188290-36-0Relevant articles and documents
The photoinduced reaction of 2-iodothiophene in solutions of n-heptane, dichloromethane and methanol
Herrera,Nieto,Olleta,Lane
, p. 398 - 406 (2011)
The photoinduced reaction of 2-iodothiophene in n-heptane, dichloromethane and methanol was studied at room temperature from experiments carried out with degassed solutions. The photoproducts of the reaction were mainly thiophene and small amounts of iodine in all three solvents used. The concentration of 2-iodothiophene decreases throughout photolysis, following a first-order rate law and the pseudo-first-order rate constants were determined in the three solvents used. The photochemistry of the system was quantified determining the quantum yields of 2-iodothiophene consumption and thiophene formation in n-heptane solutions. The results show that under the experimental conditions of this research, products deriving only from the reaction of the thienyl radical were observed. To support the experimental results, calculations were performed of the ionization potential of the thienyl radical, electron affinity of the iodine atom and free energy of solvation of the corresponding iodide and carbocation in the different solvents used. Copyright
Surface-Induced Heterocycle Formation: Sulfur Atom Abstraction during Cyclization
Gellman, Andrew J.
, p. 4435 - 4440 (1991)
We have studied the mechanism of a novel cyclization reaction in which acetylene abstracts sulfur from the Pd(111) surface in the form of thiophene. The proposed mechanism is one in which adsorbed acetylene first dimerizes to form a C4H4 intermediate which is then capable of abstracting atomic sulfur to form thiophene. The appearance of thiophene in the gas phase is then rate limited by thiophene desorption kinetics. This sequential mechanism has also been proposed for acetylene cyclotrimerization to benzene on the clean Pd(111) surface. Thiophene formation from acetylene is sensitive to both the surface sulfur coverage and the temperature at which the sulfur overlayer is produced. The reaction of a C4H4 species produced from cis-3,4-dichlorocyclobutene exhibits exactly the same sensitivity to surface characteristics and hence is identified as the intermediate produced by acetylene dimerization. We discuss the potential of this chemistry as a process for the regeneration of catalytic surfaces deactivated by sulfur contamination.
HETEROCYCLIZING PROPERTIES OF FERRISILICATE IN THE REACTION OF n-PENTANE WITH HYDROGEN SULFIDE
Ryashentseva, M. A.,Belanova, E. P.,Minachev, Kh. M.,Kucherov, A. V.
, p. 1551 - 1555 (1990)
Unlike the iron-modified pentasil, the ferrisilicate has high heterocyclizing activity in the formation of 2-methylthiophene from hydrogen sulfide and n-pentane.During the reaction and the subsequent regenerations a considerable proportion of iron ions leaves the ferrisilicate lattice.The heterocyclizing activity is probably related to the formation of a highly dispersed Fe sulfide phase in the zeolite channels.
Heterocyclization Sites on the Sulfided Pd(111) Surface
Gellman, Andrew J.
, p. 790 - 795 (1992)
We have examined the heterocyclization of acetylene (C2H2) to thiophene (C4H4S) on the sulfided Pd(111) surface.This reaction has been found to occur at defects in the sulfided surface which can be produced either by annealing the surface to temperatures >800 K or by sulfiding the surface to near-saturation.At 300 K both thiophene and CO will adsorb selecetively at these defects and can be used to titrate the surface defect concentration.The yield of thiophene from the acetylene heterocyclization reaction is correlated with the defect concentration as measured by these methods and, hence, it appears that the reaction occurs at defects in the sulfided surface.Vibrational spectra indicate that CO adsorbed at these defects is bound in a bridging configuration between Pd atoms indicating that the defects expose the metallic substrate.
Competitive carbon-sulfur vs carbon-carbon bond activation of 2-cyanothiophene with [Ni(dippe)H]2
Grochowski, Matthew R.,Li, Ting,Brennessel, William W.,Jones, William D.
, p. 12412 - 12421 (2010)
The processes of C-C and C-S bond cleavage have been studied with the homogeneous organometallic compound [Ni(dippe)H]2 (1). When 1 is reacted with 2-cyanothiophene at room temperature, cleavage of the nitrile-substituted C-S bond occurs, forming the Ni-metallacycle complex (dippe)Ni(κ2-S,C-SCH=CHCH=C(CN)) (2a), which has been fully characterized by NMR spectroscopy and X-ray diffraction. 2a was converted to the C-CN cleavage product (dippe)Ni(CN)(2-thiophenyl) (3) when heated in solution. On closer inspection, four other intermediates were observed by 31P NMR spectroscopy at low temperature. Structures for the intermediates were elucidated through a combination of independent synthesis, theoretical calculations, chemical characterization, and experimental precedent. A kinetic product (dippe)Ni(κ2-S,C-SC(CN)=CHCH=CH) (2b) was formed from cleavage of the nonsubstituted C-S bond, as well as a Ni(0) η2- nitrile intermediate, (dippe)Ni(η2-C,N-2-cyanothiophene) (4), and a dinuclear mixed Ni(0)-Ni(II) product (6b). A complete DFT analysis of this system has been carried out to reveal comparative details about the two bond cleavage transition states.
Influence of the texture of chromia catalysts on their activity in synthesis of 2-methylthiophene
Ryashentseva,Brueva
, p. 1694 - 1697 (2002)
The texture of Cr2O3-K2O/Al 2O3 catalysts containing oxides of rare earth elements (REE) was studied. The catalysts are used for the synthesis of 2-methylthiophene by the reaction of H2S with n-pentane or piperilene. The heterocyclization of n-pentane is a consecutive reaction involving a step of dehydrogenation of initial hydrocarbon. At this step the texture of the catalyst affects the yield of 2-methylthiophene. The yield of 2-methylthiophene obtained from piperilene and H2S is independent of the catalyst texture.
5-Methyl-2-thienylcalcium iodide
Koch, Alexander,Krieck, Sven,G?rls, Helmar,Westerhausen, Matthias
, p. 12534 - 12539 (2018)
The reduction of 2-bromo- and 3-bromothiophene with calcium powder gives impure thienylcalcium complexes due to interference of various subsequent metalation and calcium-halogen exchange reactions as well as ether degradation. Therefore, calcium-iodine exchange succeeds via the reaction of trimethylsilylmethylcalcium halide with 3-iodothiophene in tetrahydrofuran at -78 °C in the presence of chloro-trimethylsilane, leading to the quantitative formation of 3-(trimethylsilyl)thiophene. The synthesis and isolation of a thienylcalcium halide, a heavy Grignard reagent with a thienyl group, is possible via the reduction of 2-iodo-5-methylthiophene with activated calcium in THF. Substitution of the thf ligands in 5-methyl-2-thienylcalcium iodide ([5-MeThien-2-Ca(thf)4I], 1) by dissolution in tetrahydropyran (THP) leads to the thp complex of 5-methyl-2-thienylcalcium iodide ([5-MeThien-2-Ca(thp)4I], 2). A low field shift of the calcium-bound carbon atom is characteristic of thienylcalcium complexes.
Synthesis of tungsten thienyl complexes via C-H bond activation of thiophenes
Sakaba, Hiroyuki,Yumoto, Takahiro,Watanabe, Sanae,Kabuto, Chizuko,Kabuto, Kuninobu
, p. 14 - 15 (2003)
The reactions of cis-Cp*W(CO)2(MeCN)Me (1) with thiophene or 3-methylthiophene resulted in selective α-C-H bond activation to give cis-Cp*W(CO)2(MeCN)R [R = 2-C4H3S (2a), 2-C4H2S-4-Me (2b)]
Investigation of the mechanism of catalytic recyclization of furan to thiophene
Mashkina
, p. 1063 - 1067 (2010)
Investigation of the formation of thiophene from furan and hydrogen sulfide at various catalysts showed that the activity of the catalysts increases with increase in the strength and concentration of Lewis acid centers. It was found by IR spectroscopy that if the degree of coverage of the aluminum oxide surface with hydrogen sulfide is higher than monolayer its dissociative chemisorption does not occur. Mechanism was postulated wich assume that the reaction takes place through stage with the formation of a surface intermediate, including coordination of the α-carbon atoms of the furan ring with the Lewis acid center and with the sulfur atom of molecular hydrogen sulfide.
FORMATION OF THIENOTHIOPHENES IN THE HIGH TEMPERATURE REACTION OF 2-CHLOROTHIOPHENE WITH COMPOUNDS CONTAINING THE C2H5S GROUP
Korchevin, N. A.,Sukhomoazova, E. N.,Turchaninova, L. P.,Efremova, G. G.,Kalinina, N. A.,et al
, p. 857 - 860 (1988)
The high temperature gas-phase reaction of 2-chlorothiophene with a mixture of diethyl disulfide and diethyl trisulfide constitutes a simple one-step synthesis of a 4:1 mixture of thioeno- and thieno-thiophenes.Their total yield depends on the nature of the donor of the ethylthio group.
