Routes to highly substituted thiophenol derivatives

Syntheses of highly substituted thiophenol derivatives that incorporate steric bulk into the ligand framework via ortho and para tert-butyl substituents are reported. S-Benzyl and trityl protection were investigated and the effects of substituents on the Newman-Kwart rearrangement of the thiocarbamate discussed. Single crystal X-ray structures are reported for three compounds and demonstrate the role of hydrogen bonding in stabilising the thiophenol to oxidation.     

Reaction of trifluoromethyl-containing enones with thiophenol derivatives

The reaction of trifluoromethyl-containing enones with thiophenol derivatives has been studied. Reactions with 4-methylthiophenol proceed with the formation of either ketosulfides or a pyran derivative. Reactions of trifluoromethyl-containing enones with 2-mercaptobenzaldehyde lead to 3-trifluoroacetyl-substituted 2H-thiochromenes. M. V. Lomonosov Moscow State University, Moscow 119899, Russia N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow 117907, Russia. Department of Chemistry, University of Durham, South Road, Durham, Great Britain, DH1 3LE. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 618–626, May, 1999.     

Oxidative coupling of thiols to disulfides using a solid anhydrous potassium phosphate catalyst

Thiols are oxidized to the corresponding disulfides with a mild base, anhydrous potassium phosphate, under ambient conditions in the presence of air.     

Synthesis of diaryl disulfides via the reductive coupling of arylsulfonyl chlorides

A facile synthesis of diaryl disulfides from arylsulfonyl chlorides in the presence of triphenylphosphine has been developed.     

Synthesis of selenocystine derivatives from cystine by applying the transformation reaction from disulfides to diselenides

A stepwise conversion of a disulfide (SS) to a diselenide (SeSe) bond through the corresponding iodide intermediate was implemented and was applied to the synthesis of selenocystamine and l-selenocystine derivatives from cystamine and l-cystine, respectively, in moderate yields.     

Near-ultraviolet photodissociation of thiophenol

H(D) Rydberg atom photofragment translational spectroscopy has been used to investigate the dynamics of H(D) atom loss C6H5SH(C6H5SD) following excitation at many wavelengths lambda phot in the range of 225-290 nm. The C6H5S cofragments are formed in both their ground (X(2)B1) and first excited ((2)B2) electronic states, in a distribution of vibrational levels that spreads and shifts to higher internal energies as lambda(phot) is reduced. Excitation at lambda(phot) > 275 nm populates levels of the first (1)pi pi* state, which decay by tunnelling to the dissociative (1)pi sigma* state potential energy surface (PES). S-H torsional motion is identified as a coupling mode facilitating population transfer at the conical intersection (CI) between the diabatic (1)pi pi* and (1)pi sigma* PESs. At shorter lambda(phot), the (1)pi sigma* state is deduced to be populated either directly or by efficient vibronic coupling from higher (1)pipi* states. Flux evolving on the (1)pi sigma* PES samples a second CI, at longer R(S-H), between the diabatic (1)pi sigma* and ground ((1)pi pi) PESs, where the electronic branching between ground and excited state C6H5S fragments is determined. The C6H5S(X(2)B1) and C6H5S((2)B2) products are deduced to be formed in levels with, respectively, a' and a' vibrational symmetry-behavior that reflects both Franck-Condon effects (both in the initial photoexcitation step and in the subsequent in-plane forces acting during dissociation) and the effects of the out-of-plane coupling mode(s), nu11 and nu16a, at the (1)pi sigma*/(1)pi pi CI. The vibrational state assignments enabled by the high-energy resolution of the present data allow new and improved estimations of the bond dissociation energies, D0(C6H5S-H) < or = 28,030 +/- 100 cm(-1) and D0(C6H5S-D) < or = 28,610 +/- 100 cm(-1), and of the energy separation between the X(2)B1 and (2)B2 states of the C6H5S radical, T(00) = 2800 +/- 40 cm(-1). Similarities, and differences, between the measured energy disposals accompanying UV photoinduced X-H (X = S, O) bond fission in thiophenol and phenol are discussed.     

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.     

Facile C-S coupling reaction of aryl iodide and thiophenol catalyzed by Cu-grafted furfural functionalized mesoporous organosilica

A new functionalized mesoporous organosilica has been designed via Schiff-base condensation of furfural and 3-aminopropyltriethoxy-silane (APTES) followed by its hydrothermal co-condensation with tetraethylorthosilicate (TEOS) in the presence of a cationic surfactant CTAB. Subsequent reaction of this mesoporous organosilica with Cu(OAc)(2) in absolute ethanol leads to the formation of a new Cu(II)-grafted mesoporous organosilica catalyst 1. Powder XRD, HR TEM, FE SEM, N(2) sorption and FT IR spectroscopic tools are used to characterize the materials. This Cu-anchored mesoporous material acts as an efficient, reusable catalyst in the aryl-sulfur coupling reaction between aryl iodide and thiophenol for the synthesis of value added diarylsulfides.     

Peroxide-mediated oxidative coupling of primary alcohols and disulfides: Synthesis of 2-substituted benzothiazoles

A peroxide-mediated protocol for the synthesis of 2-substituted benzothiazoles was developed, starting from bis(o-aminophenyl) disulfides and primary alcohols. Eleven differently 2-substituted benzothiazoles were prepared in moderate to excellent yields using di-tert-butyl peroxide (DTBP) as an oxidant.     

A useful Pd-catalyzed Negishi coupling approach to benzylic sulfonamide derivatives

A mild catalytic system to access diversely functionalized benzylic sulfonamides has been developed. Palladium-catalyzed alpha-arylation by Negishi cross-coupling of sulfonamide-stabilized anions and a wide range of aryl iodides, bromides, and triflates constitutes a practical strategy for the synthesis of various benzylic sulfonamides.     

Photooxidative degradation of polyether-based polymers

The mechanisms of photooxidation of several polyether based polymers were compared in order to give general rules of orientation of the oxidative reactions. These polymers were a poly(ether-ester) and two poly(ether-urethane)s. The behavior of the polyether component as homopolymer was also studied. This study was extended to copolymers of fluorinated olefins and allyl or vinyl ethers, and the non fluorinated homologues. The elucidation of the photooxidation mechanisms was based on the identification of the photoproducts by analysis of both the solid polymeric matrix and the gaz phase formed on irradiation. It was shown that the photochemical sensitivity of the polyether component was responsible for the rapid oxidation of the copolymers. However, in the case of the fluorinated compounds, different behaviors were observed. It was shown that the presence of the fluorine atoms strongly influenced the orientation of the reaction and modified the oxidation kinetics. The reactivity of the methylene groups in α-position of the oxygen atom of the ether groups were not found to be equivalent regarding oxidation and the secondary was more oxidizable than the tertiary one.     

Dehydro side coupling of substituted pentacene derivatives

1,2,3,4,8,9,10,11-Octaalkylpentacenes were synthesized in high yields from tetrahydropentacenes by the pentacene-DDQ adduct method in the presence of amine. Dehydro side-coupling reactions of pentacene derivatives proceeded to give the corresponding 6,6'-dipentacenyl derivatives in high yields in the presence of a catalytic amount of CSA and 0.5 equiv of DDQ. The structures of dehydro side-coupling products of substituted pentacenes were determined by NMR and X-ray analysis. The combination of acid and DDQ was necessary for the dehydro side coupling of substituted pentacenes.     

Reaction of thiophenol with some aliphatic epoxyketones

The reaction of thiophenol with 3, 4-epoxybutan-2-one, 3-methyl-3,4-epoxybutan-2-one, and 3-methyl-3. 4-epoxy-pentan-2-one is investigated. It is found that when these epoxyketones react with thiophenol, oxygen ring opening occurs at the carbon atom, to give -phenylmercapto-ß-hydroxyketones. Some reactions of the resultant compounds are investigated.     

Reaction of N-halomethyl-N-nitrourethanes with thiophenol salts

Russian Chemical Bulletin -     

Sonogashira coupling with aqueous ammonia directed to the synthesis of azotolane derivatives

Sonogashira coupling with aqueous ammonia is tolerable for the reaction of aryl iodides or terminal alkynes bearing an azobenzene group. The reaction of (4-heptyloxyphenyl)ethyne with (4-heptyloxyphenyl)-(4-iodophenyl)diazene in the presence of 1 mol% of PdCl₂(PPh₃)₂, 2 mol% of CuI, and 2 equiv of 0.5 M aqueous ammonia gives the corresponding azotolane in 87% isolated yield after stirring at room temperature for 15 h.