Recent advances in the synthesis of new benzothiazole based anti-tubercular compounds

Nano calcium zincate-assisted synthesis of benzo[d]thiazol-2-yl phenylisoxazoles: quantum computational, in silico molecular docking simulations and DNA interaction

This study introduces a new and simple method for the synthesis of a series of 3-(benzo[d]thiazol-2-yl)-5-phenylisoxazole derivatives 3(a-f), and examines its potential interactions with DNA. The synthesis includes the reaction of 2-aminobenzenethiol (1) with a variety of substituted 5-phenylisoxazole-3-carbaldehydes 2(a-f) in the presence of a cost-effective and reusable nanocatalyst, Calcium-Zincate (CaZnO2). The CaZnO2 catalyst showed a consistent and long-lasting catalytic activity over several reaction cycles and retained its unique heterogeneous properties. The resulting compounds were characterized in detail using various spectroscopic and analytical techniques in order to confirm their structures. In addition, the interaction of these synthesized compounds with calf thymus-DNA (CT-DNA) using absorption spectroscopy and viscosity measurements was assessed. In silico docking studies were performed to predict their binding affinity with human DNA (PDB ID: 1G3X). The compounds were further analyzed using the Density Functional Theory (DFT) with the B3LYP functional and the 6-31 G(d) basis set in chloroform, with the results aligning closely with the experimental findings. Furthermore, the compounds ability to cleave PUC19 DNA was assessed, along with their photoinduced nuclease activity under UV-visible light, confirmed by photo-induced cleavage assays.

Stimuli-responsive benzothiazole-phenothiazine derivatives: mechanochromism, AIE, acid sensing, and anticancer efficacy in benzo[a]pyrene-induced cancer models

Mechanofluorochromic (MFC) materials are emerging as a versatile candidate for optoelectronic and biomedical applications. In the present work, we designed and synthesized four MFC materials, namely BT-PTZ-1, BT-PTZ-2, BT-PTZO-1, and BT-PTZO-2, using Suzuki cross-coupling reaction. These materials possess benzothiazole (BT) as an acceptor moiety and different donors, including phenothiazine (PTZ) and triphenylamine (TPA), with variations in their spacer units. The photophysical properties of these derivatives have been explored, revealing solvatochromism, aggregation-induced emission (AIE), acid sensing, and mechanochromic behaviour. Single crystal X-ray analysis of BT-PTZO-2 provides crucial structural insights, revealing the twisted conformation of the TPA donor and the bent structure of the PTZ oxide spacer. The biological studies of these BT derivatives reveal the therapeutic potential against benzo[a]pyrene (B[a]P)-induced carcinogenesis in A549 (lung) and HEK293 (kidney) cells. Treatment with BT-PTZ-2 reflects anti-cancerous properties, with significant up-regulation of p53 and down-regulation of β-catenin and pNF-κB. Additionally, downregulation of mitochondrial fission protein (DRP1) and oxidative stress through DCFDA staining in lung cells are observed with BT-PTZ-2 treatment. These findings strongly suggest that BT-PTZ-2 can inhibit lung cancer cell proliferation and survival, suggesting it to be a promising anti-cancer agent. This comprehensive study of these MFC materials provides insights into their design, synthesis, and properties, in addition to their potential applications in various optoelectronic and biomedical fields.

Smartphone-assisted colorimetric detection of nickel(II) ions using a novel benzothiazole-quinoline dyad in semi-aqueous media

In this study, we present three different approaches for the colorimetric detection of Ni2+ ions using a specifically designed benzothiazole-quinoline dyad (L) synthesized via the Knoevenagel condensation reaction in high yield. The unique properties of L enable a rapid and selective response to Ni2+ ions, making it an ideal probe for practical applications. The probe L shows a pale yellow color under normal conditions. Upon interaction with Ni2+ ions, L undergoes a significant color change from pale yellow to bright orange, allowing for visual detection in semi-aqueous media. This rapid colorimetric response enables real-time monitoring of Ni2+ concentrations. The absorption maximum of L undergoes a bathochromic shift in the presence of Ni2+ ions due to ligand-to-metal charge transfer (LMCT). The probe L could form a 2 : 1 [L : Ni2+] stoichiometric complex, confirmed through Job's plot and ESI mass analysis with an estimated association constant of 2.61 × 106 M-2. The probe L could detect Ni2+ concentration down to 61 nM, 106 nM, and 129 nM via a UV-Vis spectrophotometer, smartphone-assisted RGB method, and test paper strip analysis. The binding mechanism of probe L with metal ions was studied using 1H NMR, ESI mass spectrometry, and DFT calculations. The zeta potential analysis showed a potential of -28.38 mV for the free ligand and +12.09 mV upon complexation with Ni2+. More importantly, the potential application of probe L includes the quantification of Ni2+ ions in various water samples through all three sensing approaches.

Methoxyquinolone-Benzothiazole Hybrids as New Aggregation-Induced Emission Luminogens and Efficient Fluorescent Chemosensors for Cyanide Ions

This work describes the synthesis and characterization of new quinolone-benzothiazole hybrids, the study of their aggregation-induced emission (AIE) properties, and the use of these systems as efficient fluorescent probes for cyanide ions. These conjugated derivatives are linked through a double bond favoring electronic communication, and together with their planar geometry, can strongly aggregate under solvophobic environments, leading to aggregation and exhibiting significant AIE behavior. The double bond between electroactive units is prone to nucleophilic addition reactions by cyanide ions, selectively, conducive to turning off the fluorescence properties, making this hybrid system an efficient probe for cyanide ions. These studies were theoretically explained using DFT and TD-DFT calculations.

Heterocycles and a Sorbicillinoid from the Coral-Derived Fungus Penicillium chrysogenum

A detailed chemical study of the culture of a coral-derived fungus Penicillium chrysogenum resulted in the isolation and identification of four new aromatic heterocycles chrysoquinazolinones A-B (1-2) and chrysobenzothiazoles A-B (3-4), along with a new sorbicillinoid 4-carboxylsorbicillin (5). Chrysoquinazolinones A-B (1-2) combine a quinazolinone fragment with a bicyclo[2.2.2]octane or a pyrrolidone moiety, respectively, demonstrating the unexpected structures of marine natural products. Chrysobenzothiazoles A-B (3-4) possess a benzothiazole system and are the second isolation of this class of skeleton compounds from marine organisms. The existence of the pair of enantiomers (±3) was deduced by chiral HPLC analysis. Their structures and absolute configurations were elucidated by detailed spectroscopic analysis, comparison with the literature data, single-crystal X-ray crystallographic analysis and TDDFT-ECD calculations. Compound 5 exhibited moderate cytotoxicity against K562 and NCI-H446 cell lines, with IC50 values of 15.00 μM and 16.87 μM, respectively.

Benzothiazole-quinoline based probe for simultaneous colorimetric detection of CN- and Cu2+ ions, with fluorescence sensing for Cu2+: Mechanistic insights and practical applications in environmental monitoring and cellular analysis

The development and synthesis of notably targeted and colorimetric sensor based on an azomethine compound for the distinct recognition of Cu2+ and CN- ion individually in an aqueous dimethyl formamide solution is performed. In the presence of CN- and Cu2+, the sensor BTZ showed impressive colorimetric changes, going from pale yellow to orange and pale yellow to dark yellow, respectively. In the meantime, FL spectrum (Cu2+) and UV-vis spectroscopy (CN-/Cu2+) were used to assess the sensing features. The plausible binding mechanisms of CN- and Cu2+ ions with sensor BTZ have been studied using the 1H NMR titration, Job's plot and DFT technique. The bathochromic shift produced by the intramolecular charge transfer (ICT) transition may have been the source of the phenomenon. Furthermore, CN- ion in the commercial substance is quickly identified and measured with the naked eye by using sensor BTZ. It was found that the BTZ's LOD for CN- and Cu2+ was 0.280 × 10-7 M and 1.153 × 10-7 M, respectively. Moreover, 1:1 binding ratio for the reaction of CN- and Cu2+ ions with sensor BTZ were demonstrated by Job's plot, which was dependent on analytical data. The findings show that BTZ is an easy-to-use and practical probe for concurrently sensing cyanide and copper ions in environmental samples and living cells that have less cytotoxicity.

Assessment of the Inhibitory Efficacy of a Thiazole Derivative as an Efficient Corrosion Inhibitor for Augmenting the Resistance of MS in Acidic Environments

Numerous thiazole compounds have been developed as cutting-edge inhibitors because of a rising fascination with using corrosion inhibitors (CIs) and preventative measures to prevent mild steel (MS) from deteriorating. In this study, the ability of a novel thiazole derivative, 2-hydrazono-3-methyl-2,3-dihydrobenzo[d]thiazole hydrochloride (HMDBT), to prevent corrosion of MS (MS) in HCl has been reconnoitered using various approaches, Viz. gravimetric analysis, electrochemical (EC) analysis, and different surface characterizations. With an inhibition efficiency (IE %) of 95.35%, the outcomes elucidate that HMDBT functions as a potent MS CI that is environmentally friendly and sustainable. The computed activation and thermodynamic factors were also employed to better explain the process underpinning the inhibiting tendency of HMDBT. According to the computed values, the HMDBT molecules physically and chemically adhered to the MS surface following the Langmuir model, generating a dense protective layer that may be associated with the presence of a benzene ring and heteroatoms (S & N) in the HMDBT architecture. Based on the findings of the EIS studies, an intensification in the CI's concentration from (50 →800) ppm is ushered by increases in polarization resistance (Rp) from (80.72, 354.31) Ω cm2, and attenuation in double-layer capacitance (Cdl) from (198.78 → 44.13) μF cm-2, respectively, confirming the inhibitory proficiency of HMDBT. The IE of the inhibitor was reported around 95.35% by weight loss measurement and 89.94% through EC measurement. Theoretical analysis including density functional theory (DFT) and molecular dynamics (MD) simulations were carried out to investigate the additional effects of HMDBT on the anticorrosion effectiveness and mechanism of inhibition. The theoretical parameters that were calculated provided important assistance in comprehending the inhibitory mechanism that the CI's moieties disclosed and are in strong concord with experimental methods. To create a "green" inhibitor system, the work presented here provided a potent technique to reduce corrosion by adding a potent new inhibitor.

Facile synthesis and in silico studies of benzothiazole-linked hydroxypyrazolones targeting α-amylase and α-glucosidase

Aim: The objective of the present investigation was to design and synthesize new heterocyclic hybrids comprising benzothiazole and indenopyrazolone pharmacophoric units in a single molecular framework targeting α-amylase and α-glucosidase enzymatic inhibition. Materials & methods: 20 new benzothiazole-appended indenopyrazoles, 3a-t, were synthesized in good yields under environment-friendly conditions via cycloaddition reaction, and assessed for antidiabetic activity against α-amylase and α-glucosidase, using acarbose as the standard reference. Results: Among all the hydroxypyrazolones, 3p and 3r showed the best inhibition against α-amylase and α-glucosidase, which finds support from molecular docking and dynamic studies. Conclusion: Compounds 3p and 3r have been identified as promising antidiabetic agents against α-amylase and α-glucosidase and could be considered valuable leads for further optimization of antidiabetic agents.

Activity against Mycobacterium tuberculosis of a new class of spirooxindolopyrrolidine embedded chromanone hybrid heterocycles

A new class of structurally intriguing heterocycles embedded with spiropyrrolidine, oxindole and chromanones was prepared by regio- and stereoselectively in quantitative yields using an intermolecular tandem cycloaddition protocol. The compounds synthesized were assayed for their anti-mycobacterial activity against Mycobacterium tuberculosis (Mtb) H37Rv and isoniazid-resistant (katG and inhA promoter mutations) clinical Mtb isolates. Four compounds exhibited significant antimycobacterial activity against Mtb strains tested. In particular, a compound possessing a fluorine substituted derivative displayed potent activity at 0.39 μg mL-1 against H37Rv, while it showed 0.09 μg mL-1 and 0.19 μg mL-1 activity against inhA promoter and katG mutation isolates, respectively. A molecular docking study was conducted with the potent compound, which showed results that were consistent with the in vitro experiments.