- UV Spectrum and the Kinetics and Reaction Pathways of the Self-Reaction of CH2CH2OH Radicals
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CH2CH2OH radicals have been studied at room temperature by using a pulse radiolysis/kinetic absorption technique.The ultraviolet spectrum lies in the range 210-265 nm with a maximum absorption cross section of 2.0*10-18 cm2 molecule-1 at 210 nm.This technique has also been used to study the overall kinetics of the self-reaction of these radicals: 2CH2CH2OH (+M) --> (CH2CH2OH)2 (+M) (7a); 2CH2CH2OH (+M) --> CH3CHO + CH3CH2OH (7b), while product studies using gas chromatography have yielded information on the reaction pathways.A value of k7 = 5.6(+/-1.0)*10-11 cm3 molecule-1 s-1 and a branching ratio of k7a/(k7a + k7b) 0.88 have been measured at room temperature.
- Anastasi, Christopher,Simpson, Victoria,Munk, Jette,Pagsberg, Palle
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Read Online
- Green and Efficient: Iron-Catalyzed Selective Oxidation of Olefins to Carbonyls with O2
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A mild and operationally simple iron-catalyzed protocol for the selective aerobic oxidation of aromatic olefins to carbonyl compounds is described. Catalyzed by a Fe(III) species bearing a pyridine bisimidazoline ligand at 1 atm of O2, α- and β-substituted styrenes were cleaved to afford benzaldehydes and aromatic ketones generally in high yields with excellent chemoselectivity and very good functional group tolerance, including those containing radical-sensitive groups. With α-halo-substituted styrenes, the oxidation took place with concomitant halide migration to afford α-halo acetophenones. Various observations have been made, pointing to a mechanism in which both molecular oxygen and the olefinic substrate coordinate to the iron center, leading to the formation of a dioxetane intermediate, which collapses to give the carbonyl product. (Chemical Equation).
- Gonzalez-De-Castro, Angela,Xiao, Jianliang
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supporting information
p. 8206 - 8218
(2015/07/15)
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- Carbodeoxygenation of biomass: The carbonylation of glycerol and higher polyols to monocarboxylic acids
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Glycerol is converted to a mixture of butyric and isobutyric acid by rhodium- or iridium-catalysed carbonylation using HI as the co-catalyst. The initial reaction of glycerol with HI results in several intermediates that lead to isopropyl iodide, which upon carbonylation forms butyric and isobutyric acid. At low HI concentration, the intermediate allyl iodide undergoes carbonylation to give vinyl acetic acid and crotonic acid. Higher polyols CnH n+2(OH)n are carbonylated to the corresponding C n+1 mono-carboxylic acids. Copyright
- Coskun, Timur,Conifer, Christopher M.,Stevenson, Laura C.,Britovsek, George J. P.
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supporting information
p. 6840 - 6844
(2013/07/05)
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- Synthesis, structure, and properties of chiral liquid crystal monomers and polymers based on menthol
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To study structure-mesomorphism relationships of the monomers and polymers based on menthol, four new chiral monomers (M1-M4) and the corresponding homopolymers (P1-P4) with menthyl group were synthesized. Their chemical structures, formula, phase behavior, and thermal stability were characterized by FTIR, 1H NMR, 13C NMR, elemental analyses, differential scanning calorimetry, polarizing optical microscopy, X-ray diffraction, and thermogravimetric analysis. The selective reflection of light was investigated with ultraviolet/visible spectrometer. The influence of the mesogenic core rigidity, spacer length, and menthyl steric effect on the mesomorphism of M1-M4 and P 1-P4 was examined. By inserting a flexible spacer between the mesogenic core and the terminal menthyl groups, four target monomers and polymers could form the expected mesophase. Moreover, their melting temperature (Tm), glass transition temperature (Tg), clearing temperature (Ti), and mesophase range (δT) increased with increasing the mesogenic core rigidity; whereas the Tm and T g decreased, Ti and δT increased with an increase of the spacer length. M1 and M2 showed monotropic and enantiotropic cholesteric phase, respectively, whereas M3 and M 4 all revealed chiral smectic C (SmC*), cholesteric and cubic blue phases. In addition, with increasing temperature, the selective reflection of light shifted to the long wavelength region at the SmC* phase range and to the short wavelength region at the cholesteric range, respectively. P 1 and P2 only showed a smectic A (SmA) phase, whereas P3 and P4 exhibited the SmC* and SmA phases. All the obtained polymers had very good thermal stability.
- Hu, Jian-She,Li, Dan,Zhang, Wen-Chang,Meng, Qing-Bao
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p. 5049 - 5059
(2013/01/15)
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- Synthesis and physical properties of ferrocene derivatives (XXV) liquid crystallinity of 1,3-disubstituted ferrocene derivatives
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Liquid crystallinity of 1,3-disubstituted ferrocene derivatives was studied by DSC and polarizing microscope. The name of the derivatives is 1,3-bis[-[4-(4-methoxyphenoxycarbonyl)phenoxy]alkyloxycarbonyl]ferrocene. Nine members from n = 2 to 10 were synthesized (n is carbon number of alkyl chain in the sample). All samples except n = 2 and 4 exhibited monotropic nematic liquid crystalline phase. In addition, smectic X (not yet completely identified) was also observed in n = 8 and 10. Liquid crystalline phase transition phenomena were discussed from a viewpoint of molecular shape. Copyright Taylor & Francis Group, LLC.
- Nakamura, Naotake,Kagawa, Shinya
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experimental part
p. 150 - 159
(2012/01/03)
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- Synthesis and physical properties of ferrocene derivatives (XXIII): Phase transition and unique molecular structure of monosubstituted ferrocene derivatives
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The monosubstituted ferrocene derivatives, -[4-(4-methoxyphenoxycarbonyl) phenoxy]alkoxycarbonyl ferrocene, were synthesized in order to compare the liquid crystallinity to that of disubstituted ferrocene derivatives, 1,1'-bis[-[4-(4-methoxy-phenoxycarbonyl)phenoxy]alkoxycarbonyl]ferrocene. Some of the monosubstituted ferrocene derivatives containing relatively longer flexible spacer showed the liquid crystalline phase, nematic and/or smectic phases. The crystal structure of 2-[4-(4-methoxyphenoxycarbonyl)phenoxy] ethoxycarbonyl ferrocene was determined by X-ray diffraction method using a single crystal. The molecular structure revealed a bent structure that is almost a half of "Z" shaped molecular structure of 1,1'-bis[2-[4-(4- methoxyphenoxycarbonyl)phenoxy]ethoxycarbonyl]ferrocene.
- Nakamura, Naotake,Hiro, Kazuya,Nishikawa, Masako,Okabe, Takashi,Uno, Kenjiro
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scheme or table
p. 122 - 131
(2010/08/05)
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- Thermotropic side-chain liquid crystalline copolymers containing both mono- And bisazobenzene mesogens: Synthesis and properties
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The synthesis of a novel series of copolymers containing push-pull bisazobenzene (BAz) and monoazobenzene (MAz) groups with various N-alkyl donor groups and with spacers of two and four methylene units is presented, and the effects of the structural variables on the mesomorphic properties of the polymers are investigated. The copolymer with very short spacer (n = 2) and bulky N-ethyl group exhibits liquid crystalline (LC) properties when the BAz content is at least 30 mol %. Replacing the N-ethyl group with N-methyl increases the tendency toward smectic mesomorphism and expands the mesophases stability. If the flexible spacer is extended to four methylene units, the glass transition temperature (Tg) decreases strongly, whereas the isotropization temperature (Ti) is only slightly affected. X-ray diffraction investigations reveal an orthogonal partial bilayer smectic phase in which the mesogens are interdigitated. Annealing the BAz polymer films above Tg brings about the out-of-plane (homeotropic) orientation of chromophores and the formation of H-aggregates.
- Cojocariu, Cristina,Rochon, Paul
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p. 9526 - 9538
(2008/02/01)
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- Benzimidazole derivatives
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Compounds, pharmaceutical compositions and methods are provided that are useful in the treatment of inflammatory and immune-related conditions or disorders. In particular, the invention provides compounds which modulate the expression and/or function of proteins involved in inflammation, immune response regulation and cell proliferation. The subject compounds are 2-amino-imidazole derivatives.
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- Novel Nucleophilic Trifluoromethylation of Vicinal Diol Cyclic Sulfates
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(Matrix Presented) A novel method for highly regioselective and stereospecific nucleophilic trifluoromethylation of vicinal diol cyclic sulfates, using the reagent derived from reduction of trifluoromethyl iodide by tetrakis(dimethylamino)ethylene (TDAE), is presented.
- Takechi, Naoto,Ait-Mohand, Samia,Medebielle, Maurice,Dolbier Jr., William R.
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p. 4671 - 4672
(2007/10/03)
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- PROTEASOME INHIBITORS
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The present invention relates to proteasome inhibitors as the active ingredient carboxylic acid derivatives represented by general formula (I) or pharmaceutically acceptable salts thereof: wherein m and n are the same or different and represent an integer of 0 to 10; p is 0 or 1; R1 represents a hydrogen atom, substituted or unsubstituted alkyl, substituted or unsubstituted alicyclic alkyl, or the like; and R2 represents a hydrogen atom, COR13, or CH2OR3a, or R1 and R2 together represent the formula: X1 represents a bond, substituted or unsubstituted alkylene, substituted or unsubstituted cycloalkylene, or the like; X2 represents an oxygen atom, a sulfur atom, or NR17; R3 is has the same significance as the above R3a; R4 represents hydroxy, mercapto, substituted or unsubstituted alkoxy, or the like, or R1 and R2 together represent a bond; R5 represents a hydrogen atom, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, or the like.
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- The asymmetric synthesis of α-substituted α-methyl and α-phenyl phosphonic acids: Design, carbanion geometry, reactivity and preparative aspects of chiral alkyl bicyclic phosphonamides
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The design, preparation, structural and spectroscopic analyses of topologically unique and enantiomerically pure alkyl phosphonamides are described. In the case of α-ethyl and α-benzyl phosphonamides, the geometry of both the secondary and tertiary carbanions was determined to be planar through deprotonation/deuteration/alkylation experiments. Stereoselective alkylations of such systems proceeded in good yields and with high diastereoselectivities. The resulting α,α-alkylated phosphonamides were hydrolyzed to give the corresponding α,α-alkyl phosphonic acids with high degrees of enantiomeric purity.
- Bennani, Youssef L.,Hanessian, Stephen
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p. 13837 - 13866
(2007/10/03)
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- Syntheses and Physical Properties of Ferrocene Derivatives(III) Liquid Crystallinity of Disubstituted Ferrocene Derivatives
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A new series of 1,1'-disubstituted ferrocene derivatives, 1,1'-bisalkoxycarbonyl>ferrocene, incorporating a variable carbon number of methylene chain units has been prepared.The thermal behavior of these compounds has been examined by polarizing microscopy observations and differential scanning calorimetry measurements.Four of five kinds of samples synthesized here showed liquid crystallinity near the ambient temperature.Furthermore, these compounds have a fairly wide temperature range of liquid crystalline states. - Keywords: Ferrocene, liquid crystal, 1,1'-disubstituted derivatives, transition metal complex, phase transition
- Hanasaki, T.,Ueda, M.,Nakamura, N.
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p. 257 - 268
(2007/10/02)
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- Water-Soluble Cholesteryl-Containing Phosphorothioate Monogalactosides: Synthesis, Properties, and Use in Lowering Blood Cholesterol by Directing Plasma Lipoproteins to the Liver
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The synthesis of several monogalactoside-terminated phosphorothiolated cholesteryl derivatives is described.Monogalactosyl derivatives are coupled by phosphorothiolation to cholesterol by using ethylene glycol units as hydrophilic spacer moieties.The resulting compounds are easily soluble in water.Upon addition of such solutions to human serum (to 2mM final concentration) the compounds are readily incorporated into lipoproteins.Isolated low-density lipoprotein (LDL) and high-density lipoprotein (HDL), preloaded with the compounds, are rapidly cleared from the circulation by the liver.The hepatic association is blocked by N-acetylgalactosamine, which indicates that galactose-specific recognition sites are responsible for the increased liver uptake.The plasma clearance and hepatic uptake of LDL loaded with the compounds is substantially higher (about 2-fold) than clearance and uptake of HDL containing the compounds.The selectivity of the effects of monogalactoside-terminated phosphorothiolated cholesteryl derivatives on the in vivo behavior of LDL as compared to that of HDL indicates that these compounds might be used to lower specifically LDL levels in patients with a high LDL-cholesterol level.
- Roelen, Harlof C. P. F.,Bijsterbosch, Martin K.,Bakkeren, Hille F.,Berkel, Theo J. C. van,Kempen, Herman J. M.,et al.
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p. 1036 - 1042
(2007/10/02)
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- N-(3-[18F]fluoropropyl)-N-nordiprenorphine: synthesis and characterization of a new agent for imaging opioid receptors with positron emission tomography.
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A series of N-fluoroalkyl (1-5) and N-alkyl (6-8) analogues of the high-affinity opioid receptor antagonist diprenorphine (9) has been synthesized and evaluated with in vitro binding assays. Three of the N-fluoroalkyl compounds were prepared with the positron-emitting radionuclide 18F (1a, 2a, 5a), and their biodistribution was determined in rats. Compounds 2a and 5a were made by using a two-step labeling procedure, [18F]fluoride displacement of an iodoalkyl triflate followed by N-alkylation, that required 2 h and proceeded in 4-6% overall radiochemical yield at the end of synthesis. The effective specific activity of compounds 2a and 5a, determined by competitive receptor binding assay, was 840-1820 Ci/mmol. Compound 1a was made by the same two-step procedure, with the bromoalkyl triflate, in 0.3-0.6% radiochemical yield at an effective specific activity of 106-264 Ci/mmol. Specificity of binding in vivo was measured as the percent injected dose/gram of striatal tissue divided by the percent injected dose/gram of cerebellar tissue. The best striatum to cerebellum ratio (3.32 +/- 0.74 at 30 min) was achieved with N-(3-[18F]-fluoropropyl)-N-nordiprenorphine (2a, [18F]FPND). The high specific binding demonstrated by this compound indicates that it may be useful for in vivo imaging of opioid receptors with positron emission tomography.
- Chesis,Hwang,Welch
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p. 1482 - 1490
(2007/10/02)
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- AN EFFICIENT SYNTHESIS OF CERTAIN 5-SUBSTITUTED-2'-DEOXYURIDINE 3',5'-CYCLIC MONOPHOSPHATE P-O-ALKYL(ARALKYL) ESTERS. THE CRYSTAL AND MOLECULAR STRUCTURE OF 5-IODO-2'-DEOXYURIDINE 3',5'-CYCLIC MONOPHOSPHATE P-O-METHYL ESTER WITH AXIAL METHOXY GROUP
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Some 5-alkyl- and 5-halogeno-2'-deoxyuridine 3',5'-cyclic monophosphate P-O-alkyl(aralkyl) esters have been prepared from the silver salts of the parent cyclic monophosphates and alkyl(aralkyl) iodides.The diastereomeric phosphotriesters have been characterized by spectroscopic methods.The crystal and molecular structure of 5-iodo-2'-deoxyuridine 3',5'-cyclic monophosphate P-O-methyl ester with axial methoxy group has been determined.We failed to obtain the desired triesters from the reactions of the cAMP silver salt with alkyl iodides, contrary to previous claims in the literature.
- Beres, J.,Sandor, P.,Kalman, A.,Koritsanszky, T.,Oetvoes, L.
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p. 2405 - 2414
(2007/10/02)
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