- Spiroacetals and other venom constituents as potential wasp attractants
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The major volatile spiroacetals from the venom of both the common wasp, Vespula vulgaris and the German wasp V. germanica, viz. 7-methyl-1,6-dioxaspiro[4,5]decane and 7-ethyl-2-methyl-1,6-dioxaspiro[4,5]decane, respectively, were synthesized by known methods. These acetals, along with N-isopentylacetamide (the major volatile amide from wasp venom), 2-heptanone (a honeybee pheromone), 2-methyl-3-buten-2-ol (a component of hornet venom), cuticle wax from V. vulgaris, and venom sacs from both wasp species were assayed by EAG and olfactory bioassay for attractancy to V. vulgaris workers. Antennal responses to all test chemicals were recorded. Acetal isomers (±)-2 and (±)-3,N-isopentylacetamide, and 2-heptanone were attractive to V. vulgaris workers at levels of 1 μmol. Greater quantities of the same compounds were repellent to V. vulgaris workers.
- Weston, Roderick J.,Woolhouse, Anthony D.,Spurr, Eric B.,Harris, Richard J.,Suckling, D. Max
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Read Online
- Marine natural products. XI. An antiinflammatory scalarane-type bishomosesterterpene, foliaspongin, from the Okinawan marine sponge Phyllospongia foliascens (Pallas)
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On the basis of chemical and physicochemical evidence, the chemical structure of foliaspongin, an antiinflammatory active principle of the Okinawan marine sponge Phyllospongia foliascens (Pallas), was elucidated as a new scalarane-type bishomosesterterpene (3).
- Kikuchi,Tsukitani,Shimizu,et al.
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Read Online
- Floating ZnO QDs-modified TiO2/LLDPE hybrid polymer film for the effective photodegradation of tetracycline under fluorescent light irradiation: Synthesis and characterisation
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In this work, mesoporous TiO2-modified ZnO quantum dots (QDs) were immobilised on a linear low-density polyethylene (LLDPE) polymer using a solution casting method for the photodegradation of tetracycline (TC) antibiotics under fluorescent light irradiation. Various spectroscopic and microscopic techniques were used to investigate the physicochemical properties of the floating hybrid polymer film catalyst (8%-ZT@LLDPE). The highest removal (89.5%) of TC (40 mg/L) was achieved within 90 min at pH 9 due to enhanced water uptake by the LDDPE film and the surface roughness of the hybrid film. The formation of heterojunctions increased the separation of photogenerated electron-hole pairs. The QDs size-dependent quantum confinement effect leads to the displacement of the conduction band potential of ZnO QDs to more negative energy values than TiO2. The displacement generates more reactive species with higher oxidation ability. The highly stable film photocatalyst can be separated easily and can be repeatedly used up to 8 cycles without significant loss in the photocatalytic ability. The scavenging test indicates that the main species responsible for the photodegradation was O2 ?-. The proposed photodegradation mechanism of TC was demonstrated in further detail based on the intermediates detected by LC-time-of-flight/mass spectrometry (LC/TOF-MS).
- Adam, Farook,Ahmad, Mohammad Norazmi,Iqbal, Anwar,Ramalingam, Rajabathar Jothi,Saidu, Usman,Sreekantan, Srimala,Wilson, Lee D.,Yahaya, Noorfatimah
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Read Online
- Hydrodeoxygenation of C4-C6 sugar alcohols to diols or mono-alcohols with the retention of the carbon chain over a silica-supported tungsten oxide-modified platinum catalyst
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The hydrodeoxygenation of erythritol, xylitol, and sorbitol was investigated over a Pt-WOx/SiO2 (4 wt% Pt, W/Pt = 0.25, molar ratio) catalyst. 1,4-Butanediol can be selectively produced with 51% yield (carbon based) by erythritol hydrodeoxygenation at 413 K, based on the selectivity over this catalyst toward the regioselective removal of the C-O bond in the -O-C-CH2OH structure. Because the catalyst is also active in the hydrodeoxygenation of other polyols to some extent but much less active in that of mono-alcohols, at higher temperature (453 K), mono-alcohols can be produced from sugar alcohols. A good total yield (59%) of pentanols can be obtained from xylitol, which is mainly converted to C2 + C3 products in the literature hydrogenolysis systems. It can be applied to the hydrodeoxygenation of other sugar alcohols to mono-alcohols with high yields as well, such as erythritol to butanols (74%) and sorbitol to hexanols (59%) with very small amounts of C-C bond cleavage products. The active site is suggested to be the Pt-WOx interfacial site, which is supported by the reaction and characterization results (TEM and XAFS). WOx/SiO2 selectively catalyzed the dehydration of xylitol to 1,4-anhydroxylitol, whereas Pt-WOx/SiO2 promoted the transformation of xylitol to pentanols with 1,3,5-pentanetriol as the main intermediate. Pre-calcination of the reused catalyst at 573 K is important to prevent coke formation and to improve the reusability.
- Betchaku, Mii,Cao, Ji,Liu, Lujie,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi,Yabushita, Mizuho
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supporting information
p. 5665 - 5679
(2021/08/16)
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- Method for synthesizing diene compounds based on aldehyde-ketone condensation reaction
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The invention provides a method for synthesizing diene compounds based on an aldehyde-ketone condensation reaction. The method comprises the following steps: firstly, under the action of a condensation catalyst, performing a condensation reaction on ketone compounds and aldehyde compounds to obtain condensation products; then, under the action of a reduction catalyst, performing a reduction reaction on the condensation products obtained in the previous step to obtain reduction products; under the action of a catalyst, performing a dehydration reaction on the reduction products obtained in theprevious step to obtain the diene compounds. According to the method, ketone, aldehyde as well as homologues of ketone and aldehyde which are cheap and easy to obtain can be used as raw materials forsynthesizing the diene compounds such as butadiene, piperylene as well as homologues of butadiene and piperylene, experimental conditions are mild, the operation is simple, and a large-scale synthesisprospect is achieved.
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Paragraph 0172; 0176; 0177; 0215; 0219; 0220
(2019/05/08)
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- Method used for preparing 1,3-dihydric alcohol via Prins condensation reaction
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The invention relates to a method used for preparing a 1,3-dihydric alcohol via Prins condensation reaction. According to the method, an olefin and a formaldehyde aqueous solution are taken as reaction substrates, and direct preparation of the 1,3-dihydric alcohol is carried out under catalytic effect of an acidic composite metal oxide. The reaction process comprises following steps: the formaldehyde aqueous solution is mixed with a catalyst, and an obtained mixture is delivered into a pressure vessel for sealing; the olefin gas is added, stirring is carried out, and reaction is carried out for more than 2h at a temperature higher than 80 DEG C. After reaction, the catalyst is easily collected via separation from a reaction system, and can be recycled for a plurality of time, and the highest yield of the 1,3-dihydric alcohol is 90%.
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Paragraph 0026; 0027
(2016/10/10)
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- NOVEL RUTHENIUM COMPLEX AND METHOD FOR PREPARING METHANOL AND DIOL
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Provided is a method for preparing methanol and diol from cyclic carbonate, comprising: under a hydrogen atmosphere, in an organic solvent, and with the presence of a ruthenium complex (Ru(L)XYY') and an alkali, conducting a hydrogenation reduction reaction on the cyclic carbonate or polycarbonate to obtaib methanol and diol. Also provided is a ruthenium complex prepared from ruthenium and a tridentate amido diphosphine ligand. Also provided is a deuterated methanol and deuterated diol preparation method by substituting the hydrogen and ruthenium complex with deuterium.
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Paragraph 0088
(2015/09/23)
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- Reduction of aromatic and aliphatic keto esters using sodium borohydride/MeOH at room temperature: a thorough investigation
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Reduction of keto esters is a valuable alternative to produce diols. Sodium borohydride/MeOH system at room temperature and short reaction time efficiently reduced α, β, γ, and δ-keto esters having α-keto esters as the most reactive. The ester functionality was reduced effectively due to the presence of oxo group that somehow facilitates the formation of ring intermediate. As expected, the chemoselective experiments showed that ester functionality was not reduced using this system. This study presents a simple, easy, and benign reduction process of various keto esters to its corresponding diols.
- Kim, Juryoung,De Castro, Kathlia A.,Lim, Minkyung,Rhee, Hakjune
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supporting information; experimental part
p. 3995 - 4001
(2010/07/05)
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- Oxygen-directed intramolecular hydroboration
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Metal-free homoallylic oxygen-directed intramolecular hydroboration is reported. Regioselectivities from 20:1 to 82:1 favoring the 1,3-dioxy-substituted products have been achieved using Me2S·BH3/TfOH followed by standard oxidative workup. Branching at the C5 position improves regioselectivity. Copyright
- Rarig, Robert-Andre F.,Scheideman, Matthew,Vedejs, Edwin
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scheme or table
p. 9182 - 9183
(2009/02/03)
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- Methanol and fuel alcohol production for an oxygenate to olefin reaction system
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The present invention provides various processes for producing C1 to C4 alcohols, optionally in a mixed alcohol stream, and optionally converting the alcohols to light olefins. In one embodiment, the invention includes directing a first portion of a syngas stream to a methanol synthesis zone wherein methanol is synthesized. A second portion of the syngas stream is directed to a fuel alcohol synthesis zone wherein fuel alcohol is synthesized. The methanol and at least a portion of the fuel alcohol are directed to an oxygenate to olefin reaction system for conversion thereof to ethylene and propylene.
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Page/Page column 10-12
(2008/06/13)
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- Samarium(III)-Catalyzed Hydroboration of Olefins with Catecholborane. AGeneral Approach to the Synthesis of Boronate Esters
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A broad selection of olefins undergo hydroboration with catecholborane in a reaction that is catalyzed by a range of samarium(III) as well as other lanthanide complexes.
- Evans, David A.,Muci, Alexander R.,Stuermer, Rainer
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p. 5307 - 5309
(2007/10/02)
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- Regioselective Opening of Epoxy Alcohols: Mild Chemo- and Stereoselective Preparation of Iodohydrins and 1,2-Diols
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Several 2,3-epoxy alcohols have been opened, at -60 deg C, with MgI2, leading to the corresponding 3-iodo 1,2-diols with a high level of regio- and chemoselectivity.The iodohydrins can be reduced "in situ", by means of nBu3SnH, to the corresponding 1,2-diols.The chemo-, regio-, and stereocontrol of the reaction makes the method of wide use.Furthermore, epoxy alcohol derivatives (acetyl, benzyl, or TBMS) still maintain a strong preference for C-3 attack of the nucleophile.The experimental data strongly suggest that a metal (Mg) centered chelate is formed throughout the reaction, which gives rise to the regioselective delivery of the iodiode ion.
- Bonini, Carlo,Righi, Giuliana,Sotgiu, Giovanni
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p. 6206 - 6209
(2007/10/02)
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- Stereoselective Syntheses of Alkohols, XXV. - Generation of Enol Borates and Their Addition to Aldehydes
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Ketone-derived enol borates, especially those having a 4,4,5,5-tetramethyl-1,3,2-dioxaborolane unit, are stable compounds,which have been prepared either by borylation of lithium enolates or by oxidation of vinylboronates.These E- or Z-enol borates add to aldehydes in a stereoconvergent reaction leading to syn-aldols.Aldehyde-derived enol borates have a high tendency towards polymerization.Their in-situ addition to aldehydes generates 4-alkoxy-1,3,2-dioxaborinanes, which are internally protected aldols.
- Hoffmann, Reinhard W.,Ditrich, Klaus,Froech, Sybille
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p. 977 - 986
(2007/10/02)
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- Highly Selective Amination of 1-Primary, 3-Secondary 1,3-Alkanediols. A New Approach to 3-Aminoalkyl 4-Nitrobenzoates
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1-Primary, 3-secondary 1,3-alkanediols can be selectively aminated at C-1 via OH/NH2 exchange by reaction with diethyl N-Boc-phosphoramidate in ether using triphenylphosphine/diethyl diazenedicaboxylate as condensing agent, and treatment of the resultant diethyl N-Boc-N-(3-hydroxyalkyl)phosphoramidates with 4-nitrobenzoyl chloride/pyridine, followed by dephosphorylation with hydrogen chloride in ethyl acetate.The reaction sequence affords the hydrochlorides of 3-aminoalkyl 4-nitrobenzoates in good yields.
- Gajda, Tadeusz
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p. 1108 - 1110
(2007/10/02)
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