- Synthesis and pharmacological characterisation of arctigenin analogues as antagonists of AMPA and kainate receptors
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(-)-Arctigenin and a series of new analogues have been synthesised and then tested for their potential as AMPA and kainate receptor antagonists of human homomeric GluA1 and GluK2 receptors expressed in HEK293 cells using a Ca2+ influx assay. In general, these compounds showed antagonist activity at both receptors with greater activity evident at AMPARs. Schild analysis indicates that a spirocyclic analogue 6c acts as a non-competitive antagonist. Molecular docking studies in which 6c was docked into the X-ray crystal structure of the GluA2 tetramer suggest that (-)-arctigenin and its analogues bind in the transmembrane domain in a similar manner to the known AMPA receptor non-competitive antagonists GYKI53655 and the antiepileptic drug perampanel. The arctigenin derivatives described herein may serve as novel leads for the development of drugs for the treatment of epilepsy. This journal is
- Butts, Craig P.,Collingridge, Graham L.,Jane, David E.,Mallah, Shahida,Molnár, Elek,Re?nik, Lisa-Maria,Thatcher, Robert J.,Willis, Christine L.
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supporting information
p. 9154 - 9162
(2021/11/16)
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- Trithioorthoester Exchange and Metathesis: New Tools for Dynamic Covalent Chemistry
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To expand the toolbox of dynamic covalent and systems chemistry, we investigated the acid-catalyzed exchange reaction of trithioorthoesters with thiols. We found that trithioorthoester exchange occurs readily in various solvents in the presence of stoichiometric amounts of strong Bronsted acids or catalytic amounts of certain Lewis acids. The scope of the exchange reaction was explored with various substrates, and conditions were identified that permit clean metathesis reactions between two different trithioorthoesters. One distinct advantage of S, S, S-orthoester exchange over O, O, O-orthoester exchange is that the exchange reaction can kinetically outcompete hydrolysis, thereby making the process less sensitive to residual moisture. We expect that the relatively high stability of the products might be beneficial in future supramolecular receptors or porous materials.
- Bothe, Michael,Furlan, Ricardo L. E.,Orrillo, A. Gastón,Von Delius, Max
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p. 1988 - 1994
(2019/10/22)
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- Visible-Light Photoredox-Catalyzed Thioacetalization of Aldehydes Under Metal-Free and Solvent-Free Conditions
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A first visible-light photoredox-catalyzed thioacetalization of aldehydes under metal-free and solvent-free conditions is described. Under blue LED irradiation, a reactive thiyl radical was initially generated through single-electron oxidation of thiol, w
- Du, Kai,Wang, Shao-Chien,Basha, R. Sidick,Lee, Chin-Fa
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p. 1597 - 1605
(2018/12/11)
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- Thioacetalization of aldehydes and ketones catalyzed by hexabromoacetone
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Protection of p-anisaldehydewith 1,3-propanedithiol under UV irradiation without a catalyst resulted in 87% yield of 1,3-dithiane in 20 min. Addition of hexabromoacetone further reduced the reaction time and UV irradiation also accelerated the formation o
- Chaiseeda, Kittichai,Chavasiri, Warinthorn
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p. 1034 - 1039
(2017/09/08)
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- Rhodium-catalyzed denitrogenative thioacetalization of N-sulfonyl-1,2,3-triazoles with disulfides: An entry to diverse transformation of terminal alkynes
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An efficient and useful rhodium-catalyzed denitrogenative thioacetalization of N-sulfonyl-1,2,3-triazoles has been developed for the first time. The protocol uses readily available N-sulfonyl-1,2,3-triazoles and diaryl disulfides as the starting materials. The corresponding hydrolytic and reductive products with thioacetals were obtained in good to excellent yields, and the reactions were carried out easily under mild conditions with tolerance of some functional groups. Furthermore, the generated thioacetals could be transformed into some useful compounds. Therefore, the present method provides a novel and valuable strategy for the diverse transformation of alkynes.
- Zhang, Hao,Wang, Hui,Yang, Haijun,Fu, Hua
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supporting information
p. 6149 - 6153
(2015/06/08)
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- Reduction of titanocene dichloride with dysprosium: Access to a stable titanocene(II) equivalent for phosphite-free Takeda carbonyl olefination
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The reduction of titanocene dichloride with dysprosium yields a new titanocene(ii) equivalent without the need for further stabilising ligands. This reagent can be employed in combination with dithioacetals for the olefination of different carbonyl groups and allows for a simplified all-in-one procedure.
- Bousrez,Déchamps,Vasse,Jaroschik
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supporting information
p. 9359 - 9362
(2015/06/16)
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- Graphene oxide (GO)-catalyzed chemoselective thioacetalization of aldehydes under solvent-free conditions
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An efficient method for the synthesis of open chain, cyclic, and unsymmetrical dithioacetals from aryl/hetero-aryl/aliphatic aldehydes is described. The reaction is performed using graphene oxide (GO) as the catalyst under solvent-free and aerobic conditions. High chemoselectivity is observed in the reaction as aryl/alkyl ketones do not give thioketals under the condition.
- Roy, Babli,Sengupta, Debasish,Basu, Basudeb
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supporting information
p. 6596 - 6600
(2015/01/08)
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- Mesoporous silica-functionalized dual Br?nsted acidic ionic liquid as an efficient catalyst for thioacetalization of carbonyl compounds in water
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A novel silica-functionalized dual Br?nsted acidic ionic liquid (ionic liquid with two Br?nsted acidic species) has been reported as a highly efficient catalyst for thioacetalization of carbonyl compounds. The reaction was efficiently performed in water a
- Vafaeezadeh, Majid,Dizicheh, Zahra Bahrami,Hashemi, Mohammad Mahmoodi
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- Thioacetalization of aldehydes and ketones in SDS micelles
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Aromatic aldehydes have been successfully converted into their corresponding dithioacetal, dithiolane and dithiane derivatives in excellent yields with thiol (benzyl thiol and thiophenol), 1,2-ethanedithiol and 1,3-propanedithiol using trichloroacetic acid in sodium dodecyl sulfate micelles. The same procedure is applicable to ketones, but they need more time to be converted into their thioacetals. Image Presented.
- Bahrami, Kiumars,Khodaei, Mohammad Mehdi,Tajik, Maryam,Soheilizad, Mehdi
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experimental part
p. 397 - 403
(2012/06/18)
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- Cerium triflate: An efficient and recyclable catalyst for chemoselective thioacetalization of carbonyl compounds under solvent-free conditions
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A simple and efficient chemoselective thioacetalization of carbonyl compounds has been achieved using Ce(OTf)3 (10 mol-%) as a catalyst under solvent-free conditions. Advantages of the methodology include very short reaction times, excellent yi
- Kumar, Anil,Rao, M. Sudershan,Kameshwara Rao
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experimental part
p. 135 - 140
(2010/05/18)
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- A mild method for the protection of aldehydes as dithioacetals and dithiolanes catalyzed by I2 generated in situ using Fe(NO 3)3.9H2O/Nai under heterogeneous conditions
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Structurally diverse aromatic aldehydes were thioacetalated in a clean and efficient reaction with ethane-1,2-dithiol and thiophenol based on the use of I2 generated in situ from Fe(NO3)3.9H 2O/NaI. The reaction occurs in good to high yield in dichloromethane at room temperature and the use of toxic and corrosive molecular iodine is avoided.
- Rostami, Amin,Nik, Heidar Ali Alavi,Roosta, Zahra Toodeh,Khazaei, Ardeshir
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experimental part
p. 431 - 434
(2009/12/03)
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- Nucleophilic fluoroalkylation of α,β-enones, arynes, and activated alkynes with fluorinated sulfones: Probing the hard/soft nature of fluorinated carbanions
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(Chemical Equation Presented) We have successfully accomplished the nucleophilic fluoroalkylation of α,β-enones, arynes, and activated alkynes with fluorinated sulfones. It was found that for acylic α,β-enones, although the reaction medium and the structure of the enones can all influence the regioselectivity of the nucleophilic alkylation reactions, the hard/soft nature of the carbanions played a major role. By using the 1,4- and 1,2-addition product ratio as a probe to determine the hard/soft nature of the above-mentioned four halogenated carbanions, the order of the softness of these carbanions can be given as follows: [(PhSO2) 2CF-] (20) ≈ PhSO2CCl2 - (32) > PhSO2CHF- (31) > PhSO 2CF2- (30). In the case of fluoroalkylation of aryne (35 as the precursor) and α,β-acetylenic ketones 46 with fluorobis(phenylsulfonyl)methane (21), fluorobis(phenylsulfonyl)methylated arenes 36 and β-fluorobis(phenylsulfonyl)methylated α,β-enones 47 were obtained as the corresponding products in good yields. During the reaction between 2-fluoro-2-(phenylsulfonyl)acetophenone (34) and arynes or activated alkynes 46, an intramolecular tandem reaction process leads to the formation of acyl-fluoroalkylated arenes 43 or α-acyl-β- fluoroalkylated α,β-enones 48. It turned out that the softness of a fluorine-bearing carbanion (such as 20 or 33 derived from 21 or 34) plays a crucial role for the success of the nucleophilic fluoroalkylation reactions with arynes and some activated alkynes (α,β-acetylenic ketones).
- Ni, Chuanfa,Zhang, Laijun,Hu, Jinbo
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p. 5699 - 5713
(2008/12/21)
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- A mild and chemoselective dithioacetalization of aldehydes in the presence of anhydrous copper (II) sulfate
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Various aldehydes have been protected with different thiols as dithioacetals with excellent yields using anhydrous copper sulfate as a mild and chemoselective catalyst. The reaction is carried out in a solvent and/or under solvent-free conditions. The transthioacetalization of oxyacetals into dithioacetals was also achieved in an excellent yield. Copyright Taylor & Francis Group, LLC.
- Moghaddam, Firouz Matloubi,Bardajee, Ghasem Rezanejade,Oskui, Afsane Arefi
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p. 1445 - 1450
(2007/10/03)
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- Nickel(II) chloride as an efficient and useful catalyst for chemoselective thioacetalization of aldehydes
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A wide variety of acyclic and cyclic dithioacetals can be prepared chemoselectively from the corresponding aldehydes by employing a catalytic amount of nickel(II) chloride in dry CH2Cl2-MeOH (5:1) at room temperature in good yields.
- Khan, Abu T.,Mondal, Ejabul,Sahu, Priti R.,Islam, Samimul
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p. 919 - 922
(2007/10/03)
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- Lithium bromide, a novel and highly effective catalyst for monothioacetalization of acetals under mild reaction conditions
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Lithium bromide is efficient as a catalyst for the monothioacetalization of acetals under mild reaction conditions to provide products in excellent yields with high chemoselectivity.
- Ono,Negoro,Sato
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p. 1581 - 1583
(2007/10/03)
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- Photoinduced hydrogen- and electron-transfer processes between chloranil and aryl alkyl sulfides in organic solvents. Steady-state and time-resolved studies
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The photochemical behavior of three aryl alkyl sulfides, thioanisole (TA), benzyl phenyl sulfide (BPS) and 4-methoxybenzyl phenyl sulfide (MBPS), sensitized by triplet chloranil (CA), was investigated by nanosecond laser flash photolysis and steady-state irradiation in CH2Cl2 and MeCN. The nature of the transients detected upon 355-nm laser excitation was independent of the molecular structure of the aryl alkyl sulfides but strongly affected by the solvent polarity. In particular, in CH2Cl2 the quenching process of triplet CA by aryl alkyl sulfides was accompanied by H- transfer, with formation of the CAH· and TA(-H)·/BPS(-H)·/MBPS(-H)· radicals. In contrast, a charge transfer process between triplet CA and aryl alkyl sulfides, with formation of the radical anion CA·- and radical cations of aryl alkyl sulfides, occurred in MeCN. In this solvent, a transient detected at long delay time was tentatively assigned to the anion CAH- formed by H-transfer between radical ions. In all experiments, transient species were characterized in terms of second-order decay rate constants and quantum yields of formation. Steady-state irradiation of the CA/TA system led to the stable photoadduct C6H5SCH2OC6Cl4OH in both CH2Cl2 and MeCN with quantum yields of 0.033 and 0.27, respectively. In contrast, aldehydes, thioacetals, and disulfides were the main products obtained upon irradiation of the CA/BPS and CA/MBPS systems. The photoaddition products were not observed, probably owing to their low stability. The nature of the photoproducts formed by irradiation of CA/aryl alkyl sulfides was independent of solvent properties, even though the reactivity was higher in MeCN than in CH2Cl2.
- Del Giacco, Tiziana,Elisei, Fausto,Lanzalunga, Osvaldo
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p. 1701 - 1708
(2007/10/03)
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- Synthetic Methods, III [1]: Sulfated Zirconia Catalyzed Thioacetalization of Carbonyl Compounds
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Sulfated zirconia effectively catalyzes the reaction of carbonyl compounds with 1,2-ethanedithiol or thiophenol to afford the corresponding dithioacetals as useful organosulfur synthons. Isolation of pure products in high yields by simple filtration and e
- Bandgar,Kasture
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p. 1305 - 1308
(2007/10/03)
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- Chemoselective Protection of Aldehydes as Dithioacetals in Lithium Perchlorate-Diethyl Ether Medium. Evidence for the Formation of Oxocarbenium Ion Intermediate from Acetals
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Aldehydes and acetals were very efficiently converted to acyclic and cyclic dithioacetals in 5 M lithium perchlorate/diethyl ether (LPDE) medium at ambient temperature in high yields.Spectroscopic and other experimental evidences strongly suggest the formation of oxocarbenium ion intermediates from acetals in 5 M LPDE which subsequently reacted with thiols to give the dithioacetals.Under the same conditions ketones and their acetals also reacted, albeit very slowly compared to aldehydes and acetals, to yield dithioacetals.The difference in their reactivity was successfully employed in the chemoselective dithioacetalization of aldehydes and acetals in the presence of ketones and their acetals.The chemoselective dithioacetalization of keto aldehydes has been realized with the keto group remaining intact.The present method offers a convenient, efficient, and neutral medium for the deprotection of acetals to aldehydes and also the chemoselective protection of aldehydes to dithioacetals.
- Saraswathy, V. Geetha,Sankararaman, S.
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p. 4665 - 4670
(2007/10/02)
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- Anodic gem-Difluorination of Dithioacetals
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Anodic desulfurization of dithioacetals of ketones in the presence of Et3N*3HF provided the corresponding gem-difluorocompounds while dithioacetals of aromatic and aliphatic aldehydes gave gem-difluorothioethers and monofluoro thioether, respectively.
- Yoshiyama, Tomonori,Fuchigami, Toshio
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p. 1995 - 1998
(2007/10/02)
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