- A re-examination of pressure effects on enantioselectivity in asymmetric catalytic hydrogenation
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Marked shifts in enantioselectivity in the asymmetric hydrogenation of several prochiral substrates were observed as a function of the availability of hydrogen to the catalyst in both heterogeneous and homogeneous catalytic reactions. The key kinetic parameter affecting enantioselectivity was found to be concentration of molecular hydrogen in the liquid phase, [H2], rather than hydrogen pressure in the gas phase, and it was observed that under typical reaction conditions, [H2] could differ widely from its equilibrium saturation value. It was demonstrated that the reported pressure dependence on enantioselectivity may in fact be reproduced at constant pressure for several systems by varying the rate of gas-liquid mass transfer. The general significance of the conclusions suggest that considerations of hydrogen diffusion limitations might be important in other asymmetric hydrogenation studies reported in the literature. For systems where enantioselectivity depends positively on hydrogen pressure, the intrinsic ability of a catalyst to effect asymmetric hydrogenation may be masked in a reaction carried out under conditions where gas-liquid diffusion is the rate-limiting step.
- Sun,Landau,Wang,LeBlond,Blackmond
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- Application of [Ru((R)-BINAP)(MeCN)(1-3:5,6-η-C8H11)](BF4) as a catalyst precursor for enantioselective hydrogenations
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A catalyst system employing [Ru((R)-BINAP)(MeCN)(1-3:5,6-η- C8H11)](BF4) as catalyst precursor was evaluated using the enantioselective hydrogenations of tiglic acid, α-acetamidocinnamic acid, itaconic acid, methyl tiglate, dimethyl itaconate, geraniol, ethyl acetoacetate, and dimethyl oxaloacetate as a series of typical substrates. Acetone and MeOH were used as model aprotic and protic solvents, respectively. The hydrogenation of substrates containing an α,β-unsaturated carboxylic acid functionality required stoichiometric quantities of NEt3 to occur at reasonable rates in acetone solution, while in MeOH solution it did not. The enantioselectivities were typically higher in acetone than in MeOH. This catalyst system is among the more enantioselective ruthenium-BINAP type systems reported for the catalytic hydrogenation of substrates containing an α,β-unsaturated acid or ester functionality. The enantioselectivities for the hydrogenation of ketones ranged from poor (15%) to moderate (74%). 1,4- Dicarboxylate substrates with the prochiral olefin or ketone at the 2- position were all hydrogenated in good to high ee with the same enantioface selectivity both with our system and other catalysts reported in the literature. This raised the possibility that these substrates were hydrogenated through intermediates with similar structural features.
- Daley, Christopher J.A.,Wiles, Jason A.,Bergens, Steven H.
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- Lipase-catalysed transesterification using 2,2,2-trifluoroethyl butyrate: Effect of temperature on rate of reaction and enantioselectivity
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Temperature of the reaction and the solvent used markedly influenced the enantioselectivity and rate of transesterification reaction catalysed by Candida cylindracea between 2,2,2-trifluoroethyl butyrate (TFEB) and 3,7-dimethyl-6-octenol, and that between TFEB and 2,2-dimethyl-1,3-dioxolane-4-methanol.
- Parmar,Prasad,Singh,Gupta
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- Catalytic synthesis of (R) and (S) citronellol by homogeneous hydrogenation over amidophosphinephosphinite and diaminodiphosphine rhodium complexes
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The enantioselective production of citronellol (ee = 84% R and 80% S) is performed by hydrogenation of geraniol 1 and nerol 2 over cationic rhodium complexes modified by amidophosphinephosphinite and diaminodiphosphine chiral ligands.
- Ali,Allaoud,Karim,Roucoux,Mortreux
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- Chemoselective transfer hydrogenation of aldehydes in aqueous media catalyzed by a well-defined iron(II) hydride complex
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Abstract: An iron(II) hydride PNP pincer complex is applied as catalyst for the chemoselective transfer hydrogenation of aldehydes using an aqueous solution of sodium formate as hydrogen source. A variety of aromatic, heteroaromatic, and aliphatic aldehydes could be reduced to the corresponding alcohols in good to excellent yields with a catalyst loading of 1.0?mol% at 80?°C and 1?h reaction time. If present, C–C double bonds remained unaffected in course of the reaction, even when they are conjugated to the carbonyl group of the aldehyde. The catalyst’s lifetime and activity could be improved when the reactions were conducted in an ionic liquid-based micro emulsion. Graphical abstract: [Figure not available: see fulltext.].
- Gorgas, Nikolaus,Ilic, Aleksandra,Kirchner, Karl
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- Preparative Production of Optically Active Esters and Alcohols Using Esterase-Catalyzed Stereospecific Transesterification in Organic Media
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A novel enzymatic approach to the production of optically active alcohols and esters from racemates is developed.It involves the use of esterase catalyzed transesterifications carried out in biphasic aqueous-organic mixtures.Water-insoluble substrates constitute the organic phase, while the enzyme is located in the aqueous phase.Since the fraction of the latter phase can be made very low, such an arrangement solves the problem of both the competition of an alcohol (the nucleophile) with water in the enzymatic reaction and poor solubility of most organic esters and alcohols in water.By use of porous supports (Sepharose or Chromosorb) filled with aqueous solutions of hog liver carboxyl esterase as a stereoselective catalyst and methyl propionate as a matrix ester, the following optically active alcohols and their propionic esters were produced on a preparative scale: 3-methoxy-1-butanol, 3-methyl-1-pentanol, 3,7-dimethyl-1-octanol, and β-citronellol.To overcome a rather narrow substrate specificity of hog liver carboxyl esterase, a nonspecific lipase from yeast (Candida cylindracea) also was employed as a stereoselective transesterification catalyst.Using an aqueous solution of this enzyme confined to the pores of Chromosorb and tributyrin as a matrix ester, we have prepared gram amounts of the following optically active alcohols and their butyric esters: 2-butanol, sec-phenethyl alcohol, 2-octanol, 1-chloro-2-propanol and 2,3-dichloro-1-propanol (subsequently nonenzymatically converted to optically active propylene oxide and epichlorohydrin, respectively), 6-methyl-5-hepten-2-ol, and 1,2-butanediol.
- Cambou, Bernard,Klibanov, Alexander M.
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- SYNTHESIS OF THE SEX-ATTRACTANT OF PINE SAWFLIES (DIPRION SPECIES); (2S,3R,7R)- AND (2S,3R,7S)-3,7-DIMETHYLPENTADECAN-2-Ol
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In order to establish the stereochemistry of the sex attractant of diprion species of pine sawflies, two candidate epimers, (2S,3R,7R)- and (2S,3R,7S)-3,7-dimethylpentadecan-2-ol were synthesized by the coupling reaction of optically active C5 and C12 units.The C12 units, (R)-(-)- and (S)-(+)-1-bromo-2-methylundecane were prepared from (R)-(+)-pulegone.The C5 unit, (2R,3S)-2-methyl-3-tetrahydropyranoxy-1-tosyloxybutane was derived from (2S,3S)-2-methyl-3-hydroxybutyric acid prepared by the reported procedure.
- Kikukawa, Tadashi,Imaida, Motomasa,Tai, Akira
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- Pheromone synthesis. Part 258. Synthesis of the enantiomers of the beetle pheromones ethyl 4-methylheptanoate, 4-methyloctanoic acid and 4-methyl-1-nonanol, and HPLC analysis of their derivatives to determine their enantiomeric purities
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The enantiomers of citronellal have been converted into the enantiomers of the following beetle pheromones: ethyl 4-methylheptanoate (produced by male Nicrophorus vespilloides), 4-methyloctanoic acid (produced by male Oryctes elegans), and 4-methyl-1-nonanol (produced by female Tenebrio molitor). The enantiomeric purities of the synthetic pheromones were determined by HPLC analysis of the corresponding acids after derivatization with Ohrui's reagent [(S)-1-(anthracene-2,3-dicarboximido)-2-propanol]. The enantiomers of 4-methyl-1-nonanol could also be analyzed employing another Ohrui's reagent [(1S,2S)-2-(naphthalene-2,3-dicarboximido)cyclohexane-1-carboxylic acid].
- Mori, Kenji,Akasaka, Kazuaki
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- Enantioselectivity of the bioconversion of chiral citronellal during the inhibition of wheat seeds germination
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Citronellal is one of the most prominent monoterpenes present in many essential oils. Low persistence of essential oils as bioherbicides has often been addressed because of the high volatility of these compounds. Bioconversion of citronellal by wheat seeds releases less aggressive and injurious compounds as demonstrated by their diminished germination. We demonstrated that optically pure citronellal enantiomers were reduced to optically pure citronellol enantiomers with retention of the configuration both in isolated wheat embryos and endosperms. Our findings reveal the potential of essential oils as allelopathic agents providing an insight into their mechanism of action and persistence. Copyright
- Cavalieri, Andrea,Fischer, Ravit,Larkov, Olga,Dudai, Nativ
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- The first stereoselective total synthesis of the immunosuppressive decalin derivative monascusic acid B 1
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The first stereoselective total synthesis of the immunosuppressive decalin derivative monascusic acid B has been accomplished from (R)-(+)-pulegone involving Horner-Wadsworth-Emmons and Julia-Kocienski olefination reactions and Lewis acid catalyzed intramolecular Diels-Alder cyclization. Georg Thieme Verlag Stuttgart New York.
- Kumar, Jayprakash Narayan,Das, Biswanath
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- Responses of tea tussock moth, Euproctis pseudoconspersa, to its pheromone, (R)- 10,14-dimethylpentadecyl isobutyrate, and to the S-enantiomer of its pheromone
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Field trials were conducted with each synthetic enantiomer (> 98 % ee) and blends of the two synthetic enantiomers of the female-produced sex pheromone (10,14-dimethylpentadecyl isobutyrate) of the tea tussock moth, Euproctis pseudoconspersa. Male moths were attracted to each enantiomer alone and to various blends of them. Short syntheses of both enantiomers of the pheromone from commercially available (R)- and (S)-citronellyl bromide and a method of checking the enantiomeric purity of the citronellyl bromide enantiomers are described.
- Zhao, Cheng-Hua,Millar, Jocelyn G.,Pan, Kun-Hui,Cai-Sheng
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- Furanoterpene synthesis via intramolecular nitrile oxide cycloaddition reaction: a total synthesis of (+)-menthofuran
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A fused furan assembling strategy based on an intramolecular dipolar cycloaddition reaction of nitrile oxide has been applied to a total synthesis of perfumy furanomonoterpene (+)-menthofuran (1).The key cycloaddition substrates (9) and (12) are easily prepared via straightforward routes starting from (+)-citronellal and these are treated with sodium hypochlorite and p-chlorophenyl isocyanate, respectively.The cycloaddition reactions generate 10 : 1 mixture of diastereoisomeric isoxazolines (2a) and (2b) in good to excellent yields.The isoxazolines (2a,b)thus obtained are converted to (+)-menthofuran (1) by sequential reductive hydrolysis and alkaline hydrolysis (or vice versa) followed by acid treatment of the resulting β,γ-dihydroxy ketone (14).
- Shishido, Kozo,Umimoto, Koji,Takata, Takeshi,Irie, Osamu,Shibuya, Masayuki
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- Assignment of (6R*10R*)-relative stereochemistry to the major component of the sex pheromone of the maritime pine scale, Matsucoccus feytaudi
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(2E,4E,6R,10S)-4,6,10-Trimethyl-2,4-dodecadien-7-one 1 and its (6S,10S)-isomer were synthesized. The 1H NMR spectrum of (6S,10S)-1 coincided with that reported for the major component of the sex pheromone of Matsucoccus feytaudi, which must therefore be either (6S,10S)- or (6R,10R)-1.
- Mori,Harashima
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- Reduction of carbonyl compounds via hydrosilylation catalyzed by well-defined PNP-Mn(I) hydride complexes
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Reduction reactions of unsaturated compounds are fundamental transformations in synthetic chemistry. In this context, the reduction of polarized double bonds such as carbonyl or C=C motifs can be achieved by hydrogenation reactions. We describe here a highly chemoselective Mn(I)-based PNP pincer catalyst for the hydrosilylation of aldehydes and ketones employing polymethylhydrosiloxane (PMHS) as inexpensive hydrogen donor. Graphic abstract: [Figure not available: see fulltext.]
- Weber, Stefan,Iebed, Dina,Glatz, Mathias,Kirchner, Karl
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p. 635 - 639
(2021/06/17)
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- Enantioselective Synthesis and Activity of All Diastereoisomers of (E)-Phytal, a Pheromone Component of the Moroccan Locust, Dociostaurus maroccanus
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The Moroccan locust, Dociostaurus maroccanus (Thunberg, 1815) (Orthoptera: Acrididae), is a polyphagous pest capable of inflicting large losses in agriculture under favorable environmental and climatic conditions. Currently, control of the pest relies solely on the application of conventional insecticides that have negative effects on the environment and human safety. In the search for a more rational, environmentally acceptable approach for locust control, we have previously reported that (Z/E)-phytal (1) is a male-produced candidate sex pheromone of this acridid. This molecule, with two stereogenic centers at C-7 and C-11, has four different diastereomers along with the Z/E stereochemistry of the double bond at C-2. In this paper, we present for the first time the enantioselective synthesis of the four diastereomers of (E)-phytal and their electrophysiological and behavioral activity on males and females. Our results demonstrate that the (R,R)-phytal is the most active diastereomer in both assays, significantly attracting females in a double-choice Y olfactometer, and confirming the previous chromatographic assignment as component of the sex pheromone of the Moroccan locust.
- Guerrero, Angel,Ramos, Victoria Elena,López, Sergio,Alvarez, José María,Domínguez, Aroa,Coca-Abia, María Milagro,Bosch, María Pilar,Quero, Carmen
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- Sulfonic acid anchored on silica, SiO2@SO3H: A superior solid acid catalyst for quick and solvent-free reductive-deoxygenation of ketones with NaBH3CN
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NaBH3CN as a modified hydroborate agent and due to a strong withdrawing CN group does not show any reducing ability to reduce functional groups in the absence of acidic media (pH ~ 3–4). In this study, the immobilized sulfonic acid on silica, SiO2@SO3H, was prepared and applied as a new solid acid catalyst for extremely enhancing the reducing ability of NaBH3CN. The influence of SiO2@SO3H was highlighted by performing the quick and green reduction of structurally diverse carbonyl compounds involving aldehydes, ketones, α,β-unsaturated enals and enones, α-diketones, and acyloins to the corresponding alcohols or alkanes with NaBH3CN. By the NaBH3CN/SiO2@SO3H system, aldehydes were reduced to the corresponding alcohols and ketonic compounds to alkanes as reductive-deoxygenation products. All reduction reactions were carried out within 3 min at room temperature and under solvent-free conditions to afford the products in high to excellent yields (90–98%).
- Zeynizadeh, Behzad,Kouhkan, Mehri
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p. 1521 - 1528
(2018/11/23)
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- Stereoselective Synthesis of the Antileukemic Sesquiterpene (+)-Caparratriene from L-menthol and Tiglic Aldehyde
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A stereoselective synthesis of natural (+)-caparratriene was developed starting from commercially available L-menthol and tiglic aldehyde. The key step was a Wittig reaction of the latter with the triphenylphosphorane generated from (R)-(–)-citronellyl bromide. (+)-Caparratriene as a mixture (4:1) of 2E,4E- and 2E,4Z-stereoisomers is a known anticancer agent.
- Vydrina,Kravchenko,Yakovleva,Ishmuratova,Ishmuratov, G. Yu.
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p. 461 - 463
(2018/06/11)
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- Catalytic activity of nanoscale borides: Co2B and Ni7B3 in the liquid-phase hydrogenation of citral
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Metal borides are unconventional heterogeneous catalysts. Now, two compounds – the new phase Ni7B3 and well-known Co2B – were synthesized as well-defined, nanoscale material. After characterization (X-ray diffraction, scanning electron microscopy, nitrogen physisorption) they were tested for the liquid phase hydrogenation of citral (3,7-dimethyl-2,6-octadienal) in n-hexane at different temperatures. Hydrogenation products such as geraniol, nerol, citronellal and citronellol were analyzed. The Ni-free catalyst Co2B results in the formation of nerol and geraniol or citronellol selectively, depending on the reaction time. The new compound Ni7B3 yields citronellal or citronellol, depending on the temperature. Thus, the hydrogenation potential of borides – obtained as well-characterized, unsupported heterogeneous catalysts by a one-pot synthesis procedure and post-synthetic annealing – is demonstrated. The cobalt boride preferentially hydrogenates C[dbnd]O bonds, while the nickel boride is selective for C[dbnd]C double bonds.
- Kalyon,Hofmann,Malter,Lucas,Claus,Albert
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p. 436 - 441
(2017/07/05)
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- New In(OiPr)3-MCM-41 heterogeneous catalyst in MPV reductions of unsaturated carbonyl compounds: effect of mesoporous SBA-15 and MCM-41 as supporting surfaces on catalytic activity of In(OiPr)3
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Indium tri-isopropoxide, In(OiPr)3, was immobilized on mesoporous material, MCM-41, and denoted as “In(OiPr)3-MCM-41”. This new heterogeneous catalyst was characterized by XRD, 29Si NMR-, N2 adsorption–desorption isotherms and ICP-OES techniques. The new heterogeneous catalyst, In(OiPr)3-MCM-41, was tested for the capable of catalyzed Meerwein–Ponndorf–Verley (MPV) reduction of unsaturated aldehydes and ketones with low catalyst loadings under mild conditions and showed good to excellent catalytic activities. Also, effect of supporting surfaces, both of SBA-15 and MCM-41, on catalytic activity of In(OiPr)3 were examined. In(OiPr)3-SBA-15 heterogeneous catalyst in comparison with the In(OiPr)3-MCM-41 catalyst, display comparatively higher catalytic activity in the MPV reduction of unsaturated aldehydes and ketones. Also, similiar reaction times and selectivities for the unsaturated alcohols were obtained with the In(OiPr)3-SBA-15 catalyst compared with the In(OiPr)3-MCM-41 catalyst. The reason for the lower activity observed for MCM-41 sample may be due to smaller pore size of the In(OiPr)3-MCM-41 catalyst as compared with In(OiPr)3-SBA-15 catalyst can creat restrict site accessibility for the carbonyl compounds. Eventually, effect of supporting surfaces, SBA-15 and MCM-41, on catalytic activity of In(OiPr)3 insignificant for MPV reduction of unsaturated carbonyl compounds.
- Karatas, Burcu Uysal,Oksal, Birsen S.,Karatas, Erhan
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- Organoselenium and DMAP co-catalysis: Regioselective synthesis of medium-sized halolactones and bromooxepanes from unactivated alkenes
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A catalytic system consisting of bis(4-methoxyphenyl)selenide and 4-(dimethylamino)pyridine (DMAP) has been developed for the regioselective synthesis of medium-sized bromo/iodo lactones and bromooxepanes possessing high transannular strain. 77Se NMR, mass spectrometry and theoretical studies reveal that the reaction proceeds via a quaternary selenium intermediate.
- Verma, Ajay,Jana, Sadhan,Prasad, Ch. Durga,Yadav, Abhimanyu,Kumar, Sangit
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supporting information
p. 4179 - 4182
(2016/03/19)
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- Method for preparing chiral citronellol through asymmetric catalytic hydrogenation of citral
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The invention relates to a method for preparing single chiral citronellol through asymmetric catalytic hydrogenation of E-type and/or Z-type citral in the technical field of chemical engineering. The method comprises the step of performing asymmetric hydrogenation on the E-type and/or Z-type citral to form single chiral citronellol under certain hydrogen pressure and at a certain temperature under the catalysis of a chiral rhodium complex. The reaction condition is mild, the method is convenient to operate, the reaction efficiency is higher, the product yield and the enantioselectivity can reach 99%, and the method has bright industrial application prospect.
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Paragraph 0077-0079
(2017/01/26)
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- Pheromone synthesis. Part 256: Synthesis of the four stereoisomers of 5,11-dimethylpentacosane, a new sex pheromone component of the male Galleria mellonella (L.), with high stereochemical purities as determined by the derivatization-HPLC analysis of the eight stereoisomers of 5,11-dimethyl-8-pentacosanol
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Abstract All the four stereoisomers of 5,11-dimethylpentacosane (>96.8% purity) were synthesized via the stereoisomers of 5,11-dimethyl-8-pentacosanol, whose stereoisomeric compositions could be determined precisely by their low temperature HPLC analysis after derivatization. 5,11-Dimethyl-8-pentacosanol was prepared by a Grignard reaction between 3-methylheptylmagnesium bromide and 4-methyloctadecanal, both of which were prepared from the commercially available enantiomers of citronellal (97-98% ee). Alternatively, (R)-3-methyl-1-heptanol could be prepared from methyl (R)-3-hydroxybutanoate (100% ee). Pd/C-catalyzed hydrogenation of a 5-methyl-1-alkene caused partial racemaization at C-5.
- Mori, Kenji,Akasaka, Kazuaki
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p. 4102 - 4115
(2015/06/02)
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- Identification of 6-benzyloxysalicylates as a novel class of inhibitors of 15-lipoxygenase-1
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Lipoxygenases metabolize polyunsaturated fatty acids into signalling molecules such as leukotrienes and lipoxins. 15-lipoxygenase-1 (15-LOX-1) is an important mammalian lipoxygenase and plays a crucial regulatory role in several respiratory diseases such as asthma, COPD and chronic bronchitis. Novel potent and selective inhibitors of 15-LOX-1 are required to explore the role of this enzyme in drug discovery. In this study we describe structure activity relationships for 6-benzyloxysalicylates as inhibitors of human 15-LOX-1. Kinetic analysis suggests competitive inhibition and the binding model of these compounds can be rationalized using molecular modelling studies. The most potent derivative 37a shows a Ki value of 1.7 μM. These structure activity relationships provide a basis to design improved inhibitors and to explore 15-LOX-1 as a drug target.
- Eleftheriadis, Nikolaos,Thee, Stephanie,Te Biesebeek, Johan,Van Der Wouden, Petra,Baas, Bert-Jan,Dekker, Frank J.
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p. 265 - 275
(2015/03/30)
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- Highly enantioselective hydrogenation of 2-substituted-2-alkenols catalysed by a ChenPhos-Rh complex
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Highly enantioselective hydrogenation of a variety of 2-substituted-2- alkenols has been achieved using a ChenPhos-Rh complex as catalyst, giving ≥99% ee for most substrates. Optically active antifungal agent amorolfine was first synthesised using hydrogenation as the key step. This journal is
- Wang, Quanjun,Liu, Xueying,Liu, Xian,Li, Bin,Nie, Huifang,Zhang, Shengyong,Chen, Weiping
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supporting information
p. 978 - 980
(2014/01/06)
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- General and highly efficient iron-catalyzed hydrogenation of aldehydes, ketones, and α,β-unsaturated aldehydes
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EnvIRONmentally friendly: The title hydrogenation of aldehydes, ketones, and α,β-unsaturated aldehydes is reported. In the presence of the catalyst 1, primary, secondary, and allylic alcohols were obtained in good to excellent yields under mild reaction conditions. The catalyst is easily and inexpensively prepared, and is also stable to air, water, and column chromatography. Copyright
- Fleischer, Steffen,Zhou, Shaolin,Junge, Kathrin,Beller, Matthias
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p. 5120 - 5124
(2013/06/27)
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- A molecularly defined iron-catalyst for the selective hydrogenation of α,β-unsaturated aldehydes
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A selective iron-based catalyst system for the hydrogenation of α,β-unsaturated aldehydes to allylic alcohols is presented. Applying the defined iron-tetraphos complex [FeF(L)][BF4] (L=P(PhPPh 2)3) in the presence of trifluoroacetic acid a broad range of aldehydes are reduced in high yields using low catalyst loadings (0.05-1 mol %). Excellent chemoselectivity for the reduction of aldehydes in the presence of other reducible moieties, for example, ketones, olefins, esters, etc. is achieved. Based on the in situ detected hydride species [FeH(H 2)(L)]+ a catalytic cycle is proposed that is supported by computational calculations. Copyright
- Wienh?fer, Gerrit,Westerhaus, Felix A.,Junge, Kathrin,Ludwig, Ralf,Beller, Matthias
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supporting information
p. 7701 - 7707
(2013/07/11)
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- Transformations of several monoterpenoids in the presence of aldehydes in supercritical solvents
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The reactivity of verbenol epoxide and isopulegol in supercritical solvents in the presence of aromatic aldehydes was studied using a flow type reactor and a heterogeneous catalyst (Al2O3) or no catalyst. The intramolecular transformations or interactions of reagents with the solvent prevailed in all cases; the yield of the products of intermolecular reactions of terpenoids with aldehydes was up to 1%. The aldehydes did not interact with verbenol epoxide but produced a considerable effect on the distribution of its isomerization products.
- Anikeev,Sivcev,Il'Ina,Korchagina,Statsenko,Volcho,Salakhutdinov
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p. 382 - 387
(2013/07/26)
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- Ruthenium-catalyzed asymmetric transfer hydrogenation of allylic alcohols by an enantioselective isomerization/transfer hydrogenation mechanism
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Reducing hazards: A asymmetric transfer hydrogen reaction was developed to reduce prochiral allylic alcohols in high yield and excellent enantioselectivity (see example). Mechanistic studies indicate a novel enantioselective isomerization/transfer hydrogenation mechanism. This new reaction is much safer than high-pressure hydrogenation using H2 gas. Copyright
- Wu, Ruoqiu,Beauchamps, Marie G.,Laquidara, Joseph M.,Sowa Jr., John R.
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experimental part
p. 2106 - 2110
(2012/04/11)
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- Rapid aqueous borohydride reduction of carbonyls under sealed-tube microwave conditions
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Ketones and aldehydes are conveniently and rapidly reduced to the corresponding alcohols in good yields using sodium borohydride under sealed-tube microwave conditions in either 95% ethanol or water. In purely aqueous systems, highly aliphatic substrates are sluggish, but this can be overcome by introducing sodium dodecyl sulfate (SDS) at the critical micelle concentration. With a 2:1 substrate/borohydride ratio and a reaction temperature of 100°C, reduction is typically complete within 1min in 95% ethanol and 5min in water/SDS. The methodology is well suited for parallel and combinatorial synthetic approaches.
- Murphree, S. Shaun,Mason, Jeremy D.,Bean, Theodore G.,Perry, Michelle C.
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experimental part
p. 1979 - 1986
(2012/06/04)
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- Synthesis of all the stereoisomers of 6-methyl-2-octadecanone, 14-methyl-2-octadecanone, and 6,14-dimethyl-2-octadecanone, sex pheromone components of the Lyclene dharma dharma moth, from the enantiomers of citronellal
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The enantiomers of citronellal were converted to all the stereoisomers of 6-methyl-2-octadecanone, 14-methyl-2-octadecanone, and 6,14-dimethyl-2- octadecanone, the female-produced sex pheromone components of the Lyclene dharma dharma moth. Three wellestablished procedures, the Wittig reaction, alkylation of alkynes, and acetoacetic ester synthesis, were employed for the carbon-carbon bond formation to connect the building blocks.
- Shikichi, Yasumasa,Mori, Kenji
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p. 1943 - 1951
(2013/01/15)
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- Stabilized hemiacetal complexes as precursors for the controlled release of bioactive volatile alcohols
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Hemiacetals of pyridine-2-carbaldehyde derivatives and volatile alcohols can be stabilized in organic solution in the presence of protons or different metal cations. Despite the inherent instability of hemiacetals in H 2O, stabilizing them with zinc(II) triflate and adding them to a cationic surfactant formulation resulted in the slow release of the alcohol from cotton surfaces being treated with the hemiacetal complex. Stabilized hemiacetals might thus be suitable delivery systems of bioactive volatiles by rapid hydrolysis in H2O-based media.
- Buchs, Barbara,Fieber, Wolfgang,Drahonovsky, Dusan,Lehn, Jean-Marie,Herrmann, Andreas
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scheme or table
p. 689 - 701
(2012/08/08)
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- Synthesis of (-)-astrogorgiadiol
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Astrogorgiadiol is a naturally occurring Vitamin D analogue that, in cell culture, downregulates the production of the cytokine osteopontin (OPN). OPN has been implicated in virulent asthma, and OPN knockout mice do not develop osteoporosis. As we have pursued whole animal studies with astrogorgiadiol, we have increased the scale of the synthesis. We report an improved preparation of the A-ring synthon and the scale-up of the diasteromerically pure D-ring/sidechain chiron.
- Taber, Douglass F.,Raciti, David M.
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experimental part
p. 10229 - 10233
(2012/02/03)
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- Aliphatic C-H to C-C conversion: Synthesis of (-)-cameroonan-7α-ol
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In the course of a synthesis of the tricyclic sesquiterpene (-)- cameroonan-7α-ol from the acyclic (〈)-citronellal, seven aliphatic C-H bonds were converted to C-C bonds, and three rings and four new stereogenic centers were established. 2011 American Chemical Society.
- Taber, Douglass F.,Nelson, Christopher G.
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experimental part
p. 1874 - 1882
(2011/06/23)
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- Pheromone synthesis. Part 245: Synthesis and chromatographic analysis of the four stereoisomers of 4,8-dimethyldecanal, the male aggregation pheromone of the red flour beetle, Tribolium castaneum
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All four stereoisomers of 4,8-dimethyldecanal (1) were synthesized from the enantiomers of 2-methyl-1-butanol and citronellal. Enantioselective GC analysis enabled separation of (4R,8R)-1 and (4R,8S)-1 from a mixture of (4S,8R)-1 and (4S,8S)-1, when octakis-(2,3-di-O-methoxymethyl-6-O-tert-butyldimethylsilyl)- γ-cyclodextrin was employed as a chiral stationary phase. Complete separation of the four stereoisomers of 1 on reversed-phase HPLC at -54 °C was achieved after oxidation of 1 to the corresponding carboxylic acid 12 followed by its derivatization with (1R,2R)-2-(2,3-anthracenedicarboximido) cyclohexanol, and the natural 1 was found to be a mixture of all the four stereoisomers.
- Akasaka, Kazuaki,Tamogami, Shigeyuki,Beeman, Richard W.,Mori, Kenji
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scheme or table
p. 201 - 209
(2011/02/27)
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- Synthesis of all the stereoisomers of 6-methyl-2-octadecanone, 6,14-dimethyl-2-octadecanone, and 14-methyl-2-octadecanone, the components of the female-produced sex pheromone of a moth, Lyclene dharma dharma
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All of the stereoisomers of the components of the female-produced sex pheromone of a moth, Lyclene dharma dharma, were synthesized. They are (R)- and (S)-6-methyl-2-octadecanone, (6R,14R)-, (6R,14S)-, (6S,14R)-, and (6S,14S)-6,14-dimethyl-2-octadecanone, and (R)- and (S)-14-methyl-2-octadecanone. Enantiomers of citronellal and methyl (S)-3-hydroxy-2-methylpropanoate were the starting materials, and olefin cross metathesis was employed as the key reaction.
- Mori, Kenji
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scheme or table
p. 2798 - 2805
(2009/08/15)
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- Site-saturation mutagenesis of tryptophan 116 of saccharomyces pastorianus old yellow enzyme uncovers stereocomplementary variants
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Site-saturation mutagenesis was used to generate all possible replacements for Trp 116 of Saccharomyces pastorianus (formerly Saccharomyces carlsbergensis) old yellow enzyme (OYE). Our original hypothesissthat smaller amino acids at position 116 would allow better acceptance of bulky 3-alkylsubstituted 2-cyclohexenonessproved incorrect. Instead, Phe and Ile replacements favored the binding of some substrates in an opposite orientation, which yielded reversed stereochemical outcomes compared to that of the wild-type OYE. For example, W116I OYE reduced (R)- and (S)-carvone to enantiomeric products, rather than the diastereomers produced by the wild-type OYE. Deuterium labeling revealed that (S)-carvone reduction by the W116I OYE occurred by the same pathway as that by the wild type (net trans-addition of H2), proving that different substrate binding orientations were responsible for the divergent products. Trp 116 mutants also afforded different stereochemical outcomes for reductions of (R)- perillaldehyde and neral. Preliminary studies of an OYE family member whosenative sequence contains Ile at position 116 (Pichia stipitis OYE 2.6) revealed that this enzyme's stereoselectivity matched that of the wild-t ype S. pastorianus OYE, showing that the identity of the residue at position 116 does not solely determine the substrate binding orientation. Computational docking studies using an induced fit methodology successfully reproduced the majority of the experimental outcomes. These computational tools will allow preliminary in silico screening of additional residues to identify those most likely to control the substrate binding orientation and provide some guidance to future experimental studies.
- Padhi, Santosh Kumar,Bougioukou, Despina J.,Stewart, Jon D.
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experimental part
p. 3271 - 3280
(2009/07/30)
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- DIOPHEP, a chiral diastereoisomeric bisphosphine ligand: synthesis and applications in asymmetric hydrogenations
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Novel optically active diphosphine ligands, known as DIOPHEP, have been designed and synthesized starting from a derivative of tartaric acid. The ligands conjugate the sp3 chirality of the precursor of DIOP with the atropisomeric chirality of a biaryl scaffold. The stereorecognition abilities of DIOPHEP-Ru complex catalysts have been investigated in the asymmetric catalytic hydrogenation of some standard substrates suggesting a close relationship between dihedral angles and enantioselectivity.
- Cesarotti, Edoardo,Abbiati, Giorgio,Rossi, Elisabetta,Spalluto, Paola,Rimoldi, Isabella
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p. 1654 - 1659
(2008/12/22)
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- Synthetic scope of Ru(OH)x/Al2O3-catalyzed hydrogen-transfer reactions: An application to reduction of allylic alcohols by a sequential process of isomerization/meerwein-ponndorf-verley-iype reduction
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Reduction of allylic alcohols can be promoted efficiently by the supported ruthenium catalyst Ru(OH)x/Al2O3. Various allylic alcohols were converted to saturated alcohols in excellent yields by using 2-propanol without any additives. This Ru(OHx/Al 2O3-catalyzed reduction of a dienol proceeds only at the allylic double bond to afford the corresponding enol, and chemoselective isomerization and reduction can be realized under similar conditions. The catalysis is truly heterogeneous and the high catalytic performance can be maintained during at least three recycles of the Ru(OH)x/Al 2O3 catalyst. The transformation of allylic alcohols to saturated alcohols consists of three sequential reactions: oxidation of allylic alcohols to α,β-un-saturated carbonyl compounds; reduction of α,β-unsaturated carbonyl compounds to saturated carbonyl compounds; and reduction of saturated carbonyl compounds to saturated alcohols.
- Kim, Jung Won,Koike, Takeshi,Kotani, Miyuki,Yamaguchi, Kazuya,Mizuno, Noritaka
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scheme or table
p. 4104 - 4109
(2009/05/07)
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- Synthesis of all the six components of the female-produced contact sex pheromone of the German cockroach, Blattella germanica (L.)
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All of the following six components of the female sex pheromone of the German cockroach, Blattella germanica (L.) were synthesized: (3S,11S)-3,11-dimethyl-2-nonacosanone (1), its 29-hydroxy derivative 2, its 29-oxo derivative 3, (3S,11S)-3,11-dimethyl-2-heptacosanone (4), its 27-hydroxy derivative 5, and its 27-oxo derivative 6. Both the enantiomers of citronellal were employed as the chiral sources and Wacker oxidation was employed for the introduction of the carbonyl group at C-2.
- Mori, Kenji
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p. 4060 - 4071
(2008/09/20)
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- Highly dispersed ruthenium hydroxide supported on titanium oxide effective for liquid-phase hydrogen-transfer reactions
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Supported ruthenium hydroxide catalysts (Ru(OH)x/support) were prepared with three different TiO2 supports (anatase TiO2 (TiO2(A), BET surface area: 316 m2g-1), anatase TiO2 (TiO2(B), 73m2 g-1), and rutile TiO2 (TiO2(C), 3.2 m2 g-1)), as well as an Al2O3 support (160 m2g -1). Characterizations with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR), and X-ray absorption fine structure (XAFS) showed the presence of monomeric ruthenium(III) hydroxide and polymeric ruthenium(III) hydroxide species. Judging from the coordination numbers of the nearest-neighbor Ru atoms and the intensities of the ESR signals, the amount of monomeric hydroxide species increased in the order of Ru(OH)x x/ TiO2(C) x/Al2O3 x/ TiO 2(B) x/TiO2(A). These supported ruthenium hydroxide catalysts, especially Ru(OH)x/TiO2(A), showed high catalytic activities and selectivities for liquid-phase hydrogen-transfer reactions, such as racemization of chiral secondary alcohols and the reduction of carbonyl compounds and allylic alcohols. The catalytic activities of Ru(OH)x/TiO2(A) for these hydrogen-transfer reactions were at least one order of magnitude higher than those of previously reported heterogeneous catalysts, such as Ru(OHx/Al2O 3. These catalyses were truly heterogeneous, and the catalysts recovered after the reactions could be reused several times without loss of catalytic performance. The reaction rates monotonically increased with an increase in the amount of monomeric ruthenium hydroxide species, which suggests that the monomeric species are effective for these hydrogen-transfer reactions.
- Yamaguchi, Kazuya,Koike, Takeshi,Kim, Jung Won,Ogasawara, Yoshiyuki,Mizuno, Noritaka
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scheme or table
p. 11480 - 11487
(2009/12/03)
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- Use of fragrance compositions for the prevention of the development of indole based malodours from faecal and urine based soils
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The present invention relates to the use of fragrance compositions, said fragrance compositions comprising fragrance compounds selected among: aldehydes, α, β- unsaturated aldehydes, alcohols, ketones, and mixtures thereof in any home and personal care product, each fragrance compound being able to restrict the formation of indole to less than 0.01ppm (wt/wt) after 24 hours incubation at room temperature in an airtight sealed vessel of suitable fresh human urine containing 0.28% by weight of each fragrance compound in order to prevent the development of indole based malodours from faecal and urine based soils.
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- Total synthesis of papulacandin D
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A total synthesis of the antifungal agent papulacandin D is reported. The molecule is representative of a large class of C-aryl glycosides that exhibit significant antifungal activity. The synthetic strategy bifurcates the molecule into two nearly equal subunits, the arylglycoside and 18-carbon fatty acid side chain. The key strategic transformations are (1) the palladium catalyzed, organosilanolate-based cross-coupling of a protected glucal silanol and (2) a catalytic enantioselective allylation of a dienal using allyltrichlorosilane. The synthesis was accomplished in 31 steps overall from commercial starting materials to afford over 50 mg of the natural product. Copyright
- Denmark, Scott E.,Regens, Christopher S.,Kobayashi, Tetsuya
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p. 2774 - 2776
(2008/02/02)
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- METHOD FOR THE PRODUCTION OF MENTHOL
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The invention relates to a method for producing optically active menthol from geraniol, nerol, or mixtures of geraniol and nerol by a) enantioselectively hydrogenating geraniol, nerol, or mixtures of geraniol and nerol to optically active citronellol, b) reacting the obtained optically active citronellol to optically active citronellal, c) cyclizing the obtained optically active citronellal to a mixture containing optically active isopulegol, and d) eliminating optically active isopulegol from the obtained mixture and hydrogenating the same to optically active menthol or hydrogenating the optically active isopulegol contained in the mixture to optically active menthol and eliminating the obtained optically active menthol from the mixture obtained as hydrogenation product.
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Page/Page column 23
(2008/06/13)
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- Asymmetric whole-cell bioreduction of an α,β-unsaturated aldehyde (citral): competing prim-alcohol dehydrogenase and C-C lyase activities
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Asymmetric bioreduction of (E/Z)-3,7-dimethyl-2,6-octadienal (citral) using the enoate reductase activity of whole cells of yeasts, bacteria and fungi, gave the α,β-saturated aldehyde (R)-3,7-dimethyl-6-octenal (citronellal), which constitutes an important flavour component, in up to ≥95% ee. Depending on the microorganism, various amounts of prim-alcohols (nerol/geraniol and citronellol) were formed due to the action of competing prim-alcohol dehydrogenases. Citral lyase activity-leading to the loss of a C2-fragment (acetaldehyde) forming sulcatone-and oxidation of the aldehyde moiety yielding the carboxylic acid (geranic/neric acid) were detected as additional metabolic activities.
- Hall, Melanie,Hauer, Bernhard,Stuermer, Rainer,Kroutil, Wolfgang,Faber, Kurt
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p. 3058 - 3062
(2007/10/03)
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- NaBH4/NaHSO4·H2O a heterogeneous acidic system for a mild and convenient reduction of carbonyl compounds under protic condition
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NaBH4 in the presence of sodium bisulfate (NaHSO 4·H2O), a weakly acidic reagent, efficiently reduces a variety of carbonyl compounds such as aldehydes, ketones, α, β-unsaturated aldehydes and ketones, α-diketones and acyloins to their corresponding alcohols in acetonitrile under heterogeneous condition. Reduction reactions were accomplished at room temperature or under reflux condition.
- Zeynizadeh, Behzad,Behyar, Tarifen
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p. 453 - 457
(2007/10/03)
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- Wet THF as a suitable solvent for a mild and convenient reduction of carbonyl compounds with NaBH4
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NaBH4 in wet THF can readily reduce varieties of carbonyl compounds such as aldehydes, ketones, conjugated enones, acyloins, and α-diketones to their corresponding alcohols in good to excellent yields. Reduction reactions were performed at room temperature or under reflux condition. In addition, the chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing system.
- Zeynizadeh, Behzad,Behyar, Tarifeh
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p. 307 - 315
(2007/10/03)
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- Ir-Beta zeolite as a heterogeneous catalyst for the one-pot transformation of citronellal to menthol
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Beta zeolites, impregnated with Ir, catalyze the one-pot full conversion of citronellal to menthol by consecutive acid-catalyzed cyclization and Ir-catalyzed hydrogenation, with 95% selectivity for the menthol isomers, of which 75% is the desired (-)-menthol.
- Iosif, Flori,Coman, Simona,Parvulescu, Vasile,Grange, Paul,Delsarte, Stephanie,De Vos, Dirk,Jacobs, Pierre
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p. 1292 - 1293
(2007/10/03)
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- Reduction of carbonyl compounds with NaBH4 under ultrasound irradiation and aprotic condition
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A variety of carbonyl compounds are reduced to their corresponding alcohols with sodium borohydride under ultrasound irradiation and aprotic condition. Reduction reactions are performed in THF at room temperature or under reflux condition. The product alcohols were obtained in good to excellent yields. The chemoselective reduction of aldehydes over ketones was achieved successfully with this system.
- Zeynizadeh, Behzad,Yahyaei, Saiedeh
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p. 704 - 710
(2007/10/03)
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- Treatment of osteoporosis and autoimmune disease with astrogorgiadiol
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The invention provides methods of downregulating mRNA encoding osteopontin comprising administering to a cell or mammal an amount of astrogorgiadiol effective to downregulate production of mRNA encoding osteopontin. The invention also provides methods of treating osteoporosis and autoimmune disease comprising administering to a patient in need of such treatment a therapeutically effective amount of astrogorgiadiol. Pharmaceutical compositions comprising astrogorgiadiol and a pharmaceutically acceptable carrier or diluent are also provided.
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- Synthesis of the four stereoisomers of 7-acetoxy-15-methylnonacosane, a component of the female sex pheromone of the screwworm fly, Cochliomyia hominivorax
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The four stereoisomers of 7-acetoxy-15-methylnonacosane (1), a component of the female sex pheromone of the New World screwworm fly (Cochliomyia hominivorax) were synthesized. The stereogenic center at C-15 of 1 originated from that of the enantiomers of citronellal, and that at C-7 was generated by lipase-catalyzed asymmetric acetylation of (3RS,11R)- and (3RS,11S)-17-methyl-1- trimethylsilylpentacos-1-yn-3-ol (13). Three of the stereoisomers of 1 showed equivalent good pheromone activity, while the activity of (7R,15R)-1 was weak.
- Mori, Kenji,Ohtaki, Takashi,Ohrui, Hiroshi,Berkebile, Dennis R.,Carlson, David A.
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p. 1768 - 1778
(2007/10/03)
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- Titanyl Acetylacetonate as an Efficient Catalyst for a Mild and Convenient Reduction of Carbonyl Compounds with NaBH4 under Aprotic Condition
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Titanyl acetylacetonate, TiO(acac)2, is used as an efficient catalyst for the reduction of carbonyl compounds with sodium borohydride under aprotic condition. Reduction reactions are performed in CH3CN and THF. The corresponding alcohols are obtained in high to excellent yields and the chemoselective reduction of aldehydes over ketones is achieved successfully.
- Zeynizadeh, Behzad
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p. 1220 - 1226
(2007/10/03)
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- Method for preparing a benzylic-type ether
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The invention concerns a method for preparing a benzylic-type ether from an aromatic compound. The inventive method for preparing a benzylic-type ether from an aromatic compound is characterised in that it consists in: in a first step, acylating an aromatic compound by reacting said aromatic compound with an acylating agent, in the presence of an efficient amount of zeolite or a Friedel-Crafts catalyst leading to a ketonic compound; in a second step, reducing the carbonyl group into carbinol leading to a benzylic alcohol; in a third step, etherifying the hydroxyl group, by reacting the benzylic alcohol with another alcohol, in the presence of an efficient amount of zeolite.
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- Process for producing optically active 3, 7-dimethyl-6-octenol and process for producing intermediate therefor
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Provided is citronellol, which has an elegant rosy fragrance and is extremely useful for fragrance impartation to aromatic articles. A mixture of an alkylamine and isoprene in a molar ratio of from 1:4 to 1:4.5 is subjected to telomerization at 80 to 100° C. for 2.5 to 3.5 hours in the presence of an alkyllithium catalyst and/or phenyllithium catalyst to obtain a nerylamine compound containing 2 to 10 wt % α-nerylamine compound represented by general formula (4). From this nerylamine compound, citronellol containing 2 to 10 wt % optically active 3,7-dimethyl-7-octenol is produced through the reaction steps of asymmetric isomerization, hydrolysis, and hydrogenation.
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- Synthesis of the 1,5-dimethylic chiron enantiomers, 3,7,11-trimethyldodec-10-en-1-ol: Application to enantiomeric syntheses of tribolure and a marine fatty acid
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A convenient synthesis of the title chiron antipodes has been developed starting from (±)-citronellol via a sequential acetylation protocol using two lipases. The different stereoisomers of the chiron were then functionalized by simple routes to (4R,8R)-dimethyldecanal, an insect pheromone and (5R,9R)-5,9,13-trimethyltetradecanoic acid, a marine phospholipid fatty acid.
- Sankaranarayanan,Sharma, Anubha,Chattopadhyay, Subrata
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p. 1373 - 1378
(2007/10/03)
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- Synthesis of (-)-astrogorgiadiol
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Reaction of Rh2(S)-PTPA4 with the (R)-citronellol-derived α-diazo-β-ketoester 1 led to the formation of cyclic β-ketoester 2 in 95% yield and 48% diastereomeric excess. The purity of 2 was increased to >99% de after one crystallization. To demonstrate its utility in steroid total synthesis, the β-ketoester 2 was carried on to secosteroid (-)-astrogorgiadiol (3), a naturally occuring vitamin D analogue with antiproliferative properties.
- Taber,Malcolm
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p. 944 - 953
(2007/10/03)
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- Complexes of transition metals with novel axial asymmetric compounds as the ligands
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The invention provides a metal complex comprising a ligand and a metal. The ligand is an aminophosphine compound represented by the following formula (1) The metal is rhodium, ruthenium, iridium or nickel.
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- PERFUME COMPOSITION
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A perfume composition contains specified ketones, salicylates and alcohols/acetates/propionates. Use of such a perfume composition inhibits development of human body malodour. The combination of specified materials makes it possible to avoid inclusion of individual components with powerful, unacceptable odours. The perfume composition may be used in various products notably in a fabric conditioning product used during the rinsing or tumble drying of fabrics after washing to soften the fabrics.
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- 2,2',5,5'-tetramethyl-4,4'-bis(diphenylphoshino)-3,3'-bithiophene: A new, very efficient, easily accessible, chiral biheteroaromatic ligand for homogeneous stereoselective catalysis
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The four-step straightforward synthesis of enantiopure (+)- and (-)- 2,2',5,5'-tetramethyl-4,4'-bis(diphenylphoshino)-3,3'-bithiophene (tetraMe- BITIOP), anew C2-symmetry chelating ligand for transition metals, is described, starting from 2,5-dimethylthiophene. The complexes of this electron-rich diphosphine with Ru(II) and Rh(I) were used as catalysts in some homogeneous hydrogenation reactions of prostereogenic carbonyl functions of α- and β-ketoesters, of prostereogenic carbon-carbon double bonds of substituted acrylic acids, and of N-acetylenamino acids. The enantiomeric excesses were found to be excellent in all the experiments and comparable with the best results reported in the literature for the same reactions, carried out under similar experimental conditions, with the metal complexes of the most popular chiral diphosphine ligands as catalysts.
- Benincori, Tiziana,Cesarotti, Edoardo,Piccolo, Oreste,Sannicolo, Franco
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p. 2043 - 2047
(2007/10/03)
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- Ring closing metathesis directed synthesis of (R)-(-)-muscone from (+)- citronellal
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A concise and simple synthesis of the valuable perfumery ingredient (R)- (-)-muscone 1 has been achieved through ring closing olefin metathesis (RCM) aided macrocyclization protocol as the key step. Commercially available starting material (R)-(+)-citronellal 3 has been employed as a building unit in preparing the acyclic diolefinic substrate 16, which in turn was exposed to bis(tricyclohexylphosphine)benzylideneruthenium dichloride catalyst 2 to afford the cyclic RCM reaction product 17 in 78% yield. Catalytic hydrogenation of 17 furnished enantiomerically pure (R)-(-)-muscone 1. (C) 2000 Elsevier Science Ltd.
- Kamat, Vijayendra P.,Hagiwara, Hisahiro,Katsumi, Tomoko,Hoshi, Takashi,Suzuki, Toshio,Ando, Masayoshi
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p. 4397 - 4403
(2007/10/03)
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