- On the mechanism of a modified Perkin condensation leading to α-phenylcinnamic acid stereoisomers - Experiments and molecular modelling
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A modified Perkin condensation leading to α-phenylcinnamic acid stereoisomers affords predominantly or exclusively the (E)-isomer. Reaction duration, temperature, and polarity of the solvent affect the isomeric distribution only to a minor extent. However, geometry optimization of the stereoisomers by semiempirical quantum chemical methods revealed that their thermodynamic stabilities in the absolute minimum are the same. (E)-(Z)-isomerization under the conditions of the Perkin condensation resulted in an equilibrium mixture of nearly 1:1 composition, thus corroborating the results of the computations. Comparing the detailed potential energy maps of the isomers obtained at the semiempirical level of theory may explain the controversy. The (Z)-isomer has a structured potential energy surface with few but well-defined minima, whereas that of the (E)-isomer shows an extended flat plateau enabling this isomer to approach a minimum (which is close to the global one) right after its formation.
- Palinko, Istvan,Kukovecz, Akos,Toeroek, Bela,Koertvelyesi, Tamas
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- Hydrocarboxylation of alkynes with formic acid over multifunctional ligand modified Pd-catalyst with co-catalytic effect
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Hydrocarboxylation of terminal alkynes with formic acid (FA) was accomplished over a multifunctional ligand (L2) modified Pd-catalyst, advantageous with 100% atom-economy, free use of CO and H2O, mild reaction conditions, and high yields (56–89%) of α,β-unsaturated carboxylic acids with 100% regioselectivity to the branched ones. The multifunctional ligand of L2 as a zwitterion salt containing the phosphino-fragment (-PPh2), Lewis acidic phosphonium cation and sulfonate group (-SO3?), was constructed on the skeleton of 1.1′-binaphthyl-2.2′-diphenyl phosphine (BINAP) upon selective quaternization by 1,3-propanesultone. It was found that L2 conferred to the Pd-catalyst the co-catalytic effect, wherein the phosphino-coordinated Pd-complex was responsible for activation of all the substrates (including CO, FA and alkyne), and the incorporated phosphonium cation was responsible for synergetic activation of FA. The 1H NMR spectroscopic analysis supported that FA was truly activated by the incorporated Lewis acidic phosphonium cation in L2 via “acid-base pair” interaction. The in situ FT-IR spectra demonstrated that, the presence of Ac2O and NaOAc additives in the catalytic amount could dramatically promote the in situ release of CO from FA, which was required to initiate the hydrocarboxylation.
- Chen, Xiao-Chao,Guo, Lin,Liu, Lei,Liu, Ye,Lu, Yong,Yao, Yin-Qing,Zhao, Xiao-Li
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p. 322 - 332
(2022/01/06)
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- Click amidations, esterifications and one–pot reactions catalyzed by Cu salts and multimetal–organic frameworks (M–MOFs)
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Amides and esters are prevalent chemicals in Nature, industry and academic laboratories. Thus, it is not surprising that a plethora of synthetic methods for these compounds has been developed along the years. However, these methods are not 100% atom economical and generally require harsh reagents or reaction conditions. Here we show a “spring–loaded”, 100% atom–efficient amidation and esterification protocol which consists in the ring opening of cyclopropenones with amines or alcohols. Some alkyl amines react spontaneously at room temperature in a variety of solvents and reaction conditions, including water at different pHs, while other alkyl amines, aromatic amines and alcohols react in the presence of catalytic amounts of simple Cu2+ salts or solids. A modular reactivity pattern (alkyl amines >> alkyl alcohols >> phenols >> aromatic amines) enables to design orthogonal and one–pot reactions on well–defined catalytic Multimetal–Organic Frameworks (M–MOFs, M= Cu, Ni, Pd), to easily functionalize the resulting cinnamides and cinnamic esters to more complex molecules. The strong resemblance of the amidation and esterification reaction conditions here reported with the copper–catalyzed azide–alkyne cycloaddition (CuAAC) allows to define this fast, clean and flexible protocol as a click reaction.
- Armentano, Donatella,Ferrando-Soria, Jesús,Greco, Rossella,Leyva-Pérez, Antonio,Palomar-De Lucas, Brenda,Pardo, Emilio,Tiburcio, Estefanía
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- Access to α,β-unsaturated carboxylic acids through water-soluble palladium catalyzed hydroxycarbonylation of alkynes using water as the solvent
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A sulfoxantphos modified palladium-catalyzed synthesis of α,β-unsaturated carboxylic acids from alkynes with CO and H2O was described. The atom-economic hydroxycarbonylation of various symmetrical and unsymmetrical alkynes can be achieved with chemo-, stereo-, and regioselectivity, affording the corresponding carboxylic acids in good to excellent yields. Using water as the reaction solvent, the water-soluble palladium catalyst was easily separated from the product and could be reused for 5 cycles.
- Gao, Mingjie,Jia, Xiaofei,Lv, Jinhe,Ren, Xinyi,Song, Jiaxin,Xie, Congxia,Zhang, Jinrong,Zhang, Kai,Zhao, Jinyu,Zhou, Ziqin,Zong, Lingbo
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p. 4708 - 4713
(2021/07/26)
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- Palladium catalyzed 8-aminoimidazo[1,2-: A] pyridine (AIP) directed selective β-C(sp2)-H arylation
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Palladium catalyzed arylation of the inert β-C(sp2)-H bond of carboxylic acid derivatives is reported herein for the first time utilizing 8-aminoimidazo[1,2-a]pyridine (AIP) as an efficacious and new inbuilt 6,5-fused bicyclic removable directing group. This protocol is scalable, exhibits high levels of β-site selectivity and tolerates a broad spectrum of functional groups. This journal is
- Mondal, Biswajit,Ghosh, Prasanjit,Kundu, Mrinalkanti,Das, Tapas Kumar,Das, Sajal
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p. 360 - 364
(2021/01/29)
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- Method for synthesizing alpha-acrylic acid compound by catalyzing carbon dioxide and alkyne with palladium
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The invention belongs to the technical field of organic synthesis, and discloses a method for synthesizing an alpha-acrylic acid compound by catalyzing carbon dioxide and alkyne with palladium. The preparation method comprises the following steps: adding an alkyne compound, a palladium salt catalyst, alkali, a diphosphine ligand, a silane reducing agent and a solvent into a high-pressure reactionkettle, introducing carbon dioxide, stirring and reacting at 60-120 DEG C, washing a reaction liquid with water for extraction, and separating for purification to obtain the alpha-acrylic acid compound. By using the palladium salt as the catalyst and the diphosphine ligand as the ligand, the method has the characteristics of high yield, single selectivity, wide substrate applicability and the like. In addition, by taking the alkyne compound and carbon dioxide as raw materials in the reaction, the method has the advantages as follows: the raw materials are simple and easily available, the operation is simple and convenient and the atom economy is high.
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Paragraph 0117-0123
(2020/05/02)
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- Exploration of New Biomass-Derived Solvents: Application to Carboxylation Reactions
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A range of hitherto unexplored biomass-derived chemicals have been evaluated as new sustainable solvents for a large variety of CO2-based carboxylation reactions. Known biomass-derived solvents (biosolvents) are also included in the study and the results are compared with commonly used solvents for the reactions. Biosolvents can be efficiently applied in a variety of carboxylation reactions, such as Cu-catalyzed carboxylation of organoboranes and organoboronates, metal-catalyzed hydrocarboxylation, borocarboxylation, and other related reactions. For many of these reactions, the use of biosolvents provides comparable or better yields than the commonly used solvents. The best biosolvents identified are the so far unexplored candidates isosorbide dimethyl ether, acetaldehyde diethyl acetal, rose oxide, and eucalyptol, alongside the known biosolvent 2-methyltetrahydrofuran. This strategy was used for the synthesis of the commercial drugs Fenoprofen and Flurbiprofen.
- Gevorgyan, Ashot,Hopmann, Kathrin H.,Bayer, Annette
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p. 2080 - 2088
(2020/02/20)
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- Stereospecific Electrophilic Fluorocyclization of α,β-Unsaturated Amides with Selectfluor
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An efficient fluorocyclization of α,β-unsaturated amides through a formal halocyclization process is developed. The reaction proceeds under transition-metal-free conditions and leads to the formation of fluorinated oxazolidine-2,4-diones with excellent regio- and diastereoselectivity. The evaluation of the reaction mechanism based on preliminary experiments and density functional theory calculations suggests that a synergetic syn-oxo-fluorination occurs and is followed by an anti-oxo substitution reaction. The reaction opens a new window in the field of stereospecific fluorofunctionalization.
- Fei, Haiyang,Fu, Yao,Jalani, Hitesh B.,Li, Guigen,Lu, Hongjian,Wu, Hongmiao,Xu, Zheyuan,Zhu, Lin
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- Nickel nanoparticle-catalyzed carboxylation of unsaturated hydrocarbon with CO2 using sulfur-modified Au-supported nickel material
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A hydrocarboxylation reaction of alkyne or styrene derivatives with CO2 proceeded smoothly by using an air-stable nano-sized nickel catalyst supported on sulfur-modified gold (SANi), giving functionalized acrylic acids and phenylpropionic acids including an anti-inflammatory drug, Flurbiprofen. Notably, SANi could be recycled several times without a significant decrease of the yield.
- Taniguchi, Takahisa,Saito, Nozomi,Doi, Ryohei,Kimoto, Arato,Hoshiya, Naoyuki,Fujiki, Katsumasa,Shuto, Satoshi,Fujioka, Hiromichi,Arisawa, Mitsuhiro,Sato, Yoshihiro
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supporting information
p. 1406 - 1409
(2019/11/05)
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- Anti-neuroinflammatory stilbene analogues as well as preparation method and application thereof
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The invention provides anti-neuroinflammatory stilbene analogues as well as a preparation method and an application thereof. The anti-neuroinflammatory stilbene analogues have the structure as followsin the description, wherein R1 is H, halogeno, C1-C5 saturated straight chain alkyl and C1-C3 saturated straight chain alkyl substituted by one or more halogen atoms; and R2 is H, O(CH2)mCH3, halogen, hydroxyl, C1-C5 saturated straight chain alkyl and C1-C3 saturated straight chain alkyl substituted by one or more halogen atoms. According to a lead compound discovery method based on molecular assembly, a new skeleton molecule is designed by assembling two fragments of pyrimidine piperazine and stilbene, and a series of stilbene analogues are synthesized. The compounds have significant anti-neuroinflammatory activity, can permeate blood-brain barrier and can be used as a lead compound in treatment of senile dementia.
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Paragraph 0028; 0031; 0032
(2018/09/08)
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- Carboxylation of styrenes with CBr4 and DMSO via cooperative photoredox and cobalt catalysis
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Cooperative photoredox and cobalt catalyzed carboxylation of styrenes with CBr4 to afford the corresponding α,β-unsaturated carboxylic acids has been realized through radical addition and Kornblum (DMSO) oxidation. DMSO serves as the oxidant, oxygen source and solvent under these photocatalytic conditions.
- Song, Cai-Xia,Chen, Ping,Tang, Yu
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p. 11233 - 11243
(2017/02/26)
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- Following palladium catalyzed methoxycarbonylation by hyperpolarized NMR spectroscopy: A: para hydrogen based investigation
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Pd(OTf)2(bcope) is shown to react in methanol solution with diphenylacetylene, carbon monoxide and hydrogen to produce the methoxy-carbonylation product methyl 2,3 diphenyl acrylate alongside cis- and trans-stilbene. In situ NMR studies harnessing the parahydrogen induced polarization effect reveal substantially enhanced 1H NMR signals in both protic and aprotic solvents for a series of reaction intermediates that play a direct role in this homogeneous transformation. Exchange spectroscopy (EXSY) measurements reveal that the corresponding CO adducts are less reactive than their methanol counterparts.
- Guan, Dexin,Jonathan Holmes,López-Serrano, Joaquín,Duckett, Simon B.
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p. 2101 - 2109
(2017/07/15)
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- Palladium-Catalyzed Hydrocarboxylation of Alkynes with Formic Acid
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A palladium-catalyzed hydrocarboxylation of alkynes with formic acid has been developed. The method provides acrylic acid and derivatives in good yields with high regioselectivity without the need to handle toxic CO gas. Nontoxic: Acrylic acids are an important chemical feedstock. The title reaction provides acrylic acid and derivatives in good yields with high regioselectivities without the need to handle toxic CO gas.
- Hou, Jing,Xie, Jian-Hua,Zhou, Qi-Lin
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supporting information
p. 6302 - 6305
(2015/05/20)
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- Synthesis of 2-(hetero)aryl-5-(trimethylsilylethynyl)oxazoles from (hetero)arylacrylic acids
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A three-step method for the synthesis of 2-(hetero)aryl-5-(trimethylsilylethynyl)oxazoles is described. Easily accessible bis(trimethylsilyl)acetylene and acrylic acid derivatives are used as starting materials for the preparation of mono- and disubstituted 5-(trimethylsilyl)pent-1-en-4-yn-3-ones. Oxidative phthalimidoaziridination of these enynones provides the key 2-acyl-1-phthalimidoaziridines that are further utilized in the thermal expansion of the three-membered ring to furnish the target functionalizable oxazoles.
- Pankova, Alena S.,Stukalov, Alexander Yu.,Kuznetsov, Mikhail A.
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p. 1826 - 1829
(2015/04/27)
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- Cs2CO3-promoted carboxylation of N-tosylhydrazones with carbon dioxide toward α-arylacrylic acids
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A Cs2CO3-promoted carboxylation of N-tosylhydrazones and CO2 has been developed. The reaction proceeded efficiently at 80 C under atmospheric CO2, gave the corresponding α-arylacrylic acids in moderate to good yields. This method was featured with (1) the employment of Cs2CO3 rather than nBuLi as the base; (2) a reaction temperature of 80 C rather than -78 C.
- Sun, Song,Yu, Jin-Tao,Jiang, Yan,Cheng, Jiang
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p. 2855 - 2860
(2015/03/18)
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- Synthesis of combretastatin analogs: Evaluation of in vitro anticancer activity and molecular docking studies
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This study is based on the synthesis of a series of combretastatin analogs with different substitutions on one aryl moiety and a carboxylic group in connecting chain. Cis-configuration with respect to aryl groups was established by X-ray crystal analysis. All the synthesized compounds were evaluated for anticancer activity against a panel of cell lines. Six compounds 1a, 1b, 1c, 1k, 1n, and 1p showed marked anticancer activity against human colon (colo-205), lung (A549), ovary (IGROV-1), prostrate (PC-3), CNS (SF-295), leukemia (THP-1), and breast (MCF-7) cell lines. Out of these, 1b showed remarkable inhibitory activity comparable to paclitaxel against lung cancer cell line with IC50 3.9 μM. Importance of carboxylic group in the synthesized compounds was studied by flexible docking study of 1b which showed the importance of carboxylic group interactions with colchicine-binding site of ab-tubulin. Springer Science+Business Media, LLC 2011. Springer Science+Business Media, LLC 2011.
- Kumar, Sunil,Sapra, Sameer,Kumar, Raj,Gupta, Manish Kumar,Koul, Surrinder,Kour, Tandeep,Saxena, Ajit Kumar,Suri, Om Prakash,Dhar, Kanahya Lal
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p. 3720 - 3729
(2013/02/23)
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- NOVEL HISTONE DEACETYLASE INHIBITORS
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Provided herein are novel, stilbene like compounds of the general formula (I), their derivatives, analogs, tautomeric forms, stereoisomers, polymorphs, hydrates, metabolites, prodrugs, solvates, pharmaceutically acceptable salts and compositions thereof. These compounds can inhibit HDACs and are useful as a therapeutic or ameliorating agent for diseases that are involved in cellular growth such as WO 2009/047615 A2 malignant tumors, autoimmune diseases, skin diseases, infections, inflammation, etc.
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Page/Page column 35
(2010/09/07)
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- Friedel-Crafts alkylation of benzene with 1,2-diphenyl-2-propanol, 1-chloro-2,3-diphenylpropane and 2-methyl-1-phenyl-2-butanol
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The alkylation of benzene with 1,2-diphenyl-2-propanol (1) using AlCl 3/CH3NO2 catalyst gave a mixture of 1,2,2- (4) and 1,1,2-triphenylpropane (5) as product alkylates. With 85% H 2SO4 catalyst, the product consisted of E-1,2-diphenylpropene (6) after 2 h of a mixture of 5 and 6 after 18 h. Similar alkylation of benzene with 1-chloro-2,3-diphenylpropane (2) using AlCl 3 catalyst gave a mixture consisting of 4, 5 and 6. Finally, alkylation of benzene with 2-methyl-1-phenyl-2-butanol (3) using AlCl 3/CH3NO2 gave 2-methyl-1,1-diphenylbutane (10) as sole product alkylate. The identities of the products were confirmed spectroscopically and by comparison with unequivocally prepared samples. Mechanisms are proposed to rationalise the observed results.
- Khalaf, Ali A.,Awad, Ibrahim M.,El-Emary,El-Aal, H.A.K. Abd
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experimental part
p. 595 - 600
(2011/08/21)
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- NOVEL HISTONE DEACETYLASE INHIBITORS
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Provided herein are novel, stilbene like compounds of the general formula (I), their derivatives, analogs, tautomeric forms, stereoisomers, polymorphs, hydrates, metabolites, prodrugs, solvates, pharmaceutically acceptable salts and compositions thereof. These compounds can inhibit HDACs and are useful as a therpeautic or ameliorating agent for diseases that are involved in cellular growth such as malignant tumors, autoimmune diseases, skin diseases, infections, inflammation, etc.
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Page/Page column 50
(2009/05/30)
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- Development and application of a direct vinyl lithiation of cis-stilbene and a directed vinyl lithiation of an unsymmetrical cis-stilbene
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Equation Presented The vinyl deprotonation of cis-stilbene can be readily achieved using s-BuLi in THF at -25°C. The generated 1-lithio-1,2- diphenylethene undergoes an in situ Z-to-E isomerization, and subsequent reaction with electrophiles results in an efficient stereoselective synthesis of trisubstituted alkenes. A directed vinyl lithiation of the unsymmetrical cis-stilbene 2-styryl-phenyl-carbamic acid tert-butyl ester can be achieved regioselectively, thereby expanding this methodology for further synthetic applications in indole chemistry.
- Cotter, Juliet,Hogan, Anne-Marie L.,O'Shea, Donal F.
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p. 1493 - 1496
(2008/02/02)
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- A non-cope among the cope rearrangements of 1,3,4,6-tetraphenylhexa-1,5- dienes
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The set of 1,3,4,6-tetraphenylhexa-1,5-dienes (1) represents a perturbation of Cope's rearrangement by four radical-stabilizing phenyl groups all positioned to drive the transition region toward the homolytic- colligative end of the mechanistic spectrum. The appearance of (Z)-isomers being suppressed thermodynamically by a steric interaction of +2.6 kcal mol- 1 per cis double bond, an equilibration that is stereochemically not of any Cope type, emerges as the predominant reaction. It is an interconversion of rac-(E,E)-1 and meso-(E,E)-1 (48:52; 77.3-115.3 °C) with the following values of the enthalpy, entropy, and volume of activation: ΔH(+) = 30.7 ± 0.2 kcal mol-1, ΔS(+) = +2.1 ± 0.4 cal mol-1 K-1, and ΔV(+) = +13.5 ± 0.1 cm-3 mol-1, respectively. Structures have been established by X- ray crystallographic analysis; a possible relationship between dihedral angle and bond lengths in the styrene portions is proposed. The entropy of activation is incompatible with a chair or boat Cope rearrangement; the volume of activation is neither low enough for a pericyclic Cope ('concerted') mechanism nor high enough for a homolytic-colligative mechanism involving full dissociation as the rate-determining step. Trapping and a crossover experiment give some but only partial support to the intermediacy of free radicals. At higher temperatures, however, electron spin resonance experiments demonstrate an equilibrium with kinetically free (E,E)-1,3- diphenylallyl radicals. These observations are rationalized in terms of geometric reorganization within the confines of a 'cage'. Resolution by chiral chromatography of rac-(E,E)-1 allows recognition of a fast racemization (40-65 °C), of which ΔH(+) (21.3 ± 0.1 kcal mol-1), DS(+) (-13.2 ± 0.3 cal mol-1 K-1), and ΔV(+) (-7.4 ± 0.4 cm-3 mol-1) are consistent with a pericyclic Cope rearrangement. Enriched (Z)-isomers undergo Cope rearrangements in accord with the known influence of axiality and the chair/boat alternative on the energy of the transition region.
- Doering,Birladeanu, Ludmila,Sarma, Keshab,Blaschke,Scheidemantel, Ursula,Boese,Benet-Bucholz, Jordi,Klaerner,Gehrke, Jan-Stephan,Zimny, Bernd Ulrich,Sustmann,Korth, Hans-Gert
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p. 193 - 203
(2007/10/03)
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- Protonation and ring closure of stereoisomeric α-substituted cinnamic acids in superacidic media studied by 13C NMR spectroscopy and computations
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Five α-substituted cinnamic acids [(E)- and (Z)-2,3-diphenyl-, (E)- and (Z)-3-(2-methoxyphenyI)-2-phenyl- and (E)-2-(2-methoxyphenyl)-3-phenyl-propenoic acids] have been protonated in fluorosulfonic acid at -78°C. Protonation of the carboxylic group and a second protonation on the methoxy group at -78°C or the ring bearing the methoxy group at 0°C have been observed by 13C NMR spectroscopy. Upon protonation (Z)-α-phenylcinnamic acid is transformed to a protonated indenol derivative. Dehydrative ring closure begins at -78°C and goes to completion at 0°C. Similar transformations of the other studied Z-acid are suppressed by the deactivating effect of the protonated methoxy group. Only protonation has been observed for the E-acids at -78°C as well as 0°lculations at the HF/3-21G level provide the equilibrium structures of the corresponding cations. Results of IGLO/13C NMR shift calculations are in good agreement with the experimental findings.
- Palinko, Istvan,Burrichter, Arwed,Rasul, Golam,Toeroek, Bela,Prakash, G. K. Surya,Olah, George A.
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p. 379 - 385
(2007/10/03)
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- Base-catalyzed ring openings of benzocyclobutenones and -ols
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The base-catalyzed ring opening of a number of isomeric E- and Z-benzylidenebenzocyclobutenones and -ols has been studied in both protic and aprotic solvents.Cleavage of the C1-C2 bond results in the formation of stilbenes with mainly, and at times exclusively, retained stereochemistry.For the alcohols, these results point to an oxyanion-induced carbon-carbon bond cleavage leading to a vinyl anion that is protonated with retention of configuration in the protic solvents rather than to an electrocyclic ring opening to an alkoxy o-quinodimethane.Reaction of the Z isomer of benzylidenebenzocyclobutenol with methyllithium in THF at 20 deg C causes isomerization to the E isomer, cleavage of the C1-C2 bond, and recyclization of the resultant isomerized vinyl anion. - Key words: benzylidenebenzocyclobutenones, base-catalyzed ring opening; benzylidenebenzocyclobutenols, base-catalyzed ring opening.
- Bradley, J. C.,Durst, T.
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p. 1660 - 1665
(2007/10/02)
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- Analysis of the 13C and 1H Spectra of Mixtures of Benzylidene Derivatives
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The 1H and 13C NMR spectra of methyl (E)-2,3-diphenylprop-2-enoate and methyl (E)-2-(2-phenylethenyl)benzoate resulting from the electrocyclic ring opening of benzocyclobutenone starting materials have been assigned.A combination of direct detection 2D NMR techniques, COSY, HETCOR, and FLOCK, provided the assignments of the 1H and 13C resonances. - Keywords: NMR 1H NMR 13C NMR Benzylidene derivatives
- Bradley, J. C.,Williams, A. J.
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p. 496 - 498
(2007/10/02)
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- SYNTHESIS OF BENZOFURO- AND BENZOTHIENOPHENANTHRIDONES BY TWOFOLD PHOTOCHEMICAL DEHYDROCYCLIZATION REACTION
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Four new N-(p-chlorophenyl)carboxamides 1 - 4 of 9-phenanthrene-, 5-naphthofuran-, and 5-naphtho- and 4-naphthothiophenecarboxylic acids have been synthesized.All carboxanilides were exposed to UV oxidative irradiation in methanolic solution.In the case of 2 and 3 corresponding benzo-furophenanthridin-10(9H)-one 5 and benzo-thienophenanthridin-10(9H)-one 6 are isolated.
- Karminski-Zamola, G.,Bajic, M.
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p. 1325 - 1334
(2007/10/02)
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- Electron Transfer Reactions. Reaction of Furanones and Bifurandiones with Potassium and Oxygen
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Treatment of furanones (1a - c, 25, 34) and bifurandiones (23, 37) with potassium in THF gave rise to radical anion intermediates, which reacted with oxygen to give superoxide and ultimately products derived through the reaction of superoxide with the starting furanones and bifurandiones.Thus, the reaction of 1a with potassium gave a mixture of 4-oxo-2,2,4-triphenylbutanoic acid (7a), 1,3,3-triphenyl-2-propen-1-one (11a), and benzoic acid (12).The reaction of 11a itself, under similar conditions, gave a mixture of benzophenone (18a) and 12.Similar reactions have been observed in the case of 1b and c.The bifurandione 23, on treatment with potassium, gave a mixture of the 2(5H)-furanone 25, 2,3-diphenylpropenoic acid (31), and 12.The reaction of 25 itself with potassium under similar conditions gave the same mixture of 31 and 12.Treatment of 3-phenyl-2(3H)-benzofuranone (34) with potassium, however, did not give any isolable product; only the starting material could be recovered.Under similar conditions, the bifurandione 37 gave the fragmentation product 34.Cyclic voltammetric studies have been employed to measure the reduction potentials, leading to radical anions, and these intermediates have been characterized through their electronic spectra.
- Pandey, Bipin,Tikare, Ravindra K.,Muneer, Mohammed,Kamat, Prashant V.,George, Manapurathu V.
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p. 917 - 928
(2007/10/02)
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- Isomerisation of α-Phenylcinnamic Acids with Potassium Amide in Liquid Ammonia
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Treatment of trans- or cis-α-phenylcinnamic acids (1) with KNH2 in liquid ammonia results in equilibration.The cis- acid obtained from trans-β-deutero-α-phenylcinnamic acid (9) retains 76percent of deuterium.Exposure of dl-2,3-diphenyl-β-alanine to KNH2/N
- Kessar, S. V.,Nadir, U. K.,Narula, Suchita,Kumar, Pawan,Mohammad, Taj
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- SYNTHESIS AND PROPERTIES OF HETEROCYCLIC CARBOXONIUM SYSTEMS VII.* SYNTHESIS AND PROPERTIES OF 2-BENZYL-SUBSTITUTED 1,3-DIOXOLANIUM SALTS
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A method was developed for the synthesis of 2-benzyl-substituted 1,3-dioxolanium salts by acylation of pinacone by arylacetyl chlorides in the presence of silver perchlorate or of boron trifluoride etherate.The reactions of the salts with various aldehydes, acetals, ketals, ethyl orthoformate, and organomagnesium compounds were investigated.
- Mezheritskaya, L. V.,Matsovskaya, E. S.,Dorofeenko, G. N.
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p. 174 - 178
(2007/10/02)
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