- Di-tert-Butyl Peroxide-Mediated Atom-Transfer Radical Addition of 2-Chlorodithiane to Aryl Alkynes under Mild Conditions
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Atom transfer radical addition (ATRA) of 2-chlorodithiane onto aryl alkynes through the use of di-tert-butyl peroxide as an oxidant at room temperature directly affords a variety of synthetically valuable β-chloro-(Z)-vinyl dithianes in good yields with high regioselectivities and without the assistance of any transition metals. It provides an operationally simple pathway to access vinyl dithianes with controlled formation of a new C(sp2) - C bond and a C(sp2) - Cl bond.
- Lai, Junshan,Tian, Lixia,Liang, Yongping,Zhang, Yuan,Xie, Xingang,Fang, Bowen,Tang, Shouchu
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Read Online
- Novel benzenesulfonamide-bearing pyrazoles and 1,2,4-thiadiazoles as selective carbonic anhydrase inhibitors
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Two series comprising 20 novel benzenesulfonamides bearing thioureido-linked pyrazole 8 and amino-1,2,4-thiadiazole 10 were synthesized and assayed as human carbonic anhydrase (hCA) inhibitors against isoforms I and II as well as the tumor-associated isof
- Kumar, Rajiv,Kumar, Amit,Ram, Sita,Angeli, Andrea,Bonardi, Alessandro,Nocentini, Alessio,Gratteri, Paola,Supuran, Claudiu T.,Sharma, Pawan K.
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- MTA-Cooperative PRMT5 Inhibitors
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The present invention relates to compounds that inhibit Protein Arginine N-Methyl Transferase 5 (PRMT5) activity. In particular, the present invention relates to compounds, pharmaceutical compositions and methods of use, such as methods of treating cancer using the compounds and pharmaceutical compositions of the present invention.
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Paragraph 0235-0236
(2021/03/19)
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- Palladium-Catalyzed Allyl-Allyl Reductive Coupling of Allylamines or Allylic Alcohols with H2as Sole Reductant
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Catalytic carbon-carbon bond formation building on reductive coupling is a powerful method for the preparation of organic compounds. The identification of environmentally benign reductants is key for establishing an efficient reductive coupling reaction. Herein an efficient strategy enabling H2 as the sole reductant for the palladium-catalyzed allyl-allyl reductive coupling reaction is described. A wide range of allylamines and allylic alcohols as well as allylic ethers proceed smoothly to deliver the C-C coupling products under 1 atm of H2. Kinetic studies suggested that the dinuclear palladium species was involved in the catalytic cycle.
- Zhou, Xibing,Zhang, Guoying,Huang, Renbin,Huang, Hanmin
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p. 365 - 369
(2021/01/26)
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- Regiodivergent Synthesis of Bis(4-oxycoumarin)-based Dioxabicycles: Exploration of [4 + 4] (Heterocyclo)reversion/addition and 1,5-Hydrogen Shift Photochromism
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Two isomeric dioxabicyclic molecular skeletons were constructed by employing the concepts of divergent synthesis. A base-mediated and an acid-catalyzed pseudo-three-component reaction of two equivalents of 4-hydroxycoumarin and (Z)-3-chloro-3-phenylacryla
- Vyasamudri, Sameer,Yang, Ding-Yah
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- Superacid-promoted synthesis of quinoline derivatives
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A series of vinylogous imines have been prepared from anilines and cinnamaldehydes. These substrates react in superacidic media to provide quinolines and related compounds. A mechanism for the conversion is proposed which involves the cyclization of dicationic superelectrophilic intermediates. Aromatization of the quinoline ring is thought to occur by superacid-promoted elimination of benzene.
- Klumpp, Douglas A.,Stentzel, Michael R.,Vuong, Hein
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supporting information
(2020/01/24)
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- Pendant Alkoxy Groups on N-Aryl Substitutions Drive the Efficiency of Imidazolylidene Catalysts for Homoenolate Annulation from Enal and Aldehyde
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Hydrogen-transfer in the tetrahedral intermediate generated from an imidazolylidene catalyst and α,β-unsaturated aldehyde forms a conjugated Breslow intermediate. This is a critical step affecting the efficiency of the NHC-catalyzed γ-butyrolactone formation via homoenolate addition to aryl aldehydes. A novel type of imidazolylidene catalyst with pendant alkoxy groups on the ortho-N-aryl groups is described. Catalyst of this sort facilitates the formation of the conjugated Breslow intermediate. Studies of the rate constants for homoenolate annulation affording γ-butyrolactones, reveal that introduction of the oxygen atoms in the appropriate position of the N-aryl substituents can increase the efficiency of imidazolylidene catalysts. Structural and mechanistic studies revealed that pendant alkoxy groups can be located close to the proton of the tetrahedral intermediate, thereby facilitating the proton transfer.
- Kyan, Ryuji,Mase, Nobuyuki,Narumi, Tetsuo,Sato, Kohei
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supporting information
p. 19031 - 19036
(2020/08/25)
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- Β - chloro - α, β - unsaturated - 1, 3 - dithiane compound preparation method and application of
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The invention provides a beta-chloro-alpha, beta-nonsaturated-1,3-dithiane compound preparation method and use. The preparation method comprises that a solvent, 2-chloro-1,3-dithiane, an alkyne compound and iodine and/or di-tert-butyl peroxide are added into a reactor, the mixture undergoes a reaction at a certain temperature and the reaction product is separated and purified so that the corresponding beta-chloro-alpha, beta-nonsaturated-1,3-dithiane compound is obtained. The preparation method utilizes cheap and easily available raw materials and realizes high efficiency preparation of the beta-chloro-alpha, beta-nonsaturated-1,3-dithiane compound by simple mixing and stirring. The preparation method has the advantages of mild reaction conditions, high yield, environmental friendliness and atom economy. The beta-chloro-alpha, beta-nonsaturated-1,3-dithiane compound can be used for preparation of a plurality of useful compound skeletons and especially for preparation of pyrazole, acridine and phenyl hydrazone compounds, a beta-chloro-alpha, beta-nonsaturated aldehyde compound, a beta-carbonyl or alpha, beta-nonsaturated-1,3-dithiane compound and an allene compound.
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- Oxazolidinone compound containing piperazine hydrazone structure
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The invention discloses an oxazolidinone compound containing a piperazine hydrazone structure. The oxazolidinone compound comprises a compound shown as a general formula (I), or stereisomer thereof, or pharmaceutically-acceptable salt thereof, or solvate thereof or prodrug thereof, wherein R1 is hydrogen, fluorine, chlorine or trifluoromethyl, R2 is -NHCOCH3 or -OH, R3 is Ar which is C5-C10 aryl substituted by any 1-3 R4 and heteroaryl, and R4 is hydrogen, hydroxyl, halogen, nitro, amino, cyan, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 alkyl substituted by hydroxyl, amino or halogen, C1-C6 alkoxy substituted by hydroxyl, amino or halogen, amino substituted by mono- or bi-(C1-C6 alkyl), C1-C6 alkyl amido, free, salty, esterified and amidated hydroxyl, C1-C6 alkyl sulfinyl, C1-C6 alkyl sulfonyl, C1-C6 alkyl acyl and carbamoyl. The oxazolidinone compound can be used for preparing drug for treating microbial infection.
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Paragraph 0153; 0154
(2017/09/02)
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- Ugi Reaction Followed by Intramolecular Diels–Alder Reaction and Elimination of HCl: One-Pot Approach to Arene-Fused Isoindolinones
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A one-pot procedure involving a four-component Ugi reaction followed by an intramolecular Diels–Alder reaction/HCl elimination cascade has been developed to provide rapid access to the isoindolinone framework in a diversity-oriented fashion. The scope of
- Huang, Jianjun,Du, Xiaochen,Van Hecke, Kristof,Van der Eycken, Erik V.,Pereshivko, Olga P.,Peshkov, Vsevolod A.
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supporting information
p. 4379 - 4388
(2017/08/23)
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- Base-Promoted Intermolecular Cyclization of Substituted 3-Aryl(Heteroaryl)-3-chloroacrylaldehydes and Tetrahydroisoquinolines: An Approach to Access Pyrrolo[2,1-a]isoquinolines
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We have developed a new base-promoted intermolecular cascade cyclization reaction of substituted 3-aryl(heteroaryl)-3-chloroacrylaldehydes and tetrahydroisoquinolines in one pot. The reaction provides a facile and practical synthesis of pyrrolo[2,1-a]isoquinolines. A number of pyrrolo[2,1-a]isoquinolines were synthesized in moderate to high yields (up to 97%).
- Yang, Ziqi,Lu, Ning,Wei, Zhonglin,Cao, Jungang,Liang, Dapeng,Duan, Haifeng,Lin, Yingjie
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p. 11950 - 11955
(2016/12/09)
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- Silver Tetrafluoroborate-Catalyzed Oxa-Diels-Alder Reaction between Electrically Neutral Dienes and Aldehydes
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Chemoselective oxa-Diels-Alder reactions between electrically neutral 1,3-dienes and various aldehydes were achieved using the commercially available silver tetrafluoroborate (AgBF4) as catalyst. This catalytic process has high functional group tolerance. Heteroatoms at the β-position of the aryl aldehydes can greatly promote the reactivity of the substrates even with heterocyclic aldehydes that were previously believed to be unreactive for the oxa-Diels-Alder reaction. In addition, acroleins with β-heteroatom substitution are also good substrates. High chemoselectivity and regioselectivity were achieved at room temperature for the oxa-Diels-Alder reaction between acroleins and stoichiometric simple 1,3-dienes.
- Zou, Xiaodong,Yang, Lizheng,Liu, Xiangli,Sun, Hao,Lu, Hongjian
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supporting information
p. 3040 - 3046
(2015/11/03)
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- Thermolysis of N-aryl enaminoimine hydrochloride derivatives: A short and general method for the synthesis of pyranoquinolin-3-one and pyranoacridin-3-one derivatives
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A short synthesis of 3H-pyrano[3,2-f]quinolin-3-one, 3H-acenaphtho[1,2-b]pyrano-[3,2-f]quinolin-3-one, and 3H-benzo[h]pyrano[3,2-a]acridin-3-one derivatives are described via thermolysis of suitable enaminoimine hydrochloride derivatives.
- Patra, Prasanta,Kar, Gandhi K.,Khatua, Biswajit
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p. 1306 - 1310
(2015/04/27)
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- Synthesis of substituted azulenes via Pt(II)-Catalyzed ring-expanding cycloisomerization
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Substituted azulenes, valuable structures for electronic devices and pharmaceuticals, have been synthesized by the platinum(II)-catalyzed intramolecular ring-expanding cycloisomerization of 1-en-3-yne with ortho-disubstituted benzene. This novel method provides an alternative route for the efficient synthesis of substituted azulenes. The reaction mechanism of selected catalytic transformations was explored using density functional calculations.
- Usui, Kazuteru,Tanoue, Kensuke,Yamamoto, Kosuke,Shimizu, Takashi,Suemune, Hiroshi
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supporting information
p. 4662 - 4665
(2015/01/16)
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- Efficient catalytic activity of transition metal ions in Vilsmeier-Haack reactions with acetophenones
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Vilsmeier-Haack (VH) formylation reactions with acetophenones are sluggish in acetonitrile medium even at elevated temperatures. However, millimolar concentrations of transition metal ions such as Cu(II), Ni(II), Co(II), and Cd(II) were found to exhibit efficient catalytic activity in Vilsmeier-Haack Reactions with acetophenones. Reactions are accelerated remarkably in the presence of transition metal ions. The VH reactions followed second order kinetics and afforded acetyl derivatives under kinetic conditions also irrespective of the nature of oxychloride (POCl3 or SOCl2) used for the preparation of VH reagent along with DMF. On the basis of UV-vis spectroscopic studies and kinetic observations, participation of a ternary precursor [M(II) S (VHR)] in the rate-limiting step has been proposed to explain the mechanism of the metal ion-catalyzed VH reaction.
- Aneesa,Rajanna,Venkateswarlu,Reddy, K. Rajendar,Kumar, Y. Arun
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p. 721 - 733
(2013/10/21)
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- Unexpected tandem reaction of new type moritabaylis- Hillman adducts promoted by [HMIM]HSO4/NANO3 system
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A tandem reaction of new type Baylis-Hillman adducts 1 was prompted by ionic liquid [Hmim]HSO4/NaNO3 system and the unexpected products 6-aryl-2H-pyran-3-carboxylates 2 and imidazolium salts 3 were efficiently formed via the rearrang
- Zhong, Weihui,Wang, Guan,Chen, Kai
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scheme or table
p. 43 - 56
(2012/02/02)
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- Continuous-flow preparation and use of β-chloro enals using the Vilsmeier reagent
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The Vilsmeier reagent is used in the preparation of a wide variety of heterocycles, such as pyrazoles, via formation of β-chloroacrolein intermediates. However, use of this extremely reactive reagent on large scale requires special precautions to avoid potentially dangerous exotherms. This article describes the safe preparation at room temperature of the Vilsmeier reagent under flow conditions for the formation of β-chloroacroleins and 3-formylchromones, as well as the use of these in multistep, continuous flow processes for the syntheses of β-acrylonitriles and polysubstituted pyrazoles.
- Pellegatti, Laurent,Buchwald, Stephen L.
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p. 1442 - 1448
(2012/10/29)
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- Efficient synthesis of a new type of baylis-hillman adducts and their stereoselective bromination
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A new type of Baylis-Hillman adducts derived from chlorovinyl aldehydes were prepared via Vilsmeier reaction of ketones with a bis(trichloromethyl) carbonate (BTC)/DMF system to construct chlorovinyl aldehydes, followed by sonochemical Baylis-Hillman reaction under solvent-free conditions. The stereoselective bromination of these new compounds with a Br2-Ph3P system has been achieved efficiently with good to excellent yields under mild conditions. Copyright Taylor & Francis Group, LLC.
- Zhong, Weihui,Jiang, Lingbo,Guo, Baoming,Wu, Yaotiao,Hong, Lingjuan,Chen, Yanhui
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experimental part
p. 2441 - 2456
(2010/09/05)
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- One-pot synthesis of new type aza- Baylis-Hillman adducts from chlorovinyl aldehydes under solvent-free condition
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A series of new type aza- Baylis-Hillman adducts were prepared in moderate yields by one-pot treatment of chlorovinyl aldehydes, benzenesulfonamides and activated olefi ns under solvent-free condition. The chlorovinyl aldehydes were obtained via chlorofor
- Zhong, Weihui,Chen, Yanhui,Wang, Guan
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body text
p. 44 - 49
(2010/07/03)
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- Synthesis of a novel series of thieno[3,2-d]pyrimidin-4-(3H)-ones
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2-Aminothieno[3,2-d]pyrimidin-4-ones were synthesized in one step by condensation of 3-amino(benzo)thiophene car-boxylate with chloroformamidine hydrochloride. Georg Thieme Verlag Stuttgart.
- Abdillahi, Ismail,Kirsch, Gilbert
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scheme or table
p. 1428 - 1430
(2010/10/03)
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- Synthesis and characterization of novel, thermally stable 2-aryl-5-dicyanovinylthiophenes and 5-aryl-5'-dicyanovinyl-2,2'-bithiophenes as potentially promising non-linear optical materials
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Two series of dicyanovinyl-substituted compounds namely 2-aryl-5-dicyanovinylthiophenes and 5-aryl-5′-dicyanovinyl-2,2′-bithiophenes were synthesized through Knoevenagel condensation of the corresponding 2-aryl-5-formyl-thiophenes and 5-aryl-5′-formyl-2,2
- Herbivo, Cyril,Comel, Alain,Kirsch,Fonseca, A. Maurício C.,Belsley, M.,Raposo, M. Manuela M.
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scheme or table
p. 217 - 226
(2010/11/05)
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- Synthesis of 5-aryl-5′-formyl-2,2′-bithiophenes as new precursors for nonlinear optical (NLO) materials
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A series of formyl-substituted 5-aryl-2,2′-bithiophenes 5 were synthesized using two different methods: Vilsmeier-Haack-Arnold reaction (VHA) or through Suzuki coupling. The synthesis of compounds 5 through the Vilsmeier-Haack-Arnold reaction, starting from inexpensive and easily available precursors such as acetophenones, gave the title compounds in low yields after four reaction steps. On the other hand Suzuki coupling of functionalized arylboronic acids 7 and the 5-bromo-5′-formyl-2,2′-bithiophene 6 gave compounds 5 in good yields in only one step.
- Herbivo, Cyril,Comel, Alain,Kirsch,Raposo, M. Manuela M.
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experimental part
p. 2079 - 2086
(2009/07/18)
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- Synthesis, cytotoxicity and effects of some 1,2,4-triazole and 1,3,4-thiadiazole derivatives on immunocompetent cells
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Novel derivatives of 4,5-substituted-1,2,4-triazole-thiones and 2,5-substituted-1,3,4-thiadiazoles were synthesized and evaluated for their cytotoxicity. The biological study indicated that compounds 4-ethyl-5-(4,5,6,7-tetrahydro-1-benzothien-2-yl)-2,4-di
- Mavrova, Anelia Ts.,Wesselinova, Diana,Tsenov, Yordan A.,Denkova, Pavletta
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experimental part
p. 63 - 69
(2009/04/07)
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- A versatile methodology for the synthesis of α,β-unsaturated 3-iminophosphines
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Fourteen new αβ-unsaturated β-chloroimines were synthesized from commercially available ketones using the Vilsmeier-Haack reagent, followed by Schiff-base condensation. Each imine was subsequently converted to an αβ-unsaturated 3-iminophosphine through either late-metal-catalyzed phosphorus-carbon cross-coupling or through an addition-elimina-tion sequence. Depending on the substituents present on the vinyl group, the resultant phosphines were isolated as either E or Z diastereomers with successful isolation of predominately single diastereomers for all fourteen new phosphines investigated. Full synthetic and spectroscopic details, as well as several X-ray crystal structures of these new imines and phosphines, are reported in addition to X-ray crystal structures of related palladium complexes.
- Shaffer, Andrew R.,Schmidt, Joseph A. R.
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experimental part
p. 2662 - 2673
(2009/12/03)
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- Synthesis and biological evaluation of guanylhydrazone coactivator binding inhibitors for the estrogen receptor
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Most patients with hormone-responsive breast cancer eventually develop resistance to traditional antiestrogens such as tamoxifen, and this has become a major obstacle in their treatment. We prepared and characterized the activity of a series of 16 guanylhydrazone small molecules that are designed to block estrogen receptor (ER) activity through a non-traditional mechanism, by directly interfering with coactivator binding to agonist-liganded ER. The inhibitory activity of these compounds was determined in cell-based transcription assays using ER-responsive reporter gene and mammalian two-hybrid assays. Several of the compounds gave IC50 values in the low micromolar range. Two secondary assays were used to confirm that these compounds were acting through the proposed non-traditional mode of estrogen inhibitory action and not as conventional antagonists at the ligand binding site.
- LaFrate, Andrew L.,Gunther, Jillian R.,Carlson, Kathryn E.,Katzenellenbogen, John A.
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experimental part
p. 10075 - 10084
(2009/04/06)
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- Design, synthesis, and biological evaluation of thiophene analogues of chalcones
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Chalcones are characterized by possessing an enone moiety between two aromatic rings. A series of chalcone-like agents, in which the double bond of the enone system is embedded within a thiophene ring, were synthesized and evaluated for antiproliferative
- Romagnoli, Romeo,Baraldi, Pier Giovanni,Carrion, Maria Dora,Cara, Carlota Lopez,Cruz-Lopez, Olga,Preti, Delia,Tolomeo, Manlio,Grimaudo, Stefania,Cristina, Antonella Di,Zonta, Nicola,Balzarini, Jan,Brancale, Andrea,Sarkar, Taradas,Hamel, Ernest
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p. 5367 - 5376
(2008/12/20)
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- Synthesis of selenophene analogues of the tacrine series: Comparison of classical route and microwave irradiation
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New 3-amino-2-selenophenecarbonitriles condensed with cyclanones to afford, in one step, analogues of Tacrine. A comparison between classical heating and microwave irradiation for the Friedlaender condensation is presented. Georg Thieme Verlag Stuttgart.
- Thomae, David,Kirsch, Gilbert,Seck, Pierre
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scheme or table
p. 1600 - 1606
(2009/04/03)
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- Titanacyclobutenes or titanium vinyl carbene complexes? Reactivity of organotitanium species generated by the reaction of γ-chloroallyl sulfides with a titanocene(II) reagent
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The reactivity of the organotitanium species generated by the reductive titanation of γ-chloroallyl sulfides with the titanocene(II) reagent [Cp2Ti{P(OEt)3}2] was studied. The organotitanium species formed from α-monosubstituted γ-chloroallyl sulfides reacted with 1,5-diphenylpentan-3-one and styrene to produce conjugated dienes and vinyl cyclopropanes as major products, thus suggesting the formation of vinyl carbene complexes as intermediates. On the contrary, the organotitanium species generated from acyclic β,γ-disubstituted γ-chloroallyl sulfides revealed titanacyclobutene-like reactivity, and their reaction with 1,5-diphenylpentan-3-one produced homoallyl alcohols. These organotitanium species did not react with styrene, but did react with dichlorophenylphosphine to afford phosphacyclobutenes. In the case of β-monosubstituted, γ-monosubstituted, and α,γ- disubstituted γ-chloroallyl sulfides, the organotitanium species reacted with both 1,5-diphenylpentan-3-one and styrene. The former reaction produced homoallyl alcohols and the latter gave vinyl cyclopropanes or unconjugated dienes. These results suggest that titanacyclobutenes and/or titanium vinyl carbene complexes are produced by the reductive titanation of γ-chloroallyl sulfides depending on their substitution patterns.
- Shono, Tomohiro,Kurashige, Rie,Mukaiyama, Ryo,Tsubouchi, Akira,Takeda, Takeshi
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p. 4074 - 4080
(2008/02/08)
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- Reactions of (Z)-3-aryl-3-chloropropenals with nucleophiles: Stereoselective formation of (E)-vinylogous esters, (E)-vinylogous amides, and vinamidinium salts
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The highly stereoselective conversions of (Z)-3-aryl-3-chloropropenals to (E)-3-alkoxy-3-arylpropenals, to (E)-3-aryl-3-morphorlinopropenals, and to vinamidinium salts are reported. The stereochemical assignments were based on 2D-NMR experiments.
- Clough, Stuart,Gupton, John,Ligali, Adepeju,Roberts, Matthew,Driscoll, David,Annett, Scott,Hewitt, Alisa,Hudson, Matthew,Jackson, Edward,Miller, Robert,Norwood, Bradley,Kanters, Rene,Wyre, Hadley,Petruzzi, Heather
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p. 7554 - 7561
(2007/10/03)
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- Ultrasonically accelerated vilsmeier haack cyclisation and formylation reactions
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Ultrasonically irradiated Vilsmeier Haack (VH) reaction with acetanilides, hydrocarbons and acetophenones exhibited dramatic rate enhancements with excellent yields. The VH reaction with acetanilides afforded 2-chloro-3-formyl quino-line derivatives, hydrocarbons underwent formylation while hydroxy acetophenones yielded 3-formyl chromones.
- Moazzam Ali, Mir,Sana, Sariah,Tasneem,Rajanna,Saiprakash
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p. 1351 - 1356
(2007/10/03)
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- Synthesis of five-membered nitrogen heterocycles from iron-substituted enals: Novel insight into the η5-cyclopentadienyl(dicarbonyl)iron residue as a versatile functional group
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Dihydropyrrolones have been synthesized from β-cyclopentadienyl(dicarbonyl)iron-substituted enals and primary amines in a novel titanium-mediated intramolecular reaction cascade. The iron compounds were readily prepared from the corresponding β-halogeno-s
- Rueck-Braun, Karola,Martin, Til,Mikulas, Mark
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p. 1028 - 1037
(2007/10/03)
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- Synthesis and stereochemistry of β-aryl-β-haloacroleins: Useful intermediates for the preparation of (Z) and (E)-2-en-4-ynecarbaldehydes and for the synthesis of rubrolides
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The synthesis of α-substituted β-aryl-β-haloacroleins by two different pathways is presented. The determination of their stereochemistry by NOE experiments is reported for the first time. Furthermore, we describe the preparation of 2-en-4-ynecarbaldehydes
- Prim, Damien,Fuss, Alexia,Kirsch, Gilbert,Silva, Artur M. S.
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p. 1175 - 1180
(2007/10/03)
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- On the regio and stereo selective formylations of acyclic alpha methylene ketones towards Vilsmeier Haack reagent
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The regio and stereo selectivities of Vilsmeier Haack reaction of ketomethylene compounds have been predicted. The possible mechanistic pathway has also been proposed.
- Chakraborty,Ray
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p. 1869 - 1876
(2007/10/02)
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- New Thiophene Derivatives as Potential Materials for Non Linear Optics
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A method of synthesis of unsymmetrical 2,5-diarylthiophenes is described using β-chloroacroleins, prepared from acetophenones, and their condensation with sodium sulfide and various benzyl bromides.
- Kirsch, Gilbert,Prim, Damien,Leising, Frederic,Mignani, Gerard
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p. 1005 - 1010
(2007/10/02)
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- SYNTHESIS OF NEW 2,5-DIARYL SELENOPHENES
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A synthesis of 2,5-parasubstituted diaryl selenophenes is described. β-Aryl-β-chloro acroleins, easily prepared from substituted acetophenones and Vilsmaier-Haack reagent, are condensed with appropriate benzylbromide derivatives to give the title compound
- Prim, Damien,Joseph, Delphine,Kirsch, Gilbert
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p. 137 - 144
(2007/10/02)
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- A simple and new synthetic method for the preparation of 2-phenyl-6-substituted quinolines
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2-phenylquinoline derivatives have been synthesized through the thermolysis of suitable enaminoimine hydrochlorides.
- Roy,Kar,Ray
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p. 1959 - 1965
(2007/10/02)
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- Nucleophilic Attacks on Carbon-Carbon Double Bonds. 33. Approaching the Retention Region from the Stereoconvergence Region in Nucleophilic Substitution of (E)- and (Z)-Methyl p-Substituted α-Formyl- and α-(tert-Butoxycarbonyl)-β-halocinnamates
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The three E/Z pairs of the highly electrophilic vinyl halides β-chloro-α-(methoxycarbonyl)-p-nitrocinnamaldehydes (6), tert-butyl methyl β-bromo(p-methylbenzylidene)- (21) and β-bromo(p-nitrobenzylidene)malonates (26) were prepared and separated.The structures of (E)-6 and (E)-21 and of intermediates in their synthesis were determined by X-ray crystallography.The stereochemistry of the substitution of the halogen by p-toluenethiolate (TolS-) and p-cresolate (TolO-) ions was investigated by using 1H NMR as the stereochemical probe.Substitution of 6 in Me2SO-d6 by TolS- proceeds with nearly complete stereoconvergence, whereas substitution by TolO- proceeds with high extent of, but not complete, retention of configuration.Cl--assisted (E)-6(Z)-6 isomerization was observed.The substitution of (E)- and (Z)-21 in Me2SO-d6 and of (E)- and (Z)-26 in 95:5 CD3CN-Me2SO-d6 by TolS- proceeds with complete retention of configuration and by TolO- with nearly complete retention.The results are discussed in terms of the multistep route of vinylic substitution via an intermediate carbanion.They corroborate the predictions of the variable transition-state theory in nucleophilic vinylic substitution that stereoconvergence will be observed for highly activated systems and that the stereochemistry should be gradually changed to retention when the electrophilicity of the vinyl halide is decreased and near the borderline when the nature of the nucleophile is changed.Comparison with other systems for which stereoconvergence was observed raises the question of the structural borderline between stereoconvergence and retention, and predictions for the stereochemical outcome in substitutions ofsystems not yet studied are given.Some stereochemical aspects of the condensation, bromine addition, and HBr elimination in the reactions leading to 21 and 26 are briefly discussed.
- Rappoport, Zvi,Gazit, Aviv
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p. 4112 - 4131
(2007/10/02)
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