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Benzothiazole derivatives have high biological activity potential and are present in many natural and medicinal products. For these reasons, the synthesis of benzothiazoles is very important in organic synthesis. In this synthetic approach, we found that the utilization of Fe3O4@DOP-Amide/Imid-CuCl2 nanocomposite in the presence of KOAc in ChCl-Urea as solvent is an eco-friendly and efficient catalytic system for the synthesis of 2-aryl benzothiazoles through one-pot three-component reactions of 2-iodoaniline and aromatic aldehydes with thiourea as sulfur source. Under this catalytic system, a broad spectrum of 2-aryl benzothiazoles were successfully synthesized with high to excellent yields. Compared to the reported catalysts or magnetic nanocatalysts, the Fe3O4@DOP-Amide/Imid-CuCl2 nanocatalyst has the following series of features: design of a magnetic ligand through ammonolysis reaction, high magnetic property of the Fe3O4@DOP-Amide/Imid-CuCl2 nanocatalyst, high catalytic activity in the synthesis of benzothiazole derivatives, reusability and high stability of the synthesized magnetic catalyst. The SEM, VSM, BET, and ICP-OES techniques revealed that the recovered Fe3O4@DOP-Amide/Imid-CuCl2 catalyst (after 8 times) had high stability because the magnetic nature, structure, and surface of the recovered catalyst was similar to the fresh catalyst. [ABSTRACT FROM AUTHOR]

In the present work, Schiff base ligands (1-4) were prepared by condensation of 2-amino-6-substituted-benzothiazole and salicyaldehyde in a 1:1 molar ratio and were further treated with diorganotindichloride R’2SnCl2 leading to a series of organotin(IV) complexes (5-20) of type R’2SnL1−4Cl [R’ = Ph, Bu, Et, Me]. The prepared Schiff base ligands and the organotin(IV) complexes were characterized by various spectroscopic techniques (1H, 13C, 119Sn NMR, FT-IR) and physical techniques. All the synthesized compounds were evaluated for in vitro antibacterial and antifungal activity against two Gram positive bacterial strains B. cereus, S. aureus, two Gram negative bacterial strains E. coli, P. aeruginosa and two fungal strains A. niger and A. flavus by serial dilution method. The spectral data revealed that the complexes were pentacoordinated with bidentate ligands coordinated through oxygen and nitrogen. The results of antimicrobial activity revealed that the synthesized complexes were more toxic towards Gram positive bacterial strains as compared to Gram negative bacterial strains. From the results of QSAR analysis, it was indicated that the antimicrobial activity of the synthesized compounds were controlled by topological parameters (molecular connectivity indices). [ABSTRACT FROM AUTHOR]

Cellulose is among the most abundant natural carbon-based biopolymers containing free OH groups with nucleophilic character for bonding to Lewis acids such as TiCl. Nano-TiCl/cellulose as a bio-based and eco-friendly Lewis acid catalyst was prepared via reaction of nano-cellulose and TiCl in dichloromethane as solvent under room temperature conditions. This catalyst has been characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, powder X-ray diffraction, energy dispersive X-ray spectroscopy, X-ray fluorescence techniques, and transmission electron microscopy. Nano-TiCl/cellulose has been shown to effectively promote multi-component synthesis of 4 H-pyrimido[2,1- b]benzothiazole derivatives by reaction of aldehydes, β-ketoester, and 2-amino benzothiazole under thermal conditions in polyethylene glycol 400 as solvent. Simple methodology,an eco-friendly catalyst, a clean procedure, easy work-up, and excellent yields are some of the important advantages of this protocol. Graphical Abstract: [ABSTRACT FROM AUTHOR]

A new series of benzothiazole amide derivatives ( 9a- l) were synthesized and characterized by Fourier-transform infrared (FT-IR), mass, and H and C nuclear magnetic resonance (NMR) spectroscopic techniques. The antimitotic activity of the newly synthesized compounds was determined by the Allium assay method, from which mitotic index values were calculated. Here, 9g (14.0 %) and 9l (14.5 %) showed mitotic index values most comparable to that of standard drug (14.4 %), while the remaining compounds showed lower mitotic index values; hence, these compounds inhibit the regular cell division process and are the most promising antimitotic agents. Based on the structural activity relationship, the maximum percentage inhibition was observed for compounds containing electron-withdrawing group, revealing enhanced antimitotic activity, while compounds with electron-donating groups such as furan ( 9g) and methyl ( 9l) were comparable to standard. The newly synthesized compounds were also screened for antimicrobial activity, with some of them showing remarkable activity. Graphical Abstract: [ABSTRACT FROM AUTHOR]

The calcinized eggshell as an efficient and green catalyst has been prepared from chicken eggshell waste and is characterized by different analytical techniques such as FT-IR, XRD, TGA, SEM, and EDAX. A series of substituted 2-arylbenzothiazoles have been synthesized by reaction of o-aminothiophenol and aromatic aldehydes under solvent free conditions using a grinding method at room temperature. The reaction proceeds smoothly in excellent yields (86-97 %), short reaction time (15-48 min), and with an easy work-up procedure. The reuse of catalyst and purification of products by non-chromatographic methods are some additional features of the present protocol. The calcinized eggshell is a safe, inexpensive, and a green catalyst with high catalytic efficiency obtained from renewable resources. [ABSTRACT FROM AUTHOR]

A series of N-phenyl-substituted and disubstituted guanidinyl benzothiazole derivatives 4a- 4m were synthesized and characterized as novel antimicrobial and antioxidant agents. The in-vitro antioxidant activities of these compounds were evaluated and compared with commercial antioxidants, using ascorbic acid (AA) and employing 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid (ABTS) assay. The results showed that IC values of compounds 4a and 4m were similar to the IC values of the standard. This assay indicates the good activities of these compounds. In addition, the in-vitro antimicrobial activities of these compounds were evaluated and the results demonstrated that the compounds 4i and 4l exhibited excellent antimicrobial activities. Compounds 4c and 4i having electron withdrawing groups at p-position and compound 4l and 4m having electron donating groups at o-position showed better antimicrobial activities compared to the standard. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Some 4-(1,3-benzothiazol-2-yl)-benzoyl-1 H-pyrazole derivatives have been synthesized by reaction of o-aminothiophenol ( 1) with different electrophilic and nucleophilic reagents. All of the newly synthesized compounds were evaluated for cytotoxicity against breast cancer cell line MCF-7. Two of the compounds were more potent than tamoxifen and three were as potent as tamoxifen. These results were consistent with percentage inhibition of human VEGF compared with control untreated cells. [ABSTRACT FROM AUTHOR]

A mild, simple, and efficient solvent-free method, with sulfonated rice husk ash as solid acid catalyst, has been developed for preparation of benzimidazole, benzoxazole, and benzothiazole derivatives. The products are obtained in good to high yields after very short reaction times, and the catalyst can be reused five times without loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

A new series of derivatives bearing benzothiazol-2-one or benzothiazole ring system conjugated to other different heterocycles were prepared using 5,6-dimethoxy-3-benzothiazol-2(3 H)-one ( 1) as a starting material. The structures of the newly synthesized products have been established based on analytical and spectral data. In addition, the anti-inflammatory and antinociceptive activities of some of the products were evaluated. Our data showed that many derivatives have promising activities as anti-inflammatory and antinocicepative agents. [ABSTRACT FROM AUTHOR]

Two new iridium(III) complexes containing benzothiazol-2-yl carbazole derivative as a cyclometalated ligand (L) and picolinate (pic) or acetylacetonate (acac) as the ancillary ligand, Ir(III) bis(3-(benzothiazol-2-yl)-9-butyl-carbazole)(picolinate) [Ir(L)(pic)] and Ir(III) bis(3-(benzothiazol-2-yl)-9-butyl-carbazole)(acetylacetonate) [Ir(L)(acac)], were synthesized and characterized by elemental analysis, H NMR, FT-IR, and UV-Vis absorption spectra. Both the iridium(III) complexes emit intense green-yellow emissions, indicating that they are useful for the fabrication of organic light-emitting diodes. [ABSTRACT FROM AUTHOR]

A simple and eco-friendly procedure for synthesis of 2-arylbenzothiazoles in high yields by cyclo-condensation reaction of 2-aminothiophenol and aldehydes in the presence of bismuth nitrate (Bi(NO)) as heterogeneous catalyst is described. The reaction was performed in ethanol under reflux with HO as oxidant. The effects of the solvent and the quantity of the catalyst on the reaction were investigated. This method has several advantages, for example excellent yields, simple procedure, and short reaction times. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A series of new compounds bearing a 1,3-benzothiazol-2-one nucleus have been synthesized using 5,6-dimethyl-3-(2-oxo-propyl)-1,3-benzothiazol-2-one ( 1) as a key starting compound. The reaction of 1 with some nucleophilic compounds led to the formation of compounds 2, 3, 4, 5a, b, 6 and 7a, b. The thiosemicarbazone derivatives 7a, b were treated with a number of halo ketones to produce the new heterocyclic compounds 9- 13, while their reaction with acid anhydrides led to the formation of the derivatives 14 and 15. Also, compound 1 was condensed with different aromatic aldehydes to afford the corresponding chalcones 18- 22. The structures of all the novel compounds have been determined by analytical and spectral data. Some of the compounds were selected to be evaluated as anti-inflammatory and analgesic agents. [ABSTRACT FROM AUTHOR]