Xanthate Derivative Research Articles

Synthesis and characterization of guar gum xanthate derivative super adsorbent hydrogel for the capturing of heavy metal ions from wastewater

The Guar Gum Xanthate based hydrogel GGmX-g-poly(AA-co-HEMA) has been successfully synthesized by using the graft copolymerization of two monomers, acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) hydrogel. The synthesis follows the free-radical graft polymerization method. UV-visible spectroscopy (UV), Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Point zero charge (PZC), and field emission scanning electron microscopy (FESEM) were employed for the characterization of the synthesized hydrogel. This hydrogel has shown a high swelling ratio of 430.2 g/g and retention of 75.82% in distilled water which is a notable result. By using GGmX-g-poly(AA-co-HEMA) hydrogel, the maximum percentage of heavy metal ions removal from wastewater was found to be 98.5(±1.5)% and 97.1(±1.5) at optimum pH 6 and 6.5 for Cu2+ and Ni2+ solutions respectively. The Langmuir adsorption isotherm fits best for the adsorption data indicating a monolayer adsorption with maximum adsorption capacity of 423.72 (±26.1) mg/g and 404.85 (±31.4) mg/g for Cu2+ and Ni2+ ions respectively. The pseudo-second-order kinetic model provides the most accurate depiction of adsorption kinetics with rate constant 9.1 × 10−4 (±1.37×10−4)g/(mg.min) for Cu2+ and 8.3 × 10−4 (±1.24×10−4)g/(mg.min) for Ni2+ ions, respectively. The negative ΔG value (-4.75 kJ/mol for Cu2+ and −3.26 kJ/mol for Ni2+ ions) and positive value of ΔH (57.55 (±5.41) kJ/mol for Cu2+ and 40.60(±5.37) kJ/mol for Ni2+ ions) suggested the process to be spontaneous, endothermic, and feasible. It has been found that the hydrogel has excellent regenerative capacity with the % adsorption has been found to be 84.8% for Cu2+ and 82.4% for Ni2+ ions for the fifth cycle.

A green flotation collector towards efficient separation of chalcopyrite from pyrite with high selectivity

Xanthate, due to its superior collecting ability, is widely used in the field of minerals flotation. However, its weak selectivity and foul odor make it difficult to separate chalcopyrite from pyrite and reduce pollution. This work provides an efficient and odorless collector to selectively separate chalcopyrite from pyrite. Amide group was introduced into xanthate and an efficient and odorless xanthate derivative was designed, potassium O-(6-(butylamino)-6-oxohexyl) xanthate (PBAHX), to selectively separate chalcopyrite and pyrite. The flotation results showed that PBAHX exhibited superior selectivity, the separation index of PBAHX for chalcopyrite and pyrite is 2.65 while that of the traditional sodium isobutyl xanthate (SIBX) is 1.29, and enabled the separation of chalcopyrite and pyrite. The electronic-nose detection demonstrated that the odor intensity of PBAHX was lower than SIBX. Subsequently, “horizontal” adsorption model was formed for the adsorption of PBAHX on pyrite to explain the differences in flotation results. Besides, hydrogen bonds may be produced between collector molecules to dampen odor. PBAHX shows potential as a green and effective alternative to sulfide mineral flotation.

Gold(III) heteroleptic complexes with SNS-thiosemicarbazonate ligands as cytotoxic agents: Experimental and computational insights into the mechanism of action

New gold(III) heteroleptic complexes of general formula [AuX(dmtsc)], with (dmtsc)2– = (diethylaminothiocarbonyl)benzimidoyl-morpholinyl-thiosemicarbazonate and X = xant– (ethyl xanthate) or damp– (dimethyl-1-phenylmethanamine), were synthesized and compared to the chlorido precursor [AuCl(dmtsc)]. The characterization of the new complexes included FTIR, elemental analysis, molar conductivity, UV–Vis, 1H and 13C NMR spectroscopies and ESI(+)-MS. In addition, the xanthate derivative was analyzed by single-crystal X-ray diffraction. In vitro assays against three tumor cell lines (B16-F10, HCT-8 and MDA-MB-231) showed that the gold(III) complexes display remarkable antiproliferative effects on human breast adenocarcinoma cell line with influence of the co-ligands. The cytotoxicity on VERO cells was also investigated revealing that the organometallic complex [Au(damp)(dmtsc)] was the most selective compound for MDA-MB-231, although not the most active. Attempting to comprehend their behavior in biological medium, studies involving the interactions with possible biological targets were performed by experimental methods and theoretical docking simulations. Their results indicated that HSA might be a probable carrier of the compounds in the biological medium, whereas DNA is not supposed to be their main target. On the other hand, all compounds totally inhibited thioredoxin reductase enzyme (TrxR) at the concentration of 50 μM and formed significant molecular interactions, suggesting that it might be one of the molecular targets of these gold(III) complexes.

PH- and H2O2-sensitive drug delivery system based on sodium xanthate: Dual-responsive supramolecular vesicles from one functional group

Nano-drug delivery systems with multiple stimulus-responsive capabilities have superior response performance and efficient drug release. Nevertheless, it is sophisticated to construct multiple stimulus-responsive systems where the two or more functional groups need to be introduced simultaneously. Xanthate, one functional group with pH and H2O2 stimulus responsiveness, has significant potential applications for building dual-responsive drug delivery system. Herein, we present a novel dual stimuli-responsive supramolecular drug delivery system by using sodium xanthate derivative (SXD) as guest molecule and quaternary ammonium capped pillar[5]arene (QAP5) as host molecule through host-guest interaction on the basis of electrostatic interaction. The amphiphile QAP5⊃SXD could self-assemble into vesicles to efficiently load the anti-cancer drug DOX. The experimental results showed that QAP5⊃SXD nanoparticles could achieve efficient drug delivery and controlled release in the tumor microenvironment. Cytotoxicity experiments proved that DOX@QAP5⊃SXD nanoparticles could significantly improve the anticancer efficiency of free DOX on cancer cells. The present study provides an efficient strategy to develop supramolecular nanocarriers with dual-responsiveness in one functional group for controlled drug release.

ZrO2 and Rice-Husk-Xanthate Adduct: An Efficient Bioderived Catalyst for Synthesis of Spiro[4H-pyran-4,3′-indoline

The reaction of dry and pulverized rice husk with alkaline CS2 followed by treatment of the resulting xanthate derivative with zirconyloxychloride at room temperature led to functionalization of the xanthated biomass with sodium zirconate grouping. The as-prepared sodium salt of the rice-husk xanthatozirconate was characterized physicochemically and found to be an efficient, robust, and recyclable catalyst for the three-component synthesis of some spiro[4H-pyran-4,3′-indoline]s in water.

Synthesis and evaluation of [99mTcN]2+ core and [99mTcO]3+ core labeled complexes with 4-nitroimidazole xanthate derivative for tumor hypoxia imaging

A 4-nitroimidazole xanthate ligand (NMXT) was synthesized and radiolabeled with [99mTcN]2+ core and [99mTcO]3+ core to obtain 99mTcN-NMXT and 99mTcO-NMXT, respectively. The two 99mTc-complexes were prepared with high radiochemical purity and had good stability. The partition coefficient results indicated both of them were hydrophilic, and cellular uptake studies showed they exhibited good hypoxic selectivity. From the biodistribution study results, 99mTcO-NMXT showed more favourable tumor uptake (1.73 ± 0.14 ID%/g) and higher tumor/muscle ratio (7.01 ± 0.16) than 99mTcN-NMXT at 4 h post-injection. Single photon emission computed tomography (SPECT) imaging study of 99mTcO-NMXT showed there was a visible accumulation in tumor site, suggesting it would be a promising candidate as a tumor hypoxia imaging agent.

Investigating the selectivity of a xanthate derivative for the flotation separation of chalcopyrite from pyrite

Separating chalcopyrite, an important copper-containing ore, from pyrite is an important mineral-processing objective. Herein, we report the synthesis of S-hydroxyethyl-O-isobutyl xanthate (HEIBX), a novel surfactant bearing both hydroxyl and thione groups, through the attachment of a hydroxyethyl group to sodium isobutyl xanthate (SIBX), and its first application as a flotation collector for the selective flotation-separation of chalcopyrite from pyrite. The flotation mechanism involving HEIBX and chalcopyrite or pyrite was investigated by DFT calculations, UV–vis spectroscopy, contact-angle and surface-tension measurements, flotation and zeta-potential experiments, as well as FTIR spectroscopy and XPS. Incorporation of the hydroxyethyl group was observed to increase the molecular properties of SIBX by increasing the number of active sites, arrangement density, selectivity and hydrophobicity, thereby improving its flotation performance. Chalcopyrite was separated from pyrite using 4 × 10−5 mol·L−1 HEIBX at pH ∼8.0. Furthermore, we found that the hydroxyl and thione functional groups adsorb onto the chalcopyrite surface though the formation of COCu and CSCu bonds.

Study of the Influence of Xanthate Derivative Structures on Copper Sulfide Mineral Adsorption Under Acidic Conditions

Adsorption of commercial xanthate derivatives on copper sulfide mineral (covellite, CuS) was studied by kinetics and isotherm adsorption experiments. The adsorption of xanthate derivatives was confirmed by FTIR (Fourier transform infrared spectroscopy) and XPS (X-ray photoelectron spectroscopy) results. Experiments were performed with two different xanthate derivatives, C-4410 (O-pentyl S-2-propenyl ester) and C-4940 (isobutyl xanthogen ethyl formate), on individual doses of 0.05 g of powdered covellite. It was found that the equilibrium times at pH 2, 4, and 6 were different for both xanthate derivatives. The shortest times were achieved at pH 2 and 4. The results suggest that C-4110 can be used as collector in a wide range of pH, while C-4940 is limited to lower pH values. Pseudo first- and pseudo second-order kinetics models were thus applied to the experimental data for pH 2. The information obtained from the kinetics models combined with XPS allowed proposing the adsorption mechanism for the covellite-xanthate derivative pair. The adsorption takes place through a non-covalent interaction for C-4410 and chemisorption process for C-4940. The best-fitting isotherm models for C-4410 and C-4940 adsorption were Redlich–Peterson and Freundlich, respectively, which yield a maximum adsorption capacity of 57.07 mg g−1 for C-4410 and 44.62 mg g−1 for C-4940.

Expedited Synthesis of Matrine Analogues through an Oxidative Cascade Addition/Double‐Cyclization Radical Process

The addition of a nicotinate–xanthate derivative to N‐allylindoles and N‐allylpyrroles resulted in polycyclic heterocycle‐fused pyridonaphthyridines through a tandem radical intermolecular/intramolecular oxidative addition reaction sequence that created three new C–C bonds and two new rings in a single event. Such polyheterocycles showcase the matrine alkaloid framework and are similar to indole–monoterpenoid natural products.

β-Oxygen Effect in the Barton–McCombie Deoxygenation Reaction: Further Experimental and Theoretical Findings

The chemistry of (S)-methyl xanthates derived from xylo- and ribo-furanose derivatives in the presence of the stannyl radical is investigated. Xanthate derived from β-xylo-furanose affords exclusively a deoxygenated product; whereas, under the same reaction conditions, the α-ribo-furanose xanthate derivative produces quantitatively a hemithioacetal compound. We reasoned that in the case of the β-xylo-furanose derivative, a favorable β-oxygen effect in the Barton-McCombie deoxygenation reaction is operating where, according to theoretical calculations, unusual molecular orbital interactions (and not strain, as previously proposed) are present. These orbital interactions involve the SOMO (intermediary generated from the stannyl radical addition) with the σ* orbital of the bond undergoing cleavage and this with the two C-O antibonding orbitals anti oriented. Such molecular orbital interactions are not present in the α-ribo-furanose; therefore, the β-scission is highly delayed, and due to the reversibly nature of the stannyl radical addition, the ribo-furanose xanthate is forced to take an alternative route: the homolytic substitution (S(H)2) of the sulfide sulfur by stannyl radical. This radical addition gives the alkoxythiocarbonyl radical, which is trapped by Bu3SnH before the elimination of carbonyl sulfide; subsequently, radical stannyl addition followed by radical reduction produces the hemithioacetal.

N-Alkenyl Indoles as Useful Intermediates for Alkaloid Synthesis

A mild cross-coupling reaction to access several N-alkenyl-substituted indoles has been developed. The coupling procedure involves treating a NH-indole with various alkenyl bromides using a combination of 10 mol % of copper(I) iodide and 20 mol % of ethylenediamine as the catalyst in dioxane at 110 °C in the presence of K(3)PO(4) as the base. When treated with acid, these unique enamines produce a dimeric product derived from a preferred protonation reaction at the enamine π-bond. A cationic cyclization reaction of the readily available 2-(2-(1H-indol-1-yl)allyl)cyclopentanol was utilized to construct tetracyclic indole derivatives with a quaternary stereocenter attached to the C(2)-position of the indole ring. An alternative strategy for selective functionalization at the C(2)-position of a N-alkenyl-substituted indole derivative that was also studied involves a radical cyclization of a xanthate derivative. The work described provides an attractive route to the tetracyclic core of some vinca alkaloids, including the tetrahydroisoquinocarbazole RS-2135.

A Synthetic Route to Fully Substituted Chiral Cyclopentylamine Derivatives: Precursors of Carbanucleosides

Removal of silyl protection from D-glucose derived substrate 6 afforded 7, which upon acetonide deprotection followed by reaction with N-benzylhydroxylamine furnished two isomeric isoxazolidinocyclopentane derivatives via spontaneous cyclization of an in situ generated nitrone. The methyl xanthate derivative of the tertiary hydroxyl group of one isomer was isolated and subjected to radical deoxygenation reaction to form epimeric products, while with the other isomer it underwent spontaneous 1,2-elimination to form a mixture of the two possible endocyclic olefins. Hydrogenolytic cleavage of the isoxazolidine rings of the purified products followed by insertion of 5-amino-4-chloropyrimidine moiety and purine ring construction smoothly afforded structurally unique carbanucleoside analogues. Various spectroscopic methods on the synthesized compounds and X-ray analysis on one important intermediate were used to assign the structures and stereochemistry of the products.

Synthesis and bio evaluation of a new fatty acid derivative labelled with technetium‐99m

Abstract123I‐iodophenylpentadecanoic acid (IPPA) and 123I‐beta‐methyliodophenylpentadecanoic acid (BMIPP) are radiolabelled fatty acid derivatives used for assessment of myocardial viability. Because of limited accessibility of 123I in the clinical scenario, a 99m‐technetium‐based agent would be more advantageous. In this context, a xanthate derivative of 15‐hydroxypentadecanoic acid (HPDA) was synthesized for radiolabelling with [99mTcN]2+ intermediate.Direct reaction of the HPDA with carbon disulphide in presence of crushed sodium hydroxide in dry tetrahydrofuran resulted in moderate yield of the desired xanthate product. The prepared ligand was radiolabelled with [99mTcN]2+ intermediate and the resultant complex was characterized by paper electrophoresis and HPLC. The labelled preparation was assessed for its myocardial extraction and retention characteristics using Swiss mice model.The HPDA xanthate derivative was obtained in a low yield of ∼30%. Labelling via the [99mTcN]2+intermediate gave more than 95% complexation. During in vivo studies with the [TcN]2+ labelled complex maximum heart uptake observed was 3.10%ID/g at 5 min p.i., which cleared out rapidly, with retention of 0.79%ID/g of the activity at 60 min p.i.The 99mTcN‐HPDA xanthate derivative showed some uptake in the heart but rapid wash out and substantial uptake in the background organs (blood, liver and lungs) led to unfavourable critical ratios at all the time points of study. Copyright © 2006 John Wiley & Sons, Ltd.

A novel [ 99mTc [tbnd]N] 2+ complex of metronidazole xanthate as a potential agent for targeting hypoxia

A xanthate derivative (L) at the pendant hydroxy group of metronidazole, a nitroimidazole known to possess affinity for hypoxic tumors, has been used as the carrier molecule for targeted delivery of the gamma-emitting radioisotope 99mTc to tumors. The xanthate residues (S 2 −) from two molecules of this ligand (L) were used for chelation with the [ 99mTcN] 2+ intermediate to form a square pyramidal and neutral [ 99mTcN/L 2] complex in >95% yield using a low ligand concentration of 1 mg/mL (∼3 × 10 −3 M). Biodistribution studies carried out in Swiss mice bearing fibrosarcoma tumor showed selective accumulation of the injected activity in the tumor (1.44 ± 0.26% per gram 1 h pi) with major clearance through hepatobiliary route. The complex showed high tumor/muscle ratio (2.15 and 3.35 at 1 and 3 h post-injection, respectively) and tumor/blood ratio, which were comparable to hypoxia targeting agents 99mTc-BMS181321 and 99mTc-BRU59-21 reported earlier.

Synthesis, characterization and crystal structure of a zinc bis-dithiocarboxylate derivative

The zinc(II) complex, Zn(3,5-di- t-butyl-4-hydroxybenzene-dithiocarboxylate) 2(pyridine) ( 3) was obtained by the reaction of Zn(CH 3CN) 4(BF 4) 2 with the sodium salt of 3,5-di- t-butyl-4-hydroxybenzene-dithiocarboxylate ( 1) with subsequent recrystallization from pyridine. The latter salt ( 1) was prepared by the deprotonation of 2,6-di- t-butylphenol with NaH in THF, followed by reaction with carbon disulfide at ambient temperature. The structure of complex 3 was established by X-ray crystallography and shown to be of a distorted trigonal bipyramidal geometry with one sulfur atom from each of the dithiocarboxylate ligands occupying the axial sites. By way of contrast, Na(2,4-di- t-butylphenolate) was found to react with CS 2 to afford the xanthate derivative, Na(O-2,4-di- t-butylphenyldithiocarbonate) ( 4).

Synthesis of 4‐vinylquinoline: Pyrolytic rearrangement of the 4‐(1‐hydroxyethyl)quinoline and related derivatives

AbstractThe synthesis of 4‐vinylquinoline has been carried out by means of the Wittig reaction between 4‐quino‐linecarbaldehyde and the methyl triphenylphosphonium ylide in dimethyl sulphoxide in good yield. Dehydration of the 4‐(1‐hydroxyethyl)quinoline and their xanthate derivative, give equimolar amounts of 4‐ethylquinoline and 4‐acetylquinoline while small amounts of 4‐vinylquinoline were found. Dehydrochlorination of 4‐(1‐chloroethyl)quinoline in ethanol‐sodium hydroxide provides 4‐ethyl‐3‐ethoxyquinoline in good yield, but 4‐vinylquinoline is a minor reaction product.

New type of stable fire-resistant cellulose xanthate derivative

New type of stable fire-resistant cellulose xanthate derivative

Thiosugars. I. Synthesis of 2,3-dithiosugars (author's transl)

Methyl 2, 3-dideoxy-2, 3-dithio-α-D-altropyranoside derivatives were synthesized by the thermal rearrangement of xanthate derivative of methyl 4, 6-O-benzylidene-3-S-benzyl-3-deoxy-3-thio-α-D-altropyranoside (III) or methyl 4, 6-O-benzylidene-2-S-benzyl-2-deoxy-2-thio-α-D-altropyranoside (IV).

Paper Chromatographic Evaluation of Menthol

A method is described for the conversion of menthol to a xanthate derivative which is isolated and treated with p -aminobenzaldehyde which produces a red color. The strong acidity of the color reagent regenerates menthol which is determined quantitatively by a paper chromatographic procedure which is described.