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Stephen W. C. Chung - One of the best experts on this subject based on the ideXlab platform.
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Development and validation of a method for determination of residues of 15 pyrethroids and two metabolites of Dithiocarbamates in foods by ultra-performance liquid chromatography–tandem mass spectrometry
Analytical and Bioanalytical Chemistry, 2012Co-Authors: Stephen W. C. ChungAbstract:This paper reports a novel approach for the detection, confirmation, and quantification of 15 selected pyrethroid pesticides, including pyrethins, and two metabolites of Dithiocarbamates in foods by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS–MS). The proposed method makes use of a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure that combines isolation of the pesticides and sample cleanup in a single step. Analysis of pyrethroids and Dithiocarbamate metabolites was performed by UPLC–MS–MS operated with electrospray and atmospheric pressure chemical ionization, respectively. Two specific precursor–product ion transitions were acquired per target compound in multiple reaction monitoring (MRM) mode. Such acquisition achieved the minimum number of identification points according to European Commission (EC) document no. SANCO/10684/2009, thus fulfilling the EC point system requirement for identification of contaminants in samples. The method was validated with a variety of food samples. Calibration curves were linear and covered from 1 to 800 μg kg^−1 in the sample for all target compounds. Average recoveries, measured at mass fractions of 10 and 100 μg kg^−1 for pyrethroids and 5 and 50 μg kg^−1 for Dithiocarbamate metabolites, were in the range of 70–120% for all target compounds with relative standard deviations below 20%. Method limits of quantification (MLOQ) were 10 μg kg^−1 and 5 μg kg^−1 for pyrethroids and Dithiocarbamate metabolites, respectively. The method has been successfully applied to the analysis of 600 food samples in the course of the first Hong Kong total diet study with pyrethroids and metabolites of Dithiocarbamates being the pesticides determined. Figure UPLC–MS/MS chromatogram for twenty target analytes spiked at the MLOQ level
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development and validation of a method for determination of residues of 15 pyrethroids and two metabolites of Dithiocarbamates in foods by ultra performance liquid chromatography tandem mass spectrometry
Analytical and Bioanalytical Chemistry, 2012Co-Authors: Stephen W. C. ChungAbstract:This paper reports a novel approach for the detection, confirmation, and quantification of 15 selected pyrethroid pesticides, including pyrethins, and two metabolites of Dithiocarbamates in foods by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS–MS). The proposed method makes use of a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure that combines isolation of the pesticides and sample cleanup in a single step. Analysis of pyrethroids and Dithiocarbamate metabolites was performed by UPLC–MS–MS operated with electrospray and atmospheric pressure chemical ionization, respectively. Two specific precursor–product ion transitions were acquired per target compound in multiple reaction monitoring (MRM) mode. Such acquisition achieved the minimum number of identification points according to European Commission (EC) document no. SANCO/10684/2009, thus fulfilling the EC point system requirement for identification of contaminants in samples. The method was validated with a variety of food samples. Calibration curves were linear and covered from 1 to 800 μg kg−1 in the sample for all target compounds. Average recoveries, measured at mass fractions of 10 and 100 μg kg−1 for pyrethroids and 5 and 50 μg kg−1 for Dithiocarbamate metabolites, were in the range of 70–120% for all target compounds with relative standard deviations below 20%. Method limits of quantification (MLOQ) were 10 μg kg−1 and 5 μg kg−1 for pyrethroids and Dithiocarbamate metabolites, respectively. The method has been successfully applied to the analysis of 600 food samples in the course of the first Hong Kong total diet study with pyrethroids and metabolites of Dithiocarbamates being the pesticides determined.
Azim Ziyaei Halimehjani - One of the best experts on this subject based on the ideXlab platform.
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synthesis of novel α β unsaturated sulfonic acid derivatives containing Dithiocarbamate xanthate groups by ring opening of an α β unsaturated γ sultone
Synlett, 2020Co-Authors: Maryam Khalili Foumeshi, Azim Ziyaei Halimehjani, Petr BeierAbstract:An efficient method is disclosed for the synthesis of novel α,β-unsaturated sulfonic acid derivatives containing Dithiocarbamate/xanthate groups through ring opening of an α,β-unsaturated γ-sultone with dithiocarbamic acid salts or xanthates prepared in situ. Treatment of the primary products with hydrochloric acid afforded the corresponding β-chloro-γ-(dithiocarbamato)propanesulfonic acids in excellent yields.
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Synthesis of N,S-Heterocycles and Dithiocarbamates by the Reaction of Dithiocarbamic Acids and S-Alkyl Dithiocarbamates with Nitroepoxides.
Organic Letters, 2017Co-Authors: Azim Ziyaei Halimehjani, Yazdanbakhsh Lotfi NosoodAbstract:A facile and efficient procedure for the synthesis of substituted thiazole-2(3H)-thiones and thiazolidine-2-thiones by the reaction of primary amines, carbon disulfide, and nitroepoxides is described. By using secondary amines in this protocol, the corresponding Dithiocarbamate-substituted phenyl-2-propanones were prepared in excellent yields. In addition, substituted thiazoles and 1-(alkylthio)-1-phenylpropan-2-ones were prepared in reactions of S-alkyl Dithiocarbamates and nitroepoxides.
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Multicomponent synthesis of Dithiocarbamates starting from vinyl sulfones/sulfoxides and their use in polymerization reactions
RSC Advances, 2016Co-Authors: Azim Ziyaei Halimehjani, Reza Mohtasham, Abbas Shockravi, Jürgen MartensAbstract:A catalyst- and solvent-free procedure for the synthesis of Dithiocarbamates from amines, carbon disulfide (CS2) and vinyl sulfones/sulfoxides is reported. This protocol provides a simple, high yielding and green approach for the synthesis of novel Dithiocarbamates with commercially available starting materials. Also, three-component polyaddition of diamines, CS2 and divinyl sulfone was successfully performed without the use of a catalyst to provide the corresponding polymers containing Dithiocarbamate (dithiourethane) and sulfone moieties.
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Synthesis of a new series of Dithiocarbamate-linked peptidomimetics and their application in Ugi reactions
RSC Advances, 2013Co-Authors: Azim Ziyaei Halimehjani, Mohammad Amin Ranjbari, Hamed Pasha ZanussiAbstract:Novel peptidomimetics containing Dithiocarbamate groups were synthesized via the Ugi reaction. Also, Dithiocarbamates of natural amino acids were prepared and were used successfully in Ugi reactions to prepare novel peptidomimetics bearing amino acid and Dithiocarbamate groups in a single structure. In addition the prepared Dithiocarbamates based on amino acids are converted to the corresponding amides.
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investigation of the reaction of dithiocarbamic acid salts with aromatic aldehydes
Organic Letters, 2012Co-Authors: Azim Ziyaei Halimehjani, Mojtaba Hajilou Shayegan, Mohammad Mahmoodi Hashemi, Behrouz NotashAbstract:A reaction of dithiocarbamic acid salts with carbonyl compounds was investigated for the first time in the presence of BF3·OEt2. The reaction is temperature dependent and gives gem-bis(Dithiocarbamates) at 35–45 °C as a molecule with high equivalents of Dithiocarbamate groups. At lower temperatures (15–20 °C), the 2-iminium-1,3-dithietane is obtained as the only product. The structure of a 2-iminium-1,3-dithietane was accomplished by X-ray crystallographic analysis.
Kojima Shoji - One of the best experts on this subject based on the ideXlab platform.
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Prevention of renal toxicity of cis-diamminedichloroplatinum by Dithiocarbamates in rats.
Toxicology Letters, 1993Co-Authors: Shimada Hideaki, Sugimachi Naho, Funakoshi Takayuki, Kojima ShojiAbstract:Abstract The protective effects of various Dithiocarbamates such as N- benzyl- d -glucamine Dithiocarbamate (BGD), N-p- hydroxymethylbenzyl- d -glucamine Dithiocarbamate (HBGD), N-p- carboxybenzyl- d -glucamine Dithiocarbamate (CBGD), and N- methyl- d -glucamine Dithiocarbamate (MGD) on DDP-induced renal toxicity in rats were studied. The rats received the simultaneous i.v. injection of DDP (20 μmol kg ) and a chelating agent (40 μmol kg ). Significant increase in blood urea nitrogen (BUN) level was observed 5 days after DDP injection. The increase in BUN level was completely prevented by only HBGD and CBGD among these chelating agents. Treatment with CBGD completely prevented against DDP-induced body weight loss. BGD and MGD treatment did not prevent the increase in BUN level or body weight loss. HBGD and CBGD were the most effective in decreasing the renal platinum content, resulting in maximum protection against the DDP-induced renal damage. The antitumor efficacy of DDP in the Walker 256 carcinoma-bearing rats was not affected by CBGD administration.
Edward R. T. Tiekink - One of the best experts on this subject based on the ideXlab platform.
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a new structural motif for cadmium Dithiocarbamates crystal structures and hirshfeld surface analyses of homoleptic zinc and cadmium morpholine Dithiocarbamates
Zeitschrift Fur Kristallographie, 2019Co-Authors: Jimmy Ahmad, Siti Nadiah Abdul Halim, Mukesh M Jotani, Edward R. T. TiekinkAbstract:The crystal and molecular structures of two homoleptic morpholine-derived Dithiocarbamates of zinc, binuclear {Zn[S2CN(CH2CH2)2O)2]2}2 (1), and cadmium, one-dimensional coordination polymer {Cd[S2CN(CH2CH2) 2O)2]2}2 (2), are described. In 1, a centrosymmetric binuclear molecule is found as there are equal numbers of chelating and bidentate bridging Dithiocarbamate ligands; weak transannular Zn · · · S interactions are found within the resultant eight-membered { · · · SCSZn}2 ring which has the form of a chair. The resultant 4 + 1 S5 donor set is highly distorted with the geometry tending towards a squarepyramid. By contrast, a square-planar geometry is found in centrosymmetric 2 defined by symmetrically chelating Dithiocarbamate ligands. The presence of Cd · · · S secondary bonding in the crystal of 2 leads to a distorted 4 + 2 S6 octahedron and a linear coordination polymer, which is unprecedented in the structural chemistry of cadmium Dithiocarbamates. The analyses of the Hirshfeld surfaces for 1 and 2 show the dominance of H · · · H, S · · · H/H · · · S and O · · · H/H · · · O contacts to the surface, i.e. contributing around 90 and 80%, respectively.
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perplexing coordination behaviour of potentially bridging bipyridyl type ligands in the coordination chemistry of zinc and cadmium 1 1 dithiolate compounds
Crystals, 2018Co-Authors: Edward R. T. TiekinkAbstract:The X-ray structural chemistry of zinc and cadmium 1,1-dithiolates (for example, xanthate, dithiophosphate and Dithiocarbamate) with potentially bridging bipyridyl-type ligands (for example, 4,4′-bipyridine) is reviewed. For zinc, the xanthates and dithiophosphates uniformly form one-dimensional coordination polymers, whereas the zinc Dithiocarbamates are always zero-dimensional, reflecting the exceptional chelating ability of Dithiocarbamate ligands compared with xanthates and dithiophosphates. For cadmium, one-dimensional coordination polymers are usually found, reflecting the larger size of cadmium compared with zinc, but zero-dimensional aggregates are sometimes found. Steric effects associated with the 1,1-dithiolate-bound R groups are shown to influence supramolecular aggregation and, when formed, polymer topology in order to reduce steric hindrance; the nature of the bipyridyl-type ligand can also be influential. For the Dithiocarbamates of both zinc and cadmium, in instances where the Dithiocarbamate ligand is functionalised with hydrogen bonding potential, extended supramolecular architectures are often formed via hydrogen bonding interactions. Of particular interest is the observation that the bipyridyl-type ligands do not always bridge zinc or cadmium 1,1-dithiolates, being monodentate instead, often in the presence of hydrogen bonding. Thus, hydroxyl-O–H…N(pyridyl) hydrogen bonds are sometimes formed in preference to M←N(pyridyl) coordinate-bonds, suggesting a competition between the two modes of association.
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tin Dithiocarbamates applications and structures
Applied Organometallic Chemistry, 2008Co-Authors: Edward R. T. TiekinkAbstract:The uses and potential utility of tin/organotin Dithiocarbamate, −S2CNR′2, compounds are reviewed. Various derivatives exhibit exciting potential as anti-cancer agents, anti-microbial agents and insecticides, e.g. against mosquito larvae. Tin Dithiocarbamates have also proven useful as precursors for tin sulfide nanoparticles. There is a wealth of structural data available for such compounds and with the exception of the diorganotin bis(Dithiocarbamate) compounds, R2Sn(S2CNR′2)2, compounds for which different structural motifs are evident, there is a certain degree of homogeneity in the molecular structures for each class of compound unless there are additional coordination sites on the R and/or R′ groups. Owing to the strong coordination potential of the Dithiocarbamate ligand for tin, supramolecular aggregates involving secondary Sn…S interactions are the exception rather than the norm. Copyright © 2008 John Wiley & Sons, Ltd.
Claudiu T Supuran - One of the best experts on this subject based on the ideXlab platform.
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Dithiocarbamates strongly inhibit the β class carbonic anhydrases from mycobacterium tuberculosis
Journal of Enzyme Inhibition and Medicinal Chemistry, 2013Co-Authors: Alfonso Maresca, Fabrizio Carta, Daniela Vullo, Claudiu T SupuranAbstract:A series of N-mono- and N,N-disubstituted Dithiocarbamates have been investigated as inhibitors of two β-carbonic anhydrases (CAs, EC 4.2.1.1) from the bacterial pathogen Mycobacterium tuberculosis, mtCA 1 (Rv1284) and mtCA 3 (Rv3273). Both enzymes were inhibited with efficacies between the subnanomolar to the micromolar one, depending on the substitution pattern at the nitrogen atom from the Dithiocarbamate zinc-binding group. Aryl, arylalkyl-, heterocyclic as well as aliphatic and amino acyl such moieties led to potent mtCA 1 and 3 inhibitors in both the N-mono- and N,N-disubstituted Dithiocarbamate series. This new class of β-CA inhibitors may have the potential for developing antimycobacterial agents with a diverse mechanism of action compared to the clinically used drugs for which many strains exhibit multi-drug/extensive multi-drug resistance.
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Dithiocarbamates strongly inhibit carbonic anhydrases and show antiglaucoma action in vivo
Journal of Medicinal Chemistry, 2012Co-Authors: Fabrizio Carta, Mayank Aggarwal, Alfonso Maresca, Robert Mckenna, Emanuela Masini, Andrea Scozzafava, Claudiu T SupuranAbstract:A series of Dithiocarbamates were prepared by reaction of primary/secondary amines with carbon disulfide in the presence of bases. These compounds were tested for the inhibition of four human (h) isoforms of the zinc enzyme carbonic anhydrase, CA (EC 4.2.1.1), hCA I, II, IX, and XII, involved in pathologies such as glaucoma (CA II and XII) or cancer (CA IX). Several low nanomolar inhibitors targeting these CAs were detected. The X-ray crystal structure of the hCA II adduct with morpholine Dithiocarbamate evidenced the inhibition mechanism of these compounds, which coordinate to the metal ion through a sulfur atom from the Dithiocarbamate zinc-binding function. Some Dithiocarbamates showed an effective intraocular pressure lowering activity in an animal model of glucoma.
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Dithiocarbamates are strong inhibitors of the beta class fungal carbonic anhydrases from cryptococcus neoformans candida albicans and candida glabrata
Bioorganic & Medicinal Chemistry Letters, 2012Co-Authors: Simona Maria Monti, Fabrizio Carta, Alfonso Maresca, Francesca Viparelli, Giuseppina De Simone, Friedrich A Muhlschlegel, Andrea Scozzafava, Claudiu T SupuranAbstract:Abstract A series of N -mono- and N , N -disubstituted Dithiocarbamates have been investigated as inhibitors of three β-carbonic anhydrases (CAs, EC 4.2.1.1) from the fungal pathogens Cryptococcus neoformans , Candida albicans and Candida glabrata , that is, Can2, CaNce103 and CgNce103, respectively. These enzymes were inhibited with efficacies between the subnanomolar to the micromolar range, depending on the substitution pattern at the nitrogen atom from the Dithiocarbamate zinc-binding group. This new class of β-CA inhibitors may have the potential for developing antifungal agents with a diverse mechanism of action compared to the clinically used drugs for which drug resistance was reported, and may also explain the efficacy of Dithiocarbamates as agricultural antifungal agents.
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characterization and inhibition studies of an α carbonic anhydrase from the endangered sturgeon species acipenser gueldenstaedti
Journal of Enzyme Inhibition and Medicinal Chemistry, 2011Co-Authors: Sevgi Kolayli, Fatma Yaylaci Karahalil, Huseyin Sahin, Barbaros Dincer, Claudiu T SupuranAbstract:An α-carbonic anhydrase (CA, EC 4.2.1.1) was purified and characterized kinetically from erythrocytes of the sturgeon Acipenser gueldenstaedti, an endangered species. The sturgeon enzyme (AgCA) showed kinetic parameters for the CO2 hydration reaction comparable with those of the human erythrocytes enzyme hCA II, being a highly active enzyme, whereas its esterase activity with 4-nitrophenyl acetate as substrate was lower. Sulphonamide inhibitors (acetazolamide, sulphanilamide) strongly inhibited AgCA, whereas metal ions (Ag+, Zn2+, Cu2+ and Co2+) were weak, millimolar inhibitors. Several widely used pesticides (2,4-dichlorophenol, Dithiocarbamates, parathion and carbaryl) were also assayed as inhibitors of this enzyme. The Dithiocarbamates were low micromolar AgCA inhibitors (IC50 of 16–18 µM), whereas the other pesticides inhibited the enzyme with IC50s in the range of 102–398 µM. The wide use of Dithiocarbamate pesticides may be one of the factors enhancing the vulnerability of this sturgeon species to p...