106-24-1Relevant articles and documents
Selective Hydrogenation of Aldehydes Using a Well-Defined Fe(II) PNP Pincer Complex in Biphasic Medium
Weber, Stefan,Brünig, Julian,Zeindlhofer, Veronika,Schr?der, Christian,St?ger, Berthold,Limbeck, Andreas,Kirchner, Karl,Bica, Katharina
, p. 4386 - 4394 (2018)
A biphasic process for the hydrogenation of aldehydes was developed using a well-defined iron (II) PNP pincer complex as model system to investigate the performance of various ionic liquids. A number of suitable hydrophobic ionic liquids based on the N(Tf)2? anion were identified, allowing to immobilize the iron (II) catalyst in the ionic liquid layer and to facilitate the separation of the desired alcohols. Further studies showed that targeted Br?nsted basic ionic liquids can eliminate the need of an external base to activate the catalyst.
Snider,B.B. et al.
, p. 1679 - 1682 (1979)
Large Pore Bifunctional Titanium-Aluminosilicates: the Inorganic Non-enzymatic Version of the Epoxidase Conversion of Linalool to Cyclic Ethers
Corma, A.,Iglesias, M.,Sanchez, F.
, p. 1635 - 1636 (1995)
Bifunctional aluminosilicate catalysts containing framework Ti are prepared, with two different topologies and pore sizes; these samples contain both acid and oxidizing catalytic sites and are highly selective for carrying out multistep reactions with selectivities close to those obtained with epoxidases, this is shown to occur for the oxidation of linalool to cyclic hydroxy ethers.
Gold catalysis for selective hydrogenation of aldehydes and valorization of bio-based chemical building blocks
Silva, Rerison J. M.,Fiorio, Jhonatan L.,Vidinha, Pedro,Rossi, Liane M.
, p. 2162 - 2169 (2019)
Gold catalysts are best known for their selectivity in oxidation reactions, however, there is a promising future for gold in selective hydrogenations. Herein, the hydrogenation of several aldehydes and important bio-based chemical building blocks, namely 5-hydroxymethylfurfural (5-HMF), furfural and vanillin, was performed throughout the combination of Au nanoparticles with Lewis bases. The Au-amine ligand (e.g., 2,4,6-trimethylpyridine) catalytic system could reduce the aldehyde carbonyl group selectively, without reducing alkene moieties or opening the furanic ring that occur on most traditional catalysts. Otherwise, the reduction of nitro group is preferential and the catalytic system was used for the synthesis of furfurylamines, important intermediates in the synthesis of different pharmaceuticals (e.g., furosemide), through the selective reductive amination of furfural starting from nitro-compounds. Moreover, a fully heterogeneous gold catalyst embedded in N-doped carbon (Au@N-doped carbon / TiO2) was able to perform these reactions in successive recycles without the addition of ligands, with impact in the development of a continuous flow process for biomass valorization.
REACTION OF HIGHLY ACTIVE MAGNESIUM WITH ISOPRENE, MYRCENE, OCIMENE, AND PIPERYLENE
Cheskis, B. A.,Moiseenkov, A. M.,Struchkova, M. I.,Semenovskii, A. V.
, p. 285 - 290 (1981)
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Asymmetric bioreduction of activated alkenes using cloned 12-oxophytodienoate reductase isoenzymes OPR-1 and OPR-3 from Lycopersicon esculentum (tomato): A striking change of stereoselectivity
Hall, Melanie,Stueckler, Clemens,Kroutil, Wolfgang,Macheroux, Peter,Faber, Kurt
, p. 3934 - 3937 (2007)
(Chemical Equation Presented) Tomato source: 12-Oxophytodienoate reductase isoenzymes OPR1 and OPR3 from tomato possess a broad substrate spectrum for the asymmetric bioreduction of α,β-unsaturated enals, enones, dicarboxylic acids, and N-substituted male-imides (see scheme). Stereocomplementary behavior of both isoenzymes was observed in the reduction of a nitroalkene that led to the formation of opposite stereoisomers in high enantiomeric excess.
SELECTIVE REDUCTION OF ALDEHYDES IN PRESENCE OF A KETONE WITH CHLOROTRIMETHYLSILANE AND NICKEL BORIDE
Borbaruah, M.,Barua, N. C.,Sharma, R. P.
, p. 5741 - 5742 (1987)
It has been shown that a combination of chlorotrimethylsilane and nickel boride effects the chemoselective reduction of an aldehyde in presence of a ketonic carbonyl group.
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Burrell,J.W.K. et al.
, p. 2144 - 2154 (1966)
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Lipase-catalyzed separation of geometrical isomers: Geraniol-nerol
Gupta, Pankaj,Taneja, Subhash C.,Shah, Bhahwal A.,Sethi, Vijay K.,Qazi, Ghulam N.
, p. 1110 - 1111 (2007)
The substrate/lipase ratio as well as pH of the buffer medium played important roles in the resolution of geometrical isomeric mixture of geraniol-nerol. Based on the results, an immobilized lipase from Pseudomonas fluorescens (PFL) was found effective in selective transesterifications whereas Pseudomonas sp. Lipase (PSL) was found to be useful in hydrolyzing the esters. Copyright
Functional investigation and applications of the acetylesterase activity of the Citrus sinensis (L.) Osbeck peel
Fontana, Gianfranco,Bruno, Maurizio,Maggio, Antonella,Rosselli, Sergio
, p. 4502 - 4507 (2021)
The hydrolysis of acetyl moieties on a set of commercially relevant substrates was performed by employing the whole tissue of Citrus sinensis (L.) Osbeck peel as an efficient biocatalyst in mild reaction conditions with high degree of regioselectivity. The reaction is done in aqueous media and the product is easily recovered. Optimal reaction conditions were deduced and two practical applications were investigated: the elaboration of acetylglicerols and the preparation of vitamin K1 precursor. Peel waste (flavedo and albedo) from orange juice manufacturing was successfully employed as a biocatalyst.
A mild and selective deprotection of p-methoxybenzyl (PMB) ether by magnesium bromide diethyl etherate-methyl sulfide
Onoda, Toshihiko,Shirai, Ryuichi,Iwasaki, Shigeo
, p. 1443 - 1446 (1997)
The magnesium bromide diethyl etherate (MgBr2 · OEt2)-methyl sulfide (Me2S) system is useful for the mild and chemo-selective deprotection of p-methoxybenzyl (PMB) ether in the presence of 1,3-diene, t-butyldimethylsilyl (TBDMS) ether, benzoate, benzyl ether and acetonide.
Corey et al.
, p. 3183 (1975)
Hydrolysis of isoprenyl diphosphates with the acid phosphatase from Cinnamomum camphora
Izumi,Ashida,Yamamitsu,Hirata
, p. 81 - 84 (1996)
Direct observations of the enzymatic hydrolysis of C10 acyclic allylic isoprenyl diphosphates by an acid phosphatase from the leaves of Cinnamomum camphora (camphor tree) were made using 1H and 31P NMR spectrometers. The measurements indicated that the allylic primary diphosphates, geranyl diphosphate and neryl diphosphate, were hydrolysed to their corresponding alcohols in a sequential manner via their corresponding monophosphates, whereas the allylic tertiary diphosphate, linalyl diphosphate, was hydrolysed only to its corresponding monophosphate.
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Tsuzuki,K. et al.
, p. 1469 - 1472 (1977)
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Syntheses of α,β-Epoxy Silyl Ketones
Scheller, Markus E.,Schweizer, W. Bernd,Frei, Bruno
, p. 264 - 270 (1989)
The synthesis of the α,β-epoxy-acylsilanes 1 and 2 starting from the allylic silyl alcohols (E)- and (Z)-3, respectively, by epoxidation with t-BuOOH/VO(acac)2 followed by oxidation with Collins reagent (CrO3/pyridine) in up to 70percent overall yields, is described.The acid-catalyzed rearrangement of the epoxy-silyl alcohols 4A+B and 5A+B led to the novel unstable diastereomeric α-silyl-β-hydroxy-aldehydes 9 and 10, respectively.The structure of 10 was established by X-ray crystal-structure analysis of the corresponding alcohol 11.
ISOMERIZATION OF ALLYLIC ALCOHOLS CATALYZED BY VANADIUM OR MOLYBDENUM COMPLEXES.
Matsubara,Okazoe,Oshima,Takai,Nozaki
, p. 844 - 849 (1985)
Isomerization of primary allylic alcohols proceeds in dichloromethane at 25 degree C in the presence of the catalyst prepared in situ from VO(acac)//2 or MoO//2(acac)//2, and Me//3SiOOSiMe//3 to give tertiary isomers in good yields. The catalysts are also effective for the rearrangements of sec. yields tert. allylic alcohols. The isomerization of an allenyl allylic alcohol, 6-methyl-1,2,5-heptatrien-4-ol, gives either (E)-2-methyl-3,5,6-heptarien-2-ol or (E)-6-methyl-3,5-heptadien-2-one selectively depending on the reaction conditions.
A mild, efficient, and inexpensive protocol for the selective deprotection of TBDMS ethers using KHSO4
Arumugam, Pandurangan,Karthikeyan, Ganesan,Perumal, Paramasivan T.
, p. 1146 - 1147 (2004)
Potassium hydrogensulfate in 30% aq. methanol deprotects a variety of tert-butyldimethylsilyl ethers at room temperature in excellent yields.
Titanyl acetylacetonate as an efficient catalyst for regioselective 1,2-reduction of α,β-unsaturated carbonyl compounds and conversion of α-diketones & acyloins to vicinal diols with sodium borohydride
Zeynizadeh, Behzad
, p. 525 - 530 (2005)
α,β-Unsaturated aldehydes and ketones were reduced readily and exclusively to their corresponding allylic alcohols with NaBH4 and catalytic amounts of titanyl acetylacetonate at room temperature. Reduction reactions were carried out in CH3CN or THF. This reducing system was also efficient for the reduction of α-diketones and acyloins to their corresponding vicinal diols in CH3CN.
Valenzuela,Cori
, p. 3089 (1967)
Derguini-Boumechal et al.
, p. 1181 (1977)
Three-Dimensionally Hierarchical Pt/C Nanocomposite with Ultra-High Dispersion of Pt Nanoparticles as a Highly Efficient Catalyst for Chemoselective Cinnamaldehyde Hydrogenation
Hu, Duo,Fan, Wenqian,Liu, Zhi,Li, Ling
, p. 779 - 788 (2018)
A monolithic carbon-supported Pt nanocomposite with an interconnected three-dimensionally hierarchical porous carbon framework and ultra-high dispersion of Pt nanoparticles (Pt/3DHPC) is synthesized by using an effective “liquid phase impregnation template” strategy. The obtained Pt/3DHPC possesses rich mesoporosity and a low amount of oxygen-containing functional groups, which notably improve the accessible internal surface area of macropores, number of active Pt sites, and electron transfer ability. When used as a catalyst for the selective cinnamaldehyde (CMA) hydrogenation towards cinnamyl alcohol (CMO), Pt/3DHPC exhibits high CMA conversion (92.7 %) and CMO selectivity (91.1 %) at 1 h reaction time, and the corresponding activity (1553.7 h?1) greatly surpasses not only the single-sized mesoporous carbon and microporous activated carbon-supported counterparts but also the previously reported Pt catalysts dispersed on other forms of carbon. Furthermore, Pt/3DHPC can be reused at least fifteen times without pronounced decay owing to the strong interaction between Pt and carbon. The present work demonstrates the validity of multiscale control in carbon-supported Pt catalysts by overall consideration of the mass transportation, and the accessibility, quantity, and capability of active sites towards chemoselective hydrogenation of CMA, which is expected to be extended to other catalysis-related processes.
Regioselective Hydroxylations of 1,3-Dienes via Hydrocobaltation Reactions. Facile Conversion of Myrcene to Geraniol and to (+/-)-Linalool
Howell, Amy R.,Pattenden, Gerald
, p. 103 - 104 (1990)
Regioselective (1,4-) hydrocobaltation of myrcene (1) leads to a 2:1 mixture of (E)- and (Z)-allylcobaloximes (2) which can be converted via the corresponding hydroxylamines (5) to geraniol (6a) and nerol (6b); by contrast, in the presence of molecular oxygen, (2) is converted into the peroxyallylcobalt complex (7), a precursor to linalool (8) and to linalool oxide (10).
A domain swapping approach to elucidate differential regiospecific hydroxylation by geraniol and linalool synthases from perilla
Sato-Masumoto, Naoko,Ito, Michiho
, p. 46 - 54 (2014)
Geraniol and linalool are acyclic monoterpenes found in plant essential oils that have attracted much attention for their commercial use and in pharmaceutical studies. They are synthesized from geranyl diphosphate (GDP) by geraniol and linalool synthases, respectively. Both synthases are very similar at the amino acid level and share the same substrate; however, the position of the GDP to which they introduce hydroxyl groups is different. In this study, the mechanisms underlying the regiospecific hydroxylation of geraniol and linalool synthases were investigated using a domain swapping approach and sitedirected mutagenesis in perilla. Sequences of the synthases were divided into ten domains (domains I to IV-4), and each corresponding domain was exchanged between both enzymes. It was shown that different regions were important for the formation of geraniol and linalool, namely, domains IV-1 and -4 for geraniol, and domains III-b, III-d, and IV-4 for linalool. These results suggested that the conformation of carbocation intermediates and their electron localization were seemingly to be different between geraniol and linalool synthases. Further, five amino acids in domain IV-4 were apparently indispensable for the formation of geraniol and linalool. According to three-dimensional structural models of the synthases, these five residues seemed to be responsible for the different spatial arrangement of the amino acid at H524 in the case of geraniol synthase, while N526 is the corresponding residue in linalool synthase. These results suggested that the side-chains of these five amino acids, in combination with several relevant domains, localized the positive charge in the carbocation intermediate to determine the position of the introduced hydroxyl group.
Metal-doped mesoporous ZrO2catalyzed chemoselective synthesis of allylic alcohols from Meerwein-Ponndorf-Verley reduction of α,β-unsaturated aldehydes
Akinnawo, Christianah Aarinola,Bingwa, Ndzondelelo,Meijboom, Reinout
, p. 7878 - 7892 (2021)
Meerwein-Ponndorf-Verley reduction (MPVr) is a sustainable route for the chemoselective transformation of α,β-unsaturated aldehydes. However, tailoring ZrO2 catalysts for improved surface-active sites and maximum performance in the MPV reaction is still a challenge. Here, we synthesized mesoporous zirconia (ZrO2) and metal-doped zirconia (M_ZrO2, M = Cr, Mn, Fe, and Ni). The incorporation of metal dopants into zirconia's crystal framework alters its physico-chemical properties such as surface area and total acidity-basicity. The prepared catalysts were evaluated in the MPVr using 2-propanol as a hydrogen donor under mild reaction conditions. The catalysts' remarkable reactivity depends mainly on their surface mesostructure's intrinsic properties rather than the specific surface area. Cr_ZrO2, which is stable and sustainable, presented superior activity and 100% selectivity to unsaturated alcohols. The synergistic effect between Cr and Zr species in the binary oxide facilitated the Lewis acidity-induced performance of the Cr_ZrO2 catalyst. Our work presents the first innovative application of a well-designed mesoporous Cr_ZrO2 in the green synthesis of unsaturated alcohols with exceptional reactivity. This journal is
Use of short time-on-stream attenuated total internal reflection infrared spectroscopy to probe changes in adsorption geometry for determination of selectivity in the hydrogenation of citral
Daly,Manyar,Morgan,Thompson,Delgado,Burch,Hardacre
, p. 2470 - 2478 (2014)
A new experimental procedure based on attenuated total reflection infrared spectroscopy has been developed to investigate surface species under liquid phase reaction conditions. The technique has been tested by investigating the enhanced selectivity in the hydrogenation of α,β-unsaturated aldehyde citral over a 5% Pt/SiO2 catalyst toward unsaturated alcohols geraniol/nerol, which occurs when citronellal is added to the reaction. The change in selectivity is proposed to be the result of a change in the citral adsorption mode in the presence of citronellal. Short time on stream attenuated total internal reflection infrared spectroscopy has allowed identification of the adsorption modes of citral. With ssno citronellal, citral adsorbs through both the C = C and C = O groups; however, in the presence of citronellal, citral adsorption occurs through the C = O group only, which is proposed to be the cause of the altered reaction selectivity.
Me3SI-promoted chemoselective deacetylation: a general and mild protocol
Gurawa, Aakanksha,Kashyap, Sudhir,Kumar, Manoj
, p. 19310 - 19315 (2021/06/03)
A Me3SI-mediated simple and efficient protocol for the chemoselective deprotection of acetyl groups has been developedviaemploying KMnO4as an additive. This chemoselective deacetylation is amenable to a wide range of substrates, tolerating diverse and sensitive functional groups in carbohydrates, amino acids, natural products, heterocycles, and general scaffolds. The protocol is attractive because it uses an environmentally benign reagent system to perform quantitative and clean transformations under ambient conditions.