- Organocatalytic Enantioselective Michael-Aldol[3+2] Annulation for the Synthesis of Nitro-Methanobenzo[7] annulenes
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We report an enantioselective Michael-Aldol[3+2] annulation between 2-alkyl-3-hydroxynaphthalene-1,4-diones and nitroalkenes using a bifunctional thiourea catalyst, and a series of nitro-methanobenzo[7]annulenes with potential biological activities were synthesized in good yields with excellent enantio- and diastereoselectivities. A gram-scale synthesis and further transformation of the product demonstrated the synthetic value of this reaction.
- Liu, Jin-Yu,Zhang, Xiao-Hai,Zhang, Yang
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supporting information
p. 5008 - 5011
(2021/09/28)
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- Enantioselective catalytic approach to the C23–C28 subunit of 24α-methyl steroids
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Enantioselective synthesis of C23–C28 subunit of campestane steroids based on catalytic methods is reported. The synthesis was started from (S)-2-isopropyl-4-nitrobutan-1-ol, which is easily accessible by the reaction between isovaleraldehyde and nitroethylene catalyzed by only 2% of (S)-trimethylsilyldiphenylprolinol. Removal of one “extra” carbon from the nitroalcohol was achieved by Ni-catalyzed hydrodecarboxylation of the redox-active ester intermediate. The synthesized C23–C28 fragment was attached to a steroidal core by Julia-Kocienski reaction of a steroidal aldehyde with metallated C23–C28 sulfone. The obtained product of olefination was easily transformed to a precursor of campesterol and (Z)-22-dehydrocampesterol.
- Yakimchyk, Viktoryia S.,Kazlova, Volha V.,Hurski, Alaksiej L.,Savchenko, Rimma G.,Kostyleva, Svetlana A.,Zhabinskii, Vladimir N.,Khripach, Vladimir A.
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supporting information
p. 82 - 90
(2019/05/24)
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- Poly(ethylene glycol) supported metal nitrates as well-organized reagents for hunsdiecker conversion of α,β-unsaturated acids to β-nitrostyrenes under solvent and acid-free conditions
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Poly(ethylene glycol) (PEG) supported metal nitrates such as ferric nitrate and manganese nitrate were accomplished as well-organized reagents for Hunsdiecker conversion of α,β-unsaturated acids to β-nitrostyrenes under acid-free and solvent free conditions using grindstone technique. However, in the case of unsaturated aliphatic acids, nitro alkene derivatives were obtained as products. PEG-400 was found the best among the other PEGs (PEG-200,300, 400, 600, 3000 and 6000) used in this protocol.
- Ramesh,Shylaja,Ramgopal,Rao, A. Sambashiva,Rajanna
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p. 1798 - 1800
(2019/07/17)
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- Synthesis of nitroolefins and nitroarenes under mild conditions
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1,3-Disulfonic acid imidazolium nitrate {[Dsim]NO3} was prepared and characterized as a new ionic liquid and nitrating agent for the ipso-nitration of various arylboronic acids and nitro-Hunsdiecker reaction of different α,β-unsaturated acids and benzoic acid derivatives, by in situ generation of NO2 to give various nitroarenes and nitroolefins without using any cocatalysts and solvents under mild conditions.
- Zarei, Mahmoud,Noroozizadeh, Ehsan,Moosavi-Zare, Ahmad R.,Zolfigol, Mohammad A.
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p. 3645 - 3650
(2018/04/14)
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- Zeolite Y-assisted nitration of aromatic and heterocyclic compounds and decarboxylative nitration of α,β-unsaturated acids under non-conventional conditions
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Zeolite Y was found to be an efficient catalyst for a facile nitration of aromatic compounds with acetonitrile as the solvent in the presence of small amounts of HNO3 at room temperature. The reactions afforded mono-nitro derivatives of aromatic compounds in about three hours under stirred conditions with high yields and regioselectivity. The reaction times drastically reduced to about 20 min under sonication and to about 20 s under microwave irradiation. Zeolite is recovered after completion of the reaction and recycled for three to four times without any problem. The approach is particularly appropriate for the conversion of unsaturated cinnamic acids into nitrostyrenes.
- Sudhakar Chary,Rajanna,Krishnaiah,Srinivas
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p. 1430 - 1434
(2016/03/08)
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- HERBICIDAL COMPOUNDS
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The present invention relates to a compound of formula (I) wherein: wherein R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11 and G are as defined herein; and wherein the compound of formula (I) is optionally present as an agrochemically acceptable salt thereof. These compounds are thought to be suitable for use as herbicides. The invention therefore also relates to a method of controlling weeds, especially grassy monocotyledonous weeds, in crops of useful plants, comprising applying a compound of formula (I), or a herbicidal composition comprising such a compound, to the plants or to the locus thereof.
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Page/Page column 90
(2016/05/24)
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- Asymmetric dearomatization of β-naphthols through a bifunctional-thiourea-catalyzed michael reaction
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An intermolecular asymmetric dearomatization reaction of β-naphthols with nitroethylene through a chiral-thiourea-catalyzed Michael reaction is described. Enantioenriched functionalized β-naphthalenones with an all-carbon quaternary stereogenic center could thus be easily constructed from simple naphthol derivatives in good yields and excellent enantioselectivity (up to 79 % yield, 98 % ee). An intermolecular asymmetric dearomatization reaction of β-naphthols with nitroethylene through a chiral-thiourea-catalyzed Michael reaction is described. Enantioenriched functionalized β-naphthalenones with an all-carbon quaternary stereogenic center were easily constructed in good yields and excellent enantioselectivity (up to 79 % yield, 98 % ee).
- Wang, Shou-Guo,Liu, Xi-Jia,Zhao, Qun-Chao,Zheng, Chao,Wang, Shao-Bo,You, Shu-Li
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supporting information
p. 14929 - 14932
(2016/02/05)
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- Metal-free ring expansion of indoles with nitroalkenes: A simple, modular approach to 3-substituted 2-quinolones
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3-Substituted 2-quinolones are obtained via a novel metal-free transannulation reaction of 2-nitroolefins with 2-substituted indoles in polyphosphoric acid. This acid-mediated cascade transformation operates via the ANRORC (Addition of Nucleophile, Ring Opening, and Ring Closure) mechanism and can be used in combination with the Fisher indole synthesis to offer a practical three-component hetero-annulation approach to 2-quinolones from arylhydrazines, 2-nitroalkenes, and acetophenone. An alternative entry to this chemistry employing the alkylation of electron-rich arenes and hetarenes with 1-(2-indolyl)-2-nitroalkene has also been demonstrated.
- Aksenov, Alexander V.,Smirnov, Alexander N.,Aksenov, Nicolai A.,Aksenova, Inna V.,Matheny, Jonathon P.,Rubin, Michael
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p. 8647 - 8656
(2015/03/03)
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- Catalytic Asymmetric Reactions of 4-Substituted Indoles with Nitroethene: A Direct Entry to Ergot Alkaloid Structures
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A domino Friedel-Crafts/nitro-Michael reaction between 4-substituted indoles and nitroethene is presented. The reaction is catalyzed by BINOL-derived phosphoric acid catalysts, and delivers the corresponding 3,4-ring-fused indoles with very good results in terms of yields and diastereo- and enantioselectivities. The tricyclic benzo[cd]indole products bear a nitro group at the right position to serve as precursors of ergot alkaloids, as demonstrated by the formal synthesis of 6,7-secoagroclavine from one of the adducts. DFT calculations suggest that the outcome of the reaction stems from the preferential evolution of a key nitronic acid intermediate through a nucleophilic addition pathway, rather than to the expected "quenching" through protonation.
- Romanini, Simone,Galletti, Emilio,Caruana, Lorenzo,Mazzanti, Andrea,Himo, Fahmi,Santoro, Stefano,Fochi, Mariafrancesca,Bernardi, Luca
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supporting information
p. 17578 - 17582
(2015/12/05)
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- Ultrasonically Assisted Rate Enhancements in Trichloroisocyanuric Acid/DMF/NaNO2 Triggered Nitration of Aromatic Compounds and Decarboxylative Nitration of α,β-Unsaturated Acids
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An efficient and safe method for nitration of aromatic compounds and decarboxylative nitration of α,β-unsaturated acids was developed using trichloroisocyanuric acid (TCICA)/dimethylformamide (DMF) in the presence of NaNO2. The reaction times of conventional protocol reduced from 8-10 h to 1.0-1.5 h (60-90 min) under sonication, even though the yields are comparable under both the conditions.
- Kumar, Mukka Satish,Rajanna, Kamatala Chinna,Venkateswarlu, Marri,Venkanna, Purugula,Saiprakash, Pondichery Kuppuswamy
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p. 2251 - 2258
(2015/09/22)
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- HERBICIDALLY ACTIVE 2-(SUBSTITUTED-PHENYL)-CYCLOPENTANE-1,3-DIONE COMPOUNDS AND DERIVATIVES THEREOF
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The present invention relates to a compound of formula (I): wherein the substituents are as defined herein, and wherein the compound of formula (I) is optionally present as an agrochemically acceptable salt thereof. These compounds are thought to be suitable for use as herbicides. The invention therefore also relates to a method of controlling weeds, especially grassy monocotyledonous weeds, in crops of useful plants, comprising applying a compound of formula (I), or a herbicidal composition comprising such a compound, to the plants or to the locus thereof.
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Page/Page column 117-118
(2014/11/11)
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- Ultrasonic and microwave-assisted synthesis of β-nitro styrenes and nitro phenols with tertiary butyl nitrite under acid-free conditions
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Tertiary butyl nitrite (TBN) is an acid-free and safe nitrating agent that provides preferentially β-nitrostyrenes with cinnamic acids and corresponding nitro derivatives with phenols in good yields under classical conditions. However, ultrasonic and microwave-assisted reactions reduced the reaction times substantially and enhanced the yields from good to excellent. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Kumar, M. Satish,Rajanna,Reddy, K. Rajendar,Venkateswarlu,Venkanna
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supporting information
p. 2672 - 2677
(2013/07/26)
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- Oxalylchloride/DMF as an efficient reagent for nitration of aromatic compounds and nitro decarboxylation of cinnamic acids in presence of KNO 3 or NaNO2 under conventional and nonconventional conditions
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Nitration of aromatic compounds and cinnamic acids with oxalylchloride/DMF afforded the corresponding nitro derivatives in the presence of KNO3 or NaNO2 under conventional and nonconventional (ultrasonic and microwave) conditions. The present methodology offers several benefits such as excellent yields, simple work-up procedure, and short reaction times. The yields obtained under present methodology are comparable with those obtained from (POCl3/DMF/KNO3 or NaNO2) and (SOCl 2/DMF/KNO3 or NaNO2) systems followed by shorter reaction times. The reaction times of sonication and microwave conditions are very shorter than those of the conventional conditions.
- Kumar, M. Satish,Reddy, K. Rajendar,Rajanna,Venkanna,Krishnaiah
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p. 977 - 983
(2013/06/05)
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- Unexpected heterocyclization of electrophilic alkenes by tetranitromethane in the presence of triethylamine. Synthesis of 3-nitroisoxazoles
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Novel reaction of tetranitromethane (TNM) with electrophilic alkenes in the presence of triethylamine yielding substituted 3-nitroisoxazoles was found and studied. Triethylamine increases the reactivity of TNM toward electrophilic alkenes promoting their heterocyclization, and the reactions proceed in an unusual way. A variety of α,β-unsaturated aldehydes, ketones, esters, amides, phosphonates, and nitro and sulfur compounds was involved in the heterocyclization reaction, and a wide range of functionalized 3-nitroisoxazoles was obtained in good to high yields. The scope and limitations of the reaction and the mechanistic aspects are discussed.
- Volkova, Yulia A.,Averina, Elena B.,Grishin, Yuri K.,Bruheim, Per,Kuznetsova, Tamara S.,Zefirov, Nikolai S.
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supporting information; experimental part
p. 3047 - 3052
(2010/07/15)
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- Amino acids and catalytic preparatory methods
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The invention provides novel compounds and methods to carry out organocatalytic Michael additions of aldehydes to nitroethylene catalyzed by a proline derivative to provide α-substituted-γ-nitroaldehydes. The reaction can be rendered enantioselective when a chiral pyrrolidine catalyst is used, allowing for Michael adducts in nearly optically pure form (e.g., 96-99% e.e.). The Michael adducts can bear a single substituent or dual substituents adjacent to the carbonyl. The Michael adducts can be efficiently converted to protected γ2-amino acids, which are essential for systematic conformational studies of γ-peptide foldamers.
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Page/Page column 12
(2009/10/30)
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- Enantioselective organocatalytic Michael addition of aldehydes to nitroethylene: Efficient access to γ2-amino acids
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Enantioselective organocatalytic Michael addition of aldehydes to nitroethylene catalyzed by (S)-diphenylprolinol silyl ether provides β-substituted-δ-nitroalcohols in nearly optically pure form (96-99% ee). The Michael adducts bear a single substituent adjacent to the carbonyl and can be efficiently converted to protected γ2-amino acids, which are essential for the systematic conformational studies of γ-peptide foldamers. Copyright
- Chi, Yonggui,Guo, Li,Kopf, Nathan A.,Gellman, Samuel H.
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p. 5608 - 5609
(2008/12/22)
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- Metal nitrate driven nitro Hunsdiecker reaction with α,β-unsaturated carboxylic acids under solvent-free conditions
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Hunsdiecker reactions with α,β-unsaturated carboxylic acids were conducted under solvent-free conditions in the presence of a few drops of HNO3 together with a variety of metal nitrates [Mg(NO3)2, Sr(NO3)2], Al(NO3)3, Ca(NO3)2, Ni(NO3)2, Cd(NO3)2, Zn(NO3)2, Hg(NO3)2, AgNO3, ZrO(NO3)2, UO2(NO3)2, Th(NO3)2] or ammonium nitrate. α,β-Unsaturated aromatic carboxylic acids underwent nitro decarboxylation to afford β-nitro styrenes in moderate to good yields, while α,β-unsaturated aliphatic carboxylic acids underwent decarboxylation to yield the corresponding nitro derivatives.
- Ramgopal,Ramesh,Chakradhar,Reddy, N. Maasi,Rajanna
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p. 4043 - 4045
(2008/02/04)
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- THE USE OF N-ARYL DIAZASPIRACYCLIC COMPOUNDS IN THE TREATMENT OF ADDICTION
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Compounds, compositions and methods for treating drug addiction, nicotine addiction, and/or obesity are disclosed. The compounds are N-aryl diazaspirocyclic compounds, bridged analogs of N-heteraryl diazaspirocyclic compounds, or prodrugs or metabolites of these compounds. The aryl group can be a five- or six-membered heterocyclic ring (heteroaryl). The compounds are effective at inhibiting dopamine production and/or secretion, and accordingly are effective at inhibiting the physiological "reward" process that is associated with ingestion of nicotine and/or illicit drugs. The compounds and compositions can be administered in effective amounts to inhibit dopamine release, wihout resulting in appreciable adverse side effects (e.g., side effects such as significant increases in blood pressure and heart rate, significant negative effects upon the gastro-intestinal tract, and significant effects upon skeletal muscle).
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Page/Page column 55
(2010/10/20)
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- Kinetics and mechanisms of the gas-phase elimination of 2-substituted primary, secondary and tertiary hydroxy groups in nitroalkanes
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The kinetics of the gas-phase elimination of several 2-substituted primary, secondary and tertiary hydroxy groups in nitroalkanes were determined in a static reaction system over the temperature range 220-400°C and pressure range of 29-235 Torr. The reactions, in seasoned vessels, are homogeneous and unimolecular and obey a first-order rate law. The presence of secondary and tertiary hydroxy substituent at the 2-position of the nitro group in nitroalkanes leads to a retro-aldol type of decomposition. The mechanism may be rationalized in terms of a six-membered cyclic transition state to give the corresponding aldehyde or ketone and the nitroalkane, respectively. However, some of the primary 2-hydroxy groups in nitroalkanes undergo a dehydration process with very limited isomerization to the corresponding alkyl nitrate. The mechanism of dehydration is believed to proceed through a six-membered rather than the already reported four-membered cyclic transition state to give the nitroalkene and water. In the case of the primary hydroxy substituent in 2-methyl-2-nitro-1-pentanol, the products of elimination are HNO2 gas and 3-hydroxy-2-methyl-1-propene. This reaction is rationalized in terms of a four-membered cyclic transition state type of mechanism. The kinetic and thermodynamic parameters of the hydroxynitroalkane substrates are presented and discussed. Copyright 2004 John Wiley & Sons, Ltd.
- Dominguez, Rosa Maria,Herize, Armando,Rotinov, Alexandra,Alvarez-Aular, Alvaro,Visbal, Gonzalo,Chuchani, Gabriel
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p. 399 - 408
(2007/10/03)
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- Inter- and intramolecular stereoselective protonation of enols
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Kinetic control of the stereoselectivity of protonation of enolates and other delocalized species commonly affords the less stable diastereomer as a consequence of the considerable exothermicity and resulting sp2 transition-state hybridization of the α-carbon. Protonation then is from the less hindered face of the enolate. The present study is aimed at reversing this phenomenon by intramolecular delivery of the proton. The approach employed required the synthesis of two enolate precursors, one with a 2-pyridyl group strategically close to the α-carbon and the other with a phenyl group in the same location. The synthesis required 15 steps and involved new methodology. Intramolecular proton transfer, reversing the usual stereoselectivity, was successful. The selectivity proved to depend on several factors including the exo versus endo configuration of the diastereomer reacting, the proton donor employed, and the concentration of the proton donor. A kinetic analysis permitted the determination of the relative reaction orders of the protonation on the two faces of the enolate.
- Zimmerman, Howard E.,Wang, Pengfei
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p. 9216 - 9226
(2007/10/03)
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- Method for the conversion of 3- and 4-methylcatechol to benzaldehyde
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The 3- and 4-methylcatechols are converted to the corresponding benzaldehyde by first alkylating the hydroxyl groups to form an alkylated methylcatechol. The methyl group is then converted to a methyl dibromide group using 1,3-dibromo-5,5-dimethylhydantoin in the presence of a non-polar, non-reactive solvent such as carbon tetrachloride and heptane and a radical initiator having a ten hour half-life temperature in the range of 47 DEG to 55 DEG C. The dibromide is then hydrolyzed to form the aldehyde.
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- Alkylation of ketone and ester lithium enolates with nitroethylene
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Nitroethylene is a '+CH2CH2NH2' and '+CH2CHO' synthon which has not been widely used in conjugate addition reactions, due in part to its reputation for facile anionic polymerization. In the present report, we describe the first systematic study of the scope and limitations of the conjugate addition of ketone and ester enolates to nitroethylene. Synthetically useful yields are obtained for ketone and ester enolates of a variety of structural types.
- Flintoft, Rebecca J.,Buzby, Jennifer C.,Tucker, John A.
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p. 4485 - 4488
(2007/10/03)
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- Kinetics and Formation Mechanism of Nitroethylene from Nitroethyl Esters of Aliphatic Carboxylic Acids
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Thermal decomposition of nitroethyl carboxylates of aliphatic acids in gas phase within temperature range 205-245°C up to conversion 70-80% follows the law of first order reaction resulting in nitroethylene and the corresponding acid. Reaction is complicated by heterogeneous processes but at S/V 0.53-0.54 cm-1 the rate constant is close to that of homogeneous decomposition. The initial pressure of the compound's vapor (at p0 > 100 mm Hg) and addition of inhibitors of chain reactions (tolyene, nitrogen oxide) do not affect the rate of decomposition. At decrease of the pKa of acid from 4.86 to 0.66 the decomposition rate increases 2.5-fold.
- Stepanov,Kruglyakova
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p. 1395 - 1397
(2007/10/03)
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- Study of the mechanism of ethylene oxidation by palladium(II) complexes containing nitro and/or nitrato ligands in chloroform
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Complexes of Pd(NOn)2-mCLmL2 (where n = 2, 3; m = 0, 1, 2; L = CH3CN, CD3CN) were synthesized and their reactivities towards ethylene and propylene oxidation in a chloroform medium were investigated. The detailed mechanism of ethylene oxidation by dinitro- and mono-nitrato complexes of palladium in chloroform solutions was studied by IR and 1H NMR spectroscopy. The structures and routes of decomposition of the intermediates to reaction end products are proposed.
- Beck,Gusevskaya,Stepanov,Likholobov,Nekipelov,Yermakov,Zamaraev
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p. 167 - 179
(2008/10/08)
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- FURAN DERIVATIVES HAVING ANTI-ULCER ACTIVITY
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Compounds of formula (I): STR1 wherein: A represents a CH-NO 2 group or a N-CN group;B represents CH 2, O, S or a direct bond;R represents a bicyclic or polycyclic residue, variously substituted and functionalized;R 1 and R 2, which may be the same or different, are hydrogen or C 1-C 4 alkyl groups; andn and m, which may be the same or different, are 0, 1, 2, 3 or 4; are valuable pharmacological agents.
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- Reversal of electronic Substituent Effects in the Retro-Diels-Alder Reaction. A Charge Neutral Analogue of Oxyanion-Accelerated Cycloreversion
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The retro-Diels-Alder reaction of anthracene cycloadducts is influenced by the dienophile substituents in the following ways: (1) electron-withdrawing groups increase the rate of the reaction; (2) strongly conjugating substituents make the reaction much faster than predicted by classical electron-withdrawing or -donating ability, in the best case by a factor of 3 x 106, and (3) there is no observable steric effect, in contrast to literature statements to the contrary.
- Nanjappan, Palaniappan,Czarnik, Anthony W.
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p. 2851 - 2853
(2007/10/02)
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- Nitroethylene: A Stable, Clean, and Reactive Agent for Organic Synthesis
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Contrary to current belief, nitroethylene is a stable reagent and holds promise as a useful and reactive synthon.Nitroethylene can be prepared in 20-25-g lots, and standard, refrigerated solutions in common solvents provide a good and ready source of the reagent.The reagent purity can be easily monitored by titration against tetraphenylcyclopentadienone (tetracyclone) coupled with the isolation of the colorless crystalline adduct.With reactive substrates, nitroethylene reacts with greatest ease at low temperatures, leading to functionalized systems having potential for further elaboration.With systems that require heating, the limited stability of nitroethylene itself complicates the course of the reaction.Cyclopentadiene, 5-cyclopentadiene, 5-(methoxymethyl)cyclopentadiene, 5-(1,3-dithianyl)cyclopentadiene, 5-(trimethylsilyl)cyclopentadiene, and spiroheptadiene readily gave (4 + 2) adducts with nitroethylene, each possessing attraction as a synthetic intermediate.Adducts from furan and acetoxyfulvene undergo rearrangement via ? cleavage.The (4 + 2) adduct from 9-diazofluorene spontaneously extrudes nitrogen, leading to spironitrocyclopropane.Indole readily undergoes Michael addition to give 80percent 3-(nitroethyl)indole and 15percent of novel bis adduct.The 2,6 Michael adduct arises with 1-morpholinocyclohexene, and β-pinene undegoes an ene reaction with nitroethylene.Novel 2-nitroethyl phosphonates, useful in Wittig-Horner reactions, arise from nitroethylene and phosphites in tert-butyl alcohol.
- Ranganathan, Darshan,Rao, C.Bhushan,Ranganathan, Subramania,Mehrotra, Ashok K.,Iyengar, Radha
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p. 1185 - 1189
(2007/10/02)
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- Dienes useful in the preparation of 1,2,3,4,4a,5,6,7-octahydro-7-aryl-isoquinolines
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Dienes of the formula SPC1 Wherein R1 and R2 are hydrogen, lower alkyl, lower alkenyl, aryl-lower alkyl, aryl-lower alkenyl, or heterocycle and Z is phenyl, substituted phenyl, naphthalene or heterocycle are disclosed. These compounds are useful as intermediates in the preparation of various pharmaceutically active 1,2,3,4,-4a,5,6,7-octahydro-7-aryl-isoquinolines.
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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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