- Comparison of the Key Aroma Compounds in Fresh, Raw Ginger (Zingiber officinale Roscoe) from China and Roasted Ginger by Application of Aroma Extract Dilution Analysis
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By application of a comparative aroma extract dilution analysis on the volatile fractions isolated by solvent extraction and solvent-assisted flavor evaporation (SAFE) from fresh raw Chinese ginger (Zingiber officinale Roscoe) and roasted ginger, 21 or 33 odorants, respectively, with flavor dilution (FD) factors in the range of 32-4096 were identified. In raw ginger, the highest FD factors were found for (E)-isoeugenol, 1,8-cineol, vanillin, geranial, and linalool. After roasting, in particular, the FD factors of 3-(methylthio)propanal (cooked potato-like), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (caramel-like), 3-hydroxy-4,5-dimethyl-2(5H)-furanone (seasoning-like), and geraniol were substantially increased. The application of static headspace/olfactometry (SHO) on ground raw ginger revealed a high FD factor for highly volatile acetaldehyde which clearly decreased after roasting. By contrast, the SHO application revealed high FD factors for malty smelling methylpropanal and 3-methylbutanal, which both were exclusively detected in roasted ginger. Thirteen odorants, namely, decanoic acid, (Z)-2-decenal, (Z)-4-decenal, (E)-4,5-epoxy-(E)-2-decenal, (E)-4,5-epoxy-(E)-2-undecenal, fenchol, (Z)-3-hexenal, 3-hydroxy-4,5-dimethyl-2(5H)-furanone, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 3-methyl-2-buten-1-thiol, 2-methylpropanal, (E)-2-nonenal, and 1-nonen-3-one, were identified in ginger for the first time. Chiral analysis showed a much higher percent by weight portion for the (R)-enantiomer in citronellal, citronellol, and linalool, which was not much changed during pan-frying.
- Schaller, Tanja,Schieberle, Peter
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- A Convenient Preparation of Ketones by the Oxidation of Secondary Alcohols with Chromium(VI) Trioxide in Aprotic Solvent in the Presence of "Wet"-Aluminium Oxide
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The oxidation of aliphatic and alicyclic secondary alcohols with chromium(VI) trioxide in the presence of "wet"-aluminium oxide in hexane gave the corresponding ketones in excellent yields under mild conditions.
- Hirano, Masao,Nagasawa, Sonoko,Morimoto, Takashi
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- Synthesis of (sulfonyl)methylphosphonate analogs of prenyl diphosphates
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Syntheses of several (sulfonyl)methylphosphonate analogs of geranyl, neryl, and farnesyl diphosphates are described. Key steps include utilization of an (E)-selective Horner-Wadsworth-Emmons olefination which couples an aldehyde to the sulfone phosphonate moiety, and a selective reduction of the resulting dienyl sulfone phosphonate substrates.
- Lodewyk, Michael W.,Lui, Victor G.,Tantillo, Dean J.
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- TRANSITION-METAL CATALYZED OXIDATION OF ALCOHOLS TO ALDEHYDES AND KETONES BY MEANS OF Me3SiOOSiMe3
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Pyridinium dichromate-Me3SiOOSiMe3 system has been found to be effective for the oxidation of alcohols to the corresponding carbonyl compounds.Selective oxidation of primary alcohols in the presence of secondary ones with RuCl2(PPh3)3-Me3SiOOMe3 is also described.
- Kanemoto, Shigekazu,Oshima, Koichiro,Matsubara, Seijiro,Takai, Kazuhiko,Nozaki, Hitosi
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- Oxidations with hydrogen peroxide catalysed by the [WZnMn(II)2(ZnW9O34)2]12- polyoxometalate
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Polyoxometalates can be used as catalysts for the activation of molecular oxygen and 30% aqueous hydrogen peroxide for the selective transformation of various organic substrates. In this paper results are presented for the oxidation of alkenes, dienes, alkenols, and sulfides using 30% aqueous H2O2 as oxidant and [WZnMn(II)2(ZnW9O34)2]12- as catalyst. In certain but not all cases high reactivity, chemoselectivity and stereospecificity has been observed especially in the epoxidation of alkenols with primary hydroxyl units.
- Neumann,Juwiler
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- Catalysis of giant palladium cluster complexes, highly selective oxidations of primary allylic alcohols to (α,β-unsaturated aldehydes in the presence of molecular oxygen
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A giant Pd cluster, Pd561phen60(OAc)180 has high catalytic activity for the selective oxidations of various primary allylic alcohols to the corresponding α,β-unsaturated aldehydes in the presence of molecular oxygen under mild reaction conditions. A Pd cluster anchored on TiO2, also catalyzes the above oxidations; the heterogeneous Pd561 cluster catalyst is easily separated from the reaction mixture and is reusable.
- Kaneda, Kiyotomi,Fujie, Yoko,Ebitani, Kohki
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- Synthesis of Allyl Acetals and Their Catalytic Claisen-Cope Rearrangement
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We have synthesized various types of acetals using 3-methyl-3-butenal and 2-alkenyl, furfuryl, benzyl, p-substituted benzyl, and 2-pentynyl alcohols. These acetals have given corresponding aldehydes after an acid catalytic reaction. Trifluoroacetic acid (CF3COOH) was the best catalyst. The best yield attained was 79% when 3-methyl-3-butenal di(trans-2-pentenyl) acetal was used as a substrate. We also demonstrated that this reaction proceeded via a Claisen-Cope rearrangement.
- Nakabayashi, Kazuhiro,Ooho, Masato,Niino, Teppei,Kitamura, Tsugio,Yamaji, Teizo
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- Divergent synthesis of four isomers of 6,7-dihydroxy-3,7-dimethyloct-2-enoic acid, esters and evaluation for the antifungal activity
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The four isomers of 6,7-dihydroxy-3,7-dimethyloct-2-enoic acid 2 were synthesized via the selective direct Sharpless asymmetry dihydroxylation of geraniol as the key step in 35.0%-48.0% overall yields with 91.9%-97.7% ee values for esters 4 and 31.3%-36.4% overall yields with 90.3-97.5% ee values for acids 2 using cis- and trans-geraniol as raw materials. Their structures were characterized by 1H, 13C NMR and HR-ESI-MS data. The in vivo bioassay results showed that the chiral acid (Z, S)-2 was a good lead compound with 80%-100% inhibitory rates against P. cubensis, E. graminis, P. sorghi and C. gloeosporioides at the concentration of 400μg/mL.
- Wang, Weiwei,Zhang, Xiaoteng,Zhao, Yu,Liu, Xinlei,Zhang, Zhenhua,Wang, Mingan
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- Highly efficient oxidation of alcohols and aromatic compounds catalysed by the Ru-Co-Al hydrotalcite in the presence of molecular oxygen
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The ruthenium hydrotalcite having cobalt cations, Ru-Co-Al-CO3 HT, is an effective heterogeneous catalyst for the oxidation of various kinds of alcohols in the presence of molecular oxygen.
- Matsushita, Tsuyoshi,Ebitani, Kohki,Kaneda, Kiyotomi
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- Engineering the enantioselectivity of yeast old yellow enzyme Oye2Y in asymmetric reduction of (E/Z)-citral to (R)-citronellal
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The members of the Old Yellow Enzyme (OYE) family are capable of catalyzing the asymmetric reduction of (E/Z)-citral to (R)-citronellal—a key intermediate in the synthesis of L-menthol. The applications of OYE-mediated biotransformation are usually hampered by its insufficient enantioselectivity and low activity. Here, the (R)-enantioselectivity of Old Yellow Enzyme from Saccharomyces cerevisiae CICC1060 (OYE2y) was enhanced through protein engineering. The single mutations of OYE2y revealed that the sites R330 and P76 could act as the enantioselectivity switch of OYE2y. Site-saturation mutagenesis was conducted to generate all possible replacements for the sites R330 and P76, yielding 17 and five variants with improved (R)-enantioselectivity in the (E/Z)-citral reduction, respectively. Among them, the variants R330H and P76C partly reversed the neral derived enantioselectivity from 32.66% e.e. (S) to 71.92% e.e. (R) and 37.50% e.e. (R), respectively. The docking analysis of OYE2y and its variants revealed that the substitutions R330H and P76C enabled neral to bind with a flipped orientation in the active site and thus reverse the enantioselectivity. Remarkably, the double substitutions of R330H/P76M, P76G/R330H, or P76S/R330H further improved (R)-enantioselectivity to >99% e.e. in the reduction of (E)-citral or (E/Z)-citral. The results demonstrated that it was feasible to alter the enantioselectivity of OYEs through engineering key residue distant from active sites, e.g., R330 in OYE2y.
- Ying, Xiangxian,Yu, Shihua,Huang, Meijuan,Wei, Ran,Meng, Shumin,Cheng, Feng,Yu, Meilan,Ying, Meirong,Zhao, Man,Wang, Zhao
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- Direct oxidation of benzylic and allylic silyl ethers to carbonyl compounds
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Oxidation of benzylic or allylic silyl ethers with DDQ under UV irradiation leads directly to the corresponding carbonyl compounds with moderate to good yields.
- Piva, Olivier,Amougay, Aicha,Pete, Jean-Pierre
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- Selective catalysis for the oxidation of alcohols to aldehydes in the presence of cucurbit[8]uril
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Efficient selectivity for the supramolecular catalysis by cucurbit[8]uril (Q[8]) for the oxidation of aryl, allyl, and alkyl alcohols to corresponding aldehydes by o-Iodoxybenzoic acid (IBX) in aqueous solvent is reported. The relationship between the catalytic ability of Q[8] and the structure of the substrate has revealed that the catalyst prefers aryl and allyl alcohols to alkyl alcohols, and the conversions of most aryl and allyl alcohols have been increased by 30-50% in the presence of Q[8]. The catalytic selectivity suggests that the IBX oxidation proceeds via a stabilized α-Carbanion intermediate and the supramolecular catalysis should be mechanistically related to the electron density and reactivity of the α-Carbanion.
- Wang, Yong-Huan,Cong, Hang,Zhao, Fang-Fang,Xue, Sai-Feng,Tao, Zhu,Zhu, Qian-Jiang,Wei, Gang
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- Oxydation d'Alcools Benzyliques et Allyliques par le systeme MnO2/Bentonite sous irradiation aux micro-ondes ou ultrasons en absence de solvant.
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A new selective and simple method for benzylic and allylic alcohols oxidation to aldehydes is reported.The oxidation is achieved with MnO2/bentonite/microwave and MnO2/bentonite/ultrasound, both in dry medium.
- Martinez, Luis A.,Garcia, Olivia,Delgado, Francisco,Alvarez, Cecilio,Patino, Rocio
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- A Convenient Method for Conversion of Allylic Chlorides to α,β-Unsaturated Aldehydes
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Tertiary amine N-oxides were found to be effective for converting chlorides to aα,β-unsaturated aldehydes.
- Suzuki, Shigeaki,Onishi, Takashi,Fujita, Yoshiji,Misawa, Hiromitsu,Otera, Junzo
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- Samarium Iodide-Promoted Asymmetric Reformatsky Reaction of 3-(2-Haloacyl)-2-oxazolidinones with Enals
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3-(2-Haloacyl)-2-oxazolidinones were shown to react with enals in an asymmetric SmI2-promoted Reformatsky reaction to give stereochemically well-defined 3-hydroxy-4-alkenyl- and 3-hydroxy-2-methyl-4-alkenyl imides. Chirality transfer of the Evans (S)-oxazolidinone unit via a Zimmerman-Traxler-like transition state resulted in Reformatsky products with a relative syn-configuration. The absolute configuration of compounds obtained is opposite to the corresponding products obtained via aldol addition of boron enolates to enals using the same Evans oxazolidinones.
- Baro, Angelika,Dallavalle, Sabrina,Hasnik, Fabian,Laschat, Sabine,Sinast, Moritz,Sube, Tobias,Wischnat, Jonathan,Zuccolo, Marco
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- Total synthesis of 3,7-dimethyl-7-hydroxy-2-octen-1,6-olide and 3,7-dimethyl-2,6-octadien-1,6-olide
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3,7-Dimethyl-7-hydroxy-2-octen-1,6-olide (1) and 3,7-dimethyl-2,6-octadien- 1,6-olide (2), the natural bioactive compounds isolated from the fruit of Litsea cubeba and the liverwort Plagiochila rutilans, were totally synthesized using easily available cis-geraniol as raw material in short, convenient, and low-cost, five-step reactions including three steps of oxidation, cyclization, and dehydration, with an overall yield of 47.5% and 37.3%.
- Dong, Hong-Bo,Yang, Ming-Yan,Jiang, Jia-Zheng,Wang, Ming-An
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- Kinetics of thermal conversions of monoterpenic compounds in supercritical lower alcohols
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The most important information concerning thermal conversions of vegetable terpenes (α-pinene, β-pinene, turpentine, and cis-verbenol) in supercritical lower alcohols is systematized. The kinetics of selected reactions is reported and is compared with the kinetics of the same reactions in the gas and liquid phases. Thermodynamic calculations of the phase states and kinetic parameters are presented for a number of multicomponent multiphase systems containing terpenes and lower alcohols. The effect of the supercritical solvent pressure on the rate and selectivity of the selected reactions is reported.
- Anikeev,Ermakova,Chibiryaev,Kozhevnikov
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- Selective catalytic oxidation of geraniol to citral with molecular oxygen in supercritical carbon dioxide
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Selective catalytic oxidation of geraniol to citral with molecular oxygen in supercritical carbon dioxide (scCO2) has been investigated. The catalyst used was a chromium containing mesoporous molecular sieve catalyst viz. CrMCM-41. Comparison studies were performed with CoMCM-41, PtMCM-41 and PdMCM-41 catalysts. Among the various catalysts studied, CrMCM-41 showed a high conversion of geraniol and an excellent selectivity for citral. In contrast CoMCM-41, PtMCM-41 and PdMCM-41 catalysts exhibited low conversion of geraniol. However all three catalysts compared showed similar citral selectivity to CrMCM-41. The effect of CO2 pressure and reaction temperature geraniol oxidation was studied with CrMCM-41. Supercritical CO2 medium was found to enhance the conversion of geraniol and/or yield of citral. It was noticed that the catalyst can be recycled with negligible loss of conversion.
- Dapurkar, Sudhir E.,Kawanami, Hajime,Chatterjee, Maya,Rode, Chandrasekhar V.,Yokoyama, Toshirou,Ikushima, Yutaka
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- Effect of citral and citral related compounds on viability of pancreatic and human B-lymphoma cell lines
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Citral, 3,7-dimethyl-2,6-octadienal, is a key component of the essential oils extracted from several lemon-scented herbal plants. It has been demonstrated to be an effective antifungal agent and in recent years, to have antiproliferative effect in certain tumor cell lines: thus citral could be a potential anticancer drug. In this study, we investigated the effect of citral on the proliferation of pancreatic cell tumor lines (MIA PaCa-2 cells) and human B-lymphoma (DeFew cells). To analyze which part of the molecule is pivotal for the activity, we also studied the effect of several citral related compounds, in particular focusing on some chemical aspects of the terpenic scaffold. The in vitro studies revealed the significant cytotoxic activity of some of the tested compounds.
- Di Mola, Antonia,Massa, Antonio,De Feo, Vincenzo,Basile, Anna,Pascale, Maria,Aquino, Rita Patrizia,De Caprariis, Paolo
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- Selective Oxidation of Alcohol Function in Allylic Alcohols to α,β-Unsaturated Carbonyl Compounds Catalyzed by Zirconocene Complexes
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Bis(η5-cyclopentadienyl)zirconium(IV) complexes, Cp2ZrH2 (1) and Cp2Zr(O-i-Pr)2 (4), in the presence of an appropriate hydrogen acceptor such as benzaldehyde or cyclohexanone catalyze the Oppenauer-type oxidation of allylic alcohols to α,β-unsaturated carbonyl compounds.For instance, primary allylic terpenoid alcohols, geraniol and nerol, were oxidized to α- and β-citrals, which are essential compounds in the perfumery industry, in substantial yields without any treatment.Similarly, secondary allylic alcohols such as 3-hexen-2-ol and 2-cyclohexen-1-ol were alsooxidized with ease to give 3-hexen-2-one and 2-cyclohexen-1-one in 93percent and 89percent yields, respectively.But the present OPP-type oxidation by zirconocene complexes is ineffective for propargylic alcohols.
- Nakano, Tatsuya,Ishii, Yasutaka,Ogawa, Masaya
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- First evidence for the use of polyamines as nucleophiles in a regioselective palladium-catalyzed allylic amination reaction
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Palladium-catalyzed reaction of unsymmetrical allylic electrophiles with polyamines gives rise to regioisomeric allylic polyamines. An original catalytic procedure providing an efficient method for the regioselective synthesis of new classes of polyamino derivatives of biological interest is reported. Based on experimental considerations, a mechanistic rationale involving a thermodynamically controlled isomerization of the initially formed branched product is proposed to account for the total regioselectivity observed.
- Pieri, Cyril,Combes, Sébastien,Brunel, Jean Michel
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- Formulation, characterization, and antitumor properties of trans- and cis-citral in the 4T1 breast cancer xenograft mouse model
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Purpose Citral is composed of a random mixture of two geometric stereoisomers geranial (trans-citral) and neral (cis-citral) yet few studies have directly compared their in vivo antitumor properties. A micelle formulation was therefore developed. Methods Geranial and neral were synthesized. Commerciallypurchased citral, geranial, and neral were formulated in PEG-b-PCL (block sizes of 5000:10,000, Mw/Mn 1.26) micelles. In vitro degradation, drug release, cytotoxicity, flow cytometry, and western blot studies were conducted. The antitumor properties of drug formulations (40 and 80mg/kg based on MTD studies) were evaluated on the 4T1 xenograft mouse model and tumor tissues were analyzed by western blot. Results Micelles encapsulated drugs with >50% LE at 5-40% drug to polymer (w/w), displayed sustained release (t1/2 of 8-9 h), and improved drug stability at pH 5.0. The IC50 of drug formulations against 4T1 cells ranged from 1.4 to 9.9 μM. Western blot revealed that autophagy was the main cause of cytotoxicity. Geranial at 80 mg/kg was most effective at inhibiting tumor growth. Conclusions Geranial is significantly more potent than neral and citral at 80 mg/kg (p0.001) and western blot of tumor tissues confirms that autophagy and not apoptosis is the major mechanism of tumor growth inhibition in p53-null 4T1 cells.
- Zeng, San,Kapur, Arvinder,Patankar, Manish S.,Xiong, May P.
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- Oxidation of terpenic alcohols with hydrogen peroxide promoted by Nb2O5 obtained by microwave-assisted hydrothermal method
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The present work describes the synthesis of niobium oxides by microwave-assisted hydrothermal method and their evaluation as a solid catalyst in oxidation reactions of terpenic alcohols with hydrogen peroxide. Effects of main parameters of synthesis were assessed and all the prepared catalysts were characterized by physical adsorption/ desorption analyses of nitrogen, infrared and Raman spectroscopies, scanning electron microscopy and powder X-rays diffraction analyses. The strength and number of acidic sites of the catalysts were determined by potentiometric titration. Morphological and structural characterization corroborate with the activity and selectivity achieved by the niobium oxides. The reusability of the catalyst was evaluated. The impacts of main reaction variables such as temperature, catalyst, and oxidant load were assessed. Niobium oxide demonstrated to be an effective catalyst, selectively converting the nerol (model molecule) to epoxide and aldehyde. Oxidation of various terpenic alcohols was investigated. Only geraniol and nerol were selectively epoxidized, suggesting a hydroxyl group assisted reaction. Although being also allylic alcohol, linalool was unreactive toward epoxidation due to the presence of a methyl group at the same carbon atom than the hydroxy group. The use of an environmentally cheap friendly oxidant (H2O2) and efficient solid catalyst (Nb2O5) are positive aspects of this process.
- Carreira Batalha, Daniel,Hadler Marins, Natália,Lenin Villarreal Carre?o, Neftalí,Marques e Silva, Ricardo,Vieira Fajardo, Humberto,da Silva, Márcio José
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- OXIDATION OF ALCOHOLS WITH ALLYL METHYL CARBONATE BY MEANS OF RUTHENIUM CATALYST
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Ruthenium-catalyzed reaction of secondary or allylic alcohols with allyl methyl carbonate gives ketones or α,β-unsaturated aldehydes.
- Minami, Ichiro,Yamada, Mitsuru,Tsuji, Jiro
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- Iron-catalyzed aerobic oxidation of allylic alcohols: The issue of C=C bond isomerization
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An aerobic oxidation of allylic alcohols using Fe(NO3) 3·9H2O/TEMPO/NaCl as catalysts under atmospheric pressure of oxygen at room temperature was developed. This eco-friendly and mild protocol provides a convenient pathway to the synthesis of stereodefined α,β-unsaturated enals or enones with the retention of the C-C double-bond configuration.
- Liu, Jinxian,Ma, Shengming
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- Amides as bioisosteres of triazole-based geranylgeranyl diphosphate synthase inhibitors
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Geranylgeranyl diphosphate synthase (GGDPS) inhibitors are of potential therapeutic interest as a consequence of their activity against the bone marrow cancer multiple myeloma. A series of bisphosphonates linked to an isoprenoid tail through an amide linkage has been prepared and tested for the ability to inhibit GGDPS in enzyme and cell-based assays. The amides were designed as analogues to triazole-based GGDPS inhibitors. Several of the new compounds show GGDPS inhibitory activity in both enzyme and cell assays, with potency dependent on chain length and olefin stereochemistry.
- Goetz, Daniel B.,Holstein, Sarah A.,Varney, Michelle L.,Wiemer, David F.
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- A new method for the selective oxidation of allylic and benzylic alcohols
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A new method is described for the selective oxidation of allylic or benzylic alcohols, in the presence of saturated alcohols, using trimethylamine-N-oxide in the presence of an iron carbonyl.
- Pearson, Anthony J.,Kwak, Yoonhyun
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- Vanadium-doped sodium phosphomolybdate salts as catalysts in the terpene alcohols oxidation with hydrogen peroxide
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In this work, we have explored the catalytic activity of Keggin-type heteropolyanions PMo12?nVnO40(3+n)?(n= 0, 1, 2, or 3) in the form of sodium salts in green oxidation routes of terpene alcohols with hydrogen peroxide. Nerol was the model molecule selected to assess the impacts of the main reaction parameters, such as temperature, catalyst load, and stoichiometry of reactants. The impacts of the presence of vanadium at different proportions (i.e., V1, V2, and V3loads/per anion) in the structure of phosphomolybdate catalysts were assessed. All the catalysts were characterized by various techniques such as powder X-ray diffraction, attenuated diffuse reflectance infrared spectroscopy, ultraviolet-visible spectroscopy, thermogravimetric analysis, isotherms of adsorption-desorption of N2measurements of surface area, scanning electronic microscopy, energy-dispersive X-ray spectroscopy, andn-butylamine potentiometric titration. Among the catalysts assessed, Na4PMo11VO40was the most active and selective toward epoxides. The efficiency of this catalyst in the epoxidation of different terpene alcohols was investigated. Special attention was dedicated to correlating the composition and properties of the vanadium-doped phosphomolybdic catalysts with their catalytic activity.
- Ferreira, Sukarno Olavo,Rodrigues, Alana Alves,Vilanculo, Castelo Bandane,da Silva, Márcio José,da Silva, Rene Chagas
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- Dysprosium-doped zinc tungstate nanospheres as highly efficient heterogeneous catalysts in green oxidation of terpenic alcohols with hydrogen peroxide
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A green route to oxidize terpenic alcohols (nerol and geraniol) with H2O2over a solid catalyst was developed. The Dy-doped ZnWO4catalyst was synthesized by coprecipitation and microwave-assisted hydrothermal heating, containing different dysprosium loads. All the catalysts were characterized through infrared spectroscopy, powder X-ray diffraction, surface area and porosimetry, transmission electronic microscopy image, andn-butylamine potentiometric titration analyses. The influence of main reaction parameters such as temperature, the stoichiometry of reactants, loads, and catalyst nature was assessed. ZnWO42.0 mol% Dy was the most active catalyst achieving the highest conversion (98%) and epoxide selectivity (78%) in nerol oxidation. The reaction scope was extended to other terpenic alcohols (i.e., geraniol, borneol, and α-terpineol). The highest activity of ZnWO42.0 mol% Dy was assigned to the lower crystallite size, higher surface area and pore volume, higher acidity strength and the greatest dysprosium load.
- Batalha, Daniel Carreira,Mesquita Borges, Kellen Cristina,de Fátima Gon?alves, Rosana,de Matos Rodrigues, Murillo Henrique,Godinho, Mário Júnior,Fajardo, Humberto Vieira,de Oliveira Bruziquesi, Carlos Giovani,da Silva, Márcio José
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- Highly efficient oxidation of alcohols to carbonyl compounds in the presence of molecular oxygen using a novel heterogeneous ruthenium catalyst
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A ruthenium cation combined with microcrystals of cobalt hydroxide and cerium oxide acted as a highly efficient heterogeneous catalyst for the oxidation of various types of alcohols to carbonyl compounds under atmospheric pressure of molecular oxygen at 60°C. Especially, primary aliphatic alcohols could be oxidized to afford the carboxylic acids in high yields.
- Ji, Hongbing,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
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- Unraveling the role of the lacunar Na7PW11O39 catalyst in the oxidation of terpene alcohols with hydrogen peroxide at room temperature
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In this work, we have assessed the activity of various Keggin heteropolyacid (HPA) salts in a new one-pot synthesis route of valuable products, which were obtained from the oxidation of terpenic alcohols (i.e., aldehyde, epoxide, and diepoxide), using a green oxidant (i.e., hydrogen peroxide) at mild conditions (i.e., room temperature). Lacunar Keggin HPA sodium salts were the goal catalysts investigated in this reaction. Starting from the HPAs (H3PW12O40, H3PMo12O40, and H4SiW12O40), we synthesized lacunar sodium salts (Na7PW11O39, Na7PW11O39 and Na8SiW11O39) and a saturated salt (Na3PW12O40). All of them were investigated in oxidation reactions in a homogeneous phase with nerol as a model molecule. Na7PW11O39 was the most active and selective towards the oxidation products. All the catalysts were characterized by FT-IR, TG/DSC, BET, XRD, and SEM-EDS analyses and potentiometric titration. The main reaction parameters were assessed. Geraniol, α-terpineol, β-citronellol and borneol were also successfully oxidized. Special attention was dedicated to correlating the composition and properties of the catalysts with their activity.
- Vilanculo, Castelo B.,Da Silva, Márcio J.
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- Oxidizing polymers: A polymer-supported, recyclable hypervalent iodine(V) reagent for the efficient conversion of alcohols, carbonyl compounds, and unsaturated carbamates in solution
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The oxidation of various alcohols and cyclization of an olefinic carbamate succeeds with the first polymer-supported iodine(v) reagent (see scheme). The novel oxidizing polymer oxidizes sensitive and complex alcohols, including protected amino alcohols, efficiency in good excellent yields. In addition, the α,β-dehydration of a ketone is demonstrated.
- Sorg,Mengel,Jung,Rademann
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- Oxidation of Allylic Alcohols to Unsaturated Carbonyl Compounds by Ruthenium Dioxide and Dioxygen/Ruthenium Dioxide
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Ruthenium dioxide hydrate acts as an oxidant similar to MnO2 and effectively catalyzes heterogenous aerobic oxidation of allylic alcohols to yield unsaturated carbonyl compounds under mild conditions.
- Matsumoto, Masakatsu,Watanabe, Nobuko
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- Monolacunary K8SiW11O39-Catalyzed Terpenic Alcohols Oxidation with Hydrogen Peroxide
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Abstract: Lacunar potassium undecasilicotungstate salt catalyst was highly efficient in oxidation reactions of terpenic alcohols with hydrogen peroxide. Carbonylic products were selectively obtained from alcohols such as borneol, nerol, geraniol and β-citronellol. The K8SiW11O39 catalyst was synthesized in one pot reaction starting from precursor salts (KCl, Na2WO4, and Na2SiO3). The catalyst salt was characterized by FT-IR, TG/DSC, BET, XRD analyses and potentiometric titration. The main reaction parameters were assessed. Based on experimental data, a reaction pathway was proposed. In borneol oxidation, TON of 2720 was achieved, indicating the high catalytic activity. As far we know, it is the first time where the monolacunar catalyst is used without an additional introduction of metal transition into Keggin anion. A comparison of the catalytic performance of different lacunar silicotungstic acid salts exchanged with different cations was performed. The K8SiW11O39 catalyst was used without loss activity.
- da Silva, Márcio José,da Silva Andrade, Pedro Henrique,Ferreira, Sukarno Olavo,Vilanculo, Castelo Bandane,Oliveira, Cesar Macedo
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- Synthesis of β-ionone
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Preparation of β-ionone by a reaction sequence starting from acetone is described.
- Vani,Chida,Srinivasan,Chandrasekharam,Singh
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- ω-Hydroxy isoprenoid bisphosphonates as linkable GGDPS inhibitors
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The enzyme geranylgeranyl diphosphate synthase (GGDPS) is a potential therapeutic target for multiple myeloma. Malignant plasma cells produce and secrete large amounts of monoclonal protein, and inhibition of GGDPS results in disruption of protein geranylgeranylation which in turn impairs intracellular protein trafficking. Our previous work has demonstrated that some isoprenoid triazole bisphosphonates are potent and selective inhibitors of GGDPS. To explore the possibility of selective delivery of such compounds to plasma cells, new analogues with an ω-hydroxy group have been synthesized and examined for their enzymatic and cellular activity. These studies demonstrate that incorporation of the ω-hydroxy group minimally impairs GGDPS inhibitory activity. Furthermore conjugation of one of the novel ω-hydroxy GGDPS inhibitors to hyaluronic acid resulted in enhanced cellular activity. These results will allow future studies to focus on the in vivo biodistribution of HA-conjugated GGDPS inhibitors.
- Bhuiyan, Nazmul H.,Varney, Michelle L.,Bhattacharya, Deep S.,Payne, William M.,Mohs, Aaron M.,Holstein, Sarah A.,Wiemer, David F.
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Read Online
- A highly effective green catalyst Ni/Cu bimetallic nanoparticles supported by dendritic ligand for chemoselective oxidation and reduction reaction
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The highly active Ni/Cu bimetallic nanoparticles (NPs) of the different molar ratios of Ni and Cu (1:1, 1:3, 3:1) assisted by dendritic ligand 2,4,6-Tris (di-4-chlorobenzamido)-1,3-diazine were synthesized successfully confirmed by Scanning Electron Microscopy (SEM), Electron Diffraction X-ray (EDX), X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), and Transmission Electron Microscopy (TEM) analysis. These NPs were studied as a heterogeneous catalyst for the chemoselective oxidation of alcohol to the corresponding aldehyde at 30?min and chemoselective reduction of aromatic nitro substituents to the corresponding amino substituents at 20?min, while the Ni/Cu (3:1) NPs were found to be the most effective among other Ni/Cu?(1:1)?and Ni/Cu?(1:3)?NPs at room temperature under mild conditions. The Ni/Cu (3:1) NPs can be recycled for at least five successive runs with no perceptible decrease in catalytic activity. Graphic abstract: [Figure not available: see fulltext.]
- Islam, Md. Sayedul,Khan, Md. Wahab
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p. 2353 - 2369
(2021/01/07)
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- Can Br?nsted acids catalyze the epoxidation of allylic alcohols with H2O2? With a little help from the proton, the H3PMo12O40 acid did it and well
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In this work, we have explored the catalytic activity of typical Br?nsted acid in epoxidation reactions of terpene alcohols with hydrogen peroxide. Keggin heteropolyacids (HPAs) (i.e., H3PW12O40, H3PMo12O40, and H4SiW12O40) were compared to the common Br?nsted acids (i.e., sulfuric, and p-toluenesulfonic acids) in epoxidation reactions of nerol, the model molecule selected. The effects of the main reaction variable, such as temperature, time, load and sort of acid catalyst were evaluated. Among the catalysts investigated, H3PMo12O40 was the most active and selective catalyst toward epoxide nerol, the goal product. The highest conversion obtained was 99%, with a selectivity of 97% towards nerol epoxide. A discussion of the reaction mechanism was performed as the basis of experimental results and acidity properties of the catalysts. A comparison with a non-protic catalyst (i.e., Na3PMo12O40) allowed demonstrate that both Molybdenum and protons present in the H3PMo12O40 are the main active sites in this epoxidation reaction.
- Vilanculo, Castelo Bandane,da Silva, Márcio José
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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 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 0082-0086; 0089
(2021/06/23)
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- Copper-catalyzed method for preparing aldehyde or ketone compound by oxidizing alcohol with oxygen as oxidizing agent and application
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The invention discloses a copper-catalyzed method for preparing an aldehyde or ketone compound by oxidizing alcohol with oxygen as an oxidizing agent. Reaction is performed in an organic solvent for 4-48 hours at room temperature by using copper salt and nitroxide free radicals as catalysts and oxygen or air as an oxidizing agent to efficiently oxidize an alcohol compound into the corresponding aldehyde or ketone compound. The method is simple to operate, free of chlorides corrosive to equipment, available in raw materials and reagents, mild in reaction conditions, wide in substrate universality, good in functional group compatibility, convenient in separation and purification, environmentally friendly in the whole process and free of pollution, and is a method suitable for industrial production.
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Paragraph 0028-0030; 0142-0144; 0190-0195
(2020/08/18)
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- A Simple, Mild and General Oxidation of Alcohols to Aldehydes or Ketones by SO2F2/K2CO3 Using DMSO as Solvent and Oxidant
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A practical, general and mild oxidation of primary and secondary alcohols to carbonyl compounds proceeds in yields of up to 99% using SO2F2 as electrophile in DMSO as both the oxidant and the solvent at ambient temperature. No moisture- and oxygen-free conditions are required. Stoichiometric amount of inexpensive K2CO3, which generates easy to separate by-products, is used as the base. Thus, 5-gram scale runs proceeded in nearly quantitative yields by a simple filtration as the work-up. The use of a polar solvent such as DMSO, which usually promotes competing Pummerer rearrangement, is also noteworthy. This protocol is compatible with a variety of common N-, O-, and S-functional groups on (hetero)arene, alkene and alkyne substrates (68 examples). The protocol was applied (99% yield) to a formal synthesis of the important cholesterol-lowering drug Rosuvastatin. (Figure presented.).
- Zha, Gao-Feng,Fang, Wan-Yin,Leng, Jing,Qin, Hua-Li
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supporting information
p. 2262 - 2267
(2019/04/17)
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- Highly efficient and practical aerobic oxidation of alcohols by inorganic-ligand supported copper catalysis
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The oxidation of alcohols to aldehydes or ketones is a highly relevant conversion for the pharmaceutical and fine-chemical industries, and for biomass conversion, and is commonly performed using stoichiometric amounts of highly hazardous oxidants. The aerobic oxidation of alcohols with transition metal complex catalysts previously required complicated organic ligands and/or nitroxyl radicals as co-catalysts. Herein, we report an efficient and eco-friendly method to promote the aerobic oxidation of alcohols using an inorganic-ligand supported copper catalyst 1, (NH4)4[CuMo6O18(OH)6], with O2 (1 atm) as the sole oxidant. Catalyst 1 is synthesized directly from cheap and commonly available (NH4)6Mo7O24·4H2O and CuSO4, which consists of a pure inorganic framework built from a central CuII core supported by six MoVIO6 inorganic scaffolds. The copper catalyst 1 exhibits excellent selectivity and activity towards a wide range of substrates in the catalytic oxidation of alcohols, and can avoid the use of toxic oxidants, nitroxyl radicals, and potentially air/moisture sensitive and complicated organic ligands that are not commercially available. Owing to its robust inorganic framework, catalyst 1 shows good stability and reusability, and the catalytic oxidation of alcohols with catalyst 1 could be readily scaled up to gram scale with little loss of catalytic activity, demonstrating great potential of the inorganic-ligand supported Cu catalysts in catalytic chemical transformations.
- Wei, Zheyu,Ru, Shi,Zhao, Qixin,Yu, Han,Zhang, Gang,Wei, Yongge
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supporting information
p. 4069 - 4075
(2019/08/07)
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- Highly Selective and Catalytic Generation of Acyclic Quaternary Carbon Stereocenters via Functionalization of 1,3-Dienes with CO2
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The catalytic asymmetric functionalization of readily available 1,3-dienes is highly important, but current examples are mostly limited to the construction of tertiary chiral centers. The asymmetric generation of acyclic products containing all-carbon quaternary stereocenters from substituted 1,3-dienes represents a more challenging, but highly desirable, synthetic process for which there are very few examples. Herein, we report the highly selective copper-catalyzed generation of chiral all-carbon acyclic quaternary stereocenters via functionalization of 1,3-dienes with CO2. A variety of readily available 1,1-disubstituted 1,3-dienes, as well as a 1,3,5-triene, undergo reductive hydroxymethylation with high chemo-, regio-, E/Z-, and enantioselectivities. The reported method features good functional group tolerance, is readily scaled up to at least 5 mmol of starting diene, and generates chiral products that are useful building blocks for further derivatization. Systemic mechanistic investigations using density functional theory calculations were performed and provided the first theoretical investigation for an asymmetric transformation involving CO2. These computational results indicate that the 1,2-hydrocupration of 1,3-diene proceeds with high π-facial selectivity to generate an (S)-allylcopper intermediate, which further induces the chirality of the quaternary carbon center in the final product. The 1,4-addition of an internal allylcopper complex, which differs from previous reports involving terminal allylmetallic intermediates, to CO2 kinetically determines the E/Z- and regioselectivity. The rapid reduction of a copper carboxylate intermediate to the corresponding silyl-ether in the presence of Me(MeO)2SiH provides the exergonic impetus and leads to chemoselective hydroxymethylation rather than carboxylation. These results provide new insights for guiding further development of asymmetric C-C bond formations with CO2
- Chen, Xiao-Wang,Zhu, Lei,Gui, Yong-Yuan,Jing, Ke,Jiang, Yuan-Xu,Bo, Zhi-Yu,Lan, Yu,Li, Jing,Yu, Da-Gang
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p. 18825 - 18835
(2019/11/28)
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- Enantio- A nd regioselective: Ene-reductions using F420H2-dependent enzymes
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In the past decade it has become clear that many microbes harbor enzymes that employ an unusual flavin cofactor, the F420 deazaflavin cofactor. Herein we show that F420-dependent reductases (FDRs) can successfully perform enantio-, regio- A nd chemoselective ene-reductions. For the first time, we have demonstrated that F420H2-driven reductases can be used as biocatalysts for the reduction of α,β-unsaturated ketones and aldehydes with good conversions (>99%) and excellent regioselectivities and enantiomeric excesses (>99% ee). Noteworthily, FDRs typically display an opposite enantioselectivity when compared to the well established FMN-dependent Old Yellow Enzymes (OYEs).
- Mathew, Sam,Trajkovic, Milos,Kumar, Hemant,Nguyen, Quoc-Thai,Fraaije, Marco W.
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supporting information
p. 11208 - 11211
(2018/10/15)
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- Preparation method for cis-form citral
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The invention discloses a preparation method for cis-form citral. The preparation method comprises the steps that under the existence of catalyst alkali, isoprene and N-alkyl-N-trisilicon substrate amine are subjected to hydroamination reaction, and cis-form N-alkyl-N-trisilicon (3,7-dimethyl-2,6-cork alkenyl)-1-amine is obtained; (2) the cis-form N-alkyl-N-trisilicon (3,7-dimethyl-2,6-cork alkenyl)-1-amine is subjected to hydrolysis, and cis-form N-alkyl (3,7-dimethyl-2,6-cork alkenyl)-1-amine is obtained; (3) under the existence of a catalyst, a molecule of hydrogen is dehydrogenized from the cis-form N-alkyl (3,7-dimethyl-2,6-cork alkenyl)-1-amine, and N-alkyl(3,7-dimethyl-2,6-diene-octyl)-1-imine is obtained; (4) the N-alkyl (3,7-dimethyl-2,6-diene-octyl)-1-imine is subjected to acidichydrolysis, and cis-form citral and corresponding ammonium salt are obtained. The preparation method has the advantages that raw materials can be easily obtained, the operation is convenient, requirements for production equipment are lower, and a rectification method which consumes time and energy is not needed.
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- A Highly Selective Na2WO4-Catalyzed Oxidation of Terpenic Alcohols by Hydrogen Peroxide
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Sodium tungstate was found to be an active and highly selective catalyst to oxidation of various primary or secondary origin renewable alcohols by hydrogen peroxide as green oxidant. Borneol, nerol, geraniol and β-citronellol were efficiently and selectively converted to respective carbonyl derivatives by hydrogen peroxide. ATR/FT-IR measurements confirmed that Na2W(O2)4 was the specie active catalytically. The role of the main reaction variables, including temperature, reactants and catalyst concentration, solvent, and nature of substrate were also assessed. In addition to use a green oxidant, this simple and environmentally friendly catalyst system did not require additive to control pH, molecular sieves or phase transfer catalyst. Graphical Abstract: [Figure not available: see fulltext.].
- Viana, Luna Andrade Silva,da Silva, Giovanna Rodrigues Nobile,da Silva, Márcio Jose
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p. 374 - 382
(2017/12/04)
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- 2-Iodoxybenzoic Acid Tosylates: the Alternative to Dess–Martin Periodinane Oxidizing Reagents
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Two powerful hypervalent iodine(V) oxidants, DMP-OTs (1-tosyloxy-1,1-diacetoxy-1H-1λ5-benzo[d][1,2]iodoxol-3-one) and IBX-OTs (1-tosyloxy-1-oxo-1H-1λ5-benzo[d][1,2]iodoxol-3-one) show high reactivity in the oxidation of structurally complex primary and secondary alcohols, which are highly functionalized polyketide or terpene fragments or steroids. The yields of the corresponding carbonyl compounds are even higher for the protocol that uses pyridine as additive. The oxidations proceed very rapidly at room temperature leaving the protective groups and π-systems intact and affording the corresponding carbonyl compounds in good to excellent yields. Moreover, IBX-OTs is an efficient reagent for the oxidative dehydrogenation of steroidal alcohols to the corresponding enones. (Figure presented.).
- Yusubov, Mekhman S.,Postnikov, Pavel S.,Yusubova, Roza Ya.,Yoshimura, Akira,Jürjens, Gerrit,Kirschning, Andreas,Zhdankin, Viktor V.
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p. 3207 - 3216
(2017/09/11)
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- Selective Oxidation of Activated Alcohols by Supported Gold Nanoparticles under an Atmospheric Pressure of O2: Batch and Continuous-Flow Studies
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In the hunt for a simple, mild, and scalable protocol for gold nanoparticle-catalyzed oxidation of benzylic and allylic alcohols under O2, we have used commercially available gold nanoparticles supported on alumina to selectively oxidize a large range of activated alcohols to the corresponding carbonyl compounds in good yields (68–99 %) and with excellent selectivity (ca. 100 %). The true heterogeneous nature of the catalysis by gold was demonstrated, allowing us to further adapt this protocol to continuous-flow reactors by using the tube-in-tube technology, in which higher yields were obtained thanks to an improved oxygenation of the reaction medium.
- Giorgi, Pascal D.,Elizarov, Nelli,Antoniotti, Sylvain
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p. 1830 - 1836
(2017/05/29)
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- Method of manufacturing calbonyl compd.
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PROBLEM TO BE SOLVED: To provide a method of manufacturing a carbonyl compound by smoothly performing a dehydrogenation reaction while preventing side reactions.SOLUTION: A method of manufacturing a carbonyl compound includes a process of converting alcohol to aldehyde or ketone by irradiating visible light to a reaction system containing a primary alcohol or a secondary alcohol, SrTiOcarrying a Ru atom and doped with Rh atom, and water.
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Paragraph 0051; 0053
(2018/06/30)
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- Method for preparing Z-isomer by E-isomer of alpha, beta-nonsaturated carbonyl compound
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The invention provides a method for preparing a Z-isomer by an E-isomer of an alpha, beta-nonsaturated carbonyl compound. The method uses nitrogen-containing chiral binaphthol phosphoramidite to prepare a catalyst, under mild reaction condition, the E-isomer of the alpha, beta-nonsaturated carbonyl compound is efficiently conversed to the Z-isomer. The method is especially suitable for preparing neral through isomerization of partial geranial in a citral split residual material, the citral with mol ratio of the obtained geranial to neral being 1:1 can be reused for splitting the neral, raw material utilization rate is increased, and the cost is reduced.
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Paragraph 0058; 0059
(2017/04/29)
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- Bismuth-substituted "sandwich" type polyoxometalate catalyst for activation of peroxide: Umpolung of the peroxo intermediate and change of chemoselectivity
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The epoxidation of alkenes with peroxides by WVI, MoVI, VV, and TiIV compounds is well established, and it is well accepted that the active intermediate peroxo species are electrophilic toward nucleophilic substrates. Polyoxotungstates, for example, those of the "sandwich" structure, [WZn(TM-L)2(ZnW9O34)2]q- in which TM = transition metal and L = H2O, have in the past been found to be excellent epoxidation catalysts. It has now been found that substituting the Lewis basic BiIII into the terminal position of the "sandwich" polyoxometalate structure to yield [Zn2BiIII2(ZnW9O34)2]14- leads to an apparent umpolung of the peroxo species and formation of a nucleophilic peroxo intermediate. There are two lines of evidence that support the formation of a reactive nucleophilic peroxo intermediate: (1) More electrophilic sulfoxides are more reactive than more nucleophilic sulfides, and (2) nonfunctionalized aliphatic alkenes and dienes showed ene type reactivity rather than epoxidation pointing toward "dark" formation of singlet oxygen from the nucleophilic intermediate peroxo species. Allylic alcohols reacted much faster than alkenes but showed chemoselectivity toward C-H bond activation of the alcohol and formation of aldehydes or ketones rather than epoxidation. This explained via alkoxide formation at the BiIII center followed by oxidative β-elimination.
- Amanchi, Srinivasa Rao,Khenkin, Alexander M.,Diskin-Posner, Yael,Neumann, Ronny
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p. 3336 - 3341
(2015/06/16)
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- Enzyme-inspired functional surfactant for aerobic oxidation of activated alcohols to aldehydes in water
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We describe an enzyme-inspired catalytic system based on a rationally designed multifunctional amphiphile. The resulting micelles feature metal-binding sites and stable free radical moieties as well as fluorous pockets that attract and preconcentrate molecular oxygen. In the presence of copper ions, the micelles effect chemoselective aerobic alcohol oxidation under ambient conditions in water, a transformation that is challenging to achieve nonenzymatically.
- Chen, Ba-Tian,Bukhryakov, Konstantin V.,Sougrat, Rachid,Rodionov, Valentin O.
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p. 1313 - 1317
(2015/02/19)
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- Synthesis and fungicidal activities of (Z/E)-3,7-dimethyl-2,6-octadienamide and its 6,7-epoxy analogues
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In order to find new lead compounds with high fungicidal activity, (Z/E)-3,7-dimethyl- 2,6-octadienoic acids were synthesized via selective two-step oxidation using the commercially available geraniol/nerol as raw materials. Twenty-eight different (Z/E)-3,7-dimethyl-2,6-octadienamide derivatives were prepared by reactions of (Z/E)-carboxylic acid with various aromatic and aliphatic amines, followed by oxidation of peroxyacetic acid to afford their 6,7-epoxy analogues. All of the compounds were characterized by HR-ESI-MS and 1H-NMR spectral data. The preliminary bioassays showed that some of these compounds exhibited good fungicidal activities against Rhizoctonia solani (R. solani) at a concentration of 50 μg/mL. For example, 5C, 5I and 6b had 94.0%, 93.4% and 91.5% inhibition rates against R. solani, respectively. Compound 5f displayed EC50 values of 4.3 and 9.7 μM against Fusahum graminearum and R. Solani, respectively.
- Yang, Mingyan,Dong, Hongbo,Jiang, Jiazhen,Wang, Mingan
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p. 21023 - 21036
(2016/01/25)
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- Characterization of hamster NAD+-dependent 3(17)β-hydroxysteroid dehydrogenase belonging to the aldo-keto reductase 1C subfamily
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The cDNAs for morphine 6-dehydrogenase (AKR1C34) and its homologous aldo-keto reductase (AKR1C35) were cloned from golden hamster liver, and their enzymatic properties and tissue distribution were compared. AKR1C34 and AKR1C35 similarly oxidized various xenobiotic alicyclic alcohols using NAD+, but differed in their substrate specificity for hydroxysteroids and inhibitor sensitivity. While AKR1C34 showed 3α/17β/20α-hydroxysteroid dehydrogenase activities, AKR1C35 efficiently oxidized various 3β- and 17β-hydroxysteroids, including biologically active 3β-hydroxy-5α/β-dihydro-C19/C21-steroids, dehydroepiandrosterone and 17β-estradiol. AKR1C35 also differed from AKR1C34 in its high sensitivity to flavonoids, which inhibited competitively with respect to 17β-estradiol (Ki 0.11-0.69 μM). The mRNA for AKR1C35 was expressed liver-specific in male hamsters and ubiquitously in female hamsters, whereas the expression of the mRNA for AKR1C34 displayed opposite sexual dimorphism. Because AKR1C35 is the first 3(17)β-hydroxysteroid dehydrogenase in the AKR superfamily, we also investigated the molecular determinants for the 3β-hydroxysteroid dehydrogenase activity by replacement of Val54 and Cys310 in AKR1C35 with the corresponding residues in AKR1C34, Ala and Phe, respectively. The mutation of Val54Ala, but not Cys310Phe, significantly impaired this activity, suggesting that Val54 plays a critical role in recognition of the steroidal substrate.
- Endo, Satoshi,Noda, Misato,Ikari, Akira,Tatematsu, Kenjiro,El-Kabbani, Ossama,Hara, Akira,Kitade, Yukio,Matsunaga, Toshiyuki
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p. 425 - 434
(2015/11/27)
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- Practical organic solvent-free Cu(OAc)2/DMAP/TEMPO-catalyzed aldehyde and imine formation from alcohols under air atmosphere
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A highly efficient and practical organic solvent-free Cu(OAc)2/DMAP/TEMPO catalyst system for the selective aerobic oxidation of benzylic and allylic alcohols to aldehydes and phenones under an ambient air atmosphere was reported. A wide range of functional groups such as phenolic hydroxyl, amino, and methylthio are compatible with the catalyst system. The organic solvent-free aerobic oxidative imine synthesis from benzyl alcohol and amines was also achieved via the newly developed Cu(OAc)2/DMAP/TEMPO catalyst. 100 g-scale reactions for aldehyde and imine formation were achieved with over 90% yield using 0.5 mol% catalyst loading in 36 hours, presenting a potential valuable protocol for both economical and environmental considerations. This journal is
- Guan, Mingyu,Wang, Chao,Zhang, Jingyu,Zhao, Yingsheng
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p. 48777 - 48782
(2014/12/10)
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- Ruthenium-catalyzed oxidation of allyl alcohols with intermolecular hydrogen transfer: Synthesis of α,β-unsaturated carbonyl compounds
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Ruthenium-catalyzed oxidation of multisubstituted allyl alcohols in the presence of benzaldehyde gives enals or enones in good yields. Unlike the commonly reported ruthenium-catalyzed isomerization reaction of allyl alcohols to give saturated ketones, an intermolecular rather than intramolecular hydrogen transfer is involved in this transformation. This reaction offers an efficient, mild, and high-yielding method for the preparation of substituted α,β-unsaturated compounds.
- Ren, Kai,Hu, Bei,Zhao, Mengmeng,Tu, Yahui,Xie, Xiaomin,Zhang, Zhaoguo
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p. 2170 - 2177
(2014/04/03)
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- Substrate flexibility and reaction specificity of tropinone reductase-like short-chain dehydrogenases
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Annotations of protein or gene sequences from large scale sequencing projects are based on protein size, characteristic binding motifs, and conserved catalytic amino acids, but biochemical functions are often uncertain. In the large family of short-chain dehydrogenases/reductases (SDRs), functional predictions often fail. Putative tropinone reductases, named tropinone reductase-like (TRL), are SDRs annotated in many genomes of organisms that do not contain tropane alkaloids. SDRs in vitro often accept several substrates complicating functional assignments. Cochlearia officinalis, a Brassicaceae, contains tropane alkaloids, in contrast to the closely related Arabidopsis thaliana. TRLs from Arabidopsis and the tropinone reductase isolated from Cochlearia (CoTR) were investigated for their catalytic capacity. In contrast to CoTR, none of the Arabidopsis TRLs reduced tropinone in vitro. NAD(H) and NADP(H) preferences were relaxed in two TRLs, and protein homology models revealed flexibility of amino acid residues in the active site allowing binding of both cofactors. TRLs reduced various carbonyl compounds, among them terpene ketones. The reduction was stereospecific for most of TRLs investigated, and the corresponding terpene alcohol oxidation was stereoselective. Carbonyl compounds that were identified to serve as substrates were applied for modeling pharmacophores of each TRL. A database of commercially available compounds was screened using the pharmacophores. Compounds identified as potential substrates were confirmed by turnover in vitro. Thus pharmacophores may contribute to better predictability of biochemical functions of SDR enzymes.
- Reinhardt, Nicole,Fischer, Juliane,Coppi, Ralph,Blum, Elke,Brandt, Wolfgang,Draeger, Birgit
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- Redox-selective generation of aldehydes and H2 from alcohols under visible light
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Photosynthetic dehydrogenation: Potential usefulness of visible-light-induced dehydrogenation of alcohols in organic synthesis was demonstrated, in which aldehydes and H2 were afforded by using Ru/SrTiO3:Rh and water (see scheme). Water was essential for the reaction. High efficiency (TON: up to 15 400 based on Rh; H2 and aldehyde evenly generated) and high selectivity were achieved. Copyright
- Liu, Zijun,Caner, Joaquim,Kudo, Akihiko,Naka, Hiroshi,Saito, Susumu
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supporting information
p. 9452 - 9456
(2013/07/26)
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- Allylic substitution for construction of a chiral quaternary carbon possessing an aryl group
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Phenylcopper reagents derived from 2:1 PhMgBr/Cu(acac)2 and 3:1:1 PhMgBr/Cu(acac)2/ZnI2 were found to be highly reactive and regioselective in the allylic substitution of γ,γ- disubstituted secondary allylic picolinates designed for construction of a quaternary carbon, whereas the previous 2:1 ArMgBr/CuBr·Me2S reagent and that with ZnX2 were unsuccessful. The generality of the ArMgBr/Cu(acac)2 reagent was examined with enantiomerically enriched allylic picolinates, which furnished quaternary carbons with high efficiency in >92% regioselectivity and >97% chirality transfer. Two cyclohexanes with a quaternary carbon were synthesized by using these reagents.
- Feng, Chao,Kobayashi, Yuichi
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p. 3755 - 3766
(2013/06/05)
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- TEMPO-mediated electrooxidation of primary and secondary alcohols in a microfluidic electrolytic cell
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A general procedure for the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated electrooxidation of primary and secondary alcohols modified for application in a microfluidic electrolytic cell is described. The electrocatalytic system utilises a buffered aqueous tert-butanol reaction medium, which operates effectively without the requirement for additional electrolyte, providing a mild protocol for the oxidation of alcohols to aldehydes and ketones at ambient temperature on a laboratory scale. Optimisation of the process is discussed along with the oxidation of 15 representative alcohols. TEMPO and no salt in sight: A general procedure for the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated electrooxidation of primary and secondary alcohols modified for application in a microfluidic electrolytic cell is described. The reaction is performed at ambient temperature in buffered aqueous tBuOH without additional electrolyte. Copyright
- Hill-Cousins, Joseph T.,Kuleshova, Jekaterina,Green, Robert A.,Birkin, Peter R.,Pletcher, Derek,Underwood, Toby J.,Leach, Stuart G.,Brown, Richard C. D.
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experimental part
p. 326 - 331
(2012/05/07)
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- Catalytic enantioselective 1,2-diboration of 1,3-dienes: Versatile reagents for stereoselective allylation
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More with boron: The development of catalytic enantioselective 1,2-diboration of 1,3-dienes enables a new strategy for enantioselective carbonyl allylation reactions (see scheme). These reactions occur with outstanding levels of stereoselection and can be applied to both monosubstituted and 1,1-disubstituted dienes. The carbonyl allylation reactions provide enantiomerically enriched functionalized homoallylic alcohol products. Copyright
- Kliman, Laura T.,Mlynarski, Scott N.,Ferris, Grace E.,Morken, James P.
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supporting information; experimental part
p. 521 - 524
(2012/03/11)
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- Oxidation of alcohols to aldehydes and ketones using TBHP as an oxidant over LaMO3 (M = Cr, Mn, Co, Ni, Fe) perovskites
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Oxidation of a wide variety of structurally and electronically diverse primary and secondary alcohols to aldehydes and ketones was carried out using a novel catalytic system of LaCrO3 and tert-butyl hydroperoxide (TBHP) under solvent-free conditions. The methodology afforded the desired carbonyl compounds in good to excellent yields, and the catalyst can be reused several times with no significant loss in activity. Copyright Taylor & Francis Group, LLC.
- Singh, Savita J.,Jayaram, Radha V.
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experimental part
p. 299 - 308
(2011/11/13)
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- A highly selective Pd(OAc)2/pyridine/K2CO3 system for oxidation of terpenic alcohols by dioxygen
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Molecular sieves, complex organic bases and radical oxidants are commonly used in alcohols oxidation reactions. In this work, we have evaluated the beneficial effects of addition of K2CO3 to Pd(II)-catalyzed oxidation alcohols, which resulted in a remarkable increase in the oxidation reaction rates without selectivity losses. Herein, in a metallic reoxidant-free system, terpenic alcohols (β-citronellol, nerol and geraniol) were selectively converted into respective aldehydes from Pd(II)-catalyzed oxidation reactions in presence of dioxygen. High conversions and selectivities (greater than 90%) were achieved in the presence of the Pd(OAc)2/K2CO3 catalyst and pyridine excess. The exogenous role of others auxiliary anionic and nitrogen compounds was appraised. Graphical Abstract: Reaction conditions: β-citronellol (2.75 mmol); Pd(OAc)2 (0.05 mmol); pyridine (5.0 mmol); K 2CO3 (2.5 mmol); toluene (10 mL); MS3A (0.5 g); O2 (0.10 MPa); 60 °C.[Figure not available: see fulltext.]
- Carari, Danieli M.,Da Silva, Marcio J.
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experimental part
p. 251 - 258
(2012/04/10)
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- A remarkably simple α-oximation of aldehydes via organo-SOMO catalysis
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A novel α-oximation reaction of unactivated aldehydes has been achieved in excellent yields by reaction with NaNO2-FeCl3 couple and in the presence of pyrrolidine as organocatalyst.
- Gentili, Patrizia,Pedetti, Silvia
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supporting information; experimental part
p. 5358 - 5360
(2012/06/30)
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- Gold nanoparticles supported on magnesium oxide as catalysts for the aerobic oxidation of alcohols under alkali-free conditions
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Gold nanoparticles supported on magnesium oxide were shown to be efficient heterogeneous catalysts for the liquid-phase oxidation of a wide range of alcohols using molecular oxygen as a sole oxidant in the absence of co-catalysts or additives. The Au/MgO material was prepared through the deposition- precipitation method and characterized by XRD, XPS, XAS, HRTEM, UV-Vis spectroscopy, and N2 adsorption techniques. The formation of gold nanoparticles on the MgO surface under temperature programmed reduction was monitored by in situ UV-Vis-Mass spectroscopy. Various carbonylic monoterpenoids important for fragrance and pharmaceutical industries were obtained in good to excellent yields starting from biomass-based monoterpenic alcohols, such as isoborneol, perillyl alcohol, and carveol. The Au/MgO catalyst also performs a selective one-pot oxidative esterification of benzyl alcohol in alkali-free methanol solutions in the absence of any additive to give methyl benzoate in a virtually quantitative yield.
- Costa, Vinicius V.,Estrada, Miguel,Demidova, Yulia,Prosvirin, Igor,Kriventsov, Vladimir,Cotta, Rafaela F.,Fuentes, Sergio,Simakov, Andrey,Gusevskaya, Elena V.
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experimental part
p. 148 - 156
(2012/10/07)
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- Efficient one-to-one coupling of easily available 1,3-dienes with carbon dioxide
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An efficient one-to-one coupling reaction of atmospheric pressure carbon dioxide with 1,3-dienes is realized for the first time through PSiP-pincer type palladium-catalyzed hydrocarboxylation. The reaction is applicable to various 1,3-dienes including easily available chemical feedstock such as 1,3-butadiene and isoprene. This protocol affords a highly useful method for the synthesis of β,γ-unsaturated carboxylic acid derivatives from CO2.
- Takaya, Jun,Sasano, Kota,Iwasawa, Nobuharu
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supporting information; experimental part
p. 1698 - 1701
(2011/05/04)
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- Aerobic oxidation of monoterpenic alcohols catalyzed by ruthenium hydroxide supported on silica-coated magnetic nanoparticles
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Ruthenium hydroxide supported on silica-coated magnetic nanoparticles was shown to be an efficient heterogeneous catalyst for the liquid-phase oxidation of a wide range of alcohols using molecular oxygen as a sole oxidant in the absence of co-catalysts or additives. The material was prepared through the loading of the amino modified support with ruthenium(III) ions from an aqueous solution of ruthenium(III) chloride followed by treatment with sodium hydroxide to form ruthenium hydroxide species. Characterizations suggest that ruthenium hydroxide is highly dispersed on the support surface, with no ruthenium containing crystalline phases being detected. Various carbonylic monoterpenoids important for fragrance and pharmaceutical industries can be obtained in good to excellent yields starting from biomass-based monoterpenic alcohols, such as isoborneol, perillyl alcohol, carveol, and citronellol. The catalyst undergoes no metal leaching and can be easily recovered by the application of an external magnet and re-used.
- Costa, Vinicius V.,Jacinto, Marcos J.,Rossi, Liane M.,Landers, Richard,Gusevskaya, Elena V.
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experimental part
p. 209 - 214
(2011/09/19)
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