A robust one-pot synthesis of benzothiazoles from carboxylic acids including examples with hydroxyl and amino substituents

Meghdadi, Soraia; Amirnasr, Mehdi; Ford, Peter C.

doi:10.1016/j.tetlet.2012.10.035

Cited by 25 publications

(27 citation statements)

References 44 publications

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“…In continuation of our studies on the synthesis of 2-substituted benzothiazoles [28], we wish to report the synthesis of 2-(quinoline)benzothiazole, under benign and mild reaction conditions using triphenylphosphite in the simple ionic liquid tetrabutyl-ammonium bromide (TBAB) as the reaction medium, and its copper(I) complexes [Cu(qbtz)(PPh 3 )Br] and [Cu(qbtz)(PPh 3 )I]. The Xray crystal structures of both complexes are reported and their cyclic voltammetric behavior and preliminary antibacterial activity are also discussed.…”

Section: Introductionmentioning

confidence: 83%

“…The IR spectrum of the free ligand shows two bands at 1558 and 1593 cm -1 , characteristic of C=N quinoline and C=N benzothiazole stretching vibrations [28,42]. The ν(C=N) band is generally shifted to lower frequencies in copper complexes relative to the free ligand, indicating a decrease in the C=N bond order due to back bonding from the Cu(I) ion to the π* orbital of the ligand and increasing the resonance in the more planar coordinated benzothiazole ligand.…”

Section: Spectral Characterizationmentioning

confidence: 99%

“…The ligand was prepared according to a procedure reported elsewhere [28]. The synthetic approach was initiated using a mixture of quinaldic acid and 2-aminothiophenol with triphenylphosphite in the presence of the inexpensive ionic liquid tetrabutylammonium bromide (TBAB) at 120 °C.…”

Section: Synthesis Of the Ligand Qbtzmentioning

confidence: 99%

“…The unsymmetrical bidentate ligand qbtz was prepared from 2-aminothiophenol and quinaldic acid by an efficient and benign method recently developed in our laboratory, using triphenylphosphite (TPP) in the presence of the inexpensive ionic liquid tetrabutylammonium bromide (TBAB) as the reaction medium [28]. The product was precipitated by the treatment of the final viscous slurry with methanol.…”

Section: Synthesismentioning

confidence: 99%

“…In the 1 H NMR spectrum of the free ligand the ten aromatic protons appear as six doublets (H j,i,e,h,d,a ) and four triplets (H g,b,f,c ) [28]. …”

Section: Spectral Characterizationmentioning

confidence: 99%

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Synthesis, characterization and X-ray crystal structure of copper(I) complexes of the 2-(2-quinolyl)benzothiazole ligand. Electrochemical and antibacterial studies

et al. 2015

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Section: Introductionmentioning

confidence: 83%

Section: Spectral Characterizationmentioning

confidence: 99%

Section: Synthesis Of the Ligand Qbtzmentioning

confidence: 99%

Section: Synthesismentioning

confidence: 99%

“…In the 1 H NMR spectrum of the free ligand the ten aromatic protons appear as six doublets (H j,i,e,h,d,a ) and four triplets (H g,b,f,c ) [28]. …”

Section: Spectral Characterizationmentioning

confidence: 99%

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Synthesis, characterization and X-ray crystal structure of copper(I) complexes of the 2-(2-quinolyl)benzothiazole ligand. Electrochemical and antibacterial studies

et al. 2015

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

Anandaraj

Saranya

Ramesh

2023

Applied Organom Chemis

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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.

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ChemInform Abstract: A Robust One‐Pot Synthesis of Benzothiazoles from Carboxylic Acids Including Examples with Hydroxyl and Amino Substituents.

2013

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A robust one-pot synthesis of benzothiazoles from carboxylic acids including examples with hydroxyl and amino substituents

Cited by 25 publications

References 44 publications

Synthesis, characterization and X-ray crystal structure of copper(I) complexes of the 2-(2-quinolyl)benzothiazole ligand. Electrochemical and antibacterial studies

Synthesis, characterization and X-ray crystal structure of copper(I) complexes of the 2-(2-quinolyl)benzothiazole ligand. Electrochemical and antibacterial studies

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

ChemInform Abstract: A Robust One‐Pot Synthesis of Benzothiazoles from Carboxylic Acids Including Examples with Hydroxyl and Amino Substituents.

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