- Effect of oxidized arachidonic acid and hexanal on the mouse taste perception of bitterness and umami
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The oxidization of fatty acids generates many volatile compounds forming an aroma, but little is known whether mammals use gustatory sense to detect the oxidized products as a taste or only use olfactory sense to detect as an aroma. We examined in this study the effect of aqueous extracts of the compounds from autoxidized arachidonic acid (AA) ethyl ester or hexanal which is the predominant component generated from oxidized AA by the anosmic mouse licking performance to a tastant. The addition of the water extract from oxidized AA or hexanal to a quinine hydrochloride (QHC1) solution decreased the anosmic mice licking frequency at several concentrations of QHC1. Hexanal also reduced the licking frequency of anosmic mice conditioned to avoid MSG at several concentrations of monosodium glutamate (MSG). These results suggest that hexanal would affect mouse taste perception to QHC1 and MSG via the gustatory sensation.
- Yamaguchi, Susumu,Fujiwara, Hidenori,Tashima, Ikukazu,Iwanaga, Daigo,Ushio, Hideki
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Read Online
- Further Study on the One-Pot Synthesis of (E)-2-Nonenal from Castor Oil
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A one-step procedure is described for the synthesis of (E)-2-nonenal from commercial castor oil by ozonolysis in methanol, followed by reduction of the ozonide products with dimethyl sulfide and exposure of the resulting intermediate product to dilute sulfuric acid.The developed process allows the production of the aldehyde with a yield of 80percent at a purity of 95percent.The method has advantages over all those reported earlier, because of inexpensive raw material and reducing agent, recycling of the solvent and its unusual simplicity.KEY WORDS: Castor oil, 2-nonenal, ozonolysis.
- Kula, Jozef,Sikora, Magdalena,Dabrowski, Robert
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Read Online
- A convenient strategy for the synthesis of β,γ-unsaturated aldehydes and acids. A construction of skipped dienes
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A novel strategy is described for the synthesis of β,γ-unsaturated aldehydes which are the useful-synthons for the synthesis of arachidonic acid and other eicosanoid products. These β,γ-unsaturated aldehydes have been used in the total synthesis of arachidonic acid.
- Saha, Goutam,Basu, Manas K.,Kim, Seongjin,Jung, Young-Ju,Adiyaman, Yurdanur,Adiyaman, Mustafa,Powell, William S.,FitzGerald, Garret A.,Rokach, Joshua
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Read Online
- Reduction of 1,1-difluoro-1-alken-3-ols with lithium tetrahydroaluminate. Application to the synthesis of 1,1-difluoro-2-alkenes and 2-alkenals
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The reduction of 1,1-difluoro-1-alken-3-ols with lithium tetrahydroaluminate is described. The 1-fluoro-1-alken-3-ols obtained can be transformed to enals or difluoromethylated allylic derivatives.
- Telliera, Frederique,Sauvetre, Raymond
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Read Online
- Method for preparing olefine aldehyde through catalytic oxidation of enol ether
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The invention relates to the technical field of olefine aldehyde preparation, and provides a method for preparing olefine aldehyde through catalytic oxidation of enol ether. According to the invention, a palladium catalyst, a copper salt, a solvent and enol ether are mixed and subjected to a catalytic oxidation reaction to obtain olefine aldehyde. According to the method, the copper salt is used as the oxidizing agent, the mixed solvent of water and acetonitrile is used as the reaction solvent, and the volume ratio of water to acetonitrile in the mixed solvent is controlled to be (3-7): (3-7), so that the catalytic oxidation reaction can be smoothly carried out in the mixed solvent with a specific ratio, and the generation of palladium black precipitate can be avoided. The method provided by the invention has the advantages of simple steps, low reagent cost, no need of dangerous reagents, wide substrate adaptability and small catalyst dosage. Furthermore, octadecane mercaptan is added to promote the catalytic oxidation reaction, and when the dosage of the palladium catalyst is extremely low, the olefine aldehyde yield can be greatly increased by adding octadecane mercaptan.
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Paragraph 0082-0087
(2021/06/23)
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- Pt-Catalyzed selective oxidation of alcohols to aldehydes with hydrogen peroxide using continuous flow reactors
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The oxidation of alcohols to aldehydes is a powerful reaction pathway for obtaining valuable fine chemicals used in pharmaceuticals and biologically active compounds. Although many oxidants can oxidize alcohols, only a few hydrogen peroxide oxidations can be employed to continuously synthesize aldehydes in high yields using a liquid-liquid two-phase flow reactor, despite the possibility of the application toward a safe and rapid multi-step synthesis. We herein report the continuous flow synthesis of (E)-cinnamaldehyde from (E)-cinnamyl alcohol in 95%-98% yields with 99% selectivity for over 5 days by the selective oxidation of hydrogen peroxide using a catalyst column in which Pt is dispersed in SiO2. The active species for the developed selective oxidation is found to be zero-valent Pt(0) from the X-ray photoelectron spectroscopy measurements of the Pt surface before and after the oxidation. Using Pt black diluted with SiO2as a catalyst to retain the Pt(0) species with the optimal substrate and H2O2introduction rate not only enhances the catalytic activity but also maintains the activity during the flow reaction. Optimizing the contact time of the substrate with Pt and H2O2using a flow reactor is important to proceed with the selective oxidation to prevent the catalytic H2O2decomposition.
- Kon, Yoshihiro,Nakashima, Takuya,Yada, Akira,Fujitani, Tadahiro,Onozawa, Shun-Ya,Kobayashi, Shū,Sato, Kazuhiko
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supporting information
p. 1115 - 1121
(2021/02/16)
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- Saegusa Oxidation of Enol Ethers at Extremely Low Pd-Catalyst Loadings under Ligand-free and Aqueous Conditions: Insight into the Pd(II)/Cu(II)-Catalyst System
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A highly efficient and practical Pd(II)/Cu(OAc)2-catalyst system of Saegusa oxidation, which converts enol ethers to the corresponding enals with a number of diverse substrates at extremely low catalyst loadings (500 mol ppm) under ligand-free and aqueous conditions, is described. Its synthetic utility was demonstrated by large-scale applications of the catalyst system to important nature molecules. This work allows Saegusa oxidation to become a highly practical approach to preparing enals and also suggests new insight into the Pd(II)/Cu(II)-catalyst system for dehydrogenation of carbonyl compounds and decreasing Pd-catalyst loadings.
- Zhu, Quan,Luo, Yunsong,Guo, Yongyan,Zhang, Yushun,Tao, Yunhai
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p. 5463 - 5476
(2021/05/05)
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- Method for reducing carboxylic acid compound into aldehyde
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The invention discloses a method for reducing a carboxylic acid compound into aldehyde. In a nitrogen atmosphere, in an organic solvent, a ligand/Cu catalyst, the carboxylic acid compound, an anhydride compound and hydrosilane are added by a one-pot method, a reaction is performed under the condition of the temperature of 20-120 DEG C for 2-20 h, after the reaction is completed, quenching and column chromatography separation are performed to obtain the product. The carboxylic acid compound can be successfully converted into aldehyde through one-pot reaction, especially unsaturated carboxylic acid can be reduced, and the reaction yield is generally relatively high. Compared with the prior art, the method has the outstanding advantages that the cheap copper salt is used as a catalyst, so that the experiment cost is greatly reduced. Meanwhile, the used method enlarges the application range of the reaction substrate, improves the compatibility of functional groups, and provides a new synthesis way for reducing the carboxylic acid compound into aldehyde.
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Paragraph 0021-0031
(2020/02/27)
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- Porous organic polymer supported rhodium as a heterogeneous catalyst for hydroformylation of alkynes to α,β-unsaturated aldehydes
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A new porous organic polymer supported rhodium catalyst (Rh/POL-BINAPa&PPh3) has been developed for the hydroformylation of various alkynes to afford the corresponding α,β-unsaturated aldehydes with high chem- and stereoselectivity, excellent catalytic activity and good reusability (10 cycles). The heterogeneous catalyst exhibited more catalytic activity than the comparable homogeneous Rh/BINAPa/PPh3 system.
- Liang, Zuyu,Chen, Jianbin,Chen, Xin,Zhang, Kai,Lv, Jinhe,Zhao, Haowen,Zhang, Guoying,Xie, Congxia,Zong, Lingbo,Jia, Xiaofei
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supporting information
p. 13721 - 13724
(2019/11/19)
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- Enzyme-mediated enantioselective hydrolysis of 1,2-diol monotosylate derivatives bearing an unsaturated substituent
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We have succeeded in the easy preparation of optically active 1,2-diol monotosylates bearing an unsaturated substituent via enzymatic hydrolysis. Lipase PS quickly catalyzes the hydrolyses of 2-acetoxybut-3-enyl tosylate, which has a double bond, and 2-acetoxybut-3-ynyl tosylate, which has a triple bond, with excellent enantioselectivity to afford the corresponding optically active compounds. The reaction is also applicable to acetates with a longer chain, which has a double bond at the terminus. To demonstrate the applicability of this method, enantiomerically pure (R)-massoialactone, a natural coconut flavor, has been synthesized from racemic 2-acetoxypent-4-enyl tosylate in several steps. Furthermore, the enzyme can recognize the stereochemistry of olefins, and the (Z)-alkenyl structure is more suitable for the enantioselective hydrolysis than the (E)-isomer.
- Matsumoto,Oohana,Hashimoto,Usuda,Shimoda,Ohshima,Suzuki,Togawa
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supporting information
p. 3981 - 3988
(2018/06/15)
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- A colourful azulene-based protecting group for carboxylic acids
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An intensely blue-coloured protecting group for carboxylic acids has been developed. The protecting group is introduced through a Steglich esterification that couples 6-(2-hydroxyethyl)azulene (AzulE) and the carboxylic acid substrate. Deprotection is effected under basic conditions by the addition of the amidine base DBU, whereupon cleavage occurs, accompanied by a colour change. A two-step deprotection methodology comprising activation with oxalyl chloride and deprotection with a very mild base was developed for use with base-sensitive substrates. The AzulE esters were found to be compatible with other commonly employed protecting groups – silyl ethers, MOM acetals – by studying their orthogonal and concomitant deprotections. The stability of the new protecting group towards various synthetic processes – oxidation, reduction, cross-coupling, olefination and treatment with base – provided the basis of a versatility profile. This indicated that AzulE esters are sensitive to strongly oxidising and basic agents while being compatible with reducing conditions and selected other reactions. The convenience of a highly coloured protecting group for tracking material (and avoiding loss of compound) through laboratory processes warrants further investigation of this and/or related species.
- Bevan, Thomas W.,Francis-Taylor, James,Wong, Helena,Northcote, Peter T.,Harvey, Joanne E.
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supporting information
p. 2942 - 2955
(2018/05/16)
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- One-Step Bioconversion of Fatty Acids into C8-C9 Volatile Aroma Compounds by a Multifunctional Lipoxygenase Cloned from Pyropia haitanensis
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The multifunctional lipoxygenase PhLOX cloned from Pyropia haitanensis was expressed in Escherichia coli with 24.4 mg·L-1 yield. PhLOX could catalyze the one-step bioconversion of C18-C22 fatty acids into C8-C9 volatile organic compounds (VOCs), displaying higher catalytic efficiency for eicosenoic and docosenoic acids than for octadecenoic acids. C20:5 was the most suitable substrate among the tested fatty acids. The C8-C9 VOCs were generated in good yields from fatty acids, e.g., 2E-nonenal from C20:4, and 2E,6Z-nonadienal from C20:5. Hydrolyzed oils were also tested as substrates. The reactions mainly generated 2E,4E-pentadienal, 2E-octenal, and 2E,4E-octadienal from hydrolyzed sunflower seed oil, corn oil, and fish oil, respectively. PhLOX showed good stability after storage at 4 °C for 2 weeks and broad tolerance to pH and temperature. These desirable properties of PhLOX make it a promising novel biocatalyst for the industrial production of volatile aroma compounds.
- Zhu, Zhu-Jun,Chen, Hai-Min,Chen, Juan-Juan,Yang, Rui,Yan, Xiao-Jun
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p. 1233 - 1241
(2018/02/19)
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- Highly efficient Au hollow nanosphere catalyzed chemo-selective oxidation of alcohols
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Micelles of poly(styrene-b-2-vinyl pyridine-b-ethylene oxide) (PS-PVP-PEO) with core-shell-corona structures have been used as a scaffold for the fabrication of gold (Au) hollow nanospheres of particle size 26 ± 2 nm using HAuCl4 and NaBH4 as metal precursor and reducing agent, respectively. The PS core acts as a template for hollow void, the PVP shell serves as reaction sites for inorganic precursors, and PEO corona stabilizes the composite particles. Under acidic conditions, the PVP shell domain becomes positively charged pyridinum-species that electrostatically interacts with negatively charged AuCl4- ions. On reduction of these composite particles and subsequent solvent extraction leads to the formation of Au hollow nanospheres. Various analytical tools such as powder X-ray diffraction (XRD), transmission electron microscope (TEM), thermogravimetric analyses (TG/DTA), dynamic light scattering of (DLS) have been employed to characterize the polymeric micelles and hollow nanoparticles. The TEM and XRD studies confirmed the formation of highly crystalline Au hollow nanospheres. The Au hollow nanosphere/H2O2 system efficiently catalyzes the chemoselective oxidation of allylic-type unsaturated alcohols into aldehydes and ketones under mild liquid-phase conditions. The versatility of present catalytic system for the oxidation of other substrates like aliphatic-, acylic-, aromatic-, and heteroaromatic alcohols to their respective keto compounds has also been reported.
- Sasidharan, Manickam,Anandhakumar, Sundaramurthy,Bhanja, Piyali,Bhaumik, Asim
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- 1H-pyrrole-2,4-dicarbonyl-derivatives and their use as flavoring agents
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The present invention primarily relates to 1H-pyrrole-2,4-dicarbonyl-derivatives of Formula (I) wherein R1, R2, R3, Z. Z' and J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) or of a mixture of compounds of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
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- Imidazo[1,2-a]pyridine-ylmethyl-derivatives and their use as flavoring agents
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The present invention primarily relates to imidazo[1,2-a]pyridine-ylmethyl-derivatives of Formula (I) wherein R1, R2, X, W e J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
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- Tandem Benzylic Oxidation/Dihydroxylation of α-Vinyl- and α-Alkenylbenzyl Alcohols
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A de novo tandem benzylic oxidative dihydroxylation of α-vinyl- and α-alkenylbenzyl alcohols has been developed to give α,β-dihydroxypropiophenones (=2,3-dihydroxy-1-phenylpropan-1-ones) and α,β-dihydroxyalkyl phenones. This method was shown to be substrate-selective and specific for the oxidation of benzylic alcohols.
- Fernandes, Rodney A.,Kattanguru, Pullaiah
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- Synthesis of α,β-unsaturated aldehydes and nitriles via cross-metathesis reactions using Grubbs' catalysts
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A series of α,β-unsaturated aldehydes and nitriles of significant interest in the fragrance industry have been prepared using Grubbs' catalysts in cross-metathesis reactions of electron-deficient olefins (i.e., acrolein, crotonaldehyde, methacrolein, and acrylonitrile) with various 1-alkenes, including 1-decene, 1-octene, 1-hexene and 2-allyloxy-6-methylheptane. The latter is of particular interest, as it has not previously being used as a substrate in cross-metathesis reactions and allows access to valuable intermediates for the synthesis of new fragrances. Most reactions gave good selectivity of the desired CM product (≥90%). Detailed optimisation and mechanistic studies have been performed on the cross-metathesis of acrolein with 1-decene. Recycling of the catalyst has been attempted using ionic liquids.
- Rountree, Sandra M.,Taylor, Sarah F.R.,Hardacre, Christopher,Lagunas, M. Cristina,Davey, Paul N.
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- Highly efficient Cu(I)-catalyzed oxidation of alcohols to ketones and aldehydes with diaziridinone
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A novel and efficient Cu(I)-catalyzed oxidation of alcohols has been achieved with di-tert-butyldiaziridinone as the oxidant under mild conditions. A wide variety of primary and secondary alcohols with various functional groups can be oxidized to aldehydes and ketones in high yields. The reaction proceeds under neutral conditions making it compatible with acid- or base-sensitive substrates, and it is amenable to gram scale.
- Zhu, Yingguang,Zhao, Baoguo,Shi, Yian
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supporting information
p. 992 - 995
(2013/04/10)
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- Aerobic oxidation of primary aliphatic alcohols to aldehydes catalyzed by a palladium(II) polyoxometalate catalyst
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A hexadecyltrimethylammonium salt of a "sandwich" type polyoxometalate has been used as a ligand to attach a palladium(II) center. This Pd-POM compound was an active catalyst for the fast aerobic oxidation of alcohols. The unique property of this catalyst is its significant preference for the oxidation of primary versus secondary aliphatic alcohols. Since no kinetic isotope effect was observed for the dehydrogenation step, this may be the result of the intrinsically higher probability for oxidation of primary alcohols attenuated by steric factors as borne out by the higher reactivity of 1-octanol versus 2-ethyl-1-hexanol. The reaction is highly selective to aldehyde with little formation of carboxylic acid; autooxidation is inhibited. No base is required to activate the alcohol. The fast reactions appear to be related to the electron-acceptor nature of the polyoxometalate ligand that may also facilitate alcohol dehydrogenation in the absence of base.
- Barats, Delina,Neumann, Ronny
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scheme or table
p. 293 - 298
(2010/04/28)
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- Biooxidation of Primary Alcohols to Aldehydes through Hydrogen Transfer Employing Janibacter terrae
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Chemoselective oxidations still represent a challenge for chemists. Lyophilized cells of Janibacter terrae were employed for the chemoselective oxidation of primary alcohols to the corresponding aldehydes by hydrogen transfer with the use of acetaldehyde as the hydrogen acceptor. Secondary alcohol moieties were transformed at a much slower rate. The substrate spectrum encompasses substituted benzyl alcohols, whereby substrates with a substituent in the meta position were well tolerated, whereas only very small substituants were tolerated in the ortho position. Furthermore, nalkanols and allylic alcohols were transformed with good conversions. The biocatalyst was compatible with DMSO as a water miscible organic solvent up to 30 % v/v.
- Orbegozo, Thomas,De Vries, Johannes G.,Kroutil, Wolfgang
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experimental part
p. 3445 - 3448
(2010/09/05)
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- Ruthenium-catalyzed tandem cross-metathesis/wittig olefination: Generation of conjugated dienoic esters from terminal olefins
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In the presence of ruthenium-based olefin metathesis catalysts and triphenylphosphine, α,β-unsaturated aldehydes can be olefinated with diazoacetates. This ruthenium-catalyzed transformation has been employed in tandem with olefin cross-metathesis to convert terminal olefins into 1,3-dienoic esters in a single operation.
- Murelli, Ryan P.,Snapper, Marc L.
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p. 1749 - 1752
(2008/02/02)
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- Highly regioselective terminal alkynes hydroformylation and Pauson-Khand reaction catalysed by mesoporous organised zirconium oxide based powders
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Zirconia-silica mesoporous powders act as very efficient heterogeneous catalysts for both alkyne hydroformylation and Pauson-Khand reaction and yield regioselectivities opposite to those usually observed. The Royal Society of Chemistry 2006.
- Goettmann, Frederic,Le Floch, Pascal,Sanchez, Clement
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p. 180 - 182
(2008/02/08)
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- Characterization of 9-fatty acid hydroperoxide lyase-like activity in germinating barley seeds that transforms 9(S)-hydroperoxy-10(E),12(Z)- octadecadienoic acid into 2(E)-nonenal
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Previously, we reported that 2(E)-nonenal, having a low flavor threshold (0.1 ppb) and known as the major contributor to a cardboard flavor (stale flavor) in stored beer, is produced by lipoxygenase-1 and a newly found factor named 9-fatty acid hydroperoxide lyase-like (9-HPL-like) activity in malt. To assess the involvement of 9-HPL-like activity in beer staling, we compared the values of the wort nonenal potential, an index for predicting the staleness of beer, with the lipoxygenase and 9-HPL-like activity of 20 commercial malts. There was a significant correlation between the malt 9-HPL-like activity and the values of wort nonenal potential (r = 0.53, P 0.05), while the correlation between malt lipoxygenase activity and the wort nonenal potential was statistically insignificant. Analysis of the partially purified 9-HPL-like activity from embryos of germinating barley seeds indicated that 9-HPL-like activity consisted of fatty acid hydroperoxide lyase and 3Z:2E isomerase.
- Kuroda, Hisao,Kojima, Hidetoshi,Kaneda, Hirotaka,Takashio, Masachika
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p. 1661 - 1668
(2008/02/03)
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- Stereoselective preparation of functionalized acyclic alkenylmagnesium reagents using i-PrMgCl-LiCl
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(Chemical Equation Presented) Acyclic functionalized alkenyl iodides are converted with high stereoselectivity to the corresponding functionalized alkenylmagnesium derivatives by the reaction with i-PrMgCl-LiCl between -40 and -20°C. Functional groups such as a nitrile, chloride, iodide, and ester are readily tolerated. The conversion of an alkenyl iodide bearing a keto group to the corresponding silylated cyanohydrin allows preparation of the corresponding Grignard reagent affording, after acylation and deprotection, unsaturated 1,4-diketones.
- Ren, Hongjun,Krasovskiy, Arkady,Knochel, Paul
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p. 4215 - 4217
(2007/10/03)
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- A convenient route to α,β-unsaturated aldehydes based on polymer-supported α-selenoaldehydes
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Polystyrene-supported (4-phenylseleno)morpholine was synthesised and could be used as an efficient α-selenenylating agent for saturated aldehydes; subsequent oxidation of polystyrene-supported α-selenoaldehydes and the products from the Wittig reaction of them with chloromethylidenetriphenylphosphorane with an excess of 30% hydrogen peroxide at room temperature afforded α,β-unsaturated aldehydes in good yields and purities.
- Sheng, Shou-Ri,Wu, Lu-Ling,Huang, Xian
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p. 258 - 259
(2007/10/03)
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- Synthesis and reactivity of Z and E functionalized allylic fluorides
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The allylic fluorides 1 and 2 are used as models to study the effect of the allylic C-F bond on the diastereoselectivity of reactions occurring on the vicinal double bond, as well as the compatibility of this C-F bond with various reagents. The configurational stability of the Z double bonds in enals and enones 1 and 3 is noteworthy. This allowed us to perform various types of reactions (including thermal Diels-Alder cycloadditions) on derivatives 1 with full control of the Z geometry.
- Prakesch, Micha?l,Grée, Danielle,Grée, René
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p. 8833 - 8841
(2007/10/03)
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- The aldol condensation of acetaldehyde and heptanal on hydrotalcite-type catalysts
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The aldol condensation of acetaldehyde and heptanal has been carried out in the liquid phase between 353 and 413 K using different types of solid base catalysts: MgO with strong Lewis basic sites, Mg(Al)O mixed oxides with acid-base pairs of the Lewis type obtained from hydrotalcite precursor, and rehydrated Mg(Al)O mixed oxides with Bronsted basic sites. The influence of several reaction parameters, temperature, acetaldehyde to heptanal molar ratio, nature of solvent (hexane, toluene, ethanol), has been investigated. A comparative study of the catalysts has been performed in the such defined optimal reaction conditions, i.e., 373 K, acetaldehyde/heptanal molar ratio, 2/1; and ethanol/reactants molar ratio, 5/1. Mg(Al)O mixed oxides calcined below 673 K are the most selective catalyst to 2-nonenal, the cross-condensation product formed when in the first step proton abstraction occurs from acetaldehyde. Acid-base pairs of moderate basic strength are suitable when this cross-condensation is the desired reaction. Stronger Lewis basic sites of MgO or Bronsted-type basic sites of the rehydrated mixed oxide tend to favor the formation of carbanion from heptanal. This latter leads to the formation of 2-pentyl-2-butenal and 2-pentyl-2-nonenal by cross-condensation with acetaldehyde and self-condensation, respectively.
- Tichit, Didier,Lutic, Doina,Coq, Bernard,Durand, Robert,Teissier, Remy
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p. 167 - 175
(2007/10/03)
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- Precursors for fragrant ketones and fragrant aldehydes
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The present invention refers to fragrance precursors of formula I for a fragrant ketone of formula II and one or more fragrant aldehydes or ketones of formula III and IV, These fragrance precursors are useful in perfumery, especially in the fine and functional perfumery.
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- Synthesis of α,β-unsaturated aldehydes and methyl carboxylic esters from 2-acetylenic phenyl sulfides
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2-Alkynylthio benzenes were reduced to 2-Alkenylthio benzenes with diisobutyl aluminum hydride. Mono chlorination of these compounds with sulfuryl chloride and pyridine followed by hydrolysis, in the presence of Cu(II) salts, gave α,β-unsaturated aldehydes. 2-Alkynylthio benzenes were converted into 2-Alkynyl 1,1-bis thiobenzenes by monochlorination with sulfuryl chloride and pyridine followed by treatment with thiophenol and triethylamine. These substances were then converted to α,β-unsaturated methyl carboxylic esters by way of isomerization with sodium methoxide to the corresponding allene and treatment with hydrochloric acid and methanolysis in the presence of iodine.
- Fortes, Carlos C.,Garrote, Clevia F. D.
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p. 3917 - 3941
(2007/10/03)
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- Synthesis and Some Properties of 1-Fluoro-1-alken-3-ols
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The reduction of 1,1-difluoro-1-alken-3-ols with lithium tetrahydroaluminate is described. 1-Fluoro-1-alken-3-ols obtained can be transformed to enals or difluoromethylated allylic derivatives.
- Tellier, Frederique,Sauvetre, Raymond
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p. 4223 - 4226
(2007/10/02)
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- Synthesis of α,β-Unsaturated Aldehydes through Palladium Catalyzed Regioselective Hydrogen Migration
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Treatment of cyclic carbonate of 3-alkene-1,2-diols or 4-methylcarbonate of 2-alkene-1,4-diols with a catalytic amount of Pd(PPh3)4 in aqueous THF or AcOH gave α,β-unsaturated aldehydes in good yields.The reaction can be interpreted by the regioselective 1,4-hyrogen migration of ?-allylpalladium intermediate.
- Minami, Tatsuya,Hanaoka, Miyoji
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p. 9425 - 9428
(2007/10/02)
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- Reactivity of 3-Nitro-5,6-Dihydro-4H-Pyran with Organoalanes: Preparation of (E)-α, β-Ethylenic Aldehydes
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3-Nitro-5,6-dihydro-4H-pyran reacts with organoalanes and gives 1,4 addition products.In suitable hydrolysis conditions, the reaction results in the formation of aldehydes that are C1-homologues of the chain transferred by the alane.
- Menicagli, Rita,Guagnano, Vito,Malanga, Corrado
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p. 1871 - 1876
(2007/10/02)
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- 3-Nitro-5,6-dihydro-4H-pyran, a Latent -CHO Equivalent: A New Synthesis of Aldehydes
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3-Nitro-5,6-dihydro-4H-pyran reacts with organoaluminum compounds and, after hydrolysis with 3 N HCl, gives aldehydes arising from a formal carbonylation of the alane.
- Menicagli, R.,Malanga, C.,Guagnano, V.
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p. 2867 - 2870
(2007/10/02)
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- An Isotopic Study (2H and 18O) of the Enzymatic Conversion of Linoleic Acid into Colneleic Acid with Carbon Chain Fracture: the Origin of Shorter Chain Aldehydes
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Contrary to earlier reports, the divinyl 9-ether oxygen of colneleic acid is shown by experiment with 18O2 to originate from oxygen, not water.Using -9(S)-hydroperoxyoctadeca-10(E),12(Z)-dienoic acid, made enzymatically from synthetic linoleic acid, it is found that the distribution of deuterium as determined by NMR and mass spectrometry in the fractured carbon chain of colneic acid formed by potato enzyme, is consistent with the intervention of an epoxy carbonium ion intermediate.Though divinyl acids such as colneleic and colnelenic acid give the expected shorter chain aldehydes on treatment with aqueous acid, it is likely that the latter are formed in most plants by trapping of a monovinyl oxonium ion rather than by rehydration of colneleic and colnelenic acid.
- Crombie, Leslie,Morgan, David O.,Smith, Elisabeth H.
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p. 567 - 575
(2007/10/02)
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- A NEW SYNTHESIS OF α,β-UNSATURATED ALDEHYDES
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The two carbon homologation of carbonyl compounds to α,β-unsaturated aldehydes is achieved by the Wittig-Horner reaction with N-methoxy N-methyl diethylphosphonoacetamide 1 followed by lithium aluminium hydride reduction.
- Nuzillard, Jean-Marc,Boumendjel, Ahcene,Massiot, Georges
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p. 3779 - 3780
(2007/10/02)
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- A Simple Route to α,β-Unsaturated Aldehydes from Prop-2-ynols
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2-Ynols can be isomerised stereoselectively to (2E)-enals with a ruthenium complex as catalyst.
- Ma, Dawei,Lu, Xiyan
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p. 890 - 891
(2007/10/02)
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- ONE-POT CONVERSION OF ALKYNES AND ALKENES INTO ONE-CARBON HOMOLOGATED ALDEHYDES VIA HYDROZIRCONATION-ISOCYANIDE INSERTION-HYDROLYSIS
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The reaction of monoorganozirconocene chlorides and diorganozirconocenes with relatively unhindered isocyanides, such as n-BuNC, followed by hydrolysis with 50percent HOAc or dilute HCl can produce the corresponding aldehydes in good yields.
- Negishi, Ei-ichi,Swanson, Douglas R.,Miller, Steven R.
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p. 1631 - 1634
(2007/10/02)
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- Different Rates of Geometric Isomers of Linoleate Hydroperoxide in Acid-catalyzed Decomposition
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Methyl linoleate hydroperoxide was decomposed with 0.1M HCl in acetone-water (9:1, v/v) at 30 deg C.The decrease in four isomers of the hydroperoxide was monitored by HPLC without any derivatization.In both isomers having 13- and 9-hydroperoxy groups, those having trans,trans dienes decomposed more rapidly than those having cis,trans dienes.In all the isomers, the rates of decomposition were first order with respect to concentrations of the hydroperoxides.The yields of 2-nonenal and 12-oxo-10-dodecenoate were also measured by GC-MS. 12-Oxo-10-dodecenoate was produced only from the 13-isomers and 2-nonenal from the 9-isomers.The rapid decomposition of the trans,trans isomers didn't seem to be responsible for the formation of these aldehyde products.
- Tokita, Masako,Morita, Makio
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p. 3545 - 3550
(2007/10/02)
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- REACTIVITY OF THE 1-t.BUTYLTHIO-3-METHOXY-1-ALKENES TOWARDS METALATING AGENTS, II. ALLYLIC DEPROTONATION OF THE E-ISOMERS AND OF THE Z-PROPENYL DERIVATIVE.
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Deprotonation of the title compounds with a lithiating agent and subsequent alkylation furnish the 1-substituted products 4.The 1-t.butylthio-3-methoxy-1-lithio-1-alkenes 3 become new equivalents of the hypothetical anions I.
- Ruel, O.,Ekogha, C. Bibang Bi,Julia, S. A.
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p. 4829 - 4832
(2007/10/02)
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- 4-(Dimethylamino)pyridinium Chlorochromate, a New Selective Reagent for the Oxidation of Allylic and Benzylic Alcohols
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4-(Dimethylamino)pyridinium chlorochromate (3) is a mild selective reagent for the oxidation of complex allylic and benzylic alcohols to the corresponding carbonyl compounds.
- Guziec, Frank S.,Luzzio, Frederick A.
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p. 1787 - 1789
(2007/10/02)
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- A NEW SYNTHETIC METHOD FOR PELLITORINE
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A stereoselective synthesis of N-isobutyl-E,E-2,4-decadienamide, so called pellitorine is described in which the elimination reaction of acetic acid from 2-acetoxy-E-3-decenenitrile providing 2,4-decadienenitrile in a high yield was used as a key reaction.
- Mandai, Tadakatsu,Gotoh, Jiso,Otera, Junzo,Kawada, Mikio
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p. 313 - 314
(2007/10/02)
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- Catalytic rearrangement
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Process for converting secondary and tertiary acetylenic carbinols to the corresponding alpha,beta-unsaturated carbonyl compounds by rearranging the carbinol with (trilower alkyl-, tricycloalkyl-, triaryl- or triarylalkyl-siloxy)-vanadium oxide catalyst in the presence of a silanol where either the vanadium oxide or the silanol contains a phenyl group substituted with at least one electron withdrawing group.
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