Potassium O-ethyl Dithiocarbonate Research Articles

Nucleophilic Addition of Potassium O-Ethyl Dithiocarbonate to Baylis-Hillman Adducts Using 9-BBN as Catalyst

An efficient diastereoselective Michael addition of the commercial potassium O-ethyl dithiocarbonate to Baylis-Hillman adducts in the presence of 9-BBN (9-borabicyclo[3.3.1]nonane) as a Lewis acid is reported. 9-BBN both protected the hydroxyl group and activated the carbonyl of the Michael acceptor.

Grafting of Polymer Brushes from Xanthate-Functionalized Silica Particles.

Monodisperse silica particles (SiPs) were surface-modified with a newly designed silane coupling agent comprising a triethoxysilane and an alkyl halide, namely, 6-(triethoxysilyl)hexyl 2-bromopropionate, which was further treated with potassium O-ethyl dithiocarbonate (PEX) to immobilize xanthate molecules on the particle surfaces. Surface-initiated macromolecular design via interchange of xanthates (MADIX) polymerization of vinyl acetate (VAc) was conducted with the xanthate-functionalized SiPs. The polymerization was well controlled and produced SiPs coated with poly(vinyl acetate) (PVAc) with a well-defined target molar mass and a graft density of about 0.2 chains nm-2 . Dynamic light scattering and TEM measurements revealed that the hybrid particles were highly dispersible in good solvents without any aggregation. The PVAc brushes were hydrolyzed with hydrochloric acid to produce poly(vinyl alcohol) brushes on the SiP surfaces. In addition, the number of xanthate molecules introduced on the SiP surfaces could be successfully controlled by adjusting the concentration of PEX. Thus, the SiPs have two functionalities: xanthates able to act as a MADIX chain-transfer agent and alkyl bromide initiation sites for atom transfer radical polymerization (ATRP). By using these unique bifunctional particles, mixed polymer brushes were constructed on the SiPs by MADIX of VAc followed by ATRP of styrene or methyl methacrylate.

Removal and confinement of Hg(II) by polyurethane foam functionalized with potassium O-ethyldithiocarbonate

Polyurethane foam functionalized with potassium O-ethyldithiocarbonate was evaluated as an extractant material for Hg(II). Several parameters such as pH, mass amount and extraction time were studied. Under the best conditions, a 86% of mercury extraction was achieved. Dubinin–Radushkevich isotherm model indicated that the nature of interaction between functionalized foam and Hg(II) is chemical. Regarding interferents, metallic ions Ag(I) and Sn(IV) have a significant influence on the Hg extraction percentage. In the case of silver, it had a synergistic effect increasing the percentage of mercury due to a metallophilic interaction. Also, once the mercury was extracted, its leaching from the functionalized polyurethane foam was evaluated by means of two sequential extraction procedures. In this way, the functionalized foam emerges as a good material for the removal and confinement of chemical species. Obtained results show that mercury extraction is successful even from complex solution and that mercury-foam material is stable under extreme chemical and temperature conditions.

An efficient copper-catalyzed synthesis of 2-mercaptobenzothiazole through S-arylation/heterocyclization of 2-haloaniline with potassium xanthate

ABSTRACTA mild and efficient methodology to produce 2-mercaptobenzothiazoles in DMF via ortho-haloaniline coupling with potassium O-ethyl dithiocarbonate catalyzed by copper without a ligand has been developed.

Efficient, Iron-Catalyzed Synthesis of 2-Mercaptobenzothiazole Through S-Arylation/Heterocyclization of 2-Haloaniline with Potassium Xanthate

A mild and practical method for the synthesis of 2-mercaptobenzothiazole has been developed by using iron as an efficient catalyst. The present tandem reaction process allows access to a wide range of 2-mercaptobenzothiazoles in good to excellent yields by the reaction of 2-haloaniline with potassium O-ethyl dithiocarbonate in the presence of FeF3 as a catalyst and 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl as a ligand under an atmosphere of argon.

Synthesis and Antimicrobial Activity of 6-Thioxo-6,7-dihydro-2H-[1,2,4]triazino[2,3-c]-quinazolin-2-one Derivatives.

Potassium 8-R1-9-R2-10-R3-3-R-2-oxo-2H-[1,2,4]triazino[2,3-c]quinazoline-6-thiolates 2.1–2.26 were synthesized via cyclocondensation of 6-R-3-(3-R1-4-R2-5-R3-aminophenyl)-1,2,4-triazin-5-ones 1.1–1.26 with carbon disulfide, potassium hydroxide, and ethanol or with potassium O-ethyl dithiocarbonate in 2-propanol. The corresponding thiones 3.1–3.26 were obtained by treatment of 2.1–2.26 with hydrochloric acid. It was found that the nature of the substituents in positions 3, 4, and 5 of the corresponding 6-R-3-(3-R1-4-R2-5-R3-aminophenyl)-1,2,4-triazin-5-ones were affected on the terms of the reaction. The structures of compounds were proven by a complex of physicochemical methods (1H, 13C NMR, LC–MS, and EI-MS). The results of the antibacterial and antifungal activity assay allowed the determination of the high sensitivity of Staphylococcus aureus ATCC 25923 (MIC 6.25–100 μg/mL, MBC 12.5–200 μg/mL) to the synthesized compounds.

An environmentally benign procedure for the synthesis of substituted 2-thiobenzothiazoles, 2-thiobenzoxazoles, 2-thiobenzimidazoles, and 1,3-oxazolopyridine-2-thiols

An improved environmentally benign procedure for the synthesis of substituted 2-thio-benzothia(oxa)zoles, 2-thiobenzimidazoles, and 1,3-oxazolopyridine-2-thiols by cyclization of 2-aminophenols, 2-aminothiophenols, 1,2-phenylenediamines, or 2-amino-3-hydroxypyridines with potassium O-ethyldithiocarbonate in PEG 400 or glycerol under directed microwave irradiation is described. The method can be applied to the synthesis of a variety of derivatives.

Great influence of a small amount of capping agents on the morphology of SnS particles using xanthate as precursor

Several hierarchical tin sulfide (SnS) architectures have been prepared based on the reaction of tin dichloride (SnCl 2·2H 2O) with potassium O-ethyldithiocarbonate (ethylxanthate, C 2H 5OCS 2K) via a solvothermal route in N, N-dimethylformamide (DMF) solution at 180 °C for 24 h. By varying experimental parameters such as reaction temperature, reaction time and the ratios of reactants, various morphologies of three-dimensional (3D) superstructures assembled by SnS nanosheets, nanoribbons and nanorods were obtained. The as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). For a typical molar ratio of C 2H 5OCS 2K/SnCl 2 = 2, the addition of a slight excess of C 2H 5OCS 2K (molar ratio of C 2H 5OCS 2K/SnCl 2 = 2.4) resulted in one-dimensional growth of lamellar SnS particles and their assembly into flowerlike superstructures. Similarly, for the molar ratio of C 2H 5OCS 2K/SnCl 2 = 2, if a small amount of capping agent (1 mL potassium oleate in 40 mL DMF solution) was employed, SnS microspheres aggregated by nanorods were formed. Possible mechanisms for the formation of 3D SnS microstructures were proposed. Optical properties of the products were also studied.

The Preparation and Photocatalytic Activity of Ni-Doped ZnS Nanoparticles

Zinc sulfide nanoparticles as undoped and doped with nickel have been prepared by the reaction of Zn(CH3COO)2 and Ni(CH3COO)2 with potassium O-ethyldithiocarbonate (ethyl xanthate, C2H5OCS2k) at 80 in N, N - dimethylformamide (DMF) solution for 24 h. The structures of the products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and their optical properties were studied by UV-Vis spectroscopy. The photocatalytic experiment by degrading methyl orange in aqueous solution under UV light indicated that the degradation efficiency of Ni (6%)-doped ZnS nanoparticles increased to 75% with comparison to 43% of degradation efficiency for undoped ZnS nanoparticles.

ChemInform Abstract: Single-Electron-Transfer-Initiated Thermal Reactions of Arylmethyl Halides. Part 15. The Reaction of Triphenylmethyl Bromide with Potassium O-Ethyl Dithiocarbonate (Potassium Xanthate) in Benzene and Cumene. A Note of Caution on the A

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Design of Core−Shell-Type Nanoparticles Carrying Stable Radicals in the Core

Utilizing the self-assembled core-shell-type polymeric micelle technique, high-performance nanoparticles possessing stable radicals in the core and reactive groups on the periphery were prepared. The anionic ring-opening polymerization of ethylene oxide (EO) was carried out using potassium 3,3-diethoxypropanolate as an initiator, followed by mesylation with methanesulfonyl chloride to obtain acetal-poly(ethylene glycol)-methanesulfonate (acetal-PEG-Ms; 1). Compound 1 was reacted with potassium O-ethyldithiocarbonate, followed by treatment with n-propylamine to obtain heterobifunctional PEG derivatives containing both sulfanyl and acetal terminal groups (acetal-PEG-SH) (2) in a highly selective and quantitative manner. Poly(ethylene glycol)-block-poly(chloromethylstyrene) (acetal-PEG-b-PCMS) (3) was synthesized by the free-radical telomerization of chloromethylstyrene (CMS) using 2 as a telogen. The chloromethyl groups in the PCMS segment of the block copolymer (3) were quantitatively converted to 2,2,6,6-tetramethylpiperidinyloxys (TEMPOs) via the amination of 3 with 4-amino-TEMPO to obtain acetal-PEG-b-PCMS containing TEMPO moieties (4). The obtained 4 formed core-shell-type nanoparticles in aqueous media when subjected to the dialysis method: the cumulant average diameter of the nanoparticles was about 40 nm, and the nanoparticles emitted intense electron paramagnetic resonance (EPR) signals. The TEMPO radicals in the core of the nanoparticles showed reduction resistance even in the presence of 3.5 mM ascorbic acid. This means that these nanoparticles are anticipated as high-performance bionanoparticles that can be used in vivo.

Surface and Capillary Forces Encountered by Zinc Sulfide Microspheres in Aqueous Electrolyte

The colloid probe technique was used to investigate the interactions between individual zinc sulfide (ZnS) microspheres and an air bubble in electrolyte solution. Incorporation of zinc ions into the electrolyte solution overcomes the disproportionate zinc ion dissolution and mimics high-volume-fraction conditions common in flotation. Determined interaction forces revealed a distinct lack of long-ranged hydrophobic forces, indicated by the presence of a DLVO repulsion prior to particle engulfment. Single microsphere contact angles were determined from particle-bubble interactions. Contact angles increased with decreasing radii and with surface oxidation. Surface modification by the absorption of copper and subsequently potassium O-ethyldithiocarbonate (KED) reduced repulsive forces and strongly increased contact angles.

Bifunctional Ion Exchange Resin with Thiol and Quaternary Ammonium Groups for the Sorption of Arsenate

A bifunctional resin with thiol and quaternary ammonium groups was prepared from a macroporous strongly basic anion exchange resin of the styrene-divinylbenzene type. The key step of the synthesis is the reaction of the quaternary benzyltrimethylammonium group of the ion exchange resin with suitable sulfur-containing nucleophiles. Three synthetic routes are described: direct conversion to thiol with sodium sulfide, reaction with potassium O-ethyl dithiocarbonate followed by decomposition of the dithiocarbonate with ammonia or acid and conversion to polymeric isothiuronium salt by the reaction with thiourea and subsequent alkaline hydrolysis to thiol. Sorption of arsenate on thiol resin and its Fe(III) complex was studied.

SYNTHESIS OF IMIDAZO[4,5-C] AND TRIAZEPINO|6,5-C]CINNOLINES

Hofmann degradation of 4-amino-8-methylcinnoline-3-carboxamide (1) gave 3,4-diaminocinnoline 2 which was employed to prepare imidazo and 2-substitutedimidazo[4,5-c]cinnolines 3. On the other hand, reaction of 4-aminocinnoline-3-carboxylic acid hydrazides 4 with ethyl chloroformate or potassium O-ethyl dithiocarbonate afforded 2,3,4,5-tetrahydro-1H-1,2,4- triazepino[6,5-c]cinnoline-2,5-diones 6 and the corresponding 2-thiones 7, respectively. Furthermore, reacting 4 with excess orthoesters gave mixtures of 4,5-dihydro-1H-1,2,4-triazepino[6,5-c]cinnolin-5-ones 9 and 3-(ethoxyalkylidenamino) pyrimi-do[5,4-c] cinnoline-4-ones 10 which were separated and characterized.

ChemInform Abstract: Regio- and Stereo-selectivity Issues in Radical Brominations of Allylic Units of Vinylogous Esters/Carbonates Bearing the 2,3,4,6-Tetra-O-acetyl-β-D-glucopyranosyl Auxiliary and in Nucleophilic Displacements of the Derived Allylic Bro

Under radical conditions, N-bromosuccinimide effects bromination of the methyl group of the 1-oxyallyl unit of (E)-3-methyl-4-(2′,3′,4′,6′-tetra-O-acetyl-β-D-glucopyranosyloxy)but-3-en-2-one 1a, (E)-2-methyl-1-(2′,3′,4′,6′-tetra-O-acetyl-β-D-glucopyranosyloxy)pent-1-en-3-one 1b and methyl/ethyl (E)-2-methyl-3-(2′,3′,4′,6′-tetra-O-acetyl-β-D-glucopyranosyloxy)prop-2-enoate 1c/1d to give the bromoethyl derivatives 14a–14d. Displacement of the bromine atom of compounds 14a–c occurs without allylic rearrangement (in Me2CO under reflux and/or in MeCN at ambient temperature) with sodium azide (to give the azidomethyl derivatives 15a–c), potassium O-ethyl dithiocarbonate [to give the ethoxy(thiocarbonyl)thiomethyl derivatives 16a–c] and with potassium thiocyanate (to give the thiocyanatomethyl derivatives 17a–c). Silver(I) thiocyanate in acetonitrile also effects the 14a → 17a conversion. Compounds 14a, 14b and 14d react with sodium acetate in boiling acetonitrile to give largely the rearranged acetates 19a/20a, 19b/20b and 19d/20d with a moderate degree of stereoselection under kinetically controlled conditions. However, equilibration slowly occurs under the reaction conditions (requiring the presence of NaOAc) to give mainly the unrearranged acetates 18a, 18b and 18d. With silver(I) acetate in acetonitrile, the bromides 14a and 14d are transformed into the rearranged acetates 19a/20a and 19d/20d with a good degree of stereoselection and without appreciable equilibration. The reaction of the bromide 14a with silver(I) oxide and acetic acid parallels that observed with sodium acetate, the equilibration of the acetates 18a, 19a and 20a being induced by acetic acid. The bromide 14a reacts with alcohols at ambient temperature in the presence of silver(I) oxide to give, in kinetically controlled reactions, mixtures of rearranged alkoxy derivatives of types 24/25 and unrearranged alkoxy derivatives of type 23. Although the former products predominate, their proportion in the mixture declines as the size of the alcohol increases. Similar results are observed for the bromides 14b and 14d. The ambident reactivity of allylic bromides of type 14 towards nucleophiles is consistent with the principle of hard and soft acids and bases. p

Regio- and stereo-selectivity issues in radical brominations of allylic units of vinylogous esters/carbonates bearing the 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl auxiliary and in nucleophilic displacements of the derived allylic bromides †

Under radical conditions, N-bromosuccinimide effects bromination of the methyl group of the 1-oxyallyl unit of (E)-3-methyl-4-(2′,3′,4′,6′-tetra-O-acetyl-β-D-glucopyranosyloxy)but-3-en-2-one 1a, (E)-2-methyl-1-(2′,3′,4′,6′-tetra-O-acetyl-β-D-glucopyranosyloxy)pent-1-en-3-one 1b and methyl/ethyl (E)-2-methyl-3-(2′,3′,4′,6′-tetra-O-acetyl-β-D-glucopyranosyloxy)prop-2-enoate 1c/1d to give the bromoethyl derivatives 14a–14d. Displacement of the bromine atom of compounds 14a–c occurs without allylic rearrangement (in Me2CO under reflux and/or in MeCN at ambient temperature) with sodium azide (to give the azidomethyl derivatives 15a–c), potassium O-ethyl dithiocarbonate [to give the ethoxy(thiocarbonyl)thiomethyl derivatives 16a–c] and with potassium thiocyanate (to give the thiocyanatomethyl derivatives 17a–c). Silver(I) thiocyanate in acetonitrile also effects the 14a → 17a conversion. Compounds 14a, 14b and 14d react with sodium acetate in boiling acetonitrile to give largely the rearranged acetates 19a/20a, 19b/20b and 19d/20d with a moderate degree of stereoselection under kinetically controlled conditions. However, equilibration slowly occurs under the reaction conditions (requiring the presence of NaOAc) to give mainly the unrearranged acetates 18a, 18b and 18d. With silver(I) acetate in acetonitrile, the bromides 14a and 14d are transformed into the rearranged acetates 19a/20a and 19d/20d with a good degree of stereoselection and without appreciable equilibration. The reaction of the bromide 14a with silver(I) oxide and acetic acid parallels that observed with sodium acetate, the equilibration of the acetates 18a, 19a and 20a being induced by acetic acid. The bromide 14a reacts with alcohols at ambient temperature in the presence of silver(I) oxide to give, in kinetically controlled reactions, mixtures of rearranged alkoxy derivatives of types 24/25 and unrearranged alkoxy derivatives of type 23. Although the former products predominate, their proportion in the mixture declines as the size of the alcohol increases. Similar results are observed for the bromides 14b and 14d. The ambident reactivity of allylic bromides of type 14 towards nucleophiles is consistent with the principle of hard and soft acids and bases. p

Convenient Strategies for the Preparation of Modified 2(3H)-Benzothiazolethiones

Abstract 4-Alkyl-2-bromoanilines and 4-alkoxy-2-chloroanilines were synthesized conveniently and submitted to cyclization reaction with potassium O-ethyl dithiocarbonate to afford 6-substituted 2(3H)-benzothiazolethiones in good yields.

Synthesis of (2S,3S)-3-amino-2-phenylthietane

Homochiral (2S,3S)-3-amino-2-phenylthietane ( 6) was synthesized by the action of potassium O-ethyldithiocarbonate on 1,3-ditosylate ( 3) or 1,3-diiodide ( 7) derived from (1S,2S)-2-amino-1-phenyl-1,3-propanediol( 1).

Nitrido-technetium and -rhenium complexes with chelating phosphines: synthesis, reactivity and crystal structures

Nitrido-technetium(V) and -rhenium(V) complexes of general formula [MNCl2L][M = Tc or Re; L = bis(diphenylphosphinoethyl)propylamine (L1), 1,8-bis(diphenylphosphino)-3,6-dioxaoctane (L2) or 1,1,1-tris(diphenylphosphinomethyl)ethane (L3)] have been synthesized and characterized. They were prepared by the reduction of [TcVINCl4]– or by the replacement of the two triphenylphosphines of [MNCl2(PPh3)2](M = Re or Tc) by bidentate or tripodal polyphosphine ligands L. Reaction of these complexes with an excess of potassium O-ethyl dithiocarbonate yields neutral dithiocarbonate compounds [MN(S2CO)L], while cationic and neutral complexes [MN(S2CNEt2)L]+ and [MN(S2CNEt2)2] were obtained upon reaction with K(S2CNEt2). The crystal structures of [TcNCl2L1] and [TcNCl2L2] have been determined by X-ray crystallography; the complex [TcNCl2L1] shows square-pyramidal co-ordination at technetium with the Tc atom displaced from the basal plane towards the N atom by 0.410 A. An unusual trigonal-bipyramidal geometry is observed for [TcNCl2L2]. The TcN bond distances (1.60 A) in both complexes are indicative of a strong triple bond.

The reaction of triphenylmethyl bromide with potassium O-ethyl dithiocarbonate (potassium xanthate) in benzene and cumene. A note of caution on the application of the radical trap dicyclohexylphosphine as a probe for electron-transfer-initiated reactions of triphenylmethyl halides

The title reaction was studied under conditions where homolysis of the triphenylmethyl-to-sulphur bond of the dithiocarbonate 1d, its main product does not take place, or is negligible. Triphenylmethane 1c, triphenylmethanol 1g and benzophenone were obtained as further products under argon in cumene and in the presence of oxygen in benzene, respectively. This, together with ESR studies, indicates that part of the dithiocarbonate 1d results from single-electron transfer from O-ethyl dithiocarbonate anion to triphenylmethyl bromide 1a and out-of-cage recombination of triphenylmethyl and xanthyl radicals 6a. The main pathways leading to dithiocarbonate 1d appear, under the conditions studied, to be either a polar pathway consisting of two successive SN2′-type steps [mechanism 2, Scheme 3] and/or an SET-type reaction [mechanism 3, Scheme 3] with rapid in-cage recombination of triphenylmethyl and xanthyl radicals 6a. The hydrogen-atom donor dicyclohexylphosphine (DCPH) may not be used for trapping of the triphenylmethyl radicals formed in the title reaction because DCPH acts as a single-electron donor towards bromide 1a, i.e. it itself generates triphenylmethyl radicals from the bromide.