- Thermodynamically Favorable Conversion of Hydrogen Sulfide into Valuable Products through Reaction with Sodium Naphthalenide
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Hydrogen sulfide (H2S) is an extremely hazardous chemical waste that is generated at large scale in many industries; its abatement has long been an energy-extensive and cost-ineffective liability due to the thermodynamic limitations of the selected approaches and low value of the final products, sulfur and water. Here we introduce an attractive method for H2S abatement that yields value-added products via a thermodynamically favorable process. Specifically, sodium naphthalenide (Na-NAP) is used to capture H2S to produce anhydrous Na2S nanocrystals and 1,4-dihydronaphthalene, which are important materials for batteries and liquid fuels, respectively. This multipurpose process is driven by the acid/base neutralization reaction between hydrogen cations from H2S and radical anions from naphthalenide. It is spontaneous and irreversible at ambient temperature and pressure, proceeding to completion very rapidly. Waste not, want not: The chemical waste hydrogen sulfide (H2S) is notorious for its production in many industries, harming creatures, corroding equipment, poisoning catalysts, and requiring energy-intensive and cost-ineffective abatements. Now a thermodynamically favorable process can convert H2S into value-added energy materials.
- Li, Xuemin,Morrish, Rachel M.,Yang, Yuan,Wolden, Colin A.,Yang, Yongan
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- A Simple Preparation of Benzo-Fused Bicycloalkadienes from 1,3-Diene-Benzoquinone Cycloadducts
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Synthetic procedures are reported for the conversion of the Diels-Alder adduct of benzoquinone and both 1,3-cyclohexadiene and 1,3-cycloheptadiene to the parent hydrocarbons, 1,4-dihydro-1,4-ethanonaphthalene (benzobicyclooctadiene) and 6,7,8,9-tetrahydro-5H-5,9-ethenobenzocycloheptene (benzobicyclononadiene), respectively.The Diels-Alder adducts can be conveniently converted into the 5,8- and 1,4-dimethoxy as well as 5,8- and 1,4-diacetoxy derivatives, respectively, of these tricyclic compounds.
- Schmid, George H.,Rabai, Jozsef
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- Synthesis and properties of 7,7-dichloro-3,4-benzobicyclo[4.1.0]heptane, its tricarbonylchromium complexes, and isomeric 7-chloro-3,4-benzobicyclo[4.1.0]heptanes
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The reaction of Cr(CO)6 with 7,7-dichloro-3,4-benzobicyclo[4.1.0]heptane gave the corresponding exo- and endo-chromium tricarbonyl complexes in a ratio of 4.5 : 1 The structures of the resulting compounds were established by NMR spectroscopy, mass spectrometry, and X-ray structural analysis. Reduction of dichlorobenzobicycloheptane and its chromium tricarbonyl complexes with LiAlH4 afforded exo- and endo-7-chloro-3,4-benzobicyclo[4.1.0]heptanes in a 3.5 : 1 ratio.
- Vorogushin,Reshetova,Akhmedov,Ustynyuk,Eremenko,Nefedov,Zinin
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- Dearomatization of naphthalene: Stereoselective cis-1,4 tandem additions promoted by osmium(II)
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The naphthalene complex of pentaammineosmium(II) (1) reacts with four different classes of electrophiles to form 1-naphthalenium species 2-5. These η3-allyl complexes react stereospecifically with a variety of nucleophiles to form cis-1,4-dihydronaphthalene complexes. The entire reaction sequence may be performed outside a glovebox in two steps using conventional techniques.
- Winemiller, Mark D.,Harman, W. Dean
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- Stereoconvergent generation of a contrasteric syn-bicyclopropylidene (=syn-Cyclopropylidenecyclopropane) by stille-like coupling
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Stereoisomerically pure endo- and exo-7-halo-7-(trimethylstannyl) benzonorcar-3-enes (=endo- and exo-(1-halo-1a,2,7,7a-tetrahydro-1H-cyclopropa[b] naphthalen-1-yl)trimethylstannane) 4 and 6 were selectively obtained by lithium-tin or magnesium-tin transmetalation in good yields (Scheme 2 and 3). The reaction of these compounds with copper(I) thiophene-2-carboxylate (CuTC) produced in both cases the corresponding CS-symmetric bicyclopropylidene (=cyclopropylidenecyclopropane) syn-1, a single diastereoisomer (Schemes 5 and 6). The structure of syn-1 was undoubtedly elucidated by X-ray single crystal diffraction. The coupling mechanism of the carbenoid cyclopropane is discussed (Scheme 7). Copyright
- Gueney, Murat,Essiz, Selcuk,Dastan, Arif,Balci, Metin,De Lucchi, Ottorino,Sahin, Ertan,Fabris, Fabrizio
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- Olefination via Cu-Mediated Dehydroacylation of Unstrained Ketones
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The dehydroacylation of ketones to olefins is realized under mild conditions, which exhibits a unique reaction pathway involving aromatization-driven C-C cleavage to remove the acyl moiety, followed by Cu-mediated oxidative elimination to form an alkene between the α and β carbons. The newly adopted N′-methylpicolinohydrazonamide (MPHA) reagent is key to enable efficient cleavage of ketone C-C bonds at room temperature. Diverse alkyl- and aryl-substituted olefins, dienes, and special alkenes are generated with broad functional group tolerance. Strategic applications of this method are also demonstrated.
- Dong, Guangbin,Xu, Yan,Zhou, Xukai
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supporting information
p. 20042 - 20048
(2021/12/03)
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- Dibenzoate esters of cis-tetralin-2,3-diol as analogs of (-)-epigallocatechin gallate: Synthesis and crystal structure of anticancer drug candidates
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(-)-Epigallocatechin gallate (EGCG), the main component of green tea extract, displays multiple biological activities. However, it cannot be used as a drug due to its low cellular absorption, instability and metabolic degradation. Therefore, there is a need to provide analogs that can overcome the limitations of EGCG. In this work, six synthetic analogs of EGCG sharing a common tetralindiol dibenzoate core were synthesized and fully characterized by 1H NMR, 13C NMR, HRMS and IR spectroscopies, and X-ray crystallography. These are (2R,3S)-1,2,3,4-tetrahydronaphthalene-2,3-diyl bis[3,4,5-tris(benzyloxy)benzoate], C66H56O10, and the analogous esters bis(3,4,5-trimethoxybenzoate), C30H32O10, bis(3,4,5-trifluorobenzoate), C24H14F6O4, bis[4-(benzyloxy)benzoate], C38H32O6, bis(4-methoxybenzoate), C26H24O6, and bis(2,4,6-trifluorobenzoate), C24H14F6O4. Structural analysis revealed that the molecular shapes of these dibenzoate esters of tetralindiol are significantly different from that of previously reported dimandelate esters or monobenzoate esters, as the acid moieties extend far from the bicyclic system without folding back over the tetralin fragment. Compounds with small fluorine substituents take a V-shape, whereas larger methoxy and benzyloxy groups determine the formation of an L-shape or a cavity. Intermolecular interactions are dominated by π-π stacking and C-H..π interactions involving the arene rings in the benzoate fragment and the arene ring in the tetrahydronaphthalene moiety. All six crystal structures are determined in centrosymmetric space groups (either P, P21/n, C2/c or I2/a).
- Chan, Tak-Hang,Fukumoto, Kozo,Nishioka, Takanori,Renzetti, Andrea,Rutherford, Ryan Noboru,Ura, Shinji
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p. 1085 - 1095
(2020/12/15)
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- Cytochrome p450 can epoxidize an oxepin to a reactive 2,3-epoxyoxepin intermediate: Potential insights into metabolic ring-opening of benzene
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Dimethyldioxirane epoxidizes 4,5-benzoxepin to form the reactive 2,3-epoxyoxepin intermediate followed by very rapid ring-opening to an o-xylylene that immediately isomerizes to the stable product 1H-2-benzopyran-1-carboxaldehyde. The present study demonstrates that separate incubations of 4,5-benzoxepin with three cytochrome P450 isoforms (2E1, 1A2, and 3A4) as well as pooled human liver microsomes (pHLM) also produce 1H-2-benzopyran-1-carboxaldehyde as the major product, likely via the 2,3-epoxyoxepin. The reaction of 4,5-benzoxepin with cerium (IV) ammonium nitrate (CAN) yields a dimeric oxidized molecule that is also a lesser product of the P450 oxidation of 4,5-benzoxepin. The observation that P450 enzymes epoxidize 4,5-benzoxepin suggests that the 2,3-epoxidation of oxepin is a major pathway for the ring-opening metabolism of benzene to muconaldehyde.
- Cote, Noah A.,Fitzgerald, Ryan W.,Greenberg, Arthur,Weaver-Guevara, Holly M.
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supporting information
(2020/10/18)
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- Chemoenzymatic Synthesis of a Chiral Ozanimod Key Intermediate Starting from Naphthalene as Cheap Petrochemical Feedstock
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Ozanimod represents a recently developed, promising active pharmaceutical ingredient (API) molecule in combating multiple sclerosis. Addressing the goal of a scalable, economically attractive, and technically feasible process for the manufacture of this drug, a novel alternative synthetic approach toward (S)-4-cyano-1-aminoindane as a chiral key intermediate for ozanimod has been developed. The total synthesis of this intermediate is based on the utilization of naphthalene as a readily accessible, economically attractive, and thus favorable petrochemical starting material. At first, naphthalene is transformed into 4-carboxy-indanone within a four-step process by means of an initial Birch reduction, followed by an isomerization of the C=C double bond, oxidative C=C cleavage, and intramolecular Friedel-Crafts acylation. The transformation of the 4-carboxy-indanone into (S)-4-cyano-1-aminoindane then represents the key step for introducing the chirality and the desired absolute S configuration. When evaluating complementary biocatalytic approaches based on the use of a lipase and transaminase, respectively, the combination of a chemical reductive amination of the 4-carboxyindanone followed by a subsequent lipase-catalyzed resolution turned out to be the most efficient route, leading to the desired key intermediate (S)-4-cyano-1-aminoindane in satisfactory yield and with excellent enantiomeric excess of 99%.
- Uthoff, Florian,L?we, Jana,Harms, Christina,Donsbach, Kai,Gr?ger, Harald
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p. 4856 - 4866
(2019/05/02)
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- Experimental and Theoretical Studies on the Aqueous Solvation and Reactivity of SmCl2 and Comparison with SmBr2 and SmI2
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Water addition to Sm(II) has been shown to increase reactivity for both SmI2 and SmBr2. Previous work in our groups has demonstrated that this increase in reactivity can be attributed to coordination induced bond weakening enabling substrate reduction through proton-coupled electron transfer. The present work examines the interaction of water with samarium dichloride (SmCl2) and illustrates the importance of the Sm-X interaction and bond distance upon water addition critical for the reactivity of the reagent system. Born-Oppenheimer molecular dynamics simulations identify substantial variations among the reductants created in solution upon water addition to SmI2, SmBr2, and SmCl2 with the latter showing the least halide dissociation. This results in a lower water coordination number for SmCl2, creating a more powerful reducing system. As previously shown with the other SmX2-water systems, coordination-induced bond-weakening of the O-H bond of water bound to Sm(II) results in significant bond weakening. In the case of SmCl2, the bond weakening is estimated to be in the range of 83 to 88.5 kcal/mol.
- Ramírez-Solís, Alejandro,Bartulovich, Caroline O.,León-Pimentel, César Iván,Saint-Martin, Humberto,Anderson, William R.,Flowers, Robert A.
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supporting information
p. 13927 - 13932
(2019/10/16)
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- Birch-Type Photoreduction of Arenes and Heteroarenes by Sensitized Electron Transfer
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The direct reduction of arenes and heteroarenes by visible-light irradiation remains challenging, as the energy of a single photon is not sufficient for breaking aromatic stabilization. Shown herein is that the energy accumulation of two visible-light photons allows the dearomatization of arenes and heteroarenes. Mechanistic investigations confirm that the combination of energy-transfer and electron-transfer processes generates an arene radical anion, which is subsequently trapped by hydrogen-atom transfer and finally protonated to form the dearomatized product. The photoreduction converts planar aromatic feedstock compounds into molecular skeletons that are of use in organic synthesis.
- Chatterjee, Anamitra,K?nig, Burkhard
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supporting information
p. 14289 - 14294
(2019/08/30)
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- Strontium-mediated selective protonation of unsaturated linkage of aromatic hydrocarbons and these derivatives
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The selective protonation of aromatic hydrocarbons with at least two or more aromatic rings and aromatic compounds bearing unsaturated linkages can be achieved by metallic strontium metal with ammonium chloride and iodine, or ammonium iodide in tetrahydrofuran. The reaction system is ammonia-free in room temperature and the reaction proceeds high selectivity in moderate to good yields.
- Ohmura, Satoshi D.,Ueno, Masaharu,Miyoshi, Norikazu
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supporting information
p. 2268 - 2271
(2018/05/16)
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- METHOD OF RETARDING AN ETHYLENE RESPONSE
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A compound of Formula I, wherein R1, R2, R3, R4, R5 and R6 are independently hydrogen, halogen, an unsubstituted alkyl, alkenyl, alkynyl, cydoalkyi, cydoalkylalkyi, aryl, phenyl, or naphthyl group, and a substituted alkyl, alkenyl, alkynyl, cydoalkyi, cydoalkylalkyi, aryl, phenyl, or naphthyl group having as a substituent a halogen, alkoxy, substituted phenoxy, unsubstituted phenoxy group or a heteroatom such as oxygen, sulfur, nitrogen, phosphorus and boron.
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Paragraph 0076-0077
(2018/04/13)
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- Birch Reduction of Aromatic Compounds by Inorganic Electride [Ca2N]+?e- in an Alcoholic Solvent: An Analogue of Solvated Electrons
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Birch reduction of aromatic systems by solvated electrons in alkali metal-ammonia solutions is widely recognized as a key reaction that functionalizes highly stable π-conjugated organic systems. In spite of recent advances in Birch reduction with regard to reducing agent and reaction conditions, there remains an ongoing challenge to develop a simple and efficient Birch reaction under mild conditions. Here, we demonstrate that the inorganic electride [Ca2N]+?e- promotes the Birch reduction of polycyclic aromatic hydrocarbons (PAHs) and naphthalene under alcoholic solvent in the vicinity of room temperature as a solid-type analogy to solvated electrons in alkali metal ammonia solutions. The anionic electrons from electride [Ca2N]+?e- are transferred to PAHs and naphthalene via alcoholysis in a polar cosolvent medium. It is noteworthy that a high conversion yield to the hydrogenated products is ascribed to the extremely high electron transfer efficiency of 98%. This simple protocol utilizing an inorganic electride offers a direct and practical strategy for the reduction of aromatic compounds and provides an outstanding reducing agent for synthetic chemistry.
- Yoo, Byung Il,Kim, Ye Ji,You, Youngmin,Yang, Jung Woon,Kim, Sung Wng
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supporting information
p. 13847 - 13853
(2018/11/23)
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- Electron-Transfer and Hydride-Transfer Pathways in the Stoltz–Grubbs Reducing System (KOtBu/Et3SiH)
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Recent studies by Stoltz, Grubbs et al. have shown that triethylsilane and potassium tert-butoxide react to form a highly attractive and versatile system that shows (reversible) silylation of arenes and heteroarenes as well as reductive cleavage of C?O bonds in aryl ethers and C?S bonds in aryl thioethers. Their extensive mechanistic studies indicate a complex network of reactions with a number of possible intermediates and mechanisms, but their reactions likely feature silyl radicals undergoing addition reactions and SH2 reactions. This paper focuses on the same system, but through computational and experimental studies, reports complementary facets of its chemistry based on a) single-electron transfer (SET), and b) hydride delivery reactions to arenes.
- Smith, Andrew J.,Young, Allan,Rohrbach, Simon,O'Connor, Erin F.,Allison, Mark,Wang, Hong-Shuang,Poole, Darren L.,Tuttle, Tell,Murphy, John A.
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supporting information
p. 13747 - 13751
(2017/10/12)
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- METHOD OF RETARDING AN ETHYLENE RESPONSE
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A method for retarding an ethylene response in a plant or plant part comprising the step of contacting the plant or plant part with an ethylene response retarding amount of benzocyclopropene and/or naphtho[b]cyclopropane.
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Paragraph 0078
(2017/05/20)
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- Cobalt-catalyzed oxidative esterification of allylic/benzylic C(sp3)–H bonds
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A protocol for the cobalt-catalyzed oxidative esterification of allylic/benzylic C(sp3)–H bonds with carboxylic acids was developed in this work. Mechanistic studies revealed that C(sp3)–H bond activation in the hydrocarbon was the turnover-limiting step and the in-situ formed [Co(III)]Ot-Bu did not engage in hydrogen atom abstraction (HAA) of a C–H bond. This protocol was successfully incorporated into a synthetic pathway to β-damascenone that avoided the use of NBS.
- Ren, Tian-Lu,Xu, Bao-Hua,Mahmood, Sajid,Sun, Ming-Xue,Zhang, Suo-Jiang
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supporting information
p. 2943 - 2948
(2017/04/26)
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- Asymmetric synthesis of azolium-based 1,2,3,4-tetrahydronaphthalen-2-ols through lipase-catalyzed resolutions
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Abstract A series of racemic trans-1,2,3,4-tetrahydronaphthalen-2-ols bearing an azole nucleus at the C-1 or C-3 position has been synthesized by ring opening reactions of the corresponding epoxides using imidazole or 1,2,4-triazole. The kinetic resolutions of these racemates were undertaken through transesterification processes, finding good levels of activities and high to excellent enantiodiscrimination values for the Pseudomonas cepacia lipase immobilized on a ceramic carrier. Investigations into the optimum reaction conditions were carried out by consideration of different organic solvents, temperatures, enzyme loadings, and reaction times. With the best conditions in hand, the experiments were later carried out toward the resolution of the related racemic cis-alcohols, which were previously obtained through a Mitsunobu and deprotection chemical sequence from the trans-stereoisomers.
- Méndez-Sánchez, Daniel,Ríos-Lombardía, Nicolás,Gotor, Vicente,Gotor-Fernández, Vicente
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p. 760 - 767
(2015/07/15)
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- Crystalline Hetero-Stereocomplexed Polycarbonates Produced from Amorphous Opposite Enantiomers Having Different Chemical Structures
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Abstract Stereocomplexation is the stereoselective interaction between two opposite enantiomeric polymers through an interlocked orderly assembly. Most studies focus on the stereocomplex formation from the crystalline opposite enantiomers having the identical structure; nevertheless, rare examples were reported regarding the crystalline stereocomplexes from enantiomeric polymers having different chemical structures. Herein we show a strategy for polymer orderly assembly through the formation of crystalline hetero-stereocomplexed polymeric materials by the cocrystallization of amorphous isotactic polycarbonates with different chemical structures and opposite configurations. The behaviors in the crystalline state are significantly different from that of the component enantiomeric polymers or their homo-stereocomplexes. This study is expected to open up a new way to prepare various semicrystalline materials having a wide variety of physical properties and degradability. Mixed enantiomers: A unique strategy for polymer assembly was demonstrated through the formation of crystalline hetero-stereocomplexed polymeric materials by the cocrystallization of amorphous isotactic polycarbonates with opposite configurations and different chemical structures. This study is expected to open up a new way to prepare various semicrystalline materials with a wide variety of physical properties and degradability.
- Liu, Ye,Wang, Meng,Ren, Wei-Min,Xu, Yue-Chao,Lu, Xiao-Bing
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supporting information
p. 7042 - 7046
(2015/06/16)
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- Carbon Dioxide Copolymerization Study with a Sterically Encumbering Naphthalene-Derived Oxide
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Poly(1,4-dihydronaphthalene carbonate) has been prepared via the catalytic coupling of carbon dioxide and 1,4-dihydronaphthalene oxide using chromium(III) catalysts. The copolymer formation is found to be greatly dependent on the steric environment around the metal center. Traditional (salen)CrIIIX/cocatalyst systems bearing bulky t-butyl groups hinder the approach of the large monomer, significantly diminishing polymer chain growth and providing the entropically favored cyclic byproduct in excess. In contrast, employing the sterically unencumbered azaannulene-derived catalyst, (tmtaa)CrIIIX/cocatalyst system (tmtaa = tetramethyltetraazaannulene) shows polymer selectivity close to 90% with three times the activity (TOF = 20-30 h-1). With the use of a bifunctional (salen)CrIII catalyst, even higher polymer selectivity (>90%) can be observed. The complete synthesis of a new bifunctional tetraazaannulene ligand for a more effective catalyst is also described herein.
- Darensbourg, Donald J.,Kyran, Samuel J.
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p. 5421 - 5430
(2015/09/15)
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- Towards a practical development of light-driven acceptorless alkane dehydrogenation
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The efficient catalytic dehydrogenation of alkanes to olefins is one of the most investigated reactions in organic synthesis. In the coming years, an increased supply of shorter-chain alkanes from natural and shale gas will offer new opportunities for inexpensive carbon feedstock through such dehydrogenation processes. Existing methods for alkane dehydrogenation using heterogeneous catalysts require harsh reaction conditions and have a lack of selectivity, whereas homogeneous catalysis methods result in significant waste generation. A strong need exists for atom-efficient alkane dehydrogenations on a useful scale. Herein, we have developed improved acceptorless catalytic systems under optimal light transmittance conditions using trans-[Rh(PMe3) 2(CO)Cl] as the catalyst with different additives. Unprecedented catalyst turnover numbers are obtained for the dehydrogenation of cyclic and linear (from C4) alkanes and liquid organic hydrogen carriers. These reactions proceed with unique conversion, thereby providing a basis for practical alkane dehydrogenations.
- Chowdhury, Abhishek Dutta,Weding, Nico,Julis, Jennifer,Franke, Robert,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 6477 - 6481
(2014/06/24)
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- Electrocatalytic debromination of open-chain and cyclic dibromides in ionic liquids with cobalt(II)salen complex as mediator
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The electrocatalytic reduction of open-chain and cyclic dibromides in ionic liquids, mediated by cobalt(II)salen, was investigated. Macro-scale constant-potential electrolysis in an undivided cell gave the corresponding debrominated products in moderate to good yields. The workup process after electrolysis proved to be much simpler in the ionic liquid than that in organic solvents. The possibility of reuse of the ionic liquid was demonstrated.
- Shen, Yi,Inagi, Shinsuke,Atobe, Mahito,Fuchigami, Toshio
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- PHENYLENE OXO-DIESTER PLASTICIZERS AND METHODS OF MAKING
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A process for making non-phthalate, 1,2-phenylene oxo-diester plasticizers for polymer compositions, by selectively hydrogenating naphthalene to form a partially hydrogenated naphthalene, oxygenating said partially hydrogenated naphthalene to form phenylene diacids, and esterifying said phenylene diacids with oxo-alcohols to form 1,2-phenylene oxo-diesters. Also a process for making phenylene oxo-diester plasticizers by selectively brominating xylenes to form bisbromomethylbenzene, catalytic carboalkoxylation of the bromo-compound to form phenylene diacetate, followed by transesterification to form the phenylene oxo-diester.
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Page/Page column 22-23
(2011/04/25)
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- Tunable phosphorescent NIR oxygen indicators based on mixed benzo-and naphthoporphyrin complexes
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A series of π-extended phosphorescent palladium(II) and platinum(II) porphyrin complexes were synthesized, in which additional benzene rings are fused radially onto at least one of the four peripheral benzo groups. The photophysical properties of the metalloporphyrins palladium(II)-meso-tetra-(4- fluorophenyl)mononaphthotribenzoporphyrin (Pd1NF), cispalladium(II)-meso-tetra- (4-fluorophenyl)dibenzodinaphthoporphyrin (Pd2NF), and palladium(II)-meso-tetra- (4-fluorophenyl)monobenzotrinaphthoporphyrin (Pd3NF) and the corresponding platinum(II) compounds (Pt1NF, cis-Pt2NF, Pt3NF) were investigated. The compounds under investigation absorb intensively in the near-infrared region (628-691 nm) and emit at room temperature at 815-882 nm. Phosphorescence quantum yields of the platinum(II) porphyrins range from 25 to 53% with luminescence decay times of 21 to 44 μs in deoxygenated toluene solutions at room temperature. The corresponding palladium(II) complexes exhibit quantum yields in the range of 7 to 18% with lifetimes of 106 to 206 μs. Density functional theory (DFT) calculations revealed nonplanar geometries for all complexes and corroborate the absorption characteristics. The subsequent π extension of the porphyrin system leads to near-infrared absorbing oxygen indicators with tailor-made luminescence properties as well as tunable oxygen sensitivity.
- Niedermair, Fabian,Borisov, Sergey M.,Zenkl, Gunter,Hofmann, Oliver T.,Weber, Hansjoerg,Saf, Robert,Klimant, Ingo
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scheme or table
p. 9333 - 9342
(2011/01/09)
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- Reduction of polycyclic aromatic hydrocarbons promoted by cobalt or manganese nanoparticles
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A new methodology for the partial reduction of polycyclic aromatic and heteroaromatic hydrocarbons under mild reaction conditions is presented, the process being a reasonable alternative to the catalytic hydrogenation or the Birch reaction. The reduction protocol described is based on the use of cobalt or manganese nanoparticles generated in situ in a simple and economic way, by reduction of commercially available CoCl2·6H2O or MnCl2·2H2O in the presence of lithium sand and the corresponding PAH, acting itself as an electron carrier. The use of a deuterium-oxide-containing cobalt(II) salt allows the simple preparation of deuterium labeled products. The regiochemistry and degree of reduction in the case of 1-substituted naphthalene derivatives markedly depends on the nature of the metal-NPs used.
- Nador, Fabiana,Moglie, Yanina,Vitale, Cristian,Yus, Miguel,Alonso, Francisco,Radivoy, Gabriel
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experimental part
p. 4318 - 4325
(2010/07/09)
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- Broadening the scope of photostimulated SmI2 reductions
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A study was conducted to demonstrate that the exploitation of the biomolecular process significantly broadened the scope of photostimulated SmI2 reduction. Two UV cells containing naphthalene, SmI2, and MeOH were set up under a preliminary test and one of them was exposed to a simple UV lamp, while the other was placed on the bench as a control under ordinary laboratory fluorescent lighting. It was observed that the reaction in the cell under the UV lamp progressed slowly, while significant reaction took place in the cell on the bench. Significant reaction was also observed when the same reaction was carried out with a mercury lamp and a filter that cut off wavelengths below 600 nm. Two methods were employed for the assessment of the photostimulated reactions. One of the methods was based on the fact that stopped flow irradiated the sample continuously in the diode array mode.
- Amiel-Levy, Mazal,Hoz, Shmaryahu
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supporting information; experimental part
p. 805 - 809
(2010/06/11)
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- Catalytic asymmetric ring-opening reaction of meso-epoxides with aryl selenols and thiols catalyzed by a heterobimetallic gallium-titanium-salen complex
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A chiral heterobimetallic Lewis acid complex has been developed as an efficient catalyst. The enantioselective desymmetrization of meso-epoxides with aryl selenols and thiols catalyzed by the heterobimetallic complex has been optimized. The optically active β-arylseleno alcohols and β-hydroxy sulfides were obtained in good yields and high enantioselec- tivities (up to 97% ee and 92% ee, respectively). A strong synergistic effect between different Lewis acids was exhibited in the catalytic process. & copy; 2009 Wiley-VCH Verlag GmbH & Co. KGaA.
- Sun, Jiangtao,Yang, Minghua,Yuan, Fang,Jia, Xuefeng,Yang, Xia,Pan, Yi,Zhu, Chengjian
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supporting information; experimental part
p. 920 - 930
(2009/11/30)
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- Molecular and morphological influences on the open circuit voltages of organic photovoltaic devices
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We explore the dependence of the dark current of C60-based organic photovoltaic (OPV) cells on molecular composition and the degree of intermolecular interaction of several molecular donor materials. The saturation dark current density, JS, is an important factor in determining the open circuit voltage, Voc. The Voc values of OPVs show a strong inverse correlation with JS. Donor materials that show evidence for aggregation in their thin-film absorption spectra and polycrystallinity in thin film X-ray diffraction result in a high dark current, and thus a low Voc. In contrast, donor materials with structures that hinder intermolecular π-interaction give amorphous thin films and reduced values of JS, relative to donors with strong intermolecular π-interactions, leading to a high Voc. This work provides guidance for the design of materials and device architectures that maximize OPV cell power conversion efficiency.
- Dolores Perez,Borek, Carsten,Forrest, Stephen R.,Thompson, Mark E.
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supporting information; experimental part
p. 9281 - 9286
(2009/12/06)
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- Birch reductions at room temperature with alkali metals in silica gel (Na2K-SG(I))
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(Chemical Equation Presented) Alkali metals in silica gel (the Na 2K-SG(I) reagent) cleanly effect Birch reductions of substrates with at least two or more aromatic rings. The reaction conditions are alcohol-free, ammonia-free, and achieve excellent yields and high selectivities at room temperature.
- Nandi, Partha,Dye, James L.,Jackson, James E.
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supporting information; experimental part
p. 5790 - 5792
(2010/01/06)
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- Ammonia-free Birch reductions with sodium stabilized in silica gel, Na-SG(I)
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Ammonia-free Birch reduction conditions were developed based upon sodium stabilized in silica gel for a variety of substrates. In general, the yields were similar to those reported for lump sodium in liquid ammonia.
- Costanzo, Michael J.,Patel, Mitul N.,Petersen, Kathryn A.,Vogt, Paul F.
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supporting information; experimental part
p. 5463 - 5466
(2010/01/11)
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- Hydroxide ion as electron source for photochemical Birch-type reduction and photodehalogenation
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The photochemical Birch-type reduction of arenes and the photodehalogenation of haloarenes by a hydroxide ion that acted as an electron source occurred in 2-PrOH. The efficiency of these photoreactions was dependent on the nature of the substrate, the concentration of NaOH, and the solvent used. These photoreactions provide an environmentally friendly method for the reduction of aromatic rings and dehalogenation.
- Yoshimi, Yasuharu,Ishise, Akihiro,Oda, Hiromu,Moriguchi, Yousuke,Kanezaki, Hiroki,Nakaya, Yukari,Katsuno, Kayoko,Itou, Tatsuya,Inagaki, Sho,Morita, Toshio,Hatanaka, Minoru
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p. 3400 - 3404
(2008/09/21)
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- Synthesis of aryl-containing terpenoids based on 1,4-dihydronaphthalene
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Successive transformations including oxidation of 1,4-dihydronaphthalene into 1,2,3,4-tetrahydronaphthalen-2-one, Reformatskii reaction of the latter with methyl bromoacetate, ozonolysis of the Reformatsky reaction product, and Emmons olefination of the aldehyde group in methyl 3-oxo-5-(2-formylphenyl) pentanate thus formed gave analogs of highly active dienoate juvenoids having an aromatic ring in their molecules.
- Kukovinets,Kislitsyn,Zainullin,Mukhamedzyanova,Galin,Abdullin
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p. 362 - 368
(2008/12/22)
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- Estimating the limiting reducing power of SmI2/H 2O/amine and YbI2/H2O/amine by efficient reduction of unsaturated hydrocarbons
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The mixture of samarium diiodide, amine, and water (SmI2/H 2O/Et3N) is known to be a particularly powerful reductant, but until now the limiting reducing power has not been determined. A series of unsaturated hydrocarbons with varying half-wave reduction potentials (E 1/2 = -1.6 to -3.4 V, vs SCE) have been treated with SmI 2/H2O/Et3N and YbI2/H 2O/Et3N, respectively. All hydrocarbons with potentials of -2.8 V or more positive were readily reduced with SmI2/H 2O/Et3N, whereas all hydrocarbons with potentials of -2.3 V or more positive were readily reduced using YbI2/H 2O/Et3N. This defines limiting values of the chemical reducing power of SmI2/H2O/Et3N to -2.8 V and of YbI2/H2O/Et3N to -2.3 V vs SCE.
- Dahlen, Anders,Nilsson, Ake,Hilmersson, Goeran
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p. 1576 - 1580
(2007/10/03)
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- The effect of pressure on hydrogen transfer reactions with quinones
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The effect of pressure on the oxidation of hydroarenes 3-9 with 2,3-dichloro-5,6-dicyano-1,4-quinone (DDQ; 1a) or o-chloranil (10), leading to the corresponding arenes, has been investigated. The activation volumes were determined from the pressure dependence of the rate constants of these reactions monitored by on-line UV/Vis spectroscopic measurements in an optical high-pressure cell (up to 3500 bar). The finding that they are highly negative and only moderately dependent on the solvent polarity (ΔV ?=-13 to -25 in MTBE and -15 to -29 cm3mol -1 in MeCN/AcOEt, 1:1) rules out the formation of ionic species in the rate-determining step and is good evidence for a hydrogen atom transfer mechanism leading to a pair of radicals in the rate-determining step, as was also suggested by kinetic measurements, studies of kinetic isotope effects, and spin-trapping experiments. The strong pressure dependence of the kinetic deuterium isotope effect for the reaction of 9,10-dihydroanthracene 5/5-9,9,10,10-D4 with DDQ (1a) can be attributed to a tunneling component in the hydrogen transfer. In the case of formal 1,3-dienes and enes possessing two vicinal C-H bonds, which have to be cleaved during the dehydrogenation, a pericyclic hydrogen transfer has to considered as one mechanistic alternative. The comparison of the kinetic deuterium isotope effects determined for the oxidation of tetralin 9/9-1,1,4,4-D4/9-2,2,3,3-D4/9-D 12 either with DDQ (1a) or with thymoquinone 1c indicates that the reaction with DDQ (1a) proceeds in a stepwise manner through hydrogen atom transfer, analogously to the oxidations of 1,4-dihydroarenes, whereas the reaction with thymoquinone 1c is concerted, following the course of a pericyclic hydrogen transfer. The difference in the mechanistic courses of these two reactions may be explained by the effect of the CN and Cl substituents in 1a, which stabilize a radical intermediate better than the alkyl groups in 1c. The mechanistic conclusions are substantiated by DFT calculations.
- Wurche, Frank,Sicking, Wilhelm,Sustmann, Reiner,Klaerner, Frank-Gerrit,Ruechard, Christoph
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p. 2707 - 2721
(2007/10/03)
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- A new, safe and convenient procedure for reduction of naphthalene and anthracene: Synthesis of tetralin in a one-pot reaction
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Reduction of naphthalene and anthracene with sodium and tert-butyl alcohol gave 1,4-dihydronaphthalene and 9,10-dihydroanthracene respectively in high yields at room temperature (r.t.) as the sole products. The synthesis of tetralin from naphthalene was carried out in a one-pot reaction via 1,4-dihydronaphthalene. The reduced products were easily isolated.
- Menzek, Abdullah,Altundas, Aliye,Gueltekin, Demet
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p. 752 - 753
(2007/10/03)
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- Utility of neodymium diiodide as a reductant in ketone coupling reactions
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Matrix presented The viability of Ndl2 as a one-electron reducing agent in organic synthesis has been examined by studying coupling reactions between alkyl chlorides and ketones and aldehydes.
- Evans, William J.,Workman, Penny S.,Allen, Nathan T.
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p. 2041 - 2042
(2007/10/03)
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- On the mechanism of arene-catalyzed lithiation: The role of arene dianions - Naphthalene radical anion versus naphthalene dianion
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The use of lithium and a catalytic amount of an arene is a well-established methodology for the preparation of organolithium reagents that manifest greater reactivity than the classical lithium-arene solutions. In order to rationalize this conduct, the participation of a highly reduced species, the dianion, is proposed and its reactivity explored. Studies of kinetics and of distribution of products reveal that the electron-transfer (ET) reactivity profile of dilithium naphthalenide in its reaction with organic chlorides excludes alternative mechanisms of halogen- lithium exchange. The process generates organolithium compounds. The dianion thus emerges along with the radical anion as a suitable candidate for catalytic cycles in certain processes. Endowed with a higher redox potential than its radical anion counterpart, dilithium naphthalene displays a broader spectrum of reactivity and so increases the range of substrates suitable for lithiation. The reaction of dilithium naphthalene with THF is one example of the divergent reactivity of the radical anion and the dianion, which has been the source of apparent misinterpretation of results in the past and has now been appropriately addressed.
- Yus, Miguel,Herrera, Raquel P.,Guijarro, Albert
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p. 2574 - 2584
(2007/10/03)
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- Stoichiometry of protonation of aromatic hydrocarbon radical anions by weak proton donors. A marked discrepancy between the number of protons used and those incorporated into the aromatic structure
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The stoichiometries of the reaction between alkali metal radical anions of biphenyl, naphthalene, phenanthrene and anthracene, and methanol and/or other proton donors have been determined by the magnetic titration technique. In the case of naphthalene radical anion and, for example, methanol as the proton source, the stoichiometry was found to be cation-dependent: Li, 2: 1; Na, 1.75: 1; K, 1.33: 1. The reaction products using the experimentally determined stoichiometric conditions were ca. 95% naphthalene and 5% dihydronaphthalene(s). Thus, a marked discrepancy is observed between the protons used and those incorporated into the naphthalene molecule. Radical anions, at concentrations comparable with those of preparative reactions, react with carbon acids or amines according to the first-order kinetic law, although the initial concentrations of the two reactants were of the same order of magnitude or even equal. Lithium anthacene radical anion reacts with phenylacetylene and diethylamine at comparable rates, although the two "acids" differ in their acidities by ca. 10 orders of magnitude. A deuterium isotope effect of 2.49 ± 0.05 was observed in the reaction between lithium anthracene radical anion and diethylamine. A general reaction scheme is proposed that involves electron transfer to the proton donor and hydrogen-atom attack on the neutral hydrocarbon as the key reaction steps.
- Screttas, Constantinos G.,Ioannou, Georgios I.,Micha-Screttas, Maria
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p. 217 - 225
(2007/10/03)
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- Spirovesamicols
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The compounds are vesamicol (hydroxylated phencyclidine (PCP) isomer trans-2-(4-phenyl-piperidino)cyclohexanol) derivatives with anticholinergic properties termed herein "spirovesamicols" which are spirofused piperidines. The compounds bind to the vesamicol receptor, a site on the cholinergic synaptic vesicle, which is associated with the vesicular transporter of acetylcholine.
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- Catalytic Cyclophanes. Part VIII. Cytochrome P-450 Activity of a Porphyrin-Bridged Cyclophane
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Following a known synthetic procedure, the porphyrin-cyclophane 1 having a porphyrin attached by two straps to an apolar cyclophane binding site was prepared.Upon metallation, the ZnII and FeIII derivatives 2 and 3, respectively, were obtained in good yields.Treatment of 3 with base yielded the μ-oxo dimer 4 in which the two oxo-bridged porphyrins moieties are both capped by cyclophane binding sites.All compounds 1-4 are freely soluble in protic solvents such as MeOH and CF3CH2OH, and the FIII derivatives 3 and 4 are active cytochrome P-450 mimics in these protic environments.Strong inclusion complexation of polycyclic aromatic hydrocarbons by 1 and 3 in alcoholic solvents was observed and quantified by 1H-NMR and UV/VIS titrations.Acenaphthylene binds in an 'equatorial' orientation which locates its reactive 1,2-double bond near the porphyrin center, whereas phenanthrene binds 'axially' with the reactive 9,10-double bond oriented away from the porphyrin.The reduction potential of 3 was not significantly altered by substrate binding.In the unbound form, the FeIII center in porphyrin 3 was found by ESR and 1H-NMR to prefer a high-spin state (S = 5/2).In CF3CH2OH, using iodosylbenzene as O-transfer agent, the FeIII derivative 3 catalyzed the oxidation of acenaphthylene to acenaphthen-1-one (14).Phenanthrene inhibited the reaction, possibly as a result of strong but nonproductive binding.Under similar conditions, isotetralin (18) was aromatized with high turnover to 1,4-dihydronaphthalene.The μ-oxo dimer 4 also showed high catalytic activity in the oxidation of acenaphthylene in MeOH, a result which provides strong evidence for efficient supramolecular catalysis.Due to as yet unknown reaction channels leading to polymeric products, poor mass balances were generally obtained in the oxidations effected in MeOH and CF3CH2OH in the presence of PhIO.
- Benson, David R.,Valentekovich, Robert,Tam, Suk-Wah,Diederich, Francois
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p. 2034 - 2060
(2007/10/02)
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- Reductive cleavage of the carbon-phosphorus bond with alkali metals. III Reactions of arylalkylphosphines
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The reductive cleavage of phenylalkylphosphines Ph2PR, PhPR2 (R = Bu, iPr) with Na/NH3 is unselective; both phenyl and alkyl groups can be cleavaged and Birch reduction may occur.Reaction of Ph2tBuP gives a high yield of diphenylphosphide.Polar groups (CO2Na, SO3Na) at the ω position of primary alkyl groups may lead to an increase in selectivity; Birch reduction is suppressed and a functionalised secondary phosphide is obtained.From diarylbenzyl- and diarylallylphosphines, the benzyl and allyl groups are selectively removed; Ar2PH and ArRPH are formed in high yield after hydrolytic work-up unless the aryl group bears F, CF3 or (CH3)2N substituents.From the reaction mixture of Ph2PCH2Ph we have isolated 1,2-diphenylethane. 2-Methoxyphenyl and 2,6-dimethoxyphenyl groups are selectively removed from Ar2BuP, ArPhBuP and Ar2P(CH2)3PAr2, forming ArBuPH, PhBuPH and ArP(H)(CH2)3(H)PAr, respectively.A double-cleavage reaction of Ar2RP may occur in low yield. 2,6-(dimethoxyphenyl-dibutylphosphine gives dibutylphosphine in moderate yield.When compounds with a 2,6-dimethoxyphenyl moiety are allowed to react with Li/THF, removal of a methyl group leads to novel phosphinophenols.It is concluded that cleavage of alkyl groups R selectively occurs when R radical is relatively stable (tBu, PhCH2> iPr > Bu).
- Doorn, Johannes A. van,Meijboom, Nico
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p. 170 - 177
(2007/10/02)
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- Cycloaddition Reactions of the Methanoannulene Derivative 9,9-Dichloro-1,4-dihydro-4a,8a-methanonaphthalene
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9,9-Dichloro-1,4-dihydro-4a,8a-methanonaphthalene (4) adds the electron-deficient dienophiles 4-phenyl-1,2,4-triazoline-3,5-dione, maleic anhydride and dimethyl acetylenedicarboxylate to the α-face to give adducts (5)-(7) respectively; the addition of the alkyne requires Lewis acid catalysis.Inverse electron-demand addition of 3,6-diphenyl-1,2,4,5-tetrazine to the monoene component of (4) in hydrophilic solvent (ethane-1,2-diol) is thwarted; the CCl2 bridge is ejected and the 1,4-dihydronaphthalene formed is captured to give (ultimately) phthalazine (16).Dimethyl 1,2,4,5-tetrazine-3,6-dicarboxylate adds to (4) to give the methanobenzophthalazine (17b).
- Halton, Brian,Russell, Sarah G. G.
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p. 555 - 565
(2007/10/02)
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- The photochemical rearrangement of 1,2-dihydronaphthalenes into 1,4-dihydronaphthalenes induced by amines
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The synthetic usefulness of the deprotonation/protonation reaction of excited 1,2-dihydronaphthalenes into 1,4-dihydronaphthalenes induced by amines has been investigated using 13 different substituted 1,2-dihydronaphthalenes and related compounds.The yield of the rearrangement ranges from 5 to 96percent.The formation of side-products depends on the position of protons in the substrate, which can be abstracted by the amine, and on competitive photoreactions.
- Cuppen, Th. J. H. M.,Berendsen, N.,Laarhoven, W. H.
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p. 168 - 171
(2007/10/02)
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- Synthesis, in Vitro Acetylcholine-Storage-Blocking Activities, and Biological Properties of Derivatives and Analogues of trans-2-(4-Phenylpiperidino)cyclohexanol (Vesamicol)
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Eighty-four analogues and derivatives of the acetylcholine-storage-blocking drug trans-2-(4-phenylpiperidino)cyclohexanol (vesamicol) were synthesized, and their potencies were evaluated with the acetylcholine active-transport assay utilizing purified synaptic vesicles from Torpedo electric organ.The parent drug exhibits enantioselectivity, with (-)-vesamicol being 25-fold more potent than (+)-vesamicol.The atomic structure and absolute configuration of (+)-vesamicol were determined by X-ray crystallography.The absolute configuration of (-)-vesamicol is 1R,2R.Structure-activity evidence indicates that (-)-vesamicol does not act as an acetylcholine analogue.Alterations to all three rings can have large effects on potency.Unexpectedly, analogues locking the alcohol and ammonium groups trans-diequatorial or trans-diaxial both exhibit good potency.A potent benzovesamicol family has been discovered that is suitable for facile elaboration of the sort useful in affinity labeling and affinity chromatography applications.A good correlation was found between potencies as assessed by the acetylcholine transport assay and LD50 values in mouse.
- Rogers, Gary A.,Parsons, Stanley M.,Anderson, D. C.,Nilsson, Lena M.,Bahr, Ben A.,et al.
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p. 1217 - 1230
(2007/10/02)
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- SILICON-MODIFIED BIRCH REDUCTION AND REDUCTIVE ALKYLATION OF POLYNUCLEAR AROMATICS
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A trimethylsilyl substituent is used to control regiochemistry, overreduction, and prevent bond cleavage during the metal/ammonia reduction of aromatic and polynuclear aromatic compounds.The trimethylsilyl group is then removed by tetrabutylammonium fluoride and replaced by either hydrogen or primary alkyl, the latter case representing overall reductive alkylation.Results are presented for naphtalene together with its 1-methyl, 2-methyl and 2-methoxy derivatives, phenanthrene and its 9-methyl and 9-ethyl derivatives, biphenyl and triptycene.
- Marcinow, Z.,Clawson, D. K.,Rabideau, P. W.
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p. 5441 - 5448
(2007/10/02)
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- THE SILICON-MODIFIED METAL AMMONIA REDUCTION OF AROMATIC COMPOUNDS
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A trimethylsilyl substituent is used to control regiochemistry in the metal-ammonia reduction of several naphthalenes, and is subsequently removed resulting in a " Misoriented Birch Reduction."
- Rabideau, Peter W.,Karrick, Gregory L.
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p. 2481 - 2484
(2007/10/02)
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- The Effect of the Hydrogen Bonding on the Photoinduced Electron Transfer Reaction of a Naphthalene-triethylamine System in the Presence of Alcohols
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The effect of the addition of alcohols on the photoinduced electron transfer reaction of a naphthalene-triethylamine system has been studied.The result show that the addition of alcohol reduces both bimolecular rate constants for the quenching of the naphthalene fluorescence by triethyamine and the quantum yields for the formation of products, in the order of 2-methyl-2-propanol 2-propanol ethanol methanol.These results are explained in terms of a hydrogen-bonding interactions between the amine and alcohols, which suppress the electron transfer process.
- Oh, Shin-Chol,Shirota, Yasuhiko,Mikawa, Hiroshi,Kusabayashi, Shigekazu
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p. 2121 - 2124
(2007/10/02)
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- THE GAS-PHASE REACTION OF FREE PHENYLIUM IONS WITH 1,3-BUTADIENE
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Formation of trans-1-phenyl-1,3-butadiene, 3-methylindene, naphthalene and isomeric dihydronaphthalenes, together with polymerization products, from gas-phase phenylium ion attack on 1,3-butadiene, reveals novel reaction pathways ascribable to the carbenic nature of phenylium ion.
- Fornarini, Simonetta,Speranza, Maurizio
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p. 341 - 343
(2007/10/02)
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