Synthesis Of Benzothiazoles Research Articles

Recent Advances for Synthesis of Benzothiazoles from Arylmethylamines

The benzofused N,S‐containing benzothiazole heterocycles and their scaffolds have remarkable biological and pharmaceutical applications. Attentively, the development towards structurally diverse benzothiazoles via C(sp3)‐H functionalization of arylmethylamines has been the main attraction for synthetic organic chemists. In this review, the various synthetic approaches from C‐H/C‐N bond functionalization of arylmethylamines/amines as a new emerging substrate are described in detail towards the synthesis of substituted benzothiazoles. Furthermore, it gives insights into substrate scope and the reaction mechanistic pathway for the formation of final targeted benzothiazole products.

Direct Synthesis of Benzothiazoles and Benzoxazoles from Carboxylic Acids Utilizing (o-CF3PhO)3P as a Coupling Reagent.

A general and efficient method for the direct synthesis of benzothiazoles and benzoxazoles from carboxylic acids with 2-aminobenzenethiols or 2-aminophenols using (o-CF3PhO)3P as a simple coupling reagent has been developed. Diverse benzothiazoles and benzoxazoles were synthesized in moderate to excellent yields. And the gram-scale preparation of benzothiazole and benzoxazole also proceeded smoothly under the mild conditions. Moreover, a plausible reaction mechanism was discussed, with (o-CF3PhO)3P and its hydrolysis product (o-CF3PhO)2P(O)H contributing to the formation of the target products as an amide synthesis coupling agent and a cyclization reaction promoter, respectively.

Preparation of functionalized magnetic nanoparticles bearing sulfonic acid as an effective reusable solid acid catalyst for the synthesis of benzothiazoles

In this study, solid acid magnetic nanoparticles Fe3O4@SiO2-S-Bu-SO3H were prepared under appropriate conditions and characterized by various analytical techniques including FT-IR, XRD, FE-SEM, EDX, and VSM. Finally, the catalytic activity of the synthesized Fe3O4@SiO2-S-Bu-SO3H MNPs was investigated for the synthesis of valuable benzothiazole derivatives by the condensation reaction of ortho-aminothiophenol and various aldehydes under ultrasonic conditions. In the presence of the inexpensive, environment-friendly, magnetically recoverable solid acid catalyst, the benzothiazoles were obtained as pure target products in excellent yields (90–98%) and short reaction times (3–11 min). The synthesized Fe3O4@SiO2-S-Bu-SO3H MNPs show great catalytic activity because of the combined effect of Brønsted acidity and high functional group density. This solid acid magnetic nanocatalyst is reusable for several cycles and can be easily segregated from the reaction mixture.

Synthesis of benzothiazole compounds based on 2D graphene oxide membrane nanoreactors.

The nanoconfinement effect plays an important role in chemical reactions. Inspired by enzymes, this work presents a new way to conduct the rapid flow synthesis of benzothiazoles in the two-dimensional (2D) nanoconfined space created by a graphene oxide membrane. The conversion reaches 96.7% in a short reaction time of less than 23 s at 22 °C.

An ecofriendly and efficient approach for three-component synthesis of benzothiazoles: research on catalytic application of Fe3O4@DOP-Amide/Imid-CuCl2 nanocomposite

An ecofriendly and efficient approach for three-component synthesis of benzothiazoles: research on catalytic application of Fe3O4@DOP-Amide/Imid-CuCl2 nanocomposite

Mechanistic insight into C−S bond construction using CO2 as a carbon source: Synthesis of benzothiazoles from 2-aminothiophenols in imidazolium acetate

DFT calculations on synthesis of benzothiazoles via cyclization of 2-aminothiophenols with CO2 and triethoxysilane have revealed a novel mechanism that fundamentally differs from previously proposed mechanisms. In this new mechanism, the acetate anion plays a pivotal role in both stages of the reaction: first, in the formation of the formoxysilane intermediate via CO2 reduction, and second, in its subsequent transformation to the product, benzothiazoles. The acetate anion acts as a nucleophile to activate the Si−H bond of triethoxysilane in the CO2 reduction stage and as a base, deprotonating 2-aminothiophenol and generating a HOAc molecule, which then acts as a proton shuttle in the subsequent transformations leading to the final product. Throughout the whole reaction process, it is the acetate anion that plays a substantial role in catalyzing the reaction by activating the Si–H bond of triethoxysilane, contrasting with the previous notion that the imidazolium cation activates CO2 through the formation of a NHC-CO2 adduct. Furthermore, the proposed mechanism offers a rational explanation for the observed inefficiency of imidazolium trifluoromethansulfonate as a catalyst for this reaction. The elucidation of this new mechanism sheds light on the intricate details of the benzothiazole synthesis and may inspire further investigations in this field.

Identification of novel benzothiazole-thiadiazole-based thiazolidinone derivative: in vitro and in silico approaches to develop promising anti-Alzheimer's agents.

Aim: The present study describes benzothiazole derived thiazolidinone based thiadiazole derivatives (1-16) as anti-Alzheimer agents.Materials & methods: Synthesis of benzothiazole derived thiazolidinone based thiadiazole derivatives was achieved using thebenzothiazole bearing 2-amine moiety. These synthesized compounds were confirmed via spectroscopic techniques (1H NMR, 13C NMR and HREI-MS). These compounds were biologically evaluated for their anti-Alzheimer potential. Binding interactions with proteins and drug likeness of the analogs were explored through molecular docking and ADMET analysis, respectively. In the novel series, compound-3 emerged as the most potent inhibitor when compared with other derivatives of the series.Conclusion: The present study provides potent anti-Alzheimer's agents that can be further optimized to discover novel anti-Alzheimer's drugs.

Simultaneous diversity-oriented synthesis of benzothiazoles and related diverse analogues by iodine-catalyzed intramolecular cyclization from identical substrates

Simultaneous diversity-oriented synthesis of benzothiazoles and related diverse analogues by iodine-catalyzed intramolecular cyclization from identical substrates

SnCl2-catalyzed multicomponent coupling: synthesis of 1,3-oxazolidine derivatives using paraformaldehyde as a C1 feedstock.

SnCl2 catalyzed the three-component coupling of aniline, epoxide, and paraformaldehyde, resulting in the synthesis of 1,3-oxazolidine derivatives. The reaction is simple and does not require any additives, bases, or oxidants, and proceeds at moderate temperature with good functional group tolerance. The scope of the utilization of paraformaldehyde as the methylene source was further extended to the synthesis of benzothiazole and 4,4'-methylenebis(N,N-dimethylaniline) using the same catalyst. A catalytic pathway was proposed based on the control experiments.

Synthesis of benzothiazoles catalyzed by [Bmim]PF6 ionic liquid in solvent-free condition

A novel, simple and efficient method for the synthesis of benzothiazoles in solvent-free conditions has been developed from 2-aminophenthiols and aldehydes, using ionic liquid [Bmim]PF6 as a catalyst. It is noteworthy that [Bmim]PF6 acts as both the catalyst and solvent, and no additional organic solvents are required in this reaction. In addition, this reaction has a wide range of substrate scope and a series of benzothiazoles are smoothly synthesized with good to excellent yields.

Synthesis and characterization of fullerene modified with copper nanoparticles catalyzed C[sbnd]H bond activation as a sustainable and green catalyst for electro synthesis of benzothiazole derivatives

In this study, our focus was on synthesizing and characterizing a fullerene modified with copper nanoparticles. This modified fullerene catalyzes for the eco-friendly synthesis of benzothiazole 5(a-m) derivatives. These derivatives are obtained through the reaction of 2-iodoaniline 1(a-f), toluene 2(a-e), and Na2S resulting in good yields (89–94 %). The nanocomposite catalyst underwent thorough characterization using various analytical techniques, including Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDS), Brunauer–Emmett–Teller (BET), Thermogravimetric analysis (TGA), Ultraviolet (UV), X-ray photoelectron spectroscopy (XPS), Cyclic voltammetry (CVs) and X Ray Diffraction Analysis (XRD) spectroscopy. By utilizing this catalyst, we achieve a more environmentally friendly approach to synthesis, reducing the requirement for hazardous and toxic reagents, and minimizing waste generation through reusability. The products obtained in this study were characterized using melting point determination, 1HNMR spectroscopy, and CHN analysis. These analytical techniques were employed to establish the identity and purity of the synthesized compounds.

Synthesis, Molecular Docking and In-silico Admet Screening of New Benzothiazole-Linked Pyrazole Prototype Derivatives: Validation of Resistant Strains and their Biological Activity

Background: The necessity for newer anti-microbial medications with prototypes has arisen as a result of the prevalence of infections caused by resistant strains of microorganisms. Objective: A series of nine novel benzothiazole-linked pyrazole prototype derivatives were synthesized in multistep reactions and evaluated for anti-microbial and anti-fungal activities. The druglikeness along with physicochemical properties of synthesized compounds were determined by docking the ligands with resistant strains. Methods: Synthesis of benzothiazole and pyrazole prototype derivatives was carried out by a sequence of reactions to attain the hydrazine carboxamide derivatives. All the synthesized compounds were characterized and evaluated for their anti-bacterial and anti-fungal activities against carbapenem-resistantresistant pseudomonas aeruginosa (CP-PA), carbapenem-resistantresistant Klebsiella pneumoniae (CP-KP), cephalosporin-resistantclostridium difficile (CR-CD), macrolideresistantresistant streptococcus pyogenes (MR-SP), Voriconazole-resistant Aspergillus Niger (VRAN) and Fluconazole-resistant Candida glabrata (FR-CG). Physico-chemical parameters were done by Medchem DesignerTM software version 5.5 and ADMET parameters by pkCSM online tool. Furthermore, molecular docking was accomplished with PyRx 0.8 by AutoDock Vina program. Results: All the synthesized derivatives were characterized and evaluated for their anti-bacterial activity, which shows the significant activity of 6i with MIC 36.17 μM on CP-PA, MIC 36.86 μM on CP-KP, MIC 38.45 μM on CR-CD, and MIC 37.09 μM on MR-SP, with respect to ciprofloxacin with an average of MIC 32 μM for all resistant bacterial strains. The prototype derivatives were also evaluated for their anti-fungal activity, in which derivative 6i was found to be significant with MIC 35.27 μM for VR-AN, MIC 34.78 μM for FR-CG, and MIC values of 25.60 μM and 27.08 μM for Nystatin for all fungal-resistant strains. In-silico predicted parameters for synthesized prototype derivatives stood to be drug-like. Conclusion: From the novel benzothiazole and pyrazole hybrid derivatives, compound 6i was found to be effective for anti-microbial and anti-fungal drugs and hence can be further explored for dual activities. Furthermore, derivatization was made to synthesize further potent derivatives for anti-microbial and anti-fungal treatments.

Synthesis of benzothiazoles and biologically active derivatives from 2-aminothiophenol

Synthesis of benzothiazoles and biologically active derivatives from 2-aminothiophenol

Fabrication of immobilized molybdenum complex on functionalized graphene oxide as a novel catalyst for the synthesis of benzothiazoles

This paper presented a novel amino-modified nano-graphene oxide supported thiophene-2-carbaldehyde Mo-complex (Mo(TC)/GO) catalyst prepared and characterized by FT-IR, SEM, TEM, TGA, EDX, BET, XRD, and N2 adsorption–desorption techniques. The catalyst presented an outstanding performance for synthesizing benzothiazole derivatives through a reaction between benzyl alcohol derivatives and 2-aminothiophenol. The heterogeneous catalyst could be facial separated and reused by filtration without any substantial decline in its catalytic activity even after five runs.

Iron(III)-Catalyzed Regioselective Synthesis of Electron-Rich Benzothiazoles from Aryl Isothiocyanates via C–H Functionalization

We report herein a direct synthetic route for the preparation of 2-arylbenzothiazoles using aryl isothiocyanates and electron-rich arenes. The synthetic route involves triflic acid promoted addition of the arenes to aryl isothiocyanates followed by FeCl3-catalyzed C-S bond formation via C-H functionalization. The approach provides the advantage of synthesis of benzothiazoles without the conventional use of aryl aldehyde/carboxylic acid precursors employing the less expensive iron(III) catalyst.

Synthesis and structural characterization of palladium pincer complexes: Sustainable synthesis of benzothiazoles

An efficient Pd(II)N^N^S pincer type catalysts‐promoted sustainable construction of pharmaceutically important benzothiazole derivatives from primary alcohols and 2‐aminothiophenol via acceptorless dehydrogenative coupling (ADC) method has been described. The newly synthesized ligand L2 and the Pd(II) complexes in addition to L1 and L3 were characterized by analytical and Fourier transform infrared spectroscopy (FT‐IR), UV–visible (UV–vis), and nuclear magnetic resonance (NMR) spectral techniques. Further, the ORTEP views of the complexes 2 and 3 were established by a single crystal XRD study, which evidenced the coordination of the thiosemicarbazone ligands and disclose the square‐planar geometry around the Pd(II) ion. The present homogeneous catalytic system involves synthesizing a range of benzothiazoles via C−S and C−N bond formation with excellent yields up to 93%. The described methodology employs a sustainable, highly abundant, and inexpensive alcohol as starting material using 1 mol% catalyst loading, and water and hydrogen gas are the only by‐products. Furthermore, a plausible mechanism involving in situ aldehyde formation via dehydrogenation of primary alcohols has been proposed. A large‐scale synthesis of 2‐(4‐methoxyphenyl)benzo[d]thiazole illustrates the synthetic utility of the present catalytic protocol.

Recent Advances in the Synthesis of Benzothiazoles : A Review

Benzothiazoles are important heterocyclic compound because of their wide range of biological and pharmacological activity. In literature, it is reported that Benzothiazoles and its derivatives possess numerous pharmacological activities like antitumor, anticonvulsant, antimicrobial, antioxidant, antitubercular, antimalarial, antifungal, anti-inflammatory and antidiabetic activities. In recent year several methods have been developed for the synthesis of Benzothiazole derivatives due to their importance in bioorganic and medicinal chemistry. The present review focuses on systematic literature report of various synthetic procedures of Benzothiazoles derivatives using different strategies from the period 2010 to 2021.

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

This review highlights the recent synthetic developments of benzothiazole based anti-tubercular compounds and their in vitro and in vivo activity. The inhibitory concentrations of the newly synthesized molecules were compared with the standard reference drugs. The better inhibition potency was found in new benzothiazole derivatives against M. tuberculosis. Synthesis of benzothiazole derivatives was achieved through various synthetic pathways including diazo-coupling, Knoevenagel condensation, Biginelli reaction, molecular hybridization techniques, microwave irradiation, one-pot multicomponent reactions etc. Other than recent synthetic developments, mechanism of resistance of anti-TB drugs is also incorporated in this review. Structure activity relationships of the new benzothiazole derivatives along with the molecular docking studies of selected compounds have been discussed against the target DprE1 in search of a potent inhibitor with enhanced anti-tubercular activity.

A novel approach towards synthesis of benzothiazoles and benzimidazoles: Eosin Y-catalyzed photo-triggered C–S and C–N bond formation

A novel metal-free and environment-friendly approach for synthesizing biologically important moieties, benzothiazoles and benzimidazoles, using photoredox catalyst Eosin Y, ethanol:water as a green solvent and atmospheric air as an oxidant has been developed.

Benoxazolone-based ionic liquid catalyzed C–S bond construction for synthesis of benzothiazoles from 2-aminothiophenols and CO2 under ambient conditions

[P4444][Benoxa] ionic liquid was discovered to be very effective for the synthesis of benzothiazoles via cyclization of 2-aminothiophenols with CO2 and hydrosilanes at ambient conditions, and a series of benzothiazoles were obtained in high yields.