623-79-0Relevant articles and documents
Dithiocarbonato nickel, palladium and platinum complexes bearing bis(diphenylphosphino)ferrocene: synthesis and X-ray structure determination
El-Khateeb, Mohammad,Tanash, Qusay,Abul-Futouh, Hassan,G?rls, Helmar,Weigand, Wolfgang
, (2019)
Abstract: The dithiocarbonato metal complexes M(κ2S,S-S2CO)(κ2P,P-dppf) {M= Ni, Pd, Pt; dppf= bis(diphenylphosphino)ferrocene} are obtained from the reaction of the metal(II) complexes [M(κ2S,S-S2COEt)2] with the dppf ligand or from the chloride substitution of M(κ2P,P-dppf)Cl2 by the O-ethyldithiocabonato anion. These complexes are produced by C-O bond cleavage by the O-ethyldithiocarbonato anion present in solution. These new complexes have been characterized by UV-Vis, NMR, IR spectroscopy and elemental analysis. The structures of the three complexes were further confirmed by single-crystal X-ray diffraction analysis. Graphical Abstract: The dithiocarbonato metal complexes M(κ2S,S-S2CO)(κ2P,P-dppf) {M= Ni, Pd, Pt, dppf= bis(diphenylphosphino)ferrocene} are obtained from the reaction of the metal(II) complexes [M(κ2S,S-S2COEt)2] with the dppf ligand or from the chloride substitution of M(κ2P,P-dppf)Cl2 by the O-ethyldithiocabonato anion. These new complexes have been characterized by UV-Vis, NMR, IR spectroscopy and elemental analysis. The structures of complexes 1–3 were further confirmed by single-crystal X-ray diffraction analysis.[Figure not available: see fulltext.].
Xanthates as Thiol Surrogates for Nucleophilic Substitution with Aryl Halides
Sokolov, Anatolii I.,Mikhaylov, Andrey A.,Baleeva, Nadezhda S.,Baranov, Mikhail S.
supporting information, p. 4350 - 4357 (2021/08/24)
We herein report an unprecedented xanthate-based protocol for the preparation of aryl-alkyl thioethers. Heating xanthates with aryl halides and namely cesium carbonate in methanol provides the target thioethers in generally good yields within short reaction times. This method allows one to avoid contact with odorous thiols and also to introduce substituents of which the corresponding thiols are virtually unavailable or inconvenient in use.
Supramolecular interactions in sodium N-(ethoxythioxomethyl)-β- alaninate-water (4/6) crystal and its application in synthesis of L-carnosine
Zhang, Shi-Jie,Xu, Feng,Yang, Wei-Ji,Hu, Wei-Xiao
, p. 1182 - 1189 (2013/02/22)
Compound sodium N-(ethoxythioxomethyl)-β-alaninate (sodium 3-(ethoxycarbonothioyl)propanoate) was synthesized and characterized by IR, 1HNMR, ESI-HRMS and single crystalX-ray diffraction. Single crystalX-ray diffraction analysis showed that the title compound crystallized in the triclinic space group P-1 with cell parameters a = 10.142 (2) A, b = 13.738 (3) A, c = 15.751 (3) A, α= 72.937 (2)°, β = 78.694 (2)°, γ = 89.999 (2)°, V = 2053.4 (7) A3, Dc = 1.464 g cm-3, Z = 2. In the extended structure of sodium N-(ethoxythioxomethyl)-β-alaninate-water (4/6), (NaL)4· 6H2O [L = CH3CH2OC(S)NHCH2CH 2COO], ligands (Ls) are stabilized by intermolecular O-H···O, N-H···O, C- H···O and weak O-H···S and C-H···S linkages, which further consolidate the crystal packing, making the ligand chains stacked along [0-1 1], and intramolecular O-H···S hydrogen bond is also observed. Each Na atom is surrounded with six O atoms, forming an octahedron and mutually bonded as tetramers. These tetramers are linked through O atom bridges from water molecules, extending as layers in the ab plane. In addition, synthesis of β-alanyl dipeptides was developed with particular focus on the preparation of L-carnosine. Springer Science+Business Media New York 2012.
The mechanisms of hydrolysis of alkyl N-alkylthioncarbamate esters at 100°C
Humeres, Eduardo,Sanchez, Maria De Nazare,Lobato, Conceicao M. L.,Debacher, Nito A.,De Souza, Eduardo P.
, p. 1483 - 1491 (2007/10/03)
The hydrolysis of ethyl N-ethylthioncarbamate (ETE) at 100°C was studied in the range of 7 mol/L HCl to 4 mol/L NaOH. The pH-rate profile showed that the hydrolysis occurred through specific acid catalysis at pH 6.5. The Hammett acidity plot and the excess acidity plot against X were linear. The Bunnett-Olsen plot gave a negative slope indicating that the conjugate acid was less hydrated than the neutral substrate. It was concluded that the acid hydrolysis occurred by an Al mechanism. The neutral species hydrolyzed with general base catalysis shown by the Bronsted plot with β = 0.48 ± 0.04. Water acted as a general base catalyst with (pseudo-)first-order rate constant, kN = 3.06 × 10-7 s-1. At pH > 6.5 the rate constants increased, reaching a plateau at high basicity. The basic hydrolysis rate constant of ethyl N,N-diethylthioncarbamate, which must react by a BAc2 mechanism, increased linearly at 1-3 mol/L NaOH with a second-order rate constant, k2 = 2.3 × 10-4 (mol/L)-1 s-1, which was 10 times slower than that expected for ETE. Experiments of ETE in 0.6 mol/L NaOH with an excess of ethylamine led to the formation of diethyl thiourea, presenting strong evidence that the basic hydrolysis occurred by the E1cb mechanism. In the rate-determining step, the E1cb mechanism involved the elimination of ethoxide ion from the thioncarbamate anion, producing an isothiocyanate intermediate that decomposed rapidly to form ethylamine, ethanol, and COS.
New radical reactions of S-alkoxycarbonyl xanthates. Total synthesis of (±)-cinnamolide and (±)-methylenolactocin
Forbes, Judith E.,Saicic, Radomir N.,Zard, Samir Z.
, p. 3791 - 3802 (2007/10/03)
Irradiation with visible light of S-alkoxycarbonyl xanthates derived from various alcohols gives rise to alkoxycarbonyl radicals with bifurcate reactivity: loss of carbon dioxide leads to deoxygenated derivatives (i.e. alkyl xanthates) whereas intramolecular addition to a suitably located double bond produces lactones; these new reactions were applied to the total synthesis of (±)-cinnamolide and (±)-methylenolactocin.
Hydrolysis and aminolysis of alkyl xanthate esters and cellulose analogues
Humeres, Eduardo,Soldi, Valdir,Klug, Marilene,Nunes, Mauricea,Oliveira, Celia M.S.,Barrie, Patrick J.
, p. 1050 - 1056 (2007/10/03)
The hydrolysis and aminolysis of a series of S-substituted O-alkylxanthate esters was studied in 20% v/v aqueous methanol at 35°C. The pH-rate profiles of the hydrolyses showed water and hydroxide-ion-catalyzed reactions. The reaction of 2,4-dinitrophenyl cellulose xanthate (CelXDNP) and p-nitrobenzyl cellulose xanthate (CelXNB) with polyalanine and lysozyme produced a covalent bond between the polypeptide and the cellulose matrix, as shown by solid-state 13C NMR. However, the nature of the bonding could not be identified. The reaction of nucleophiles (H2O, OH-, RNH2) and xanthic esters was consistent with an addition-elimination mechanism through a tetrahedral intermediate. Bronsted plots against the pKa of the nucleophile (βnu) or the nucleofuge of the substrate (βlg) were used to characterize the rate-determining step. The pKa values of the nucleophiles ranged between -1.74 and 15.74, and for the nucleofuges, they were in the range of 10.50-0.92. For nucleophiles with pKa values up to about 10, βlg was 0.10-0.15, and βnu changed from 0.48 to 0.35 for the strongest electron-withdrawing nucleofuge. It was concluded that the water-catalyzed hydrolyses, and also aminolyses with moderately basic amines, occur with rate-determining formation of the tetrahedral intermediate. For strong bases such as hydroxide ion, the disappearance of the intermediate becomes the slowest step. The reaction of cellulose xanthic esters with external nucleophiles as hydroxide ion and amines shows simple first-order kinetics and is slower than alkyl or sugar xanthates, probably due to the diffusion effect through the tight cybotactic region of cellulose.
Xanthic anhydrides: A novel and convenient source of alkoxythiocarbonyl and alkyl radicals
Forbes, Judith,Zard, Samir Z.
, p. 8257 - 8266 (2007/10/02)
Upon irradiation with visible light, xanthic anhydrides 14 undergo a chain reaction leading to xanthates 17 and involving β-scission of the intermediate alkoxythiocarbonyl radical.
A NOVEL RADICAL CHAIN REACTION OF XANTHIC ANHYDRIDES. FURTHER OBSERVATIONS ON THE INTERMEDIACY OF ALKOXYTHIOCARBONYL RADICALS IN THE BARTON-McCOMBIE REACTION.
Forbes, J. E.,Zard, S. Z.
, p. 4367 - 4370 (2007/10/02)
On irradiation with visible light, primary and secondary xanthic anhydrides undergo a radical chain reaction to give the corresponding xanthates with loss of carbon oxysulphide.
