Visible-light-promoted synthesis of diaryl sulfides under air

A convergent, organocatalytic visible-light-mediated process for the synthesis of diaryl sulfides has been developed. A broad range of aryl thiols reacted with various aryl diazonium salts in the presence of eosin Y under air atmosphere to afford the desired diaryl sulfides in high yields. This novel and environmentally friendly method provides an alternative route to established synthetic approaches.     

Syntheses of new functionalized azobenzenes for potential molecular electronic devices

New non-symmetrical azobenzene derivatives have been synthesized as potential molecular electronic switching device candidates. The Oxone^® mediated oxidation of anilines provided nitroso-functionalized arenes, which were then condensed with substituted anilines to provide a series of azobenzene derivatives that could be further converted into oligo(phenylene ethynylene)s or diazonium salts. The resulting thiolacetates, thiols, or diazonium salts are capable of forming molecular layers on the surface of gold or silicon, thereby paving the way for molecular electronics testing.     

Synthesis of 2-thio-substituted benzothiazoles via a domino condensation/S-arylation/heterocyclization process

Condensation of carbon disulfide with thiols in the presence of K(2)CO(3) generates carbonotrithioate salts in situ, which undergo coupling with 2-iodoanilines and subsequent intramolecular condensation and elimination under assistance of CuBr to afford 2-thio-substituted benzothiazoles. Both aliphatic and aromatic thiols are compatible with this process, delivering the corresponding heterocycles with good diversity.     

Formation of Disulphide Links by Dioxysulphonium-Oxidation

p-Toluenesulphonyl chloride has been used to oxidise thiols, including 1-thio-β-D-glucopyranose, or their sodium salts, to disulphides.     

Coinage Metal–Glutathione Thiolates as a New Class of Supramolecular Hydrogelators

Summary: Coinage metal salts (e.g. Au^III, Ag^I and Cu^II salts) readily react with thiols to give the corresponding metal(I) thiolates. These thiolate species are known to either self-assemble into insoluble polymeric species or to form soluble oligomers, depending on the nature of the thiol ligand. Here we demonstrate that this self-assembling ability can be applied to create supramolecular hydrogels. Glutathione (GSH), a naturally occurring tripeptide, has been used in combination with Au^III, Ag^I and Cu^II salts to obtain pH responsive hydrogels that are able to gelate 100 times their weight in water.     

An Improved Synthesis of 2,2′-Dimercaptobiphenyl

The preparation of transition-metal thiolato complexes as synthetic biomimics¹ has led to a resurgent interest in the synthesis of organic thiols and their derivatives. The compound 2,2′-dimercaptobiphenyl, 1, offers interesting possibilities as a ligand, and it has been used recently to displace iron-sulfur clusters from low molecular-weight Fe-S proteins.² The two previous preparations for 1 require a coupling reaction of diazonium salts.^3,4 Overall yields of 10%³ and 30%⁴ are made even less attractive by the need to precipitate copper by-products with H₂S after the coupling step.     

Photochemical transformations of pyridinium salts: mechanistic studies and applications in synthesis

The discovery, understanding and synthetic exploitation of the photochemical transformation of pyridinium salts are described. The investigations surrounding the remarkable transformation of pyridinium salts into a host of structurally complex motifs have helped extend the comprehension of aromatic and heteroaromatic photochemistry. The synthetic community has, in recent years, recognised the potential inherent in these compounds and has since exploited the irradiation of variously substituted pyridinium salts as key steps in the preparation of advanced intermediates in numerous synthetic programmes.     

Sequential one-pot InBr(3)-catalyzed 1,4- then 1,2-nucleophilic addition to enones

Low sensitivity toward traces of moisture and high tolerance of different functional groups make indium tribromide suitable for carrying out multistep synthetic sequences. In particular, we have realized a 1,4-conjugated addition of indoles/thiols to alpha,beta-unsaturated ketones mediated by a catalytic amount (10 mol %) of InBr(3) obtaining the desired beta-substituted ketones in good yields. The Lewis acidity of indium salts was not affected by coordinating and acid nucleophiles; therefore, the subsequent catalytic 1,2-addition of Me(3)SiCN to carbonyl compounds can be performed in one pot. With the optimized atom-efficient protocol, several polyfunctionalized alpha-silyloxy cyanohydrins were synthesized in good to excellent yields (up to 97%) and a notable level of simple 1,3-diastereoselection (up to 84:16) was recorded in the case of 2-cyclohexen-1-one 2c.     

Oxidation of Thiols to Disulfides by Oxygen in Presence of Cobalt(II) and Manganese(II) Salts of 4-Aminobenzoic Acid Supported on Silica Gel

Summary. A mixture of cobalt(II) and manganese(II) salts of 4-aminobenzoic acid supported on silica gel catalyses the oxidation of thiols to disulfides in the presence of oxygen or air.     

Oxidation of Thiols to Disulfides by Oxygen in Presence of Cobalt(II) and Manganese(II) Salts of 4-Aminobenzoic Acid Supported on Silica Gel

A mixture of cobalt(II) and manganese(II) salts of 4-aminobenzoic acid supported on silica gel catalyses the oxidation of thiols to disulfides in the presence of oxygen or air.     

Surface modification of materials: Electrografting of organic films

The modification of surfaces is possible through a number of reagents (silanes, thiols, phosphonic acids, amines, and so on) among which diazonium salts have gained an increasing importance; this short review highlights the new achievements in this field.     

Regioselective copper(I)-catalyzed C–H hydroxylation/C–S coupling: expedient construction of 2-(styrylthio)phenols

Regioselective copper(I)-catalyzed C–H hydroxylation/C–S coupling of aryl thiols with vinyl halides was developed. Starting from substituted aryl thiols and vinyl halides, various 2-(styrylthio)phenol derivatives were efficiently prepared. The application of the synthetic methodology to generate the bioactive organic intermediate was also exemplified.     

甲基锍盐的合成

在四氟硼酸银存在下，分别以硫醚、硫醇、硫酚或过硫醚为原料与碘甲烷反应制备了相应的甲基锍盐。用１ＨＮＭＲ和１３ＣＮＭＲ表征产物的结构并提出了反应的机理。     

C−S Cross-Coupling of Aryldiazonium Salts with Thiols Mediated by Gold

In this work, the coupling of aryldiazonium salts with thiols mediated by the readily accessible gold complex Me₂SAuCl is described. In the reported protocol, the addition of 2,2′-bipyridine as a ligand leads to higher yields than phosphines. The reaction proceeds at room temperature under soft mildconditions and has a broad scope in both the aryldiazonium salt and the thiol. Notably, the coupling works with aryldiazonium salts containing two additional substituents.     

Oxidation of Thiols to Disulfides with Molecular Oxygen in Subcritical Water

Summary. Molecular oxygen is used as an efficient oxidant for the oxidative coupling of thiols to disulfides in subcritical water in the absence of catalysts. The procedure utilizes water and does not require support materials and metal salts providing high yields (>90%).     

Rhodium-catalyzed alkyne hydrothiolation with aromatic and aliphatic thiols

Alkyne hydrothiolation is a potentially attractive method for the formation of vinyl sulfides, which are valuable synthetic intermediates. Known methods for hydrothiolation using alkyl thiols are quite limited. We report herein that Tp*Rh(PPh3)2 (Tp* = hydrotris(3,5-dimethylpyrazolyl)borate) is a highly active catalyst for alkyne hydrothiolation with alkyl and aryl thiols. Hydrothiolation using alkyl thiols proceeds with excellent regioselectivity, providing convenient access to branched alkyl vinyl sulfides, which are difficult to synthesize by other means. A mixture of regioisomers is obtained when using aryl thiols, with the branched isomer as the major product, opposite that reported for other Rh complexes.     

Reaction of cyclooctatetraenyldipotassium with disulfides and thiocyanato derivatives of the thiophene series

In contrast to organometallic compounds of the phenyllithium type, cyclooctatetraenyldipotassium on reaction with disulfides and thiocyanato derivatives of the thiophene series in tetrahydrofuran does not give thio ethers but enters into an electron-transfer reaction and is converted to cyclooctatetraene. Thiophene derivatives form the potassium salts of the corresponding thiols. When insufficient amounts of cyclooctatetraenyldipotassium are present, thiocyanatothiophenes are converted to disulfides. It is shown that the latter can be obtained as a result of the reaction of thienyl mercaptides with thiocyanatothiophenes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 632–636, May, 1973.     

In Process Citation

The well-known reaction between thiols and mercuric salts can be used for determination of the former. The method has been extended to determination of several organomercurials. Cysteine is used for titration of hydroxyaryl mercury compounds. The presence of a chloride or sulphur atom bound to the metal makes the method inapplicable, however.     

<Emphasis Type="Italic">N,N,N′,N′</Emphasis>-tetramethylmethanediamine,efficient reagent for thioles aminomethylation

Efficient method was developed for thiols aminomethylation using N,N,N′,N′-tetra-methylmethanediamine in the presence of Sm and Fe salts. Aminosulfides were obtained in high yields and selectivity.     

Theoretical and experimental study of optical second harmonic generation in new chiral thiolates salts

The second harmonic generation ability of new chiral thiolate salts is investigated. Aromatic thiolate anions ArS⁻ are expected from semi-empirical calculations with PM3 parameterization of the MNDO Hamiltonian to possess higher intrinsic polarizabilities than the parent neutral thiols ArSH.

Salts associating (hyper)polarizable aromatic thiolate anions with chiral cations, which ensure the noncentrosymmetry necessary to have second-order nonlinear optical effects have been synthesized. The first hyperpolarizabilities, β, of the salts are measured using hyper-Rayleigh scattering technique. Second harmonic generation powder tests (Kurtz and Perry method) carried out on various salts studied, were positive indicating that these materials crystallize in noncentrosymmetric space groups.