- DIELS-ALDER REACTIONS CATALYZED BY LEWIS ACID CONTAINING SOLIDS: RENEWABLE PRODUCTION OF BIO-PLASTICS
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The present disclosure is related to silica-based Lewis acid catalysts, being essentially devoid of strong Br?nsted acid character, and their ability to effect the [4+2] cycloaddition and dehydrative aromatization of dienes and dienophiles containing oxygenated substituents to form substituted benzene products. In some embodiments, the processes comprise contacting biomass-derived substrates with ethylene to form terephthalic acid and its derivatives.
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Paragraph 0191
(2015/01/06)
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- Synthesis of terephthalic acid via Diels-Alder reactions with ethylene and oxidized variants of 5-hydroxymethylfurfural
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Terephthalic acid (PTA), a monomer in the synthesis of polyethylene terephthalate (PET), is obtained by the oxidation of petroleum-derived p-xylene. There is significant interest in the synthesis of renewable, biomass-derived PTA. Here, routes to PTA starting from oxidized products of 5- hydroxymethylfurfural (HMF) that can be produced from biomass are reported. These routes involve Diels-Alder reactions with ethylene and avoid the hydrogenation of HMF to 2,5-dimethylfuran. Oxidized derivatives of HMF are reacted with ethylene over solid Lewis acid catalysts that do not contain strong Br?nsted acids to synthesize intermediates of PTA and its equally important diester, dimethyl terephthalate (DMT). The partially oxidized HMF, 5-(hydroxymethyl)furoic acid (HMFA), is reacted with high pressure ethylene over a pure-silica molecular sieve containing framework tin (Sn-Beta) to produce the Diels-Alder dehydration product, 4-(hydroxymethyl)benzoic acid (HMBA), with 31% selectivity at 61% HMFA conversion after 6 h at 190°C. If HMFA is protected with methanol to form methyl 5-(methoxymethyl)furan-2-carboxylate (MMFC), MMFC can react with ethylene in the presence of Sn-Beta for 2 h to produce methyl 4-(methoxymethyl) benzenecarboxylate (MMBC) with 46% selectivity at 28% MMFC conversion or in the presence of a pure-silica molecular sieve containing framework zirconium (Zr-Beta) for 6 h to produce MMBC with 81% selectivity at 26% MMFC conversion. HMBA and MMBC can then be oxidized to produce PTA and DMT, respectively. When Lewis acid containing mesoporous silica (MCM-41) and amorphous silica, or Br?nsted acid containing zeolites (Al-Beta), are used as catalysts, a significant decrease in selectivity/yield of the Diels-Alder dehydration product is observed.
- Pacheco, Joshua J.,Davis, Mark E.
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p. 8363 - 8367
(2014/06/24)
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- Preparation and reactivity of polystyrene-supported iodosylbenzene: Convenient recyclable oxidizing reagent and catalyst
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A facile preparation of novel polystyrene-supported iodosylbenzene (PS-ISB, loading of IO up to 1.50 mmol/g) from iodopolystyrene is described. This resin has been successfully used for efficient oxidation of a diverse collection of alcohols to aldehydes and ketones in the presence of BF3OEt 2. PS-ISB can also be employed as efficient co-catalyst in combination with RuCl3 in the catalytic oxidation of alcohols and aromatic hydrocarbons, respectively, to corresponding carboxylic acids and ketones using Oxone as the stoichiometric oxidant. Georg Thieme Verlag Stuttgart ? New York.
- Chen, Jiang-Min,Zeng, Xiao-Mei,Middleton, Kyle,Yusubov, Mekhman S.,Zhdankin, Viktor V.
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experimental part
p. 1613 - 1617
(2011/08/03)
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- FIBROSIS INHIBITOR
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Medicament being useful as a fibrosis inhibitor for organs or tissues, which comprises a compound of the formula (I): wherein Ring Z is optionally substituted pyrrole ring, etc.; W2 is -CO-, -SO2-, optionally substituted C1-C4 alkylene, etc.; Ar2 is optionally substituted aryl, etc.; W1 and Ar1 mean the following (1) and (2):(1) W1 is optionally substituted C1-C4 alkylene, etc.; Ar1 is optionally substituted bicyclic heteroaryl having 1 to 4 nitrogen atoms as ring-forming atoms:(2) W1 is optionally substituted C2-C5 alkylene, optionally substituted C2-C5 alkenylene, etc.; and Ar1 is aryl or monocyclic heteroaryl, which is substituted by carboxyl, alkoxycarbonyl, etc. at the ortho- or meta-position thereof with respect to the binding position of W1, or a pharmaceutically acceptable salt thereof.
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- Oxidation of benzylic alcohols and ethers to carbonyl derivatives by nitric acid in dichloromethane
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Nitric acid in dichloromethane may be successfully employed for the oxidation of benzylic alcohols and ethers to the corresponding carbonyl compounds. The proposed method proved to be of general applicability, affording very good yields of aldehydes and ketones and showing interesting chemoselectivity in many instances, allowing competitive aromatic nitration to be avoided, as well as - in the case of aldehydes - any further oxidation to carboxylic acids. The reaction probably proceeds by a radical mechanism, the active species in the oxidation process being NO2. Competitive formation of nitro esters was observed in some cases, whereas poor results were obtained with allylic and non-benzylic substrates. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Strazzolini, Paolo,Runcio, Antonio
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p. 526 - 536
(2007/10/03)
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- Pyrrole derivatives
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Pyrrole derivatives represented by the following formula: wherein Ring Z is an optionally substituted pyrrole ring, etc.; W2 is —CO—, —SO2—, an optionally substituted C1-C4 alkylene, etc.; Ar2 is an optionally substituted aryl, etc.; W2 and Ar1 mean the following (1) and (2): (1) W1 is an optionally substituted C1-C4 alkylene, etc.; Ar1 is an optionally substituted bicyclic heteroaryl having 1 to 4 nitrogen atoms as ring-forming atoms: (2) W1 is an optionally substituted C2-C5 alkylene, an optionally substituted C2-C5 alkenylene, etc.; and Ar1 is an aryl or monocyclic heteroaryl, which are substituted by carboxyl, an alkoxycarbonyl, etc. at the ortho- or meta-position thereof with respect to the binding position of W1, or a pharmaceutically acceptable salt thereof These compounds are useful as medicaments such as a fibrosis inhibitor for organs or tissues.
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- BENZOYL PIPERIDINES/PYRROLIDINES FOR ENHANCING SYNAPTIC RESPONSE
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Benzoyl piperidines and pyrrolidines and compounds of related structure are disclosed for use in enhancing synaptic responses mediated by AMPA receptors. The compounds are effective in the treatment of subjects suffering from impaired nervous or intellect
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- Substituent contributions to the transport of substituted p-toluic acids across lipid bilayer membranes
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The fluxes of p-toluic acid and seven α-methylene-substituted analogs have been determined as a function of pH across planar egg lecithin/decane bilayers to construct a set of well-isolated polar functional group contributions to the free energy of transfer from water to the bilayer transport barrier domain. Nonlinear regression analyses of flux-pH profiles using a model which accounts for unstirred layer effects yielded membrane permeability coefficients (P(RX)) that varied from 1.1 cm/s for p-toluic acid to 4.1 x 10-5 cm/s for the α-carbamoyl-p-toluic acid. Bulk organic solvent/water partition coefficients (K(RX)) were obtained for the same set of permeants using four solvent systems to identify a bulk solvent which closely resembles the chemical nature of the bilayer barrier microenvironment for these permeants. The slopes of plots of log P(RX) vs log K(RX) were 0.85, 0.91, 0.99, and 2.4, respectively, for hexadecane/water, hexadecane/water, 1,9-decadiene/water, and octanol/water with the best model solvent being that which yielded a slope closest to unity. A significant deviation in the slope from 1, as observed in the correlation with octanol/water partition coefficients, reveals that this relatively polar, hydrogen-bonding solvent is a poor model solvent for describing the barrier microenvironment for these permeants. Thus, the polar interfacial regions occupied by phospholipid head groups are not the barrier domain for the transport of the series examined in this study. The incremental group contributions to the free energy of transfer to the barrier domain (cal/mol) for the functional groups, Cl, OCH3, CN, OH, COOH, and CONH2, were found to be 325, 687, 2170, 3860, 5170, and 6060, respectively. Except for Cl, these group contributions are generally 500-1200 cal/mol smaller than those for transfer between water and hexadecane, resembling most closely the values obtained for transfer from water to 1,9-decadiene.
- Xiang,Anderson
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p. 1511 - 1518
(2007/10/02)
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