- Efficient route for the synthesis of 3,4-cycloalkoxy-2,5-diethoxycarbonyl-thiophenes obtained with bulky alkyl dibromides using trialkylamines as base-solvent
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New reaction conditions were investigated for dialkylizing diethyl 3,4-dihydroxy-2,5-thiophenedicarboxylate with sterically hindered alkyl-dibromides, using as reaction system DMF-trialkylamine or only the trialkylamine as base-solvent. This methodology produced the corresponding 3,4-cycloalkoxy-2,5-diethoxycarbonyl-thiophene derivatives faster and with better yields than those reported previously for K2CO3-DMF. Experiments were performed with triethylamine, tripropylamine, and tributylamine. Tributylamine produced the best results in a general reaction with alkyl-bromides. Aromatic amines like N,N-dimethylaniline, N-methyldiphenylamine, and triphenylamine failed to react at all. Reactions using only the tributylamine as base-solvent demonstrated that DMF is not necessary as a solvent to obtain good yields.
- Frontana-Uribe, Bernardo A.,Heinze, Jürgen
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- On the Reaction of Diethyl 3,4-Dihydroxythiophene-2,5-dicarboxylate with 1,2-Dibromoethane
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Reaction of diethyl 3,4-dihydroxythiophene-2,5-dicarboxylate (1) with an excess of 1,2-dibromoethane afforded a mixture of the 2,3-dihydrothieno-dioxine-derivative 3 and the 3-oxo-2,3-dihydrothiophene 4.Compounds 3 and 4 were characterized by spectroscopic methods. - Keywords: Dihydroxythiophenes; Alkylation; NMR Spectroscopy.
- Holzer, W.,Schmid, E.,Slatin, C.
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- Preparation method of 3,4-ethylenedioxythiophene
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A method of preparing 3,4-ethylenedioxythiophene is provided. The preparation is performed by microwave heating to greatly increase the yield and decrease the reaction time, energy consumption, solvent usage, and environmental damage.
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Paragraph 0083-0088
(2013/03/26)
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- New hydrazides and thiosemicarbazides derived from ethylenedioxythiophene as potential anticonvulsants
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A series of ethyl 7-({2-[(substituted)carbonyl]hydrazino}carbonyl)-2,3- dihydrothieno [3,4-b][1,4]dioxine-5-carboxylates (5-13) and ethyl 7-{[({2-[(substituted)carbonyl]hydra-zino}carbonothioyl)amino]carbonyl}-2, 3-dihydrothieno[3,4-b][1,4]dioxine-5-carboxy-lates (15-20) were synthesized in good yield by condensing ethyl-7-(chlorocarbonyl)-2,3-dihydrothieno[3,4-b][1,4] dioxine-5-carboxylate (4) with suitable hydrazides. The newly synthesized compounds were characterized using FTIR, 1H NMR, 13C NMR, mass spectroscopy, and elemental analyses. The anticonvulsant activity of all the title compounds was investigated against maximal electroshock-induced seizures (MES) and pentylenetetrazole (PTZ)-induced convulsion models. None of the compounds showed toxicity at the maximum dose of 2000 mg/kg. Almost all the compounds showed protection in flexion and extension stage against induced convulsion. Among them, naphthyloxy-substituted derivatives exhibited very good response against induced seizures. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. Copyright Taylor & Francis Group, LLC.
- Kulandasamy, Ravi,Adhikari, Airody Vasudeva,Taranalli, Ashok,Venkataswamy, Thimmaiah
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scheme or table
p. 1358 - 1368
(2010/08/21)
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- A new class of anticonvulsants possessing 6 Hz activity: 3,4-Dialkyloxy thiophene bishydrazones
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Thirty nine new 3,4-di(substituted)oxy-N2,N5-bis(substituted)thiophene-2,5-dicarbohydrazides were synthesized starting from ethyl thiodiglycolate through multi-step reactions. In the synthetic sequence, 3,4-dihydroxythiophene-2,5-diester (1) was obtained by condensing the ethyl thiodiglycolate with diethyl oxalate. It was derivatized using different alkyl halides to give disubstituted thiophene esters (2-5), which were then converted to corresponding hydrazides (6-9) following usual methods. Finally, these hydrazides, on treatment with various substituted carbonyl compounds underwent smooth condensation to yield target hydrazones (10-13). The new compounds were characterized using FT-IR, 1H NMR and 13C NMR, mass spectral and elemental analyses. The anticonvulsant activity of the title compounds was established after intraperitoneal (ip) administration in three seizure models, which include maximal electroshock (MES), subcutaneous pentylenetetrazole (scPTZ) and 6 Hz screens and their neurotoxicity was also evaluated. Compound 11f has emerged as an active compound with no neurotoxicity in this series. Also, the structure-activity relationship of the tested compounds was discussed.
- Kulandasamy, Ravi,Adhikari, Airody Vasudeva,Stables, James P.
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scheme or table
p. 4376 - 4384
(2009/12/28)
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- The first direct experimental comparison between the hugely contrasting properties of PEDOT and the all-sulfur analogue PEDTT by analogy with well-defined EDTT-EDOT copolymers
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The structures of poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(3,4-ethylenedithiathiophene) (PEDTT) vary only in the substituent chalcogen atoms, yet the electronic properties of the materials are surprisingly dissimilar. The difference in electronic band gaps is approximately 0.8 eV and the polymers behave very differently upon p-doping. Two new terthiophenes have been synthesised using Negishi coupling methods. The X-ray crystal structures of EDOT-EDTT-EDOT (OSO) and EDTT-EDOT-EDTT (SOS) show strong intramolecular chalcogen-chalcogen contacts which are responsible for persistent conformers in solution and solid state, although significant interchain interactions should also influence the properties of the materials. SOS and OSO can be polymerised by electrochemical oxidation to give the corresponding, well-defined poly(terthiophenes) PSOS and POSO. Spectroelectrochemical studies on all four polymers reveal strong similarities between PEDTT and PSOS, and between PEDOT and POSO. Together with independent electrochemical and absorption studies, the results indicate that the unique properties of PEDOT are influenced more by conformational effects (intrachain S...O contacts) than substituent effects. The Royal Society of Chemistry 2005.
- Spencer, Howard J.,Skabara, Peter J.,Giles, Mark,McCulloch, Iain,Coles, Simon J.,Hursthouse, Michael B.
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p. 4783 - 4792
(2007/10/03)
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- Process for preparing a compound containing a heteroaromatic group with one or more ether substituents
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A process for preparing a heteroaromatic compound having a heteroaromatic nucleus substituted with one or more ether groups comprising the step of: condensing at least one hydroxy-group of a compound having said heteroaromatic nucleus, said at least one hydroxy group (—OH) being substituted at α- or β-positions with respect to a heteroatom of said heteroaromatic nucleus, with an alcohol containing one or more primary or secondary alcohol groups, optionally substituted with nitro, amide, ester, halogen, cyano or (hetero)aromatic groups, using the redox couple of a triaryl- or trialkylphosphine and an azodioxo-compound at a temperature between ?40° C. and 160° C.
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- 3,4-Alkylenedioxy ring formation via double Mitsunobu reactions: An efficientroute for the synthesis of 3,4-ethylenedioxythiophene (EDOT) and 3,4-propylenedioxythiophene (ProDOT) derivatives as monomers for electron-rich conducting polymers
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3,4-Alkylenedioxy ring functionalized thiophenes (XDOT's) have been synthesized by double Mitsunobu reactions to yield precursors to monomers for conjugated and electrically conducting polymers, including the commercially important 3,4-ethylenedioxythiophene (EDOT).
- Zong, Kyukwan,Madrigal, Luis,Groenendaal,Reynolds, John R.
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p. 2498 - 2499
(2007/10/03)
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- Efficient synthesis of 3,4-ethylenedioxythiophenes (EDOT) by Mitsunobu reaction
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Using the Mitsunobu reaction as a key step, a general and efficient method for the synthesis of EDOT monomers has been developed. Novel substituted EDOTs and the first chiral derivatives were generated in high yields.
- Caras-Quintero, Dolores,Bauerle, Peter
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p. 2690 - 2691
(2007/10/03)
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- A facile synthesis of 3,4-dialkoxythiophenes
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Dialkylation of diethyl 3,4-dihydroxythiophenedicarboxylate followed by ester hydrolysis and acid decarboxylation provides a general route to 3,4-dialkoxythiophenes.
- Coffey,McKellar,Reinhardt,Nijakowski,Feld
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p. 2205 - 2212
(2007/10/03)
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