General Synthetic Methods for Thiazole and Thiazolium Salts

Vernin, Gaston

doi:10.1002/9780470187081.ch3

Cited by 18 publications

(8 citation statements)

References 424 publications

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“…The ring-closure is then achieved by adding an α-haloketone compound. Substitution of the chlorine atom by the nucleophilic sulfur atom is followed by another nucleophilic attack of the nitrogen atom onto the carbonyl function . Treatment of the crude N -arylhydroxythiazolidine with hydrochloric acid finally yields the desired N -arylthiazole-2-thione structures (see Scheme for a possible mechanism).…”

Section: Resultsmentioning

confidence: 99%

Photoluminescence of a New Material: Cyclometalated C^∧C* Thiazole-2-ylidene Platinum(II) Complexes

et al. 2016

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A new class of platinum(II) compounds, the 4,5-dimethyl-3-aryl-thiazole-2-ylidene platinum(II) acetylacetonato complexes, are described. Their efficient phosphorescent emission at room temperature makes them suitable for potential applications in organic light-emitting diodes. A new synthetic pathway that allows the preparation of a broad range of different N-arylthiazole-2-thiones and their subsequent conversion into the corresponding N-arylthiazolium perchlorate and hexafluorophosphate salts has been developed. Not only electron-rich (4-OMe, 4-Me, 3-Me) N-arylthiazoles but also electron-deficient ligands with a cyano or an ester group could be synthesized. From commercially available anilines N-arylthiazolium perchlorate and hexafluorophosphate salts were synthesized via ring-closure of in situ generated N-aryldithiocarbamate salts followed by a sulfur-oxidation/-substitution protocol to the air-stable carbene precursors. All reactions were performed in multigram scale in good yields. The synthesis of the corresponding platinum(II) complexes involves generating the corresponding N-arylthiazole-silver(I)-carbene complexes, transmetalation to platinum, cyclometalation, and reaction with acetylacetonate (acac). Solid-state structures of two N-arylthiazole-2-thiones, one N-arylthiazolium salt, and three N-arylthiazole-2-ylidene-platinum(II) complexes complement the analytic characterization including 195Pt NMR. The unsubstituted complex 4,5-dimethyl-3-phenylthiazole-2-ylidene-platinum(II)-acac was additionally characterized by 2D-NMR techniques (COSY, HSQC, HMBC, NOESY). Photoluminescence measurements were performed in amorphous poly(methyl methacrylate) films and revealed bluish-green emission maxima (∼500 nm) independent of the electronic structure of the thiazoles, whereas the variation of the substitution pattern at the cyclometalating aryl system led to excellent quantum efficiencies and decay lifetimes of 8.1–21.4 μs.

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Section: Resultsmentioning

confidence: 99%

Photoluminescence of a New Material: Cyclometalated C^∧C* Thiazole-2-ylidene Platinum(II) Complexes

et al. 2016

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“…Preparation of Labeled TPP and PyruVate. 4-Methyl-5-(β-hydroxyethyl)thiazole labeled with 15 N at N3 ([3-15 N]TPP) or 13 C at C2 ([2-13 C]TPP) of the thiazole ring was prepared by condensing 3-chloro-4-oxopentyl acetate with either 15 Nor 13 C-labeled thioformamide, followed by acidic hydrolysis (19,20). The isotopically labeled thiazole compound was then converted to TPP using the previously described enzymatic synthesis (21).…”

Section: Methodsmentioning

confidence: 99%

EPR Spectroscopic and Computational Characterization of the Hydroxyethylidene-Thiamine Pyrophosphate Radical Intermediate of Pyruvate:Ferredoxin Oxidoreductase

et al. 2006

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The radical intermediate of pyruvate:ferredoxin oxidoreductase (PFOR) from Moorella thermoacetica was characterized using electron paramagnetic resonance (EPR) spectroscopy at Xband and D-band microwave frequencies. EPR spectra obtained with various combinations of isotopically labeled substrate (pyruvate) and coenzyme (thiamine pyrophosphate (TPP)), were analyzed by spectral simulations. Parameters obtained from the simulations were compared with those predicted from electronic structure calculations on various radical structures. The g-values and 14 N/ 15 N-hyperfine splittings obtained from the spectra are consistent with a planar, hydroxyethylidene-thiamine pyrophosphate (HE-TPP) π-radical, in which spin is delocalized onto the thiazolium sulfur and nitrogen atoms. The 1 H-hyperfine splittings from the methyl group of pyruvate and the 13 C-hyperfine splittings from C2 of both pyruvate and TPP are consistent with a model in which the pyruvate-derived oxygen atom of the HE-TPP radical forms a hydrogen bond. The hyperfine splitting constants and g-values are not compatible with those predicted for a nonplanar, σ/n-type cation radical.Pyruvate:ferredoxin oxidoreductase (E.C.1.2.7.1) (PFOR 1 ) is a member of the 2-keto acid oxidoreductase family. This enzyme plays a central role in anaerobic fermentative metabolism by catalyzing the reversible, CoA-dependent, oxidative decarboxylation of pyruvate to acetylCoA and CO 2 (3). The two electrons generated in the oxidative reaction are transferred through [4Fe-4S] clusters in PFOR to an oxidized ferredoxin (4). PFOR is found in microbes lacking mitochondria from all three kingdoms (5). PFOR enzymes from different species have been grouped into three types depending on subunit composition (6). The different types of PFOR enzymes have between one and three [4Fe-4S] clusters. clusters are electron transfer cofactors serving as way-stops for electrons exiting the active site in the forward † This work was supported by grants from the National Institutes of Health: GM35752 G.H.R.; GM39451 S.W.R.; DK44083 T.P.B.; and Center Grant 1P20RR17675 to the University of Nebraska. S.O.M was supported by an NIH Predoctoral Training Grant T32 GM 08293. *To whom correspondence should be addressed. Telephone: (608) 262-0509; Fax: (608) 265-2904; Email: reed@biochem.wisc.edu. ‖ Current address: Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520-8066 1 Abbreviations: PFOR, pyruvate:ferredoxin oxidoreductase; CoA, coenzyme A; TPP, thiamine pyrophosphate; HE-TPP, hydroxyethylidene-thiamine pyrophosphate; EPR, electron paramagnetic resonance; ENDOR, electron nuclear double resonance; CW continuous wave; DFT, density functional theory; S/N, signal-to-noise ratio; RMSD, root mean square deviation; POX, pyruvate oxidase. to an acetyl radical followed by radical recombination with a CoA-thiyl radical (11). Elucidation of the structure of the HE-TPP radical intermediate is essential to an eventual understanding of the subsequent steps in the overall reacti...

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“…The most common and most versatile procedure for the formation of 1,3-thiazoles is the cyclocondensation of a-haloketones with appropriate thioamide derivatives [ 22 , 23 ] In this study, the reaction of commercially available a-bromoketones 1 and 2 with propionthioamide, benzothioamide, and 4-methoxybenzothioamide under basic conditions furnished the compounds 10–12 respectively ( Scheme 1 ). The formation of benzo[ d ]thiazoles 13–15 was achieved through a cyclocondensation reaction of corresponding substituted benzoic acid 3a–c and 2-aminothiophenol in the presence of a catalytic amount of polyphosphoric acid [ 8 , 24 ].…”

Section: Resultsmentioning

confidence: 99%

Antimicrobial Prospect of Newly Synthesized 1,3-Thiazole Derivatives

2011

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A new series of 1,3-thiazole and benzo[d]thiazole derivatives 10–15 has been developed, characterized, and evaluated for in vitro antimicrobial activity at concentrations of 25–200 μg/mL against Gram+ve organisms such as methicillin-resistant Staphylococcus aureus (MRSA), Gram–ve organisms such as Escherichia coli (E. coli), and the fungal strain Aspergillus niger (A. niger) by the cup plate method. Ofloxacin and ketoconazole (10 μg/mL) were used as reference standards for antibacterial and antifungal activity, respectively. Compounds 11 and 12 showed notable antibacterial and antifungal activities at higher concentrations (125–200 μg/mL), whereas benzo[d]thiazole derivatives 13 and 14 were found to display significant antibacterial or antifungal activity (50–75 μg/mL) against the Gram+ve, Gram–ve bacteria, or fungal cells used in the present study. In addition, a correlation between calculated and determined partition coefficient (log P) was established which allows future development of compounds within this series to be carried out based on calculated log P values. Moreover, compounds 13 and 14 show that the optimum logarithm of partition coefficient (log P) should be around 4.

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General Synthetic Methods for Thiazole and Thiazolium Salts

Cited by 18 publications

References 424 publications

Photoluminescence of a New Material: Cyclometalated C^∧C* Thiazole-2-ylidene Platinum(II) Complexes

Photoluminescence of a New Material: Cyclometalated C^∧C* Thiazole-2-ylidene Platinum(II) Complexes

EPR Spectroscopic and Computational Characterization of the Hydroxyethylidene-Thiamine Pyrophosphate Radical Intermediate of Pyruvate:Ferredoxin Oxidoreductase

Antimicrobial Prospect of Newly Synthesized 1,3-Thiazole Derivatives

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General Synthetic Methods for Thiazole and Thiazolium Salts

Cited by 18 publications

References 424 publications

Photoluminescence of a New Material: Cyclometalated C∧C* Thiazole-2-ylidene Platinum(II) Complexes

Photoluminescence of a New Material: Cyclometalated C∧C* Thiazole-2-ylidene Platinum(II) Complexes

EPR Spectroscopic and Computational Characterization of the Hydroxyethylidene-Thiamine Pyrophosphate Radical Intermediate of Pyruvate:Ferredoxin Oxidoreductase

Antimicrobial Prospect of Newly Synthesized 1,3-Thiazole Derivatives

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Photoluminescence of a New Material: Cyclometalated C^∧C* Thiazole-2-ylidene Platinum(II) Complexes

Photoluminescence of a New Material: Cyclometalated C^∧C* Thiazole-2-ylidene Platinum(II) Complexes