638-02-8Relevant articles and documents
MECHANISM OF RECYCLIZATION OF FURANS TO THIOPHENES AND SELENOPHENES UNDER ACID-CATALYSIS CONDITIONS. 2. KINETIC INVESTIGATIONS OF THE REACTION OF 2,5-DIALKYLFURANS WITH HYDROGEN SULFIDE AND HYDROGEN SELENIDE IN AN ANHYDROUS MEDIUM
Voronin, S. P.,Gubina, T. I.,Trushin, S. A.,Markushina, I. A.,Kharchenko, V. G.
, p. 1216 - 1220 (1989)
The effect of the concentration of the acidic component on the rates of recyclization of 2,5-dialkylfurans to thiophenes and selenophenes was studied.On the basis of the direct correlation of log k on (H0)I and the isotope effect of the solvent it was established that the reaction proceeds via a mechanism of specific acid catalysis.It was shown that the rates of the reactions with the participation of hydrogen sulfide and hydrogen selenide coincide at equal acidities and temperatures.A scheme for the mechanism of the reaction that includes a step involving the formation of the doubly protonated form of the substrate is proposed.
New method for synthesis of 2,5-disubstituted thiophenes
Gubina,Drevko,Fedina,Rogacheva,Kharchenko
, p. 650 - 652 (1999)
The use of hydrogen sulfide at the moment of formation is proposed for the recyclization of furans into thiophenes in acidic media. The advantages of this method are shown. 1999 KluwerAcademic/Plenum Publishers.
Study of the mechanism of recyclization of furans into thiophenes and selenophenes in conditions of acid catalysis. 6. Experiments with labeled atoms. Quantum chemical calculations of intermediates of recyclization and hydrolysis
Gubina,Pankratov,Labunskaya,Voronin,Kharchenko
, p. 903 - 909 (1997)
The reaction of 2-methyl-5-R-furans (R = Me, Bu, 2,2-pentyl-2-methylpentyl) with H218O was investigated. Furans and the corresponding 2,5-alkanediones containing the 18O isotope were obtained. The general characteristics of the recyclization and isotope exchange reactions were established. A kinetic study of recyclization of 2,5-dimethylfuran with 16O and 18O into 2,5-dimethylthiophene was conducted. A reverse kinetic isotope effect was found. The schemes of the mechanisms of these processes were refined based on the experimental data and quantum-chemical calculations of the recyclization and hydrolysis intermediates. 1998 Plenum Publishing Corporation.
Synthesis of substituted 1,2,4-triazines based on 1,2-bis(2,5-dimethyl-3-thienyl)ethanedione
Ivanov,Lichitskii,Dudinov,Martynkin,Krayushkin
, p. 85 - 90 (2001)
A novel, convenient method has been developed for the synthesis of 1,2-bis(2,5-dimethyl-3-thienyl)ethanedione, from which were prepared 5, 6-bis(2,5-dimethyl-3-thienyl)-1,2,4-triazines (analogs of the photochromic 1,2-diarylethenes). The principial possibility of using 1,2,4-triazines obtained as photochromic agents was investigated.
Catalytic Synthesis of Methylthiophenes
Mashkina,Khairulina
, p. 1794 - 1797 (2019/03/26)
The gas-phase reaction of dimethyl disulfide with thiophene over Co/HZSM-5 catalyst in a helium medium under atmospheric pressure at 250–350°C gave a mixture of mono-, di-, tri-, and tetramethylthiophenes with an overall selectivity of 94–96%.
Catalytic reactions of dimethyl disulfide with thiophene and benzene
Mashkina,Khairulina
, p. 72 - 81 (2016/04/20)
The gas-phase reaction of dimethyl disulfide with thiophene proceeds under the action of acid catalysts under atmospheric pressure at 160-350°C and a residence time of τ = 0.6-21 s to form thioalkylation and alkylation products. Dimethyl disulfide reacts with benzene to form only alkylation products. Catalysts containing both strong protic and Lewis acid sites, as well as basic sites of moderate strength, are the most active ones.
Reaction of dimethyl disulfide with thiophene catalyzed by zeolite
Mashkina,Khairulina
, p. 217 - 220 (2015/04/14)
Reaction of dimethyl disulfide with thiophene under the action of highly siliceous zeolite at 180-350°C and contact time 0.6-14 s resulted in formation of thioalkylation products, 2-(methylsulfanyl)- and 2,5-bis(methylsulfanyl)thiophenes and also alkylate
Electrochromic properties of novel chalcones containing triphenylamine moiety
Jin, Huiyi,Li, Xianggao,Tan, Tingfeng,Wang, Shirong,Xiao, Yin,Tian, Jianhua
, p. 154 - 160 (2014/04/17)
A series of novel electrochromic chalcones containing triphenylamine units were synthesized by Aldol reaction and characterized by NMR, IR and MS. Their optical, electrochemical properties were investigated using UV-vis, photoluminescence spectra and cyclic voltammetry. The molecular orbital energy levels and excitation energies were calculated by quantum chemical calculation. It was found that the fluorescence intensity is decreasing with formation of charge-transfer state. The existence of electron donating group on triphenylamine unites caused a significant bathochromic shift of the UV absorption maximum and increased EHOMO and ELUMO. The electrochromic property of the synthesized compounds was studied by spectroelectrochemical experiments. The results showed that the chalcones containing triphenylamine moiety presented good electrochromic stability, with a color change from yellow to blue as applied potentials ranging from 0.0 to 2.8 V. The coloring and bleaching time was in the range of 2.9-4.2 s and 1.7-3.3 s, respectively.
Investigation of the aroma-active compounds formed in the maillard reaction between glutathione and reducing sugars
Lee, Sang Mi,Jo, Ye-Jin,Kim, Young-Suk
experimental part, p. 3116 - 3124 (2011/08/05)
Aroma-active compounds formed during the thermal reaction between glutathione (GSH) and reducing sugars were analyzed by gas chromatography-mass spectrometry (GC-MS) and GC-olfactometry (GC-O) with aroma extract dilution analysis (AEDA). Application of AEDA to glutathione Maillard reaction products (GSH MRPs) led to the identification of 19 aroma-active compounds in the thermal reaction of glutathione with glucose or fructose. In addition, the carbohydrate module labeling (CAMOLA) approach was also employed to elucidate the formation pathways for selected target sulfur aroma compounds, such as 5-methylthiophene-2-carbaldehyde and 3-methylthiophene-2-carbaldehyde, which have not been reported previously. The intact carbon skeleton of glucose via 3-deoxyhexosone is incorporated into 5-methylthiophene-2-carbaldehyde with the hydrogen sulfide of GSH. On the other hand, the formation of 3-methylthiophene2-carbaldehyde may occur via the recombination of a C-4 sugar fragment and mercaptoacetaldehyde.
Carbon-sulfur bond cleavage of methyl-substituted thiophenes with iridium(III)
Grochowski, Matthew R.,Brennessel, William W.,Jones, William D.
, p. 2661 - 2667 (2009/09/26)
Reaction of [Cp*IrHCl]2 (Cp* = η5- C5Me5) with 2-methylthiophene and 2,5-dimethylthiophene at 120 °C in the presence of H2 results in the cleavage of the thiophene carbon-sulfur bond(s). In both cases