acetylene dicarboxylate (DEAD) yielded two different bonded triazolo complexes of rhodium (11 and 13) and iridium (12 and 14). In rhodium triazolo complexes, the ligands displayed a chelating mode of bonding through the carbonyl oxygen and the nitrogen atom of the benzothiazole/benzimidazole ring while in iridium triazolo complexes, the ligands retained a monodentate bonding through the nitrogen atom of the benzothiazole/benzimidazole ring and formed two triazole rings. All these complexes were characterized by various spectroscopic techniques. NMR analysis revealed the triazolo ring coordinated to the metal center via the central nitrogen in both the rhodium and iridium triazolo complexes. These complexes as well as the ligands have been studied for antibacterial, antioxidant activity as well as DNA binding studies where a few of the compounds have shown good activity. Amongst these compounds, complex 7 possessed the highest antibacterial and radical scavenging activity while ligand L1 and complexes 1 and 2 showed good affinity as DNA binders.

Four-Component Synthesis of Functionalized 1,3,4-Oxadiazole Derivatives Bearing the 2-Amino benzothiazole Moiety

Four-Component Synthesis of Functionalized 1,3,4-Oxadiazole Derivatives Bearing the 2-Amino benzothiazole Moiety

One-Photon Excitation Followed by a Three-Step Sequential Energy-Energy-Electron Transfer Leading to a Charge-Separated State in a Supramolecular Tetrad Featuring Benzothiazole-Boron-Dipyrromethene-Zinc Porphyrin-C60.

A panchromatic triad, consisting of benzothiazole (BTZ) and BF2 -chelated boron-dipyrromethene (BODIPY) moieties covalently linked to a zinc porphyrin (ZnP) core, has been synthesized and systematically characterized by using 1 H NMR spectroscopy, ESI-MS, UV-visible, steady-state fluorescence, electrochemical, and femtosecond transient absorption techniques. The absorption band of the triad, BTZ-BODIPY-ZnP, and dyads, BTZ-BODIPY and BODIPY-ZnP, along with the reference compounds BTZ-OMe, BODIPY-OMe, and ZnP-OMe exhibited characteristic bands corresponding to individual chromophores. Electrochemical measurements on BTZ-BODIPY-ZnP exhibited redox behavior similar to that of the reference compounds. Upon selective excitation of BTZ (≈290 nm) in the BTZ-BODIPY-ZnP triad, the fluorescence of the BTZ moiety is quenched, due to photoinduced energy transfer (PEnT) from 1 BTZ* to the BODIPY moiety, followed by quenching of the BODIPY emission due to sequential PEnT from the 1 BODIPY* moiety to ZnP, resulting in the appearance of the ZnP emission, indicating the occurrence of a two-step singlet-singlet energy transfer. Further, a supramolecular tetrad, BTZ-BODIPY-ZnP:ImC60 , was formed by axially coordinating the triad with imidazole-appended fulleropyrrolidine (ImC60 ), and parallel steady-state measurements displayed the diminished emission of ZnP, which clearly indicated the occurrence of photoinduced electron transfer (PET) from 1 ZnP* to ImC60 . Finally, femtosecond transient absorption spectral studies provided evidence for the sequential occurrence of PEnT and PET events, namely, 1 BTZ* -BODIPY-ZnP:ImC60 →BTZ-1 BODIPY* -ZnP:ImC60 →BTZ-BODIPY-1 ZnP* :ImC60 →BTZ-BODIPY-ZnP.+ :ImC60 .- in the supramolecular tetrad. The evaluated rate of energy transfer, kEnT , was found to be 3-5×1010 s-1 , which was slightly faster than that observed in the case of BODIPY-ZnP and BTZ-BODIPY-ZnP, lacking the coordinated ImC60 . The rate constants for charge separation and recombination, kCS and kCR , respectively, calculated by monitoring the rise and decay of C60 .- were found to be 5.5×1010 and 4.4×108 s-1 , respectively, for the BODIPY-ZnP:ImC60 triad, and 3.1×1010 and 4.9×108 s-1 , respectively, for the BTZ-BODIPY-ZnP:ImC60 tetrad. Initial excitation of the tetrad, promoting two-step energy transfer and a final electron-transfer event, has been successfully demonstrated in the present study.

Double-Stranded DNA Matrix for Photosensitization Switching

Photosensitization, originated from the activation of triplet states, is the basis of many photodynamic applications, but often competes with a series of nonradiative processes. Herein, we communic...

A Multifunctional Triphenylamine–Benzothiazole Derivative with Blue‐Shifted Mechanochromism, Acidochromism and Amplified Spontaneous Emission

AbstractA multifunctional triphenylamine (TPA) derivative P1 is synthesized, which contains a TPA skeleton and a benzothiazole group. P1 crystals show blue–green fluorescence and exhibit obviously blue‐shifted mechanochromism upon grinding. Analysis of crystal structures indicate that two adjacent antiparallel P1 molecules form strong intermolecular interactions and adopt a dimeric packing structure, which could be interrupted by mechanical stress, leading to blue‐shifted mechanochromism. Moreover, the proton‐donating acid effectively binds onto the benzothiazole moiety, which greatly enhances the electron‐accepting capacity of the benzothiazole moiety, leading to acidochromism with red‐shifted emission. Additionally, self‐assembled P1 microcrystals exhibit good optical waveguide features and this feature indicates P1 microcrystals serve simultaneously as gain materials and optical resonators for laser oscillation.