- A covalent p97/VCP ATPase inhibitor can overcome resistance to CB-5083 and NMS-873 in colorectal cancer cells
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Small-molecule inhibitors of p97 are useful tools to study p97 function. Human p97 is an important AAA ATPase due to its diverse cellular functions and implication in mediating the turnover of proteins involved in tumorigenesis and virus infections. Multi
- Zhang, Gang,Li, Shan,Wang, Feng,Jones, Amanda C.,Goldberg, Alexander F.G.,Lin, Benjamin,Virgil, Scott,Stoltz, Brian M.,Deshaies, Raymond J.,Chou, Tsui-Fen
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- Skeletally Tunable Seven-Membered-Ring Fused Pyrroles
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We describe a copper-mediated method that enables the synthesis of seven-membered-ring fused pyrroles (7-mrFPs). The protocol proceeds via an in situ spiro-intermediate ring expansion and tolerates a library of 7-mrFP derivatives with a broad range of functional groups in a simple step with tangible parameters and substrate adaptations. These rare 7-mrFPs are now accessible on a millimolar scale, and selected examples exhibit high antioxidant activity.
- Andreou, Dimitrios,Essien, Nsikak B.,Pubill-Ulldemolins, Cristina,Terzidis, Michael A.,Papadopoulos, Athanasios N.,Kostakis, George E.,Lykakis, Ioannis N.
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supporting information
p. 6685 - 6690
(2021/09/11)
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- Biological evaluation and SAR analysis of novel covalent inhibitors against fructose-1,6-bisphosphatase
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Fructose-1,6-bisphosphatase (FBPase) is an attractive target for affecting the GNG pathway. In our previous study, the C128 site of FBPase has been identified as a new allosteric site, where several nitrovinyl compounds can bind to inhibit FBPase activity. Herein, a series of nitrostyrene derivatives were further synthesized, and their inhibitory activities against FBPase were investigated in vitro. Most of the prepared nitrostyrene compounds exhibit potent FBPase inhibition (IC50 3, CF3, OH, COOH, or 2-nitrovinyl were installed at the R2 (meta-) position of the benzene ring, the FBPase inhibitory activities of the resulting compounds increased 4.5–55 folds compared to those compounds with the same groups at the R1 (para-) position. In addition, the preferred substituents at the R3 position were Cl or Br, thus compound HS36 exhibited the most potent inhibitory activity (IC50 = 0.15 μM). The molecular docking and site-directed mutation suggest that C128 and N125 are essential for the binding of HS36 and FBPase, which is consistent with the C128-N125-S123 allosteric inhibition mechanism. The reaction enthalpy calculations show that the order of the reactions of compounds with thiol groups at the R3 position is Cl > H > CH3. CoMSIA analysis is consistent with our proposed binding mode. The effect of compounds HS12 and HS36 on glucose production in primary mouse hepatocytes were further evaluated, showing that the inhibition was 71% and 41% at 100 μM, respectively.
- Chen, Haifeng,Guo, Yanrong,Han, Xinya,Hu, Wei,Huang, Yunyuan,Ren, Yanliang,Tang, Zilong,Wang, Qi,Wei, Lin,Xia, Qinfei,Yan, Jufen
-
supporting information
(2020/07/23)
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- Geometrically Selective Denitrative Trifluoromethylthiolation of β-Nitrostyrenes with AgSCF3for (E)-Vinyl Trifluoromethyl Thioethers
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An efficient copper(II)-promoted denitrative trifluoromethylthiolation under mild reaction conditions has been developed for vinyl trifluoromethyl thioethers to construct Cvinyl-SCF3 bonds with stable AgSCF3 as a source of the trifluoromethylthio. This reaction system tolerates a broad range of functional groups to commendably achieve a high product yield and excellent stereoselectivity of E/Z.
- Fang, Ge,Hong, Jianquan,Huang, Shuai,Jiang, Chao,Liu, Yang,Zhang, Wei,Zheng, Changge
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supporting information
(2020/07/03)
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- Iodolopyrazolium Salts: Synthesis, Derivatizations, and Applications
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The synthesis of iodolopyrazolium triflates via an oxidative cyclization of 3-(2-iodophenyl)-1H-pyrazoles is described. The reaction is characterized by a broad substrate scope, and various applications of these novel cyclic iodolium salts acting as useful synthetic intermediates are demonstrated, in particular in site-selective ring openings. This was finally applied to generate derivatives of the anti-inflammatory drug celecoxib. Their application as highly active halogen-bond donors is shown as well.
- Boelke, Andreas,Caspers, Lucien D.,Kuczmera, Thomas J.,Lork, Enno,Nachtsheim, Boris J.
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supporting information
p. 7261 - 7266
(2020/10/05)
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- A chiral bicyclic skeleton-tethered bipyridine-Zn(OTf)2 complex as a Lewis acid: Enantioselective Friedel-Crafts alkylation of indoles with nitroalkenes
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A conformationally rigid chiral bicyclic skeleton tethered bipyridine-Zn(OTf)2 complex facilitated the enantioselective Friedel-Crafts alkylation of indoles with trans-β-nitroarylalkenes in an enantioselective manner at elevated temperature. Indoles reacted smoothly with β-nitroarylalkenes to generate the corresponding 3-(2-nitroalkyl)indoles in good to excellent yields (up to 94%) with moderate to excellent enantioselectivities (up to 91%). The stereochemical outcome of the product from indole and trans-β-nitrostyrene in the presence of the CRCB tethered bipyridine-Zn(OTf)2 complex and the DFT calculation of the CRCB tethered bipyridine-Zn:trans-β-nitrostyrene complex support the si-face attack of indole on trans-β-nitrostyrene.
- Venkatanna, Kesa,Yeswanth Kumar, Santhakumar,Karthick, Muthupandi,Padmanaban, Ramanathan,Ramaraj Ramanathan, Chinnasamy
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p. 4077 - 4086
(2019/04/30)
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- Synthesis of Functionalized Indolines and Dihydrobenzofurans by Iron and Copper Catalyzed Aryl C-N and C-O Bond Formation
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A simple and effective one-pot, two-step intramolecular aryl C-N and C-O bond forming process for the preparation of a wide range of benzo-fused heterocyclic scaffolds using iron and copper catalysis is described. Activated aryl rings were subjected to a highly regioselective, iron(III) triflimide-catalyzed iodination, followed by a copper(I)-catalyzed intramolecular N-or O-arylation step leading to indolines, dihydrobenzofurans, and six-membered analogues. The general applicability and functional group tolerance of this method were exemplified by the total synthesis of the neolignan natural product, (+)-obtusafuran. DFT calculations using Fukui functions were also performed, providing a molecular orbital rationale for the highly regioselective arene iodination process.
- Henry, Martyn C.,Senn, Hans Martin,Sutherland, Andrew
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p. 346 - 364
(2019/01/08)
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- NHC-Catalyzed Dual Stetter Reaction: A Mild Cascade Annulation for the Syntheses of Naphthoquinones, Isoflavanones, and Sugar-Based Chiral Analogues
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The N-heterocycle carbene (NHC)-catalyzed dual Stetter cascade reaction is discovered through coupling of β-nitrostyrene with phthalaldehyde under mild conditions to furnish valuable aryl-naphthoquinones. The generality of the new reaction is validated through the development of a C-C and O-C bond forming Stetter cascade reaction using salicylaldehydes to obtain functionalized dihydroisoflavanones. The mild NHC organocatalysis is successfully employed for the construction of optically pure sugar-based naphthoquinones and dihydroisoflavanones. Herein, NHC is found as a unique and powerful organocatalyst to construct homoatomic C-C cross-coupling, heteroatomic O-C bond formation, and cascade cyclization utilizing NO2 as a leaving group at ambient temperature. A mechanistic pathway of the new metal-free catalysis is predicted on the basis of our ESI-MS study of the ongoing reaction and literature.
- Mitra, Rajendra N.,Show, Krishanu,Barman, Debabrata,Sarkar, Satinath,Maiti, Dilip K.
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- Comprehensive evaluation of antioxidant effects of Japanese Kampo medicines led to identification of Tsudosan formulation as a potent antioxidant agent
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Oxidative stress due to the overproduction of reactive oxygen species plays an important role in the pathogenesis of various diseases. In the present study, we comprehensively evaluated the antioxidant activities of 147 oral formulations of Japanese traditional herbal medicines (Kampo medicines), representing the entire panel of oral Kampo medicines listed in the Japanese National Health Insurance Drug List, using in vitro radical scavenging assays, including the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity assay, the superoxide anion scavenging activity assay, and the oxygen radical absorption capacity assay. Three of the formulations tested, namely, Tsudosan, Daisaikoto, and Masiningan, showed the most potent in vitro antioxidant activities and were selected for further investigation of their intracellular and in vivo antioxidant effects. The results of the 2′,7′-dichlorodihydrofluorescin diacetate assay demonstrated that all three Kampo medicines significantly inhibited hydrogen peroxide-induced oxidative stress in human hepatocellular liver carcinoma HepG2 cells. In addition, Tsudosan significantly increased the serum biological antioxidant potential values when orally administrated to mice, indicating that it also had in vivo antioxidant activity. The potent antioxidant activity of Tsudosan may be one of the mechanisms closely correlated to its clinical usage against blood stasis.
- Sato, Naoko,Li, Wei,Takemoto, Hiroaki,Takeuchi, Mio,Nakamura, Ai,Tokura, Emi,Akahane, Chie,Ueno, Kanako,Komatsu, Kana,Kuriyama, Noriko,Onoda, Toshihisa,Higai, Koji,Koike, Kazuo
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p. 163 - 172
(2018/11/06)
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- Synthesis, antiproliferative and pro-apoptotic effects of nitrostyrenes and related compounds in Burkitt’s lymphoma
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Background: Cancers of the lymphatic cells (lymphomas) account for approximately 12% of malignant diseases worldwide. The nitrostyrene scaffold is identified as a lead target structure for the development of particularly effective compounds targeting Burkitt’s lymphoma (BL). Objectives: The aims of the curent study were to synthesise a panel of nitrostyrene compounds and to evaluate their activity in Burkitt’s lymphoma (BL). Methods: A panel of structurally varied compounds were designed and synthesised using Henry Knoevenagel condensation reactions. Single crystal X-Ray analysis confirmed the E configuration for six examples of these novel structures. A number of nitrostyrene-related compounds were also investigated including 1,3-bis(aryl)-2-nitropropenes together with heterocyclic scaffolds containing the nitrovinyl pharmacophore such as 3-nitro-2-phenyl-2H-chromenes. The antiproliferative activities of the compounds were evaluated using the BL cell lines EBV- MUTU-1 and EBV+ DG-75 (chemoresistant) to establish preliminary structure-activity relationships. Results: Lead compounds with optimized nitrostyrene scaffolds and 3-nitro-2-phenyl-2Hchromene structures were successfully established with typical IC50 values of 0.45 μM and 0.47 μM in MUTU-1 cells and 1.41 μM and 1.92 μM, respectively, in DG-75 cells. The mechanism of cell death was identified as apoptotic and the lead compound was found to elicit comparable apoptotic effects to Taxol in Burkitt’s lymphoma cell lines MUTU-1 and DG-75. Conclusion: This class of pharmaceutically active compounds with potential for the treatment of Burkitt’s lymphoma suggest a potential role for nitrostyrene based agents in chemotherapy.
- Byrne, Andrew J.,Bright, Sandra A.,Fayne, Darren,McKeown, James P.,McCabe, Thomas,Twamley, Brendan,Williams, Clive,Meegan, Mary J.
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p. 181 - 199
(2018/03/13)
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- One-Step, Effective, and Cascade Syntheses of Highly Functionalized Cyclopentenes with High Diastereoselectivity
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Tetrabutylammonium fluoride works as an effective organocatalyst for the cycloaddition between phenacylmalononitriles and electron-deficient olefins (having substituent groups of NO2, CHO, and COR), providing a facile synthetic route to versatile multifunctionalized cyclopentenes having an allylic quaternary carbon center bearing both cyano and carboxamide groups with high yields and high diastereoselectivity. Preliminary studies reveal that these functionalized cyclopentenes are convenient precursors for making α-cyano-functionalized cyclopentadienone oximes.
- Alishetty, Suman,Shih, Hong-Pin,Han, Chien-Chung
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p. 2513 - 2516
(2018/05/17)
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- Synthesis of Benzo[4,5]imidazo[2,1-b]thiazole by Copper(II)-Catalyzed Thioamination of Nitroalkene with 1H-Benzo[d]imidazole-2-thiol
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A Copper(II)-catalyzed thioamination of β-nitroalkene with 1H-benzo[d]imidazole-2-thiol has been developed for the synthesis of benzo[4,5]imidazo[2,1-b]thiazole derivatives. A variety of N-fused benzoimidazothiazole derivatives are obtained in high yields through successive C?N and C?S bond formations. This protocol is also applicable to β-substituted β-nitroalkenes to afford 2,3-disubstituted benzoimidazothiazoles. (Figure presented.).
- Jana, Sourav,Chakraborty, Amrita,Shirinian, Valerii Z.,Hajra, Alakananda
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supporting information
p. 2402 - 2408
(2018/05/08)
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- Tetraarylphosphonium inner-salts (TAPIS) as both Lewis base catalyst and phase tag
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Tetraarylphosphonium inner-salts (TAPIS) have been designed, synthesized and verified as recyclable and reusable Lewis base catalysts. The resulted TAPIS catalyst has been successfully applied in Michael addition, cyanation and trifluoromethylation reactions.
- Guo, Shuhui,Mi, Xueling
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supporting information
p. 2881 - 2884
(2017/07/11)
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- Fe(III)/Pyridine-Mediated Decarboxylative Nitration of α,β-Unsaturated Acids with Iron Nitrate
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A novel and efficient method for the synthesis of (E)-nitroolefins in moderate to excellent yields is developed by Fe(III)/pyridine-mediated decarboxylative nitration of α,β-unsaturated acids with iron nitrate. A series of α,β-unsaturated acids are well tolerated in this procedure.
- Yang, Zan,Li, Jiao,Hua, Jie,Yang, Tao,Yi, Jianmin,Zhou, Congshan
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supporting information
p. 1079 - 1082
(2017/05/19)
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- Catalyst-free sulfa-Michael addition of pyrimidine-2-thiol to nitroolefins
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Catalyst-free sulfa-Michael addition of pyrimidine-2-thiol to nitroolefins is described. A series of 2-((2-nitro-1-arylethyl)thio)pyrimidines were efficiently synthesized. The protocol has advantages of wide range of substituents tolerance, no catalyst, additives and bases, mild condition, and high yield. The method can also extend to gram scale.
- Li, Zheng,Song, Geyang,He, Jiaojiao,Du, Yan,Yang, Jingya
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p. 686 - 698
(2017/09/06)
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- Nitration-Oximization of Styrene Derivatives with tert-Butyl Nitrite: Synthesis of α-Nitrooximes
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A highly efficient method for direct nitration-oximization of styrene derivatives using tert-butyl nitrite (t-BuONO) in DMSO was developed. The present method offers a convenient and practical approach for the synthesis of α-nitrooximes in moderate to high yields. The salient features entail mild reaction conditions, metal-free reagent, environmentally benign solvent and simple experimental procedure.
- Chumnanvej, Napasawan,Katrun, Praewpan,Pohmakotr, Manat,Reutrakul, Vichai,Soorukram, Darunee,Kuhakarn, Chutima
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p. 830 - 838
(2016/09/03)
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- Cinchona alkaloid and di-: Tert -butyldicarbonate-DMAP promoted efficient synthesis of (E)-nitroolefins
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The synthesis of nitroolefins from aldehydes and olefins is generally limited by the formation of a mixture of cis and trans compounds. Here we report an alternative, metal-free protocol for the synthesis of β-nitroolefins from arylidinemalononitrile using cinchona alkaloid along with di-tert-butyldicarbonate-DMAP in high yields with total selectivity.
- Poomathi, Nataraj,Perumal, Paramasivan T.
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p. 54495 - 54502
(2016/07/06)
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- Cu(NO3)2-catalyzed nitrodecarboxylation of α,β-unsaturated acids: facile synthesis of (E)-nitroolefins under additive-free conditions
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Abstract: An additive-free, facile, efficient, and ecofriendly protocol for synthesis of (E)-nitroolefins via nitrodecarboxylation of α,β-unsaturated acids has been developed. Cu(NO3)2 was used as both nitrating agent and catalyst. Furthermore, the presented methodology offers several advantages such as easily accessible and stable substrates, inexpensive catalyst, high to excellent yield, short reaction time, and simple posttreatment procedure. Graphical Abstract: [Figure not available: see fulltext.]
- Luo, Zai-Gang,Xu, Feng,Fang, Yu-Yu,Liu, Peng,Xu, Xue-Mei,Feng, Cheng-Tao,Li, Zhong,He, Jie
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p. 6079 - 6087
(2016/06/01)
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- Yolk-shell-structured mesoporous silica: A bifunctional catalyst for nitroaldol-Michael one-pot cascade reaction
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Great interest in heterogeneous asymmetric catalysis has focused on obtaining an enantioselective cascade reaction through a controllable active site-isolated heterogeneous catalyst. Herein, we utilize a yolk-shell-structured mesoporous silica and assemble an active site-isolated bifunctional heterogeneous catalyst, where chiral cinchonine-based squaramide molecules are anchored within a silicate channel as an outer shell while amine-functionalities are entrapped onto a silicate yolk as an inner core. Structural analyses and characterizations of the heterogeneous catalyst reveal its well-defined single-site chiral active species within its silicate network. Electron microscopy confirms the yolk-shell-structured mesoporous material. As presented in this study, as a bifunctional heterogeneous catalyst, it enables an efficiently nitroaldol-Michael cascade reaction to conduct the three-component coupling of nitromethane, aldehyde and acetylacetone into various chiral diones with high yields and up to 99% enantioselectivities in a one-pot process. As expected, this active site-isolated catalyst not only enhances the catalytic selectivity of the first-step nitroaldol condensation, but also keeps the enantioselectivity of the second-step Michael addition. Moreover, the heterogeneous catalyst can be also recovered easily and recycled repeatedly, making it an interesting feature in a three-component organic transformation.
- An, Juzeng,Cheng, Tanyu,Xiong, Xi,Wu, Liang,Han, Bin,Liu, Guohua
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p. 5714 - 5720
(2016/07/21)
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- An Acid/Base-Regulated Recyclable Strategy for Homogeneous Cinchona Alkaloid-Derived Primary Amine Organocatalysts in Aldol, Vinylogous Michael and Double-Michael Cascade Reactions
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A practical, recyclable strategy for homogeneous cinchona alkaloid-derived primary amine organocatalysts was developed by controlling the solubilities in an aqueous/organic biphasic system through regulating the pH of the aqueous phase, effecting the prot
- Wan, Jingwei,Zhao, Zhiwei,Wang, Falu,Ma, Xuebing
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supporting information
p. 5755 - 5763
(2015/09/15)
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- Mild and efficient reductive deoxygenation of epoxides to olefins with tin(II) chloride/sodium iodide as a novel reagent
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A highly efficient and green protocol is reported for the reductive deoxygenation of organic epoxides to olefins using tin(II) chloride/sodium iodide as a novel reagent. The reaction gives an excellent yield (85-96%) in ethanol under reflux within 2-10 minutes, without affecting other functional groups. The advantages of our method are the use of inexpensive reagents, the eco-friendly and green reaction conditions, and the short reaction times and high yields.
- Pathe, Gulab Khushalrao,Ahmed, Naseem
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supporting information
p. 3542 - 3552
(2015/11/17)
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- Diastereoselective synthesis of polysubstituted cyclopentanols and cyclopentenes containing stereogenic centers via domino Michael/cyclization reaction
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A highly efficient domino Michael/cyclization reaction was developed for the synthesis of cyclopentanols and cyclopentenes with four and three stereogenic centers that were generated in one-pot reaction conditions with high diastereoselectivity. The reactions proceeded through a one-pot three-component reaction of β-nitrostyrenes, malononitrile and phenacyl bromide derivatives in basic media at room temperature.
- Ahadi,Naghdiani,Balalaie,Rominger
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p. 6860 - 6866
(2015/08/24)
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- Ethylenediamine-functionalized magnetic Fe3O4@SiO2 nanoparticles: cooperative trifunctional catalysis for selective synthesis of nitroalkenes
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A magnetically separable trifunctional nanocatalyst Fe3O4@SiO2-NH2 was synthesized and characterized by TEM, FT-IR, XRD, TGA, and EA. The designed nanocatalyst was found to be highly active for selective synthesis of nitroalkenes with nitromethane and aromatic aldehyde through cooperative trifunctional catalysis of primary amine, secondary amine and Si-OH groups on the surface of the catalyst. Under the optimized conditions, various representative substrates were extended to obtain the corresponding products in moderate or excellent yields. After the reaction, the trifunctional nanocatalyst was easily recovered and recycled by applying an external magnet. In addition, a possible cooperative trifunctional catalysis mechanism was also proposed.
- Xue, Fengjun,Dong, Yahao,Hu, Peibo,Deng, Yanan,Wei, Yuping
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p. 73684 - 73691
(2015/09/15)
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- Hyperbranched polyamines: Tunable catalysts for the Henry reaction
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Hyperbranched polyethylenimine derivatives were successfully employed as catalyst in the Henry reaction. The nitroalcohol products were obtained in excellent yields within short reaction times. A one-pot synthesis of β-nitrostyrenes was developed by using ZnCl2 along with hyperbranched polyethylenimine derivatives. Georg Thieme Verlag Stuttgart New York.
- Ganesan, Subramaniapillai Selva,Ganesan, Asaithampi,Kothandapani, Jagatheeswaran
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supporting information
p. 1847 - 1850
(2014/08/18)
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- Oxone/KI-Mediated Nitration of Alkenes and Alkynes: Synthesis of Nitro- and β-Iodonitro-Substituted Alkenes
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Oxone (2KHSO5·KHSO4·K2SO4) was used to promote the nitration of alkenes and alkynes with sodium nitrite (NaNO2) and potassium iodide (KI). This stable, easy-to-handle, and environmentally benign oxidant was used under mild conditions (room temperature) and provided short reaction times. Styrene derivatives that did not contain electron-donating groups afforded the corresponding nitro alkenes in moderate to good yields, whereas aliphatic alkenes and electron-deficient alkenes were not good substrates. Under similar reaction conditions, aryl alkynes yielded β-iodonitro alkenes. Oxone (2KHSO5·KHSO4·K2SO4) was used to promote the reactions of alkenes and alkynes with sodium nitrite (NaNO2) and potassium iodide (KI) to afford the corresponding nitro and β-iodonitro-substituted alkenes, respectively, in moderate to good yields.
- Hlekhlai, Sornsiri,Samakkanad, Natthapol,Sawangphon, Tassaporn,Pohmakotr, Manat,Reutrakul, Vichai,Soorukram, Darunee,Jaipetch, Thaworn,Kuhakarn, Chutima
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p. 7433 - 7442
(2016/02/19)
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- Synthesis of nitroalkenes involving a cooperative catalytic action of iron(III) and piperidine: A one-pot synthetic strategy to 3-alkylindoles, 2H-chromenes and N-arylpyrrole
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An efficient and simple strategy has been developed to synthesize various substituted nitroalkenes involving a cooperative catalytic system of FeCl 3 and piperidine. This dual catalytic protocol simultaneously activates both electrophile and nucleophile and works under mild reaction conditions so that many sensitive functional groups were tolerated. Moreover, this cooperative catalytic reaction is also suitable for various one-pot reactions involving nitroalkenes such as, 2H-chromenes, N-arylpyrrole and Michael reaction with indole. Notably, this method is low-cost, efficient and environmentally friendly. Copyright
- Jalal, Swapnadeep,Sarkar, Soumen,Bera, Krishnendu,Maiti, Sukhendu,Jana, Umasish
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supporting information
p. 4823 - 4828
(2013/08/23)
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- Tertiary amine functionalized polyacrylonitrile fiber catalyst for the synthesis of tetrahydrothiophenes
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A tertiary amine immobilized fiber was prepared and used to efficiently catalyze tandem Michael-intramolecular Henry reactions between 1,4-dithiane-2,5-diol and trans-β-nitrostyrenes to form the corresponding tetrahydrothiophene derivatives. This newly developed fiber catalyst is applicable to a wide range of trans-β-nitroalkenes and affords good to excellent yields (75-93%) under mild conditions (with 2.5 mol % fiber catalyst at 50 °C in ethanol for 5 h). The fiber catalyst exhibits excellent recyclability and reusability (up to 10 times) after simple workup procedure with only a slight loss in catalytic activity. It is noteworthy that the major diastereomers have r-R, trans-nitro, trans-hydroxy configurations with diastereoselectivities of up to 15:1. This differs from the results obtained when the same reaction is catalyzed by a homogeneous catalyst. This is the first example of a fiber catalyst exhibiting excellent diastereoselectivity.
- Xu, Changzhu,Du, Jianguo,Ma, Lichao,Li, Guowei,Tao, Minli,Zhang, Wenqin
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supporting information
p. 4749 - 4757
(2013/06/27)
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- Catalyst functional group cooperativity in the amino acid-catalysed nitroaldol condensation reaction
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Several amino acids and their derivatives have been evaluated as organic catalysts for the nitroaldol reaction. It was found that when an unprotected amino group and an unprotected carboxylate group were present in the organocatalyst, both the nitroaldol reaction and subsequent elimination could occur to afford nitroalkenes from aromatic aldehydes and nitromethane. The best results were obtained by use of γ-amino acids derived from l-glutamine. It is suggested that the amino group is important for intermediate Schiff base formation and that the free carboxylate group facilitates the elimination step.
- Karadeniz, Leman,Astley, Stephen T.
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p. 3407 - 3415
(2013/09/23)
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- Synthesis of (E)-nitroolefins via decarboxylative nitration using t-butylnitrite (t-BuONO) and TEMPO
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Nitroolefins are usually synthesized using the Henry reaction. Here we report an alternative metal-free decarboxylative nitration protocol for the preparation of the nitroolefins from α,β-unsaturated carboxylic acids using t-butylnitrite (t-BuONO) and TEMPO. α,β-Unsaturated carboxylic acids bearing β-aromatic and β-heteroaromatic substituents gave (E)-nitroolefins exclusively under mild conditions. A radical based pathway has been proposed for this decarboxylative nitration reaction. The Royal Society of Chemistry 2013.
- Manna, Srimanta,Jana, Sandipan,Saboo, Tapish,Maji, Arun,Maiti, Debabrata
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supporting information
p. 5286 - 5288
(2013/06/27)
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- Efficient and stereoselective nitration of mono- and disubstituted olefins with AgNO2 and TEMPO
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Nitroolefin is a common and versatile reagent. Its synthesis from olefin is generally limited by the formation of mixture of cis and trans compounds. Here we report that silver nitrite (AgNO2) along with TEMPO can promote the regio- and stereoselective nitration of a broad range of olefins. This work discloses a new and efficient approach wherein starting from olefin, nitroalkane radical formation and subsequent transformations lead to the desired nitroolefin in a stereoselective manner.
- Maity, Soham,Manna, Srimanta,Rana, Sujoy,Naveen, Togati,Mallick, Arijit,Maiti, Debabrata
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supporting information
p. 3355 - 3358
(2013/04/10)
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- A predictably selective nitration of olefin with Fe(NO3) 3 and TEMPO
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Ferric nitrate with catalytic TEMPO has been identified as a useful reagent for regio- and stereoselective nitration of a wide variety of aromatic, aliphatic, and heteroaromatic olefins. This reaction provided nitroolefins in preparatively useful yields with excellent E-selectivity. Due to its mild nature and operational simplicity, the present protocol is expected to find application in synthetic setup.
- Naveen, Togati,Maity, Soham,Sharma, Upendra,Maiti, Debabrata
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p. 5949 - 5954
(2013/07/26)
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- Stereoselective nitration of olefins with tBuONO and TEMPO: Direct access to nitroolefins under metal-free conditions
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Nitroolefins are essential elements for both synthetic chemistry and medicinal research. Despite significant improvements in nitration of olefin an efficient metal-free synthesis remains elusive so far. Herein, we disclose a new set of reagents to access nitroolefins in a single step under metal-free conditions. A wide range of olefins with diverse functionalities has been nitrated in synthetically useful yields. This transformation is operationally simple and exhibits excellent E-selectivity. Furthermore, site selective nitration in a complex setup makes this method advantageous.
- Maity, Soham,Naveen, Togati,Sharma, Upendra,Maiti, Debabrata
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supporting information
p. 3384 - 3387
(2013/07/26)
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- One-pot solid phase synthesis of (E)-nitroalkenes
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An efficient one-pot protocol for the synthesis of (E)-nitroalkenes by reaction of aldehydes and nitroalkanes in the presence of polymer-bound triphenylphosphine, iodine and imidazole is described. Although the reaction works with similar efficiency with triphenylphosphine and its polymer-bound version, easy removal of the unwanted polymer-bound triphenylphosphine oxide and its recovery as triphenylphosphine provide the edge for practical application of the method.
- Rokhum, Lalthazuala,Bez, Ghanashyam
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p. 5500 - 5504
(2013/09/23)
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- One-pot synthesis of nitroalkenes via the Henry reaction over amino-functionalized MIL-101 catalysts
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Ethylenediamine moieties with different amounts were incorporated into the metal-organic framework MIL-101 to prepare the amino-functionalized MIL-101 materials, which were used as heterogeneous catalysts in the one-pot synthesis of nitroalkenes via the Henry reaction. Various reaction conditions were optimized. Under the optimized conditions, the selectivity towards nitroalkenes is extremely high in combination with nearly complete conversion of the reactant nitroalkanes. The amino-functionalized MIL-101 behaves as a true heterogeneous catalyst, can be easily recovered by filtration, and can be reused at least twice without significant loss of its catalytic performance.
- Yu, Huixian,Xie, Jianwu,Zhong, Yijun,Zhang, Fumin,Zhu, Weidong
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p. 101 - 104
(2013/01/15)
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- Mesoporous nickel hydroxyapatite nanocomposite for microwave-assisted Henry reaction
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The utility of nickel hydroxyapatite nanocomposite (Ni-HAp) as a green catalyst for solvent free, microwave-assisted Henry reaction using nitromethane and a series of aromatic aldehydes as substrates is presented. The selected catalyst performed well to afford the respective nitrostyrenes which were quantified by gas chromatography equipped with a mass spectral detector (GC-MS). A few of the products were identified from the respective nuclear magnetic resonance (NMR) spectral data.
- Neelakandeswari,Sangami,Emayavaramban,Karvembu,Dharmaraj,Kim, Hak Yong
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experimental part
p. 2980 - 2984
(2012/07/28)
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- An expeditious, highly efficient, catalyst-free and solvent-free synthesis of nitroamines and nitrosulfides by Michael addition
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A simple, atom economical, fast and highly efficient green protocol has been developed for the synthesis of nitroamines and nitrosulfides by the Michael addition of amines and thiols to nitroolefins by simple mixing or grinding. This catalyst-free and solvent-free green approach provided the addition products in quantitative yield within minutes at room temperature. This procedure does not require any water quenches, solvent separations and purification steps such as recrystallization and column chromatography.
- Choudhary, Garima,Peddinti, Rama Krishna
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body text
p. 276 - 282
(2011/04/17)
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- Virtual screening and further development of novel ALK inhibitors
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Anaplastic lymphoma kinase (ALK) has been in the spotlight in recent years as a promising new target for therapy of non-small-cell lung cancer (NSCLC). Since the identification of the echinoderm microtubule-associated protein-like 4 (EML4)-ALK fusion gene in some NSCLC patients was reported in 2007, various research groups have been seeking ALK inhibitors. Above all, crizotinib (PF-02341066) has been under clinical trial, and its therapeutic efficacy of inhibiting ALK in NSCLC has been reported. Among anticancer drugs, drug resistance appears frequently necessitating various kinds of inhibitors. We identified novel ALK inhibitors by virtual screening from the public chemical library collected by the Chemical Biology Research Initiative (CBRI) at the University of Tokyo, and inhibitors that are more potent were developed.
- Okamoto, Masako,Kojima, Hirotatsu,Saito, Nae,Okabe, Takayoshi,Masuda, Yoshiaki,Furuya, Toshio,Nagano, Tetsuo
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experimental part
p. 3086 - 3095
(2011/06/26)
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- One-pot multistep synthesis of 4-acetoxy-2-amino-3-arylbenzofurans from 1-aryl-2-nitroethylenes and cyclohexane-1,3-diones
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(Chemical Equation Presented) A novel method for synthesizing 4-acetoxy-2-amino-3-arylbenzofurans (4) from 1-aryl-2-nitroethylenes (1) and cyclohexane-1,3-diones (2) is described. The method features one-pot operation of a solution of 1 and 2 in THF with catalytic Et3N (rt, 12 h) followed with Ac2O, Et3N, and DMAP (rt, 5 h), although the process consists of 13 elementary reactions.
- Ishikawa, Teruhiko,Miyahara, Tadashi,Asakura, Mami,Higuchi, Shuichi,Miyauchi, Yayoi,Saito, Seiki
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p. 1211 - 1214
(2007/10/03)
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- Microwave-induced solvent-free, rapid and efficient synthesis of conjugated nitroalkenes using sulfated zirconia
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Sulfated Zirconia catalyzed synthesis of conjugated nitroalkenes has been carrried out under solvent-free condition using sulfated zirconia. Recyclability of catalyst, isolation of pure products by simple filtration and evaporation are important features of this method.
- Bandgar,Kasture
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p. 1239 - 1241
(2007/10/03)
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- Morpholine adsorbed on silica gel: A novel and mild basic catalyst for the synthesis of α,β-unsaturated nitroalkenes
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Syntheses of α,β-unsaturated nitroalkenes have been carried out under mild condition using morpholine adsorbed on silica gel as a novel catalyst.
- Bandgar, Babasaheb P.,Uppalla, Lav S.,Sadavarte, Vaibhav S.
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p. 949 - 952
(2007/10/03)
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- Gel entrapped base catalysed (GEBC) Henry reaction: Synthesis of conjugated nitroalkenes
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A new, simple and practical procedure for direct transformation of aldehydes or ketones and nitromethane into conjugated nitroalkenes by using novel gel entrapped base catalyst (GEBC) has been described.
- Bandgar,Uppalla
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p. 2071 - 2075
(2007/10/03)
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- Kinetics of Reversible Thiolate Ion Addition to Substituted β-Nitrostyrenes in Water. Radicaloid Transition State or Principle of Nonperfect Synchronization?
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The kinetics of reversible nucleophilic thiolate ion (RS- with R = n-Bu, HOCH2CH2, MeO2CCH2CH2 and MeO2CCH2) addition to Z-substituted β-nitrostyrenes (Z = 4-Me2N, 4-MeO, 4-MeS, 4-Me, H, 3-Cl, 4-Cl, 3-CN, 4-CN, and 3-NO2), to form ArCH(RS)CH=NO2-, have been measured in water at 20 deg C.Rate constants in the forward (k1) and reverse direction (k-1) and equilibrium constants (K1) correlate reasonably well with Hammett ?-constants for the non-?-donor substituents but show deviations for the ?-donors 4-Me2N, 4-MeO, and 4-MeS.These deviations are negativefor K1 but positive for k1 and k-1; the positive deviations for the ?-donor substituents are also observed when plotting log k1 vs log K1 (Broensted plots).The negative deviations of K1 are a consequence of resonance stabilization of the olefin.The positive deviations are attributed to a transition-state stabilization stemming from a preorganization created by the ?-donor which leads to a better delocalization of the negative charge into the nitro group.An alternative interpretation of the rate acceleration in terms of a radicaloid transition state (Gross, Z.; Hoz, S.J.Am.Chem.Soc. 1988, 110, 7489) cannot be ruled out but is shown to be less attractive and unnecessary.Broensted parameters such as βnuc, βeq, βnnuc, and βnlg, and intrinsic rate constants (k0 = k1 = k-1 when K1 = 1) were determined from the dependence on the RS- basicity for β-nitrostyrene and 3-cyano-β-nitrostyrene. βeq is low (0.5), indicating that the carbon basicity of RS- is less sensitive to electronic effects in R than its proton basicity. βnuc (βnnuc) is very low, suggesting a transition state withvery little C-S bond formation.The low βnnuc (0.22) contrasts with a large αnnuc = d log k1/d log K1 = 0.74 (variation of Z), indicating a large transition-state imbalance (αnnuc - βnnuc), as previously observed in the reaction of RS- with α-nitrostilbenes.The intrinsic rate constant (log k0 = 3.5) is also similar to that for the reaction of RS- with α-nitrostilbenes and significantly higher than for the reaction of amines with β-nitrostyrenes.Most of these features can, at least in part, be attributed to the soft acid-soft base interactions of RS- with the nitroolefins.Rate constants for carbon protonation of several of the ArCH(RS)CH=NO2- adducts by acetic acid (kHAp were also determined.They display the unusual, but for nitronate ions typical, acceleration when Ar and/or R is made more electron withdrawing.
- Bernasconi, Claude F.,Schuck, David F.
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p. 2365 - 2373
(2007/10/02)
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- Kinetics of Hydrolysis of Substituted β-Nitrostyrenes. Transition-State Imbalances and Intrinsic Rate Constants for Three Different Types of Nitronate Ion Forming Processes. Relevance to the Nitroalkane Anomaly
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A kinetic study of the hydrolysis of β-nitrostyrene and of the 4-chloro and 3-nitro derivatives in 50percent Me2SO-50percent water (v/v) at 20 deg C is reported.The mechanism involves four steps: nucleophilic addition of OH(-) or water to form ArCH(OH)CHNO2(-) (T-OH); carbon protonation of T-OH by water, H(+), and buffer acids to form ArCH(OH)CH2NO2 (T0OH); deprotonation of the OH group in T0OH to form ArCH(O(-))CH2NO2 (T-O); collapse of T-O into ArCHO and CH2NO2(-).In strongly acidic solution the aci form of T0OH, PhCH(OH)CH=NO2H (T0OH,aci), which is generated by protonation of T-OH on the nitro group, could also be detected.All steps are reversible, and the rate and equilibrium constats of most of them could be determined by a combination of kinetic experiments starting with the substrate, the products, the independently synthesized T0OH, and T-OH (generated at high pH and then subjected to a pH jump) and by measuring product ratios spectrophotometrically or by HPLC analysis.The intrinsic rate constants of the proton transfer, T-OH T0OH, are close to those for the deprotonation of nitromethane and 2-nitroethanol, and the Brnsted coefficients show a transition-state imbalance (αCH >> βB(-)) that is typical for the deprotonation of nitroalkanes.The other two processes that lead to the formation of a nitronate ion, i.e., nucleophilic addition to the olefin to form T-OH and collapse of T-O to form CH2NO2(-), show similar structure-reactivity behavior as the proton transfer, such as transition-state imbalances as manifested by αnnuc > βnnuc for nucleophilic addition and depressed intrinsic rate constants.However, these imbalances are smaller compared to the one in the proton transfers, especially so for the nucleophilic addition to the olefin.It is suggested that there is an inherent tendency for reactions leading to resonance-stabilized ions to have imbalanced transition states, but in proton transfers there are two imbalance enhancing factors, namely sp3 hybridization of the carbon in the protonated form and hydrogen bonding in the transition state, while in the collapse of T-O there is one such factor (sp3 hybridization of the carbon in T-O).
- Bernasconi, Claude F.,Paschalis, Peter
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p. 5893 - 5902
(2007/10/02)
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- Research on antitumor chemotherapy: X. β Nitrostyrene and nitrovinyl derivatives
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In previous work, the antitumoral cytotoxicity of β nitrostyrenes obtained by simplification of the aristolochic acid molecule was demonstrated. The effect of modifying the 3 characteristic parts of the β nitrostyrene molecule was then investigated. Results in vitro and in vivo indicate a probable mechanism of action for the β nitrostyrene and nitrovinyl compounds studied, and permit definition of the maximum simplification compatible with retention of biological activity.
- Dore,Viel
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