- Linear long-chain α-olefins from hydrodeoxygenation of methyl palmitate over copper phyllosilicate catalysts
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Copper phyllosilicate (CuPS) was used as a bifunctional catalyst for hydrodeoxygenation of methyl palmitate (MP) to produce long-chain α-olefins without the loss of carbon backbone. The CuPS catalysts were prepared by ammonia evaporation-hydrothermal method. The crystal structure, surface area, reducibility, Cu dispersion, Cu particle size and acidity of the catalysts were examined by XRD, BET, H2-TPR, TEM, NH3-TPD and Py-IR. The existence of Cu2+ species (octahedral (Oh)/square planar (Sq)), Cu+ and Cu0 upon calcination/reduction was investigated by in situ TR-XANES. The Cu dispersion was related to the Cu+ fraction in CuPS, while Br?nsted acid sites (BAS) depends on Cu0 particles. The MP conversion to 1-hexadecene proceeds via hydrogenation-dehydration promoted by the synergy of Cu0 surface and Br?nsted acid sites at the interface. The α-olefin selectivity depends on a balance between Cu+ and Cu loading. The 20CuPS possessing 10% Cu+ fraction, provides a high conversion of 72% with 45% α-olefin selectivity.
- Choojun, Kittisak,Huang, Ai-Lin,Lin, Yu-Chuan,Poo-arporn, Yingyot,Prasanseang, Warot,Sooknoi, Tawan
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- Discovery of Anti-TNBC Agents Targeting PTP1B: Total Synthesis, Structure-Activity Relationship, in Vitro and in Vivo Investigations of Jamunones
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Twenty-three natural jamunone analogues along with a series of jamunone-based derivatives were synthesized and evaluated for their inhibitory effects against breast cancer (BC) MDA-MB-231 and MCF-7 cells. The preliminary structure-activity relationship revealed that the length of aliphatic side chain and free phenolic hydroxyl group at the scaffold played a vital role in anti-BC activities and the methyl group on chromanone affected the selectivity of molecules against MDA-MB-231 and MCF-7 cells. Among them, jamunone M (JM) was screened as the most effective anti-triple-negative breast cancer (anti-TNBC) candidate with a high selectivity against BC cells over normal human cells. Mechanistic investigations indicated that JM could induce mitochondria-mediated apoptosis and cause G0/G1 phase arrest in BC cells. Furthermore, JM significantly restrained tumor growth in MDA-MB-231 xenograft mice without apparent toxicity. Interestingly, JM could downregulate phosphatidylinositide 3-kinase (PI3K)/Akt pathway by suppressing protein-tyrosine phosphatase 1B (PTP1B) expression. These findings revealed the potential of JM as an appealing therapeutic drug candidate for TNBC.
- Hu, Caijuan,Li, Guoxun,Mu, Yu,Wu, Wenxi,Cao, Bixuan,Wang, Zixuan,Yu, Hainan,Guan, Peipei,Han, Li,Li, Liya,Huang, Xueshi
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supporting information
p. 6008 - 6020
(2021/05/06)
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- Enantiomeric synthesis of natural alkylglycerols and their antibacterial and antibiofilm activities
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Alkylglycerols (AKGs) are bioactive natural compounds that vary by alkyl chain length and degree of unsaturation, and their absolute configuration is 2S. Three AKGs (5l–5n) were synthesised in enantiomerically pure form, and were characterised for the first time together with 12 other known and naturally occurring AKGs (5a–5k, 5o). Their structures were established using 1H and 13C APT NMR with 2D-NMR, ESI-MS or HRESI-MS and optical rotation data, and they were tested for their antibacterial and antibiofilm activities. AKGs 5a–5m and 5o showed activity against five clinical isolates and P. aeruginosa ATCC 15442, with MIC values in the range of 15–125 μg/mL. In addition, at half of the MIC, most of the AKGs reduced S. aureus biofilm formation in the range of 23%–99% and P. aeruginosa ATCC 15442 biofilm formation in the range of 14%–64%. The antibiofilm activity of the AKGs assessed in this work had not previously been studied.
- Fernández Montoya, Deicy J.,Contreras Jordan, Luis A.,Moreno-Murillo, Bárbara,Silva-Gómez, Edelberto,Mayorga-Wandurraga, Humberto
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supporting information
p. 2544 - 2550
(2019/11/13)
-
- Synthesis and surface-active properties of novel cleavable gemini surfactants
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A novel series of quaternary ammonium gemini compounds having a butynylene spacer and different hydrocarbon chain lengths (CGBu8-16) were prepared. Carbonate group inserted between the hydrocarbon chains and the polar heads make these compounds hydrolyzable. The degradation under hydrolysis of these novel series will lead to the generation of fatty alcohols and readily degradable compounds. The reagents used are biodegradable, renewable, or reusable. The surface activities and foamability in aqueous solution of the cleavable gemini compounds containing n-octyl, n-decyl, and n-dodecyl chains meet the criteria for being good surfactants and showed stable foams even at low concentrations.
- Gilbert, Elangeni Ana,Guastavino, Javier Fernando,Murguía, Marcelo César
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- Ni-Based heterogeneous catalysts for the transformation of fatty acids into higher yields of O-free hydrocarbons
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A series of novel catalytic materials were synthesized by changing the chemical compounds in the impregnation solutions. A rigid, aromatic and bidentate molecule 1,10-phenanthroline (PhN) was used as a ligand to bind Ni2+species prior to impregnation into a mesoporous KIT-5 support. Thein situsynthesized coordination compounds were impregnated into KIT-5 and the resulting materials exhibited better dispersion of metal species, being the best at a molar ratio Ni?:?PhN = 1?:?1. The materials were tested in the hydrodeoxygenation (HDO) of palmitic acid. We found that highly active and stable catalysts were obtained when using PhN as a chelating agent in the impregnation solution. The selectivity of these materials is remarkable since only O-free molecules were detected in the HDO products. Therefore, Ni-PhN complexes in combination with mesoporous SiO2can be further exploited for the catalytic transformation of biomass feedstocks.
- Aburto, Jorge,Gómez-Pérez, María Teresa,Gómora-Herrera, Diana,Valencia, Diego,Zenteno, Citlalli
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p. 3470 - 3480
(2020/06/25)
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- Ultra-low loading of Ni in catalysts supported on mesoporous SiO2 and their performance in hydrodeoxygenation of palmitic acid
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We synthesized a series of new Ni catalysts supported on mesoporous silica KIT-5. The metal loading on this support was varied (0.9-7.0 wt% NiO). The catalysts were characterized by N2 physisorption, powder XRD, XRF spectrometry, UV-vis DRS, H2-TPR, HRTEM and FT-IR with CO. The mesoporous structure is maintained in all the catalytic materials. The increase in the Ni loading resulted in the formation of crystalline phases at the KIT-5 surface. The catalysts were tested in hydrodeoxygenation (HDO) of palmitic acid. The catalytic activity increased with the metal loading, reaching a maximum by using the catalyst with 1.8 wt% NiO. On the other hand, calculation of kinetic parameters indicated the effective utilization of catalytically active Ni particles in the HDO process. Formation of oxygen-free products was higher for the catalyst with higher metal loading in this series. These catalytic materials were compared with a series of Ni catalysts supported on carbon, finding that the Ni/KIT-5 catalysts were much more active in the HDO reaction. These new catalysts supported on the mesoporous silica KIT-5 exhibited high activity with low metal loadings. This feature makes them attractive for their application in the HDO of fatty acids.
- Valencia, Diego,Zenteno, Citlalli,Morales-Gil, Perla,Díaz-García, Leonardo,Gómora-Herrera, Diana,Palacios-González, Eduardo,Aburto, Jorge
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p. 2435 - 2441
(2020/02/20)
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- Surfactant-Free Synthesis of Ultrafine Pt Nanoparticles on MoS2Nanosheets as Bifunctional Catalysts for the Hydrodeoxygenation of Bio-Oil
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Hydrodeoxygenation (HDO) of bio-oil is a crucial step for improving the bio-fuel quality, but developing highly dispersed Pt-based catalysts with high selectivity for target alkanes remains a great challenge. This study presents a fast surfactant-free method to prepare the MoS2-supported Pt catalyst for HDO. Ultrafine Pt nanoparticles with sizes of 5 nm can be readily grown on chemically exfoliated MoS2 nanosheets (NSs) via the direct microwave-assisted thermal reduction. The obtained Pt NPs/MoS2 composites show excellent catalytic performance in the conversion of palmitic acid, and the best selectivity (also the yield) of hexadecane and pentadecane is 80.56 and 19.43%, respectively.
- Fan, Xiaobin,Li, Yang,Liang, Junmei,Lin, Qianqian,Peng, Wenchao,Xu, Danyun,Zhang, Fengbao,Zhang, Qicheng
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p. 14710 - 14716
(2020/12/23)
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- Novel clamp metal complex and application thereof
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The invention discloses a method for preparing a novel clamp-shaped complex and application of the novel clamp-shaped complex in the reaction of catalytic hydrogenation of carboxylic acid ester compounds to produce corresponding alcohols and reaction of carbon dioxide catalytic hydrogenation to form formamide compounds. Carboxylic acid esters and hydrogen as raw materials or carbon dioxide, hydrogen and amine compounds as raw materials are reacted in an organic solvent condition or a solvent-free condition in the presence of a transition metal complex as a catalyst to respectively form the corresponding alcohol compounds and/or corresponding formamide compounds. The method has the advantages of being high in reaction efficiency, good in selectivity, mild in conditions, economical, environmentally-friendly, and simple in operation, and has good promotion and application prospects.
- -
-
Paragraph 0410-0412; 0438-0441
(2019/04/26)
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- Diaminodiphosphine tetradentate ligand and ruthenium complex thereof, and preparation methods and applications of ligand and complex
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The invention discloses a diaminodiphosphine tetradentate ligand and a ruthenium complex thereof, and preparation methods and applications of the ligand and the complex, and provides a ruthenium complex represented by a formula I, wherein L is a diaminodiphosphine tetradentate ligand represented by a formula II, and X and Y are respectively and independently chlorine ion, bromine ion, iodine ion,hydrogen negative ion or BH4. According to the present invention, the ruthenium complex exhibits excellent catalytic activity in the catalytic hydrogenation reactions of ester compounds, has high yield and high chemical selectivity, is compatible with conjugated and non-conjugated carbon-carbon double bond, carbon-carbon triple bond, epoxy, halogen, carbonyl and other functional groups, and hasgreat application prospects.
- -
-
Paragraph 0301-0303; 0305
(2019/11/04)
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- Selective Hydroboration of Carboxylic Acids with a Homogeneous Manganese Catalyst
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Catalytic reduction of carboxylic acid to the corresponding alcohol is a challenging task of great importance for the production of a variety of value-added chemicals. Herein, a manganese-catalyzed chemoselective hydroboration of carboxylic acids has been developed with a high turnover number (>99?000) and turnover frequency (>2000 h-1) at 25 °C. This method displayed tolerance of electronically and sterically differentiated substrates with high chemoselectivity. Importantly, aliphatic long-chain fatty acids, including biomass-derived compounds, can efficiently be reduced. Mechanistic studies revealed that the reaction occurs through the formation of active manganese-hydride species via an insertion and bond metathesis type mechanism.
- Barman, Milan K.,Das, Kuhali,Maji, Biplab
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p. 1570 - 1579
(2019/01/30)
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- Paving the way towards green catalytic materials for green fuels: Impact of chemical species on Mo-based catalysts for hydrodeoxygenation
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A series of Mo-based catalysts were synthesized by tuning the sulfidation temperature to produce mixtures of MoO3 and MoS2 as active phases for the hydrodeoxygenation (HDO) of palmitic acid. Differences in the oxidation states of Mo, and the chemical species present in the catalytic materials were determined by spectroscopic techniques. Palmitic acid was used as a fatty-acid model compound to test the performance of these catalysts. The catalytic performance was related to different chemical species formed within the materials. Sulfidation of these otherwise inactive catalysts significantly increased their performance. The catalytic activity remains optimal between the sulfidation temperatures of 100 °C and 200 °C, whereas the most active catalyst was obtained at 200 °C. The catalytic performance decreased significantly at 400 °C due to a higher proportion of sulfides formed in the materials. Furthermore, the relative proportion of MoO3 to MoS2 is essential to form highly active materials to produce O-free hydrocarbons from biomass feedstock. The transition from MoS2 to MoO3 reveals the importance of Mo-S and Mo-O catalytically active species needed for the HDO process and hence for biomass transformation. We conclude that transitioning from MoS2 to MoO3 catalysts is a step in the right direction to produce green fuels.
- Valencia, Diego,Díaz-García, Leonardo,Ramírez-Verduzco, Luis Felipe,Qamar, Amir,Moewes, Alexander,Aburto, Jorge
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p. 18292 - 18301
(2019/07/03)
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- Hydrodeoxygenation of Palmitic and Stearic Acids on Phosphide Catalysts Obtained In Situ in Reaction Medium
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Abstract: Unsupported phosphide catalysts of composition Ni2P and CoP are prepared in situ in the reaction medium from oil-soluble precursors in the course of hydrodeoxygenation of palmitic and stearic acids. The obtained catalysts are characterized by X-ray powder diffraction and X-ray photoelectron spectroscopy; they show high activity in the hydrodeoxygenation of model substrates. After 6 h of the hydrodeoxygenation reactions, the conversion of palmitic acid reaches 93 and 92% and the conversion of stearic acid is as high as 94 and 91% in the presence of nickel phosphide and cobalt phosphide, respectively. It is shown that the catalyst formed in situ can be isolated and recycled.
- Golubeva,Maksimov
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p. 1326 - 1330
(2019/12/30)
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- Mechanistic study of the selective hydrogenation of carboxylic acid derivatives over supported rhenium catalysts
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The structure and performance of TiO2-supported Re (Re/TiO2) catalysts for selective hydrogenation of carboxylic acid derivatives have been investigated. Re/TiO2 promotes selective hydrogenation reactions of carboxylic acids and esters that form the corresponding alcohols, and of amides that generate the corresponding amines. These processes are not accompanied by reduction of aromatic moieties. A Re loading amount of 5 wt% and a catalyst pretreatment with H2 at 500 °C were identified as being optimal to obtain the highest catalytic activity for the hydrogenation processes. The results of studies using various characterization methods, including X-ray diffraction (XRD), X-ray absorption fine structure (XAFS), X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy (STEM), indicate that the Re species responsible for the catalytic hydrogenation processes have sub-nanometer to a few nanometer sizes and average oxidation states higher than 0 and below +4. The presence of either a carboxylic acid and/or its corresponding alcohol is critical for preventing the Re/TiO2 catalyst from promoting production of dearomatized byproducts. Although Re/TiO2 is intrinsically capable of hydrogenating aromatic rings, carboxylic acids, alcohols, amides, and amines strongly adsorb on the Re species, which leads to suppression of this process. Moreover, the developed catalytic system was applied to selective hydrogenation of triglycerides that form the corresponding alcohols.
- Toyao, Takashi,Ting, Kah Wei,Siddiki, S. M. A. Hakim,Touchy, Abeda S.,Onodera, Wataru,Maeno, Zen,Ariga-Miwa, Hiroko,Kanda, Yasuharu,Asakura, Kiyotaka,Shimizu, Ken-ichi
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p. 5413 - 5424
(2019/10/29)
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- Elongation of the Hydrophobic Chain as a Molecular Switch: Discovery of Capsaicin Derivatives and Endogenous Lipids as Potent Transient Receptor Potential Vanilloid Channel 2 Antagonists
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The transient receptor potential vanilloid type-2 (TRPV2) protein is a nonselective Ca2+ permeable channel member of the TRPV subfamily, still considered an orphan TRP channel due to the scarcity of available selective and potent pharmacological tools and endogenous modulators. Here we describe the discovery of novel synthetic long-chain capsaicin derivatives as potent TRPV2 antagonists in comparison to the totally inactive capsaicin, the role of their hydrophobic chain, and how the structure-activity relationships of such derivatives led, through a ligand-based approach, to the identification of endogenous long-chain fatty acid ethanolamides or primary amides acting as TRPV2 antagonists. Both synthetic and endogenous antagonists exhibited differential inhibition against known TRPV2 agonists characterized by distinct kinetic profiles. These findings represent the first example of both synthetic and naturally occurring TRPV2 modulators with efficacy in the submicromolar/low-micromolar range, which will be useful for clarifying the physiopathological roles of this receptor, its regulation, and its targeting in pathological conditions.
- Schiano Moriello, Aniello,López Chinarro, Silvia,Novo Fernández, Olalla,Eras, Jordi,Amodeo, Pietro,Canela-Garayoa, Ramon,Vitale, Rosa Maria,Di Marzo, Vincenzo,De Petrocellis, Luciano
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p. 8255 - 8281
(2018/09/25)
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- Selective Hydrogenation of Carboxylic Acids to Alcohols or Alkanes Employing a Heterogeneous Catalyst
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The chemoselective hydrogenation of carboxylic acids to either alcohols or alkanes is reported, employing a heterogeneous bimetallic catalyst consisting of rhenium and palladium supported on graphite. α-Chiral carboxylic acids were hydrogenated without loss of optical purity. The catalyst displays a reverse order of reactivity upon hydrogenation of different carboxylic functions with esters being less reactive than amides and carboxylic acids. This allows for chemoselective hydrogenation of an acid in the presence of an ester or an amide function.
- Ullrich, Johannes,Breit, Bernhard
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p. 785 - 789
(2018/02/14)
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- Mechanism of supported Ru3Sn7 nanocluster-catalyzed selective hydrogenation of coconut oil to fatty alcohols
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As a promising hydrotreating catalyst, it was previously reported that Ru?OSn (Ru electronically interacts with Sn oxides) on RuSn/SiO2 was the active site for fatty acid hydrogenation, but here in this work we found that Ru3Sn7 nanoclusters on RuSn/SiO2 were responsible for the selective hydrogenation of diverse fatty acids and coconut oil to fatty alcohols. The XPS results indicated no interaction between Snδ+ and Ru0, suggesting that SnOx may exist as isolated species. In contrast, the binding energy shifts of Ru0 and Sn0 in the XPS spectra demonstrated a strong interaction, as a result of the formation of Ru3Sn7 alloy nanoclusters. It was demonstrated that the highest yield of fatty alcohol was obtained with a Sn/Ru ratio of 7/3 (hydrogenation rate: 2.45 g g-1 h-1), and the careful selection of the Sn/Ru ratio and reduction temperatures greatly suppressed the formation of Sn and SnO2 phases. The ratio of the stearyl alcohol formation rate to its consumption rate was 40.8 with Ru3Sn7/SiO2 under the selected conditions. In catalysts with a Sn/Ru ratio higher than 7/3, the presence of additional SnO2 catalyzes the formation of undesired esters at a rate of 0.31 g g-1 h-1. Excess SnO2 would be reduced to Sn at temperatures higher than 600 °C, while Sn can catalyze ester by-product formation at a rate of 0.88 g g-1 h-1. The DFT calculations showed that CH3COOH adsorbs on the Ru3Sn7 (111) surface via Sn-O interactions at the two top sites of adjacent surface Sn atoms, and such adsorption was mainly due to the electrostatic interactions between the molecule and the positively charged surface Sn atoms. The charge density difference (CDD) plots of co-adsorbed CH3CO? and OH? intermediates indicated the bonding relationships between Sn-O and Ru-α-C, suggesting that the surface Sn atoms also took part in the catalytic reaction as an important surface sorption site as well as a Ru3Sn7 structure component, while Ru atoms bonded with α-C and hydrogenated the adsorbed intermediate species with the adsorbed H? to the final alcohol. A further indication that Ru3Sn7 was the active species in the bimetallic Ru-Sn catalyst was given by the much lower energy barrier for hydrogenation of acetic acid in Ru3Sn7 (111) (81.0 kJ mol-1) compared to Ru (0001) (123.5 kJ mol-1).
- Luo, Zhicheng,Bing, Qiming,Kong, Jiechen,Liu, Jing-Yao,Zhao, Chen
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p. 1322 - 1332
(2018/03/13)
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- A colourful azulene-based protecting group for carboxylic acids
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An intensely blue-coloured protecting group for carboxylic acids has been developed. The protecting group is introduced through a Steglich esterification that couples 6-(2-hydroxyethyl)azulene (AzulE) and the carboxylic acid substrate. Deprotection is effected under basic conditions by the addition of the amidine base DBU, whereupon cleavage occurs, accompanied by a colour change. A two-step deprotection methodology comprising activation with oxalyl chloride and deprotection with a very mild base was developed for use with base-sensitive substrates. The AzulE esters were found to be compatible with other commonly employed protecting groups – silyl ethers, MOM acetals – by studying their orthogonal and concomitant deprotections. The stability of the new protecting group towards various synthetic processes – oxidation, reduction, cross-coupling, olefination and treatment with base – provided the basis of a versatility profile. This indicated that AzulE esters are sensitive to strongly oxidising and basic agents while being compatible with reducing conditions and selected other reactions. The convenience of a highly coloured protecting group for tracking material (and avoiding loss of compound) through laboratory processes warrants further investigation of this and/or related species.
- Bevan, Thomas W.,Francis-Taylor, James,Wong, Helena,Northcote, Peter T.,Harvey, Joanne E.
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supporting information
p. 2942 - 2955
(2018/05/16)
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- Samarium(II) dibromide-promoted selective deprotection of a benzoyl protective group
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The selective deprotection of a benzoyl group was very important methodology in the field of organic synthesis. Various methods for debenzoylation were investigated and developed in the past six decades, but more useful and selective strategies are now being strongly desired. In response to this strong demand, we developed the novel and selective deprotection of a benzoyl group by use of samarium(II) dibromide and a proton source. This deprotective reaction proceeded smoothly and the desired compound was obtained in good to excellent yields. In this paper, we will report the details of this deprotective reaction.
- Yokoyama, Yasuo,Oyamada, Shun,Suzuki, Junya,Maruyama, Shou,Sakusabe, Takahiro,Suzuki, Shoko
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supporting information
p. 1025 - 1032
(2018/03/23)
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- Rhenium-Loaded TiO2: A Highly Versatile and Chemoselective Catalyst for the Hydrogenation of Carboxylic Acid Derivatives and the N-Methylation of Amines Using H2 and CO2
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Herein, we report a heterogeneous TiO2-supported Re catalyst (Re/TiO2) that promotes various selective hydrogenation reactions, which includes the hydrogenation of esters to alcohols, the hydrogenation of amides to amines, and the N-methylation of amines, by using H2 and CO2. Initially, Re/TiO2 was evaluated in the context of the selective hydrogenation of 3-phenylpropionic acid methyl ester to afford 3-phenylpropanol (pH2 =5 MPa, =5 MPa, T=180 °C), which revealed a superior performance over other catalysts that we tested in this study. In contrast to other typical heterogeneous catalysts, hydrogenation reactions with Re/TiO2 did not produce dearomatized byproducts. DFT studies suggested that the high selectivity for the formation of alcohols in favor of the hydrogenation of aromatic rings is ascribed to the higher affinity of Re towards the COOCH3 group than to the benzene ring. Moreover, Re/TiO2 showed a wide substrate scope for the hydrogenation reaction (19 examples). Subsequently, this Re/TiO2 catalyst was applied to the hydrogenation of amides, the N-methylation of amines, and the N-alkylation of amines with carboxylic acids or esters.
- Toyao, Takashi,Siddiki,Morita, Yoshitsugu,Kamachi, Takashi,Touchy, Abeda S.,Onodera, Wataru,Kon, Kenichi,Furukawa, Shinya,Ariga, Hiroko,Asakura, Kiyotaka,Yoshizawa, Kazunari,Shimizu, Ken-Ichi
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supporting information
p. 14848 - 14859
(2017/10/27)
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- Selective conversion of coconut oil to fatty alcohols in methanol over a hydrothermally prepared Cu/SiO2 catalyst without extraneous hydrogen
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A novel one-pot approach selects a hydrothermally synthesized Cu/SiO2 catalyst (consisting of Cu2O·SiO2 and Cu0 surface species) to catalyze the reduction of a series of fatty esters, fatty acids, and coconut oil to fatty alcohols at 240 °C in methanol without extraneous hydrogen, attaining around 85% conversion and 100% selectivity.
- Wu, Liubi,Li, Lulu,Li, Bolong,Zhao, Chen
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p. 6152 - 6155
(2017/07/10)
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- TiO2-Supported Re as a General and Chemoselective Heterogeneous Catalyst for Hydrogenation of Carboxylic Acids to Alcohols
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TiO2-supported Re, Re/TiO2, was found to promote selective hydrogenation of carboxylic acids having aromatic and aliphatic moieties to the corresponding alcohols. Re/TiO2showed superior results compared to other transition-metal-loaded TiO2and supported Re catalysts for selective hydrogenation of 3-phenylpropionic acid. 3-phenylpropanol was produced in 97 % yield under mild conditions (5 MPa H2at 140 °C). Contrary to typical heterogeneous catalysts, Re/TiO2does not lead to the formation of dearomatized byproducts. The catalyst is recyclable and shows a wide substrate scope in the synthesis of alcohols (22 examples; up to 97 % isolated yield).
- Toyao, Takashi,Siddiki, S. M. A. Hakim,Touchy, Abeda S.,Onodera, Wataru,Kon, Kenichi,Morita, Yoshitsugu,Kamachi, Takashi,Yoshizawa, Kazunari,Shimizu, Ken-Ichi
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supporting information
p. 1001 - 1006
(2017/02/05)
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- Highly efficient conversion of fatty acids into fatty alcohols with a Zn over Ni catalyst in water
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A new route to convert fatty acids into fatty alcohols under hydrothermal conditions with a Zn reductant over an Ni catalyst is presented. The highest yield of fatty alcohols from fatty acids (81.4%) was achieved at 300 °C for 2 h with a water filling of 40%. The Zn and Ni used in this research were both commercially available powders, and thus this process provides a highly efficient and simple method for reducing fatty acids into fatty alcohols.
- Gao, Xia,Tong, Daming,Zhong, Heng,Jin, Binbin,Jin, Fangming,Zhang, Hua
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p. 27623 - 27626
(2016/04/04)
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- Effect of precursor on the catalytic properties of Ni2P/SiO2 in methyl palmitate hydrodeoxygenation
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The effect of phosphorus precursor on the physicochemical and catalytic properties of silica-supported nickel phosphide catalysts in the hydrodeoxygenation (HDO) of aliphatic model compound methyl palmitate (C15H31COOCH3) has been considered. Nickel aceta
- Shamanaev, Ivan V.,Deliy, Irina V.,Aleksandrov, Pavel V.,Gerasimov, Evgeny Yu.,Pakharukova, Vera P.,Kodenev, Evgeny G.,Ayupov, Artem B.,Andreev, Andrey S.,Lapina, Olga B.,Bukhtiyarova, Galina A.
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p. 30372 - 30383
(2017/02/23)
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- Vinyl Sulfonates: A Click Function for Coupling-and-Decoupling Chemistry and their Applications
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The term coupling-and-decoupling (CAD) chemistry refers to applications in which efficient bond formation and subsequent cleavage between two moieties is required. Within this context, the scope of the vinyl sulfonate (VSO) group as an efficient tool for CAD chemistry is reported. The coupling step relies on the click features of the Michael-type addition of diverse nucleophiles to vinyl sulfonates as a valuable methodology. The feasibility of this strategy has been proved by the high yields obtained in mild conditions with model VSO derivatives. Cleavage of the resulting sulfonate adducts either through nucleophilic substitution with different nucleophiles (for alkyl VSO groups) or through hydrolysis (for both alkyl and aryl VSO) are successful strategies for the decoupling step, the former being the most promising, as the reaction proceeds under milder conditions with thiol nucleophiles. Moreover, the click VSO coupling chemistry proves to be orthogonal with the click CuAAC reaction, which enables the VSO-CAD methodology for the preparation of hetero-bifunctional clickable and cleavable linkers for double click modular strategies. The potential of the VSO-CAD chemistry is demonstrated in two biologically relevant examples: the decoupling of sulfonates with glutathione (GSH) under conditions compatible with those of living systems; and the synthesis of homo- and heterogeneous multivalent glycosylated systems from 1-thio and 1-azido or 1-azidoethyl sugar derivatives and bis-vinyl sulfonates (homo systems) or alkynyl-VSO bifunctional clickable-cleavable linkers (hetero systems). As proof of concept, the cleavable character of these multivalent systems was demonstrated by using one of them as a reversible linker for the non-covalent assembling and chemical decoupling of two model lectins. (Figure presented.).
- Cruz, Carlos M.,Ortega-Mu?oz, Mariano,López-Jaramillo, F. Javier,Hernández-Mateo, Fernando,Blanco, Victor,Santoyo-González, Francisco
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supporting information
p. 3394 - 3413
(2016/11/13)
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- Sulfonic acid-functionalized LUS-1: an efficient catalyst for tetrahydropyranylation/depyranylation of alcohols
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Efficient acidic functionalization of mesoporous silica LUS-1 (Laval University Silica) and its application as a recyclable heterogeneous catalyst for DHP (3,4-dihydro-2H-pyran) protection of alcohols and the subsequent removal of the corresponding protecting group have been reported. This green method offers a number of advantages such as short reaction time, good yields of protection and deprotection, simple work-up procedure, recyclable catalyst, and environmentally friendly conditions.
- Rahimifard, Mahshid,Mohammadi Ziarani, Ghodsi,Badiei, Alireza
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p. 6327 - 6336
(2016/07/06)
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- Hydrodeoxygenation of methyl palmitate over MCM-41 supported nickel phosphide catalysts
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In this paper, bulk and MCM-41-supported Ni2P catalysts were synthesized by the one-step direct reduction of metal phosphate precursors. The role of cations and anions in the synthesis of Ni2P was studied. Catalytic properties for the hydrodeoxygenation (HDO) of methyl palmitate were first investigated in a continuous-flow fixed-bed microreactor. The resulting catalysts were characterized using XRD, TEM, BET, XPS, and carbon monoxide chemisorption. Results indicated that Ni2P can be synthesized at 600 °C from its phosphate precursors with a mole ratio of Ni/P = 2/1. Based on the analytical result of GC-MS, we propose a possible HDO reaction mechanism for the HDO of methyl palmitate on MCM-41-supported nickel phosphide catalysts.
- Guan, Qingxin,Wan, Fanfan,Han, Fei,Liu, Zihe,Li, Wei
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p. 467 - 473
(2015/11/10)
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- Hydrodeoxygenation (HDO) of methyl palmitate over bifunctional Rh/ZrO2 catalyst: Insights into reaction mechanism via kinetic modeling
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Hydrodeoxygenation (HDO) of triglycerides into hydrocarbons is a novel catalytic process for the production of green biofuels. In this work, the HDO reaction mechanism over Rh/ZrO2 catalyst was studied by selecting methyl palmitate as a model compound. HDO of methyl palmitate proceeded initially via the hydrogenolysis into palmitic acid intermediate, followed by sequential hydrogenation-decarbonylation reaction into pentadecane via aldehyde intermediate. Bifunctional mechanism of the Rh/ZrO2 catalyst is advocated for the HDO process, in which both Rh sites and oxygen vacancy sites on ZrO2 synergistically contribute to the catalysis. The interface between Rh nanoparticle and support was proposed to host the most active sites. Based on our earlier work, a surface reaction mechanism was proposed and slightly modified to develop a set of mechanistic kinetic models. The mechanistic model consisting of two distinct types of adsorption sites for oxygenated components and H2, gave a good fitting to the kinetic data over a broad range of reaction conditions and conversion levels.
- Bie, Yuwei,Lehtonen, Juha,Kanervo, Jaana
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p. 183 - 190
(2016/09/13)
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- Catalytic Ester Metathesis Reaction and Its Application to Transfer Hydrogenation of Esters
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We report a Ru-complex-catalyzed ester metathesis reaction where an unsymmetrical ester such as ethyl hexanoate can be transformed to a mixture of starting material, hexyl ethanoate, ethyl acetate, and hexyl hexanoate in equal proportions, as expected from a classical metathesis reaction with 0.2 mol % catalyst. A 20× excess of low boiling alcohol, such as ethanol, allows for the transfer of an acyl moiety to the sacrificial low boiling ethyl acetate product, while significantly increasing the functional group tolerance and substrate scope; yields of alcohols can reach 90%, which represents an attractive alternative to current high H2 pressure hydrogenation protocols for Ru-based ester reduction chemistry. Both reactions have not been reported previously in the field of Ru-catalyzed transformations of the ester functionality.
- Dubey, Abhishek,Khaskin, Eugene
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p. 3998 - 4002
(2016/07/06)
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- Highly efficient tetradentate ruthenium catalyst for ester reduction: Especially for hydrogenation of fatty acid esters
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A new tetradentate ruthenium complex has been developed for hydrogenation of esters. The catalysts structure features a pyridinemethanamino group and three tight chelating five-membered rings. The structure character is believed to be responsible for its high stability and high carbonylation-resistant properties. Thus, this catalyst shows outstanding performance in the catalytic hydrogenation of a variety of esters, especially for fatty acid esters, which may be used in practical applications. New insight on designing hydrogenation catalyst for reducing esters to alcohols has been provided through theoretical calculations.
- Tan, Xuefeng,Wang, Yan,Liu, Yuanhua,Wang, Fangyuan,Shi, Liyang,Lee, Ka-Ho,Lin, Zhenyang,Lv, Hui,Zhang, Xumu
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supporting information
p. 454 - 457
(2015/03/05)
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- A new designed hydrazine group-containing ruthenium complex used for catalytic hydrogenation of esters
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A hydrazine group-containing nitrogen-phosphine ligand and corresponding ruthenium complexes were synthesized. When these complexes were used for hydrogenation of esters, excellent performance was observed (TON up to 17 200). A wide substrate scope was suitable for this catalytic system.
- Tan, Xuefeng,Wang, Qingli,Liu, Yuanhua,Wang, Fangyuan,Lv, Hui,Zhang, Xumu
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p. 12193 - 12196
(2015/07/27)
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- Toward Ideality: The Synthesis of (+)-Kalkitoxin and (+)-Hydroxyphthioceranic Acid by Assembly-Line Synthesis
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The iterative homologation of boronic esters using chiral lithiated benzoate esters and chloromethyllithium has been applied to the highly efficient syntheses of two natural products, (+)-kalkitoxin and (+)-hydroxyphthioceranic acid. The chiral lithiated benzoate esters (>99% ee) were generated from the corresponding stannanes, which themselves were prepared by Hoppe-Beak deprotonation of ethyl 2,4,6-triisopropyl-benzoate with s-BuLi in the presence of (+)- or (-)-sparteine and trapping with Me3SnCl followed by recrystallization. In addition, it was found that purification between several homologations could be avoided, substantially increasing both chemical and manpower efficiency. In the case of (+)-kalkitoxin, six iterative homologations were conducted on commercially available p-MeOC6H4CH2Bpin to build up the core of the molecule before the C-B bond was converted into the desired C-N bond, without purification of intermediates. In the case of (+)-hydroxyphthioceranic acid, 16 iterative homologations were conducted on p-MeOC6H4Bpin with only four intermediate purifications before oxidation of the C-B bond to the desired alcohol. The stereocontrolled and efficient syntheses of these complex molecules highlight the power of iterative chemical synthesis using boronic esters. (Chemical Equation Presented).
- Balieu, Sebastien,Hallett, Gayle E.,Burns, Matthew,Bootwicha, Teerawut,Studley, John,Aggarwal, Varinder K.
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supporting information
p. 4398 - 4403
(2015/04/14)
-
- A Remarkably Simple Class of Imidazolium-Based Lipids and Their Biological Properties
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A series of imidazolium salts bearing two alkyl chains in the backbone of the imidazolium core were synthesized, resembling the structure of lipids. Their antibacterial activity and cytotoxicity were evaluated using Gram-positive and Gram-negative bacteria and eukaryotic cell lines including tumor cells. It is shown that the length of alkyl chains in the backbone is vital for the antibiofilm activities of these lipid-mimicking components. In addition to their biological activity, their surface activity and their membrane interactions are shown by film balance and quartz crystal microbalance (QCM) measurements. The structure-activity relationship indicates that the distinctive chemical structure contributes considerably to the biological activities of this novel class of lipids. Lipids! A series of imidazolium salts bearing two alkyl chains in the backbone were synthesized, resembling the structure of lipids. The biological activity resulting from their surface activity and membrane interaction are shown (see figure), which were determined by the alkyl chain length.
- Wang, Da,Richter, Christian,Rühling, Andreas,Drücker, Patrick,Siegmund, Daniel,Metzler-Nolte, Nils,Glorius, Frank,Galla, Hans-Joachim
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supporting information
p. 15123 - 15126
(2015/11/02)
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- Direct Ruthenium-Catalyzed Hydrogenation of Carboxylic Acids to Alcohols
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The "green" reduction of carboxylic acids to alcohols is a challenging task in organic chemistry. Herein, we describe a general protocol for generation of alcohols by catalytic hydrogenation of carboxylic acids. Key to success is the use of a combination of Ru(acac)3, triphos and Lewis acids. The novel method showed broad substrate tolerance and a variety of aliphatic carboxylic acids including biomass-derived compounds can be smoothly reduced.
- Cui, Xinjiang,Li, Yuehui,Topf, Christoph,Junge, Kathrin,Beller, Matthias
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supporting information
p. 10596 - 10599
(2015/09/02)
-
- Pd/Nb2O5/SiO2 catalyst for the direct hydrodeoxygenation of biomass-related compounds to liquid alkanes under mild conditions
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A simple Pd-loaded Nb2O5/SiO2 catalyst was prepared for the hydrodeoxygenation of biomass-related compounds to alkanes under mild conditions. Niobium oxide dispersed in silica (Nb2O5/SiO2) as the support was prepared by the sol-gel method and characterized by various techniques, including N2 adsorption, XRD, NH3 temperature-programmed desorption (TPD), TEM, and energy-dispersive X-ray spectroscopy (EDAX) atomic mapping. The characterization results showed that the niobium oxide species were amorphous and well dispersed in silica. Compared to commercial Nb2O5, Nb2O5/SiO2 has significantly more active niobium oxide species exposed on the surface. Under mild conditions (170°C, 2.5 MPa), Pd/10 %Nb2O5/SiO2 was effective for the hydrodeoxygenation reactions of 4-(2-furyl)-3-buten-2-one (aldol adduct of furfural with acetone), palmitic acid, tristearin, and diphenyl ether (model compounds of microalgae oils, vegetable oils, and lignin), which gave high yields (>94 %) of alkanes with little C-C bond cleavage. More importantly, owing to the significant promotion effect of NbOx species on C-O bond cleavage and the mild reaction conditions, the C-C cleavage was considerably restrained, and the catalyst showed an excellent activity and stability for the hydrodeoxygenation of palmitic acid with almost no decrease in hexadecane yield (94-95 %) in a 150 h time-on-stream test.
- Shao, Yi,Xia, Qineng,Liu, Xiaohui,Lu, Guanzhong,Wang, Yanqin
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p. 1761 - 1767
(2015/06/02)
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- Benzylation of arenes with benzyl ethers promoted by the in situ prepared superacid BF3-H2O
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An efficient and environmentally friendly benzylation of arenes with benzyl ethers as benzyl donors using BF3-Et2O to generate in situ the superacid BF3-H2O as an efficient promotor has been described. A wide variety of functional groups have been investigated and found to be compatible to give the desired diarylmethanes in yields of up to 99%. The crucial role of the moisture content in this transformation has been demonstrated by detailed investigations. This journal is the Partner Organisations 2014.
- Li, Yu,Xiong, Yan,Li, Xueming,Ling, Xuege,Huang, Ruofeng,Zhang, Xiaohui,Yang, Jianchun
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supporting information
p. 2976 - 2981
(2014/06/10)
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- Hydrodeoxygenation of methyl palmitate over sulfided Mo/Al 2O3, CoMo/Al2O3 and NiMo/Al 2O3 catalysts
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The catalytic properties of sulfided Mo/Al2O3, CoMo/Al2O3 and NiMo/Al2O3 catalysts in the hydrodeoxygenation of methyl palmitate as a model compound for triglyceride feedstock were studied at 300°C and 3.5 MPa in the batch reactor using n-tetradecane, m-xylene and hydrotreated straight-run gas oil (HT-SRGO). The comparison of catalyst's performance in n-tetradecane allowed us to see that the sulfided Mo/Al2O3, CoMo/Al 2O3 and NiMo/Al2O3 catalysts revealed the same rate of the methyl palmitate conversion but the rate of the intermediate oxygenates conversion decreased in order: CoMoS/Al 2O3 > NiMoS/Al2O3 > MoS 2/Al2O3. A mixture of linear saturated and unsaturated C15 and C16 hydrocarbons was produced when the oxygenates were fully consumed. The main products obtained over the Mo/Al 2O3 and CoMo/Al2O3 catalysts were C16 hydrocarbons (C16/C15-16.1 and 2.79, respectively); however, C15 hydrocarbons were preferentially formed over the NiMo/Al2O3 catalyst (C16/C 15-0.65), highlighting the different contributions of the hydrodeoxygenation (HDO) and decarboxylation/decarbonylation (DeCOx) pathways during the hydroconversion of methyl palmitate over these catalysts. Investigating the solvent's influence on the activity of the CoMo/Al 2O3 and NiMo/Al2O3 catalysts in the methyl palmitate HDO revealed that the reaction rate was decreased in the following order: n-tetradecane > HT-SRGO > m-xylene. The aromatic compounds did not retard the methyl palmitate transformation, but inhibited the conversion of the intermediate oxygenates. Decreased C16/C 15 ratios were observed over both catalysts when m-xylene was used as the reaction medium instead of n-tetradecane.
- Deliy, Irina V.,Vlasova, Evgenia N.,Nuzhdin, Alexey L.,Gerasimov, Evgeny Yu.,Bukhtiyarova, Galina A.
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p. 2242 - 2250
(2014/01/06)
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- A highly stereoselective and flexible strategy for the convergent synthesis of long-chain polydeoxypropionates: Application towards the synthesis of the glycolipid membrane components hydroxyphthioceranic and phthioceranic acid
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A highly stereocontrolled and flexible access to biologically relevant polydeoxypropionates in optically pure form has been developed. Taking advantage of our previously established strategy for the asymmetric and stereo-divergent synthesis of trideoxypropionate building blocks, we have now been able to assemble large polydeoxypropio-nate chains with defined configuration in a highly convergent manner. Central steps of this approach include two Suzuki-Miyaura cross-coupling reactions with subsequent highly diastereoselective hydrogenations to join three advanced synthetic intermediates in excellent yield and with full stereochemical control. We have applied this strategy successfully towards the asymmetric synthesis of glycolipid membrane components phthioceranic acid and hydroxyphthioceranic acid, the latter of which was synthesized on a half-gram scale.
- Pischl, Matthias C.,Weise, Christian F.,Haseloff, Stefan,Müller, Marc-Andr,Pfaltz, Andreas,Schneider, Christoph
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p. 17360 - 17374
(2015/02/19)
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- Manipulating catalytic pathways: Deoxygenation of palmitic acid on multifunctional catalysts
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The mechanism of the catalytic reduction of palmitic acid to n-pentadecane at 260 °C in the presence of hydrogen over catalysts combining multiple functions has been explored. The reaction involves rate-determining reduction of the carboxylic group of palmitic acid to give hexadecanal, which is catalyzed either solely by Ni or synergistically by Ni and the ZrO2 support. The latter route involves adsorption of the carboxylic acid group at an oxygen vacancy of ZrO2 and abstraction of the α-H with elimination of O to produce the ketene, which is in turn hydrogenated to the aldehyde over Ni sites. The aldehyde is subsequently decarbonylated to n-pentadecane on Ni. The rate of deoxygenation of palmitic acid is higher on Ni/ZrO2 than that on Ni/SiO2 or Ni/Al2O3, but is slower than that on H-zeolite-supported Ni. As the partial pressure of H2 is decreased, the overall deoxygenation rate decreases. In the absence of H 2, ketonization catalyzed by ZrO2 is the dominant reaction. Pd/C favors direct decarboxylation (-CO2), while Pt/C and Raney Ni catalyze the direct decarbonylation pathway (-CO). The rate of deoxygenation of palmitic acid (in units of mmol moltotal metal -1 h-1) decreases in the sequence r (Pt black)≈r(Pd black)>r(Raney Ni) in the absence of H2. In situ IR spectroscopy unequivocally shows the presence of adsorbed ketene (Ci?￡34;Ci?￡34;O) on the surface of ZrO2 during the reaction with palmitic acid at 260 °C in the presence or absence of H2. Biomass to biofuels: The conversion of palmitic acid to n-pentadecane over ZrO2 mainly proceeds by hydrogenation of the carboxylic acid group to give hexadecanal (rate-determining step), which is catalyzed either solely by Ni sites or synergistically by Ni sites and sites on the ZrO2 support (see scheme). In the absence of H2, ketonization is the dominant reaction catalyzed by ZrO 2. Copyright
- Peng, Baoxiang,Zhao, Chen,Kasakov, Stanislav,Foraita, Sebastian,Lercher, Johannes A.
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p. 4732 - 4741
(2013/05/22)
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- Selective switchable iron-catalyzed hydrosilylation of carboxylic acids
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Selective reduction of carboxylic acids either to aldehydes or alcohols is achieved using a one pot procedure based on iron-catalyzed hydrosilylations. Using phenylsilane and (COD)Fe(CO)3 catalyst under UV-irradiation at rt, alcohols were obtained specifically in good yields, whereas aldehydes were selectively obtained using TMDS and (t-PBO)Fe(CO)3 catalyst under thermal activation.
- Misal Castro, Luis C.,Li, Haoquan,Sortais, Jean-Baptiste,Darcel, Christophe
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supporting information
p. 10514 - 10516,3
(2020/09/02)
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- Composition and method of preparing a tomato-based topical formulation for enhanced healing of burns, ultraviolet and radiation erythema
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The present invention is a topical treatment. which can be in the form of cream, ointment, spray or other topically administered composition, which is used to enhance healing of burns, ultraviolet and radiation erythema. The treatment not only reduces pain and inflammation, prevents blistering, and maintains flexibility of the skin, but also accelerates the normal healing process.
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- Optimization of enzymatic synthesis of cetyl 2-ethylhexanoate by Novozym 435
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Waxes are esters obtained from long-chain fatty acids and long-chain alcohols which are biodegradable, biocompatible and nontoxic. Seafowl feather oil is a natural wax ester that exists on seafowl feathers. Cetyl 2-ethylhexanoate is the major ingredient of seafowl feather oil. Cetyl 2-ethylhexanoate is widely used in cosmetics as a base oil because of its lubricity, moisture retention and non-toxic properties. An optimal production of cetyl 2-ethylhexanoate by direct esterification of cetyl alcohol with 2-ethylhexanoic acid was developed using an immobilized lipase (Novozym 435) as a catalyst in n-hexane. Response surface methodology (RSM) and 5-level-4-factor central composite rotatable design (CCRD) were employed to evaluate the effects of reaction time, reaction temperature, substrate molar ratio, and enzyme amount on the yield of cetyl 2-ethylhexanoate. The results show that reaction time, reaction temperature, substrate molar ratio, and enzyme amount have significant effects on the yield of the esterification reaction. On the basis of ridge-max analysis, the optimum conditions were as follows: a reaction time of 2.65 days, a reaction temperature of 56.18 °C, a substrate molar ratio of 2.55:1, and an enzyme amount of 251.39%. The predicted and experimental values of molar conversion were 91.95 and 89.75 ± 1.06%, respectively. AOCS 2011.
- Chen, Hsiao Ching,Kuo, Chia-Hung,Chen, Hsin Hung,Liu, Yung-Chuan,Shieh, Chwen Jen
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scheme or table
p. 1917 - 1923
(2012/04/10)
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- COPOLYHYDROXYALKYLGLUTAMINES FUNCTIONALISED WITH HYDROPHOBIC GROUPS, AND USES THEREOF, ESPECIALLY IN THERAPEUTICS
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The invention relates to novel biodegradable materials which are based on modified polyamino acids and which can be used for the vectorisation of active principle(s) (AP). The invention also relates to novel pharmaceutical, cosmetic, dietary or phytosanitary compositions based on said polyamino acids. The aim of the invention is to provide a novel polymer raw material which can be used for the vectorisation of active principles and which can optimally fulfil all required specifications in said area, namely: biocompatibility, biodegradability and the ability to become easily associated with many active principles or to solubilise said principles and to release same in vivo. Said aim is achieved with novel copolyhydroxyalkylglutamines comprising glutamine units and optionally glutamate units and bearing hydrophobic groups containing between 8 and 30 carbon atoms. Said copolyhydroxyalkylglutamines are amphiphilic and can be easily and economically transformed into particles for the vectorisation of active principles, whereby said particles can form stable aqueous colloidal suspensions.
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- Metal-catalyzed rearrangement of cyclopropenes to allenes
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A novel transition-metal-catalyzed rearrangement of silylated cyclopropenes to the corresponding allenes is described. The presence of both the trimethylsilyl group on the cyclopropene and the platinum catalyst are crucial for this rearrangement.
- Li, Jingwei,Sun, Chunrui,Demerzhan, Silviya,Lee, Daesung
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supporting information; experimental part
p. 12964 - 12967
(2011/10/05)
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- Cetyl triacontanoate and other constituents from Acacia jacquemontii and Kigelia pinnata
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Leaves of Acacia jacquemontii on chemical investigation afforded a new aliphatic ester - cetyl triacontanoate along with n-triacontanol, n-octacosanol, β-sitosterol and stigmasterol while the heart wood of Kigelia pinnata gave lapachol, dehydro-α-lapachone, tecomaquinone-I, D-sesamin, paulownin, wodeshiol (kigeliol), klgelinone, β-sitosterol and stigmasterol on reinvestigation. The structures of isolated compounds were ascertained using various spectral (IR, 1H, 13C NMR, MS) techniques.
- Singh, Pahup,Khandelwal, Poonam,Sharma, Kuldeep K.,Sharma
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body text
p. 1403 - 1407
(2011/09/20)
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- Ditopic cyclodextrin-based receptors: New perspectives in aqueous organometallic catalysis
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The mass transfer properties of mono- and ditopic β-cyclodextrin-based receptors have been evaluated in a biphasic palladium-catalyzed Tsuji-Trost reaction and compared to one of the best mass-transfer promoters, namely the randomly methylated β-cyclodextrin. While monotopic receptors appeared to be poor mass-transfer promoters of long alkyl chain allyl carbonates or urethanes, cooperative effects have been evidenced with ditopic cyclodextrin-based receptors, opening new perspectives in aqueous organometallic catalysis.
- Six, Natacha,Menuel, Stephane,Bricout, Herve,Hapiot, Frederic,Monflier, Eric
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experimental part
p. 1467 - 1475
(2010/08/19)
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- Activated carbon as a mass-transfer additive in aqueous organometallic catalysis
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(Figure Presented) Carbon, on active duty: The addition of activated carbon into the reaction medium appears to be a simple and efficient method to solve mass-transfer limitations in aqueous organometallic catalysis (see figure).
- Kania, Nicolas,Leger, Bastien,Fourmentin, Sophie,Monflier, Eric,Ponchel, Anne
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experimental part
p. 6138 - 6141
(2010/07/14)
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- Polyglutamic Acids Functionalised by Histidine Derivatives and Hydrophobic Groups and the Uses Thereof, in Particular for Therapeutic Purposes
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The invention relates to novel biodegradable materials based on modified polyamino acids and suitable, in particular, for vectoring active substance(s) (AS). Said invention also relates to novel pharmaceutical, cosmetic, dietary or plant protective compositions which are based on said polyamino acids. The aim of said invention is to provide a novel polymer raw material usable for vectoring the AS and capable to optimally meet all specification in this area: biocompatibility, biodegradability, ability to become easily associated with many active substances or to solubilise them and to release said active substances in vivo. The aim is attained to 30 carbon atoms. Said polyglutamates modified by histidine derivatives are soluble with pH lower than 5 and are easily and economically convertible into active substance vectorization particles which are able to form stable aqueous colloidal suspensions. On the contrary, said modified polyglutamates are insoluble in water with a physiological pH (7.4), and thereby have to be precipitated on an injection site in the case of a subcutaneous injection.
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- Polyamino acids functionalized by hydrophobic grafts bearing an anionic charge and applications thereof, such as therapeutic applications
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The present invention relates to novel materials based on biodegradable polyamino acids that are useful especially for the vectorization of active principle(s) (AP). The invention further relates to novel pharmaceutical, cosmetic, dietetic or phytosanitary compositions based on these polyamino acids. The object of the invention is to provide a novel polymer starting material that is capable of being used for the vectorization of AP and makes it possible on the one hand to achieve high polymer/AP ratios, and on the other hand optimally to satisfy all the specifications required in the case in point: biocompatibility, biodegradability, ability to associate easily with numerous active principles or to solubilize them, and ability to release these active principles in vivo. This object is achieved by the present invention, which relates first and foremost to linear polyamino acids comprising aspartic units or glutamic units and having hydrophobic grafts comprising hydrophobic groups containing from 8 to 30 carbon atoms, at least one of these hydrophobic grafts having at least one anionic charge and/or one or more mutually identical or different ionizable groups each capable of giving rise to at least one anionic charge. These polymers are amphiphilic and anionic and are capable of being converted easily and economically to particles for the vectorization of active principles, these particles themselves being capable of forming stable aqueous colloidal suspensions.
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- Highly selective and efficient hydrogenation of carboxylic acids to alcohols using titania supported Pt catalysts
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Selective hydrogenation of carboxylic acids to alcohols and alkanes has been achieved under remarkably mild reaction temperatures and H2 pressures (333 K, 0.5 MPa) using Pt/TiO2 catalyst.
- Manyar, Haresh G.,Paun, Cristina,Pilus, Rashidah,Rooney, David W.,Thompson, Jillian M.,Hardacre, Christopher
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supporting information; experimental part
p. 6279 - 6281
(2010/10/19)
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- PRODUCTION OF DETERGENT RANGE ALCOHOLS
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This invention relates to a process for the production of a mixture of detergent-range alcohols having an average of between 8 and 20 carbon atoms per molecule. The process includes the steps of providing a hydrocarbon stream containing olefins and paraffins in which more than 5% by volume of olefin molecules in the hydrocarbon stream have a total number of carbon atoms which is different from the total number of carbon atoms of the most abundant two carbon numbers of olefins in the hydrocarbon stream; reacting the hydrocarbon stream with CO and an alcohol in the presence of a catalyst in a hydroesterification reaction to form a hydrocarbon stream containing esters and paraffins; separating esters from the hydrocarbon stream containing esters and paraffins; and subjecting the esters to a hydrogenation reaction to provide the mixed alcohol product.
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(2009/01/24)
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