- Rhodium-catalyzed [2 + 2] cycloaddition of ynamides with nitroalkenes
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In the presence of a diene-ligated rhodium complex, ynamides and nitroalkenes undergo catalytic [2 + 2] cycloadditions to provide cyclobutenamides. The presence of sodium tetraphenylborate was found to be crucial for the reactions to proceed efficiently.
- Smith, Donna L. L.,Chidipudi, Suresh Reddy,Lam, Hon Wai,Goundry, William R.
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Read Online
- Cu-Catalyzed asymmetric hydroboration of naphthylallylic compounds for enantioselective synthesis of chiral boronates
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A Cu-catalyzed regio- A nd enantioselective hydroboration of various naphthylallylic compounds affording chiral boronates with high yields and excellent enantioselectivities (up to 96% ee) was presented. The utility of the boronated products is further illustrated by other stereospecific C-B bond transformations to produce amino alcohols and other useful compounds.
- Han, Suna,Shen, Xin,Kong, Duanyang,Zi, Guofu,Hou, Guohua,Zhang, Jiaxin
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Read Online
- A Molecular Iodine-Mediated Synthesis of Cyclopenta[c]furo[3,2-b]furan-5,6-diones: Assembly of an Angular Dioxatriquinane Core
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A molecular iodine-mediated synthesis of angular oxatriqinane core from 3-acetyl-2H-chromen-2-ones, β-bromo-β-nitrostyrenes, and pyridine in the presence of Et3N in MeCN containing a trace amount of water was developed. The reaction proceeds via intermolecular Michael reaction of 2-oxo-2-(2-oxo-2H-chromen-3-yl)-1-(pyridin-1-ium-1-yl)ethan-1-ide with bromonitrostyrene followed by intramolecular Michael reaction and elimination steps. Evidence for the stereochemistry of a typical product is obtained from single-crystal X-ray analyses. The important feature of this strategy is the fact that it forms three stereogenic centers with good selectivity.
- Mohsenzadeh, Ramin,Ravaghi, Parisa,Yavari, Issa
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p. 2616 - 2623
(2022/03/14)
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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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- Catalytic Asymmetric Construction of Tertiary Carbon Centers Featuring an α-Difluoromethyl Group with CF2H-CH2-NH2as the "building Block"
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We report here for the first time a novel difluoromethylated ketimine building block condensed by thioisatin and difluoroethylamine, offering efficient access to a broad range of enantioenriched products bearing difluoroethylamine units (27 examples, ≤98% yield, >99% ee) in the presence of quinine-derived squaramide. Further transformation of the intermediate would generate a variety of versatile functional blocks like α-difluoromethyl amines, β-amino acid, and β-diamine with retention of the enantiomeric excess at the difluoromethyl-bound carbon.
- Gao, Fengyun,Guo, Yifei,Sun, Mengmeng,Wang, Yalan,Yang, Changyan,Wang, Yuqiang,Wang, Kairong,Yan, Wenjin
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supporting information
p. 2584 - 2589
(2021/04/13)
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- Method for preparing nitroolefin from aryl ethane and nitrate
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According to the method, aryl ethane and nitrate, which are cheap and easy to obtain, are used as raw materials, and the E-nitroolefin compound is synthesized through a dehydrogenation nitration reaction of copper/silver catalyzed aryl ethane under the ox
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Paragraph 0026-0046
(2020/10/05)
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- Preparation method of beta-trans-nitroolefin
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The invention relates to a preparation method of beta-trans-nitroolefin. The method comprises: sequentially adding an olefin compound, a nitration reagent and a solvent into a reaction container, mixing the substances uniformly, and carrying out constant temperature reaction for 18h under an illumination condition to obtain a reaction solution; and sequentially carrying out drying, concentration and column chromatography treatment on the reaction solution to obtain the beta-trans-nitroolefin compound. The method is simple and practicable, low in cost and high in product yield, can realize large-scale production, and has good industrial application prospects in the aspects of functional organic material, bioactive compound and drug synthesis.
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Paragraph 0078-0080
(2020/06/17)
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- A photocatalyst-free photo-induced denitroalkylation of β-nitrostyrenes with 4-alkyl substituted Hantzsch esters at room temperature
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A photocatalyst-free stereoselectively photo-induced strategy for the denitroalkylation of β-nitrostyrenes using 4-alkyl substituted Hantzsch esters as the alkyl source under xenon lamp irradiation is developed. The reaction proceeds at room temperature and affords the corresponding products in moderate to excellent yields. The oxidant di-t-butyl peroxide serves as an efficient radical initiator under irradiation of a Xenon lamp, initiating alkyl radicals from the 4-alkyl substituted Hantzsch esters.
- Duan, Chunying,Hao, Xinyu,Jin, Kun,Li, Yaming,Wang, Jiaao,Zhang, Rong,Zhang, Siyu
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supporting information
(2020/02/18)
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- Facile Synthesis of 1,3,5-Triarylbenzenes and 4-Aryl-NH-1,2,3-Triazoles Using Mesoporous Pd-MCM-41 as Reusable Catalyst
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We report mesoporous nano-Pd-MCM-41 catalyzed rapid and efficient synthesis of 1,3,5-triarylbenzenes via de-nitrative cyclotrimerization of β-nitrostyrenes. All the reactions were very fast and high yielding. The Pd-MCM-41 was also very effective in catalyzing de-nitrative [3+2] cycloaddition of β-nitrostyrenes with TMSN3 to synthesize 4-aryl-NH-1,2,3-triazoles. The catalyst was reused at least up to eight times with minimum loss of catalytic activity.
- Saha, Arijit,Wu, Chia-Ming,Peng, Rui,Koodali, Ranjit,Banerjee, Subhash
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p. 104 - 111
(2019/01/04)
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- Combined Photoredox/Enzymatic C?H Benzylic Hydroxylations
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Chemical transformations that install heteroatoms into C?H bonds are of significant interest because they streamline the construction of value-added small molecules. Direct C?H oxyfunctionalization, or the one step conversion of a C?H bond to a C?O bond, could be a highly enabling transformation due to the prevalence of the resulting enantioenriched alcohols in pharmaceuticals and natural products,. Here we report a single-flask photoredox/enzymatic process for direct C?H hydroxylation that proceeds with broad reactivity, chemoselectivity and enantioselectivity. This unified strategy advances general photoredox and enzymatic catalysis synergy and enables chemoenzymatic processes for powerful and selective oxidative transformations.
- Betori, Rick C.,May, Catherine M.,Scheidt, Karl A.
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supporting information
p. 16490 - 16494
(2019/11/03)
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- Catalytic and Mechanistic Developments of the Nickel(II) Pincer Complex-Catalyzed Hydroarsination Reaction
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Synthetic challenges have significantly slowed the development of the catalytic asymmetric hydroarsination reaction despite it being a highly attractive C?As bond formation methodology. In addition, there is a poor understanding of the main reaction steps in such reactions which limit further development in the field. Herein, key intermediates of the hydroarsination reaction catalyzed by a PCP NiII-Cl pincer complex are presented upon investigating the reaction with DFT calculations, conductivity measurements, NMR spectroscopy, and catalytic screening. The novel Ni–Cl–As interaction proposed was then contrasted against known NiII-catalyzed hydrophosphination reactions to highlight dissimilarities between them even though P and As share a close group relationship. Lastly, the asymmetric hydroarsination of nitroolefins was further developed to furnish a library of chiral organoarsines in up to 99 % yield and 80 % ee under mild conditions (?20 °C to RT) between 5 to 210 mins.
- Tay, Wee Shan,Lu, Yunpeng,Yang, Xiang-Yuan,Li, Yongxin,Pullarkat, Sumod A.,Leung, Pak-Hing
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supporting information
p. 11308 - 11317
(2019/08/07)
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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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- 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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- Concerted catalysis by nanocellulose and proline in organocatalytic Michael additions
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Cellulose nanofibers (CNFs) have recently attracted much attention as catalysts in various reactions. Organocatalysts have emerged as sustainable alternatives to metal-based catalysts in green organic synthesis, with concerted systems containing CNFs that are expected to provide next-generation catalysis. Herein, for the first time, we report that a representative organocatalyst comprising an unexpected combination of 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)-oxidized CNFs and proline shows significantly enhanced catalytic activity in an asymmetric Michael addition.
- Ranaivoarimanana, Naliharifetra Jessica,Kanomata, Kyohei,Kitaoka, Takuya
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supporting information
(2019/04/05)
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- Copper-Promoted Regioselective Synthesis of Polysubstituted Pyrroles from Aldehydes, Amines, and Nitroalkenes via 1,2-Phenyl/Alkyl Migration
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The facile copper-catalyzed synthesis of polysubstituted pyrroles from aldehydes, amines, and β-nitroalkenes is reported. Remarkably, the use of α-methyl-substituted aldehydes provides efficient access to a series of tetra- and pentasubstituted pyrroles via an overwhelming 1,2-phenyl/alkyl migration. The present methodology is also accessible to non α-substituted aldehydes, yielding the corresponding trisubstituted pyrroles. On the contrary, the use of ketones, in place of aldehydes, does not promote the organic transformation, signifying the necessity of α-substituted aldehydes. The reaction proceeds under mild catalytic conditions with low catalyst loading (0.3-1 mol %), a broad scope, very good functional-group tolerance, and high yields and can be easily scaled up to more than 3 mmol of product, thus highlighting a useful synthetic application of the present catalytic protocol. Based on formal kinetic studies, a possible radical pathway is proposed that involves the formation of an allylic nitrogen radical intermediate, which in turn reacts with the nitroalkene to yield the desired pyrrole framework via a radical 1,2-phenyl or alkyl migration.
- Andreou, Dimitrios,Kallitsakis, Michael G.,Loukopoulos, Edward,Gabriel, Catherine,Kostakis, George E.,Lykakis, Ioannis N.
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p. 2104 - 2113
(2018/02/23)
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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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- 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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- Enantioselective Conjugate Addition of 2-Acylimidazoles with Nitroalkenes Promoted by Chiral-at-Metal Rhodium(III) Complexes
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An enantioselective conjugate addition of 2-acylimidazoles with nitroalkenes catalyzed by chiral-at-metal rhodium(III) complex under mild reaction conditions was developed, affording versatile γ-nitro ketone skeletons in good yields with excellent enantioselectivities (up to >99% ee). (Figure presented.).
- Thota, Ganesh Kumar,Sun, Gui-Jun,Deng, Tao,Li, Yi,Kang, Qiang
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supporting information
p. 1094 - 1098
(2018/01/22)
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- ZrCl4-mediated synthesis of 1,2,3-triazoles from vinyl nitrates and their biological evaluation
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A ZrCl4-mediated simple method for the conversion of vinyl nitrates to 1,2,3-triazoles in excellent yields is developed. The obtained new triazoles were evaluated for their antimicrobial activity.
- Sridhar, Gattu,Somnath, Mudavath,Sharma, Gangavaram V. M.,Prashanth, Thodupunuri
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p. 551 - 556
(2017/03/15)
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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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- Chloro/bromotrimethylsilane-Cu(NO3)2·3H2O: Safe and efficient reagent system for the decarboxylative ipso-nitration and dibromination of cinnamic acids
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Further synthetic potential of halotrimethylsilane-nitrate salt mixture is revealed. A mixture of TMSX-Cu(NO3)2·3H2O system is found to be an efficient reagent system for both the decarboxylative nitration (ipso-nitration) when X?=?Cl, and dibromination of cinnamic acids, with X?=?Br, under mild conditions. The reactions are safe and simple, affording the corresponding products (E)-β-nitrostyrenes, and anti-2,3-dibromo-3-phenylpropanoic acids in high yields with high selectivity in a relatively short time. Use of hazardous and toxic nitrating systems such as acetyl nitrate and brominating agents such as molecular bromine can be avoided.
- Roshandel, Sahar,Gurung, Laxman,Mathew, Thomas,Prakash, G.K. Surya
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supporting information
p. 2842 - 2845
(2017/06/27)
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- De novo endo-functionalized organic cages as cooperative multi-hydrogen-bond-donating catalysts
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Two endo-functionalized organic cages as oxyanion hole mimics were achieved via dynamic covalent chemistry, which exhibit good size selectivity, catalytic activity and broad substrate scopes for Friedel-Crafts reactions. The modular character of the synth
- Chen, Hong-Yu,Gou, Meng,Wang, Jiao-Bing
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supporting information
p. 3524 - 3526
(2017/03/31)
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- Substituted heterocyclic compound, preparation method and uses thereof
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The present invention relates to a substituted heterocyclic compound, a preparation method and uses thereof, further to a pharmaceutical composition containing the heterocyclic compound and uses thereof, wherein the compound or pharmaceutical composition
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Paragraph 0227; 0228; 0229; 0230
(2017/04/19)
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- Iron-Mediated One-Pot Synthesis of 3,5-Diarylpyridines from β-Nitrostyrenes
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An operationally simple and mild one-pot protocol for the synthesis of a variety of 3,5-diarylpyridines from β-nitrostyrenes was achieved by using elemental iron. This reaction proceeds via reduction of the nitro group, resulting in in situ imine formation followed by trimolecular condensation with concomitant debenzylative aromatization. By employing this method, a series of symmetrical and unsymmetrical 3,5-diarylpyridines were synthesized with good to excellent yields. In addition, this method was also utilized for the synthesis of Sch-21418, an anti-inflammatory agent on gram scale.
- Sathish, Manda,Chetna, Jadala,Hari Krishna, Namballa,Shankaraiah, Nagula,Alarifi, Abdullah,Kamal, Ahmed
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p. 2159 - 2165
(2016/03/15)
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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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- Iodine catalyzed one-pot synthesis of highly substituted N-methyl pyrroles via [3 + 2] annulation and their in vitro evaluation as antibacterial agents
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A new class of highly substituted pyrroles have been synthesized via a simple, fast, and efficient method using environmentally friendly iodine catalyzed [3 + 2] annulation. N-Methyl-N-[(E)-1-(methylsulfanyl)-2-nitro-1-ethenyl]amine (NMSM) 1 and β-nitrostyrenes 3 underwent cycloaddition to afford the desired products 4 in excellent yields under solvent and metal free conditions. All the pyrrole derivatives were evaluated for their in vitro anti-bacterial activity. Among the synthesized pyrrole derivatives, 4b, 4c, 4e, 4g, 4i, 4j, 4l, 4m and 4n displayed good inhibitory properties against a panel of Gram positive and negative infectious pathogens.
- Balachandra, Biguvu,Shanmugam, Sivakumar,Muneeswaran, Thillaichidambaram,Ramakritinan, Muthiah
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p. 64781 - 64789
(2015/08/18)
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- Highly efficient iridium-catalyzed asymmetric hydrogenation of β-acylamino nitroolefins
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The first highly efficient Ir-catalyzed enantioselective hydrogenation of β-acylamino nitroolefins is reported. This reaction provides straightforward access to chiral β-amino nitroalkanes in high yields and excellent enantioselectivities (up to >99.9% ee) catalyzed by an Ir-(R,R)-f-spiroPhos complex. This journal is
- Yan, Qiaozhi,Liu, Man,Kong, Duanyang,Zi, Guofu,Hou, Guohua
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supporting information
p. 12870 - 12872
(2014/12/11)
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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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- Convenient synthesis of α-nitrooximes mediated by OXONE
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A novel OXONE mediated direct difunctionalization of alkenes with NaNO2 in aqueous acetonitrile for the synthesis of α-nitrooximes was developed. The α-nitrooximes were readily prepared in moderate to high yields at room temperature under mild reaction conditions. The present protocol offers an easy and environmentally benign approach to access various α-nitrooximes derived from styrene derivatives.
- Chumnanvej, Napasawan,Samakkanad, Natthapol,Pohmakotr, Manat,Reutrakul, Vichai,Jaipetch, Thaworn,Soorukram, Darunee,Kuhakarn, Chutima
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p. 59726 - 59732
(2015/02/19)
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- Useful extensions of the henry reaction: Expeditious routes to nitroalkanes and nitroalkenes in aqueous media
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The products of the Henry nitroaldol reaction from nitromethane and several aldehydes were reduced to the corresponding nitroalkanes with (n-Bu) 3SnH in water under microwave irradiation (80 °C/10 min), or dehydrated to the corresponding nitroalkenes with K2CO3 in water (generally 0-5 °C/20 min). Both "one-pot" reactions occur in excellent yields across a range of aliphatic and aromatic (including heteroaromatic) substrates. It seems likely that the deoxygenation of the nitroaldols occurs via coordination of an oxygen atom of the nitro group with a tin atom, which facilitates hydride delivery in the transition state. The elimination of water from the nitroaldols in mild base is likely driven by the stability of the conjugated nitroalkene products. The elimination required workup with 2 N HCl, which likely displaces a nitroalkane-nitroalkene equilibrium towards the latter. These extensions of the Henry reaction lead to products not easily obtained otherwise.
- Chandrasekhar, Sosale,Shrinidhi, Annadka
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p. 3008 - 3018
(2014/10/16)
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- A branched domino reaction: Asymmetric organocatalytic two-component four-step synthesis of polyfunctionalized cyclohexene derivatives
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Take two: By employing two equivalents of an aldehyde in an asymmetric organocatalytic domino reaction, the nucleophilic enamine intermediate is also converted into the corresponding iminium species through oxidation with o-iodoxybenzoic acid. Thus, polyfunctionalized cyclohexene derivatives are formed from two simple starting materials in good yields and stereoselectivities (see scheme; Bn=benzyl, EWG=electron-withdrawing group). Copyright
- Zeng, Xiaofei,Ni, Qijian,Raabe, Gerhard,Enders, Dieter
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supporting information
p. 2977 - 2980
(2013/04/11)
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- Regiospecific synthesis of novel cyclic nitrostyrenes and 3-substituted 2-nitronaphthalenes
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A two-step, practical, regiospecific, and readily scalable benzannulation protocol for the preparation of novel 3-alkyl- and 3-aryl-substituted 2-nitronaphthalenes is disclosed. Addition of a β-nitrostyrene or nitroalkene to a solution of freshly prepared lithiated o-tolualdehyde tert-butyl imine first leads to the formation of a nitronate, via rapid 1,4-addition, then an intramolecular aza-Henry reaction takes place to afford a six-membered carbocycle. Subsequent treatment of the reaction mixture with aqueous acid affords novel substituted cyclic nitrostyrenes that can be conveniently aromatized via a one-pot radical-induced bromination and elimination sequence to furnish the corresponding 3-alkyl- or 3-aryl-2-nitronaphthalenes in excellent yields. The straightforward syntheses of 2-aminonaphthalenes, substituted BINAMs, 2-naphthols as well as tricyclic fused 1,2,3-triazoles are also described. Georg Thieme Verlag Stuttgart. New York.
- Keene, Craig,Kuerti, Laszlo
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supporting information
p. 1719 - 1729
(2013/07/26)
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- Synthesis of substituted nitroolefins: A copper catalyzed nitrodecarboxylation of unsaturated carboxylic acids
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A novel, mild and convenient method for the nitrodecarboxylation of substituted cinnamic acid derivatives to their nitroolefins is achieved using a catalytic amount of CuCl (10 mol%) and tert-butyl nitrite (2 equiv.) as a nitrating agent in the presence of air. This reaction provides a useful method for the synthesis of β,β-disubstituted nitroolefin derivatives, which are generally difficult to access from other conventional methods. Additionally, this reaction is selective as the E-isomer of the acid derivatives furnishes the corresponding E-nitroolefins. One more salient feature of the method is, unlike other methods, no metal nitrates or HNO3 are employed for the transformation.
- Rokade, Balaji V.,Prabhu, Kandikere Ramaiah
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p. 6713 - 6716
(2013/10/01)
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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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- Rhodium-catalyzed [2 + 2] cycloaddition of ynamides with nitroalkenes
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In the presence of a diene-ligated rhodium complex, ynamides and nitroalkenes undergo catalytic [2 + 2] cycloadditions to provide cyclobutenamides. The presence of sodium tetraphenylborate was found to be crucial for the reactions to proceed efficiently.
- Smith, Donna L.L.,Chidipudi, Suresh Reddy,Goundry, William R.,Lam, Hon Wai
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supporting information
p. 4934 - 4937
(2013/01/15)
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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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- Metal halide hydrates as lewis acid catalysts for the conjugated Friedel-Crafts reactions of indoles and activated olefins
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Metal halide hydrates such as SnCl2·2H2O, MnCl2·4H2O, SrCl2·6H 2O, CrCl2·6H2O, CoCl2· 6H2O e CeCl3·7H2O were investigated as mild Lewis acids catalysts for the conjugate Friedel-Crafts reaction between indoles and activated olefins. The reactions were carried out with aliphatic unsaturated ketones over a period of days at room temperature, while chalcones reacted only under reflux conditions. The reactions with nitrostyrenes were either performed in solvent or under solventless conditions. In all cases reasonable to good yields were obtained. ?2011 Sociedade Brasileira de Qui?mica.
- Schwalm, Cristiane S.,Ceschi, Marco Antonio,Russowsky, Dennis
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scheme or table
p. 623 - 636
(2012/01/05)
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- Ambiphilic dual activation role of a task-specific ionic liquid: 2-hydroxyethylammonium formate as a recyclable promoter and medium for the green synthesis of β-nitrostyrenes
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A cost-effective task-specific ionic liquid, 2-hydroxyethylammonium formate, efficiently promotes the condensation of nitroalkanes with various aldehydes to produce β-nitrostyrenes in high to excellent yields at room temperature. This reaction does not involve any hazardous organic solvent and toxic catalyst. The ionic liquid is recovered and recycled for subsequent reactions. In addition, a novel mechanism has been proposed invoking ambiphilic dual activation influence of the ionic liquid.
- Alizadeh, Abdolhamid,Khodaei, Mohammad M.,Eshghi, Ali
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scheme or table
p. 8295 - 8298
(2011/03/17)
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- Enantioselective henry reactions catalyzed by chiral N-metal complexes containing R(+)/S(-)-α-ethylphenyl amines
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A series of novel N-metal complexes containing chiral α-ethylphenyl amines was synthesized and they catalyzed asymmetric Henry reactions affording products with high enantioselectivity.
- Luo, Mei,Yan, Bing
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supporting information; experimental part
p. 5577 - 5580
(2010/10/21)
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- A simple O-sulfated thiohydroximate molecule to be the first micromolar range myrosinase inhibitor
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New non-hydrolyzable analogues of glucosinolates have been prepared. Myrosinase inhibition was observed with modified aglycon moieties, even bulky phenothiazine analogue 6 gave reasonable inhibition. The simplest structure 8 derived from dimethylaminoethanethiol has shown to be the most potent inhibitor with an IC50 of 3.32 μM.
- Cerniauskaite, Deimante,Gallienne, Estelle,Karciauskaite, Henreta,Farinha, Andrea S.F.,Rousseau, Jolanta,Armand, Sylvie,Tatibou?t, Arnaud,Sackus, Algirdas,Rollin, Patrick
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scheme or table
p. 3302 - 3305
(2009/08/09)
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- Synthesis and biological evaluation of N-acetyl-β-aryl-1,2-didehydroethylamines as new HIV-1 RT inhibitors in vitro
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A variety of N-acetyl-β-aryl-1,2-didehydroethylamines were synthesized by direct reduction-acetylation of β-aryl-nitroolefins and assayed as HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) for the first time. Compound 7a exhibited a TI value of >13.2 with CC50 value of >0.787 mM in C8166 cells. This structure-activity relationship (SAR) study provided a new lead for design and discovery of more potent and selective analogues act as NNRTIs.
- Cheng, Pi,Jiang, Zhi-Yong,Wang, Rui-Rui,Zhang, Xue-Mei,Wang, Qian,Zheng, Yong-Tang,Zhou, Jun,Chen, Ji-Jun
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p. 4476 - 4480
(2008/02/09)
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- Asymmetric Michael addition of α-hydroxyketones to nitroolefins catalyzed by chiral diamine
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(Matrix presented) The regio-, stereo-, and enantioselective direct Michael addition of α-hydroxyketones to β-arylnitroolefins catalyzed by N-iPr-2,2′-bipyrrolidine is described. The formation of an internal hydrogen bond between the OH group of α-hydoxya
- Andrey, Olivier,Alexakis, Alexandre,Bernardinelli, Gerald
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p. 2559 - 2561
(2007/10/03)
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- A Nitro-Hunsdiecker Reaction: From Unsaturated Carboxylic Acids to Nitrostyrenes and Nitroarenes
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(Formula Presented) The nitrodecarboxylation of aromatic α,β-unsaturated carboxylic acids and ring-activated benzoic acids can be achieved using nitric acid (3 equiv) and catalytic AIBN (2 mol %) in MeCN. From the effect of various additives, the nitrodecarboxylation is postulated to involve the generation of an acyloxy radical RCO2? by a NO3? radical followed by attack of a NO2? radical.
- Das, Jaya Prakash,Sinha, Pradipta,Roy, Sujit
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p. 3055 - 3058
(2007/10/03)
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- One-pot synthesis of trans-β-alkylstyrenes
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One-pot synthesis of (E)-alkenes 5 from the reactions of aldehyde 1 and nitromethane 2 in the acetic acid solution and then with triethylborane 4 in the biphase of diethyl ether and aqueous solution in the presence of oxygen in air was reported. Various (E)-alkenes 7 could also be prepared when different kinds of secondary or tertiary alkyl iodides 6 were used under similar conditions.
- Liu, Ju-Tsung,Yao, Ching-Fa
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p. 6147 - 6150
(2007/10/03)
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- Synthesis of 3,4-diarylpyrroles and conversion into dodecaarylporphyrins; a new approach to porphyrins with altered redox potentials
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3,4-Diarylpyrroles (1) have been directly prepared in 20-50% yield by the reaction of β-nitrostyrenes with aqueous TiCl3 in 1,4-dioxane. Pyrroles 1 were also prepared via Barton-Zard pyrrole synthesis using the reaction of α-nitrostilbenes with ethyl isocyanoacetate followed by de-ethoxycarbonylation. 3,4-Diarylpyrroles have been converted into dodecaarylporphyrins by reaction with aromatic aldehydes. Various aryl groups are readily introduced at the periphery of porphyrins by this method. Phenyl substitution at any of the positions of pyrroles decreases E1/2ox while E1/2red is almost unchanged. On the other hand, substitution of the 2-thienyl group affects both the HOMO and LUMO energies, and the UV-vis spectra of dodeca-2-thienylporphyrins (4f or 4i) are extremely red-shifted.
- Ono, Noboru,Miyagawa, Hirokazu,Ueta, Takahiro,Ogawa, Takuji,Tani, Hiroyuki
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p. 1595 - 1601
(2007/10/03)
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- Microwave-Assisted Henry Reaction: Solventless Synthesis of Conjugated Nitroalkenes
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In a solventless system and under microwave irradiation, nitroalkanes react with arylaldehydes in the presence of a catalytic amount of ammonium acetate to afford, in one step, conjugated nitroalkenes without the isolation of intermediary β-nitro alcohols. - Key Words: Arylaldehydes; Nitroalkanes; Ammonium acetate; Conjugated nitroalkenes; Henry reaction; Microwave irradiation
- Varma, Rajender S.,Dahiya, Rajender,Kumar, Sudhir
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p. 5131 - 5134
(2007/10/03)
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- Potent and selective non-benzodioxole-containing endothelin-A receptor antagonists
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The benzodioxole ((methylenedioxy)benzene) group is present in a number of endothelin (ET) receptor antagonists thus far reported. As part of our own endothelin antagonist program we have developed (2R*,3R*,4S*)-1-(N,N- dibutylacetamido)-4-(1,3-benzodioxol-5-yl)-2-(4-methoxyphenyl)pyrrolidine-3- carboxylic acid (A-127722). This is a potent antagonist, binding to the ET(A) and ET(B) receptor subtypes with affinities (IC50) of 0.4 and 520 nM, respectively, and also contains the aforementioned benzodioxole. While this compound was seemingly optimized at its N-terminus, no effort had been directed toward understanding the contributions to binding affinity or receptor subtype selectivity conferred by the benzodioxole. Substitution by 1- or 2-naphthyl yielded weak antagonists. Oxygenated benzenes, such as p- anisyl, were potent compounds with IC50s in the low-nanomolar range. Simple deletion of either of the two oxygen atoms (dihydrobenzofurans) yielded extremely potent agents, possessing subnanomolar affinity for the ET(A) receptor. Additionally, the compounds showed enhanced selectivity, binding to the ET(B) receptor subtype in the micromolar range. This paper describes the development of this novel class of compounds.
- Tasker, Andrew S.,Sorensen, Bryan K.,Jae, Hwan-Soo,Winn, Martin,Von Geldern, Thomas W.,Dixon, Douglas B.,Chiou, William J.,Dayton, Brian D.,Calzadila, Samuel,Hernandez, Lisa,Marsh, Kennan C.,WuWong, J. Ruth,Opgenorth, Terry J.
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p. 322 - 330
(2007/10/03)
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- TETRALIN DERIVATIVES
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This invention relates to novel derivatives of tetralin, to the processes for their preparation, to their use as aminopeptidase inhibitors and to their end-use application as immunomodulators and as analgesic agents.
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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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