- Efficient photooxygenation of furans using oxygen with wool-immobilizing Rose Bengal as green photosensitizer
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A new type of solid-supported photosensitizer was prepared from Rose Bengal and wool via acid dye dyeing process. The wool-Rosebengal photosensitizer was characterized by Fourier transform infrared spectrometer (FTIR), scanning electron microscope and fastness test. This sensitizer was used as heterogeneous photocatalyst to promote furans oxidation to the corresponding butenolides in excellent yields (90%). The sensitizer could be easily recovered from the reaction mixture by filtration and reused in the new cycle of the reaction.
- Zhang, Yan,Wang, Wei,Li, Shushu
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- Synthetic application of photoactive porous monolithic polymers
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The oxidation of 2-furoic acid to 5-hydroxy-5H-furan-2-one has been accomplished in quantitative yield in chloroform using a novel supported photocatalyst. This material comprises Rose Bengal grafted to the surface of a highly crosslinked polystyrene-divinylbenzene polymer, which was synthesized in a porous monolithic format.
- Burguete, M. Isabel,Gavara, Raquel,Galindo, Francisco,Luis, Santiago V.
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- Modification of conjugated microporous poly-benzothiadiazole for photosensitized singlet oxygen generation in water
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Water-dispersible alkyne-bearing conjugated microporous poly-benzothiadiazoles were synthesized using thiol-yne chemistry to enhance water compatibility. The water compatible polymer networks were used as heterogeneous photocatalysts to generate singlet oxygen for the conversion of furoic acid to 5-hydroxy-2(5H)-furanone. The Royal Society of Chemistry.
- Urakami, Hiromitsu,Zhang, Kai,Vilela, Filipe
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- Rose Bengal immobilized on wool as an efficiently "green" sensitizer for photooxygenation reactions
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A new type of supported photosensitizer derived from renewable wool and Rose Bengal is described. The novel sensitizer could efficiently promote the photooxygenation of furan derivatives to the corresponding 5-hydroxy-2-(5H)- furanone in excellent yields, via singlet oxygen, using visible light as the energy source. The sensitizer could be easily recovered from the reaction mixture by a simple filtration. It is discovered that the recovered sensitizer can be reused four times.
- Zhang, Yan,Wang, Wei,He, Xun,Sang, Anguo
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- Rose Bengal Immobilized on Supported Ionic-Liquid-like Phases: An Efficient Photocatalyst for Batch and Flow Processes
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The catalytic activity of Rose Bengal (RB) immobilized on supported ionic liquid (IL)-like phases was evaluated as a polymer-supported photocatalyst. In these systems, the polymer was designed to play a pivotal role. The polymeric backbone adequately modi
- Valverde, David,Porcar, Raul,Izquierdo, Diana,Burguete, M. Isabel,Garcia-Verdugo, Eduardo,Luis, Santiago V.
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- Investigation in the series of substituted butan- and butenolides: XV. Transformations of 4-hydroxy-2-butenolide in water media at various pH values
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The 4-hydroxy-2-butenolide was established by polarographic method to undergo in water solutions fast tautomeric and acid-base transformations. Depending on pH of the medium the compound is present either as a cyclic irreducible form (at pH 0-4) or in the open-chain (carbonyl-containing) reducible forms (at pH > 4 and A -), its neutral molecule (HA) existing as linear and cyclic tautomers, and protonated forms (H2A+ and H 3A+). The formation mechanism thereof is considered.
- Strizhov,Poskonin,Badovskaya,Kupina
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- CO2-Triggered Switchable Hydrophilicity of a Heterogeneous Conjugated Polymer Photocatalyst for Enhanced Catalytic Activity in Water
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Water compatibility for heterogeneous photocatalysts has been pursued for energy and environmental applications. However, there exists a trade-off between hydrophilicity and recyclability of the photocatalyst. Herein, we report a conjugated polymer photocatalyst with tertiary amine terminals that reversibly binds CO2 in water, thereby generating switchable hydrophilicity. The CO2-assisted hydrophilicity boosted the photocatalytic efficiency in aqueous medium with minimum dosage. When CO2 was desorbed, the photocatalyst could be simply regenerated from reaction media, facilitating the repeated use of photocatalyst. Hydrophilicity/hydrophobicity control of the polymer photocatalyst was successfully showcased through a variety of organic photoredox reactions under visible-light irradiation in water.
- Byun, Jeehye,Huang, Wei,Wang, Di,Li, Run,Zhang, Kai A. I.
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- Selective hydrodeoxygenation of 5-hydroxy-2(5H)-furanone to γ-butyrolactone over Pt/mesoporous solid acid bifunctional catalyst
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Selective hydrodeoxygenation of 5-hydroxy-2(5H)-furanone (HFO) derived from furfural oxidation to γ-butyrolactone (GBL) provides a sustainable alternative to the petroleum-based process for γ-butyrolactone production. Furfural is first converted to HFO through selective photocatalytic oxidation by using air oxygen as the oxidant (yield: 85.0%). HFO is further converted to GBL through hydrodeoxygenation over noble-metal nanoparticles on mesoporous Nb-Zr mixed oxides. The conversion of HFO to GBL involves two reactions: hydrogenation catalyzed by active metal and dehydration over mesoporous solid acids. The catalytic properties of M/Nb-Zr mixed oxides (M = Pt, Ir, Ru, Rh and Pd) are related to the composition of support and active metal. The incorporation of zirconia into matrixes improves the thermal stability of mesoporous mixed oxides and increases the amounts of surface acid, which contributes to its catalytic selectivity to GBL. Pt/Nb5Zr5-550 exhibited the best catalytic performances with 97.3% selectivity of GBL at full conversion. The excellent performance can be correlated with the cooperative effect between active metal species and acid sites. The Pt-solid acid bifunctional catalysts show superior catalytic performance compared with conventional catalysts, such as Pt/H-ZSM-5, Pt/C, Rh/C or Pd/C. An overall GBL yield of 82.7% from furfural was obtained.
- Chen, Bingfeng,Li, Fengbo,Yuan, Guoqing
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- Fabrication and photocatalytic activity of fullerodendron/CaCO3 composites
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Novel composite materials consisting of fullerodendrons and CaCO 3 particles were fabricated to have better efficiency as photosensitizers in singlet photooxygenation reactions compared to pristine fullerodendrons. Moreover, fullerodendrons in
- Talukdar, Bandana,Takaguchi, Yutaka,Yanagimoto, Yasushi,Tsuboi, Sadao,Ichihara, Masahiro,Ohta, Kazuchika
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- Kinetics and Mechanism of the Photosensitized Oxidation of Furosemide
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Detection of O2(1Δg) phosphorescence emission, λmax = 1270 nm, following laser excitation and steady-state competitive methods was employed to measure total rate constants, kT, for the reactions of the diuretic furosemide, 2-methylfurane and furfurylamine with singlet oxygen in several solvents. Correlation of kT values with solvent parameters and product identification shows that the reaction mechanism is strongly solvent dependent. In aliphatic alcohols, the dependence of kT on solvent parameters is similar to the one observed for triethylamine, suggesting a reaction mechanism involving partial charge transfer from the amino group to the singlet oxygen. In nonprotic solvents, the dependence of kT on solvent parameters resembles the behavior found for 2-methylfurane and furfurylamine, implying that mostly a 2 + 4 cycloaddition mechanism of singlet oxygen to furane ring of furosemide occurs in these solvents. These mechanistic differences are explained in terms of hydrogen-bonding interactions between the carboxylic group in the aromatic ring and the amino group of furosemide. Furthermore, direct generation of O2(1Δg) by furosemide was detected. Quantum yields of 0.047 ± 0.003 and 0.078 ± 0.004 were determined in acetonitrile and benzene, respectively. This last result may be related, at least partially, to the photodynamic effects of this diuretic drug.
- Zanoccot,Günther S.,Lemp M.,De La Fuente,Pizarro U.
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- New polymer-supported photocatalyst with improved compatibility with polar solvents. Synthetic application using solar light as energy source
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A new kind of supported photocatalysts derived from low-crosslinked polystrene, containing Rose Bengal and pyridinium groups, is described. Such polymers are capable to catalyze the quantitative synthesis of 5-hydroxy-5H-furan-2-one from 2-furoic acid in methanol, via singlet oxygen, using solar light as the energy source.
- Burguete, M. Isabel,Gavara, Raquel,Galindo, Francisco,Luis, Santiago V.
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- Highly Efficient Biobased Synthesis of Acrylic Acid
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Petrochemical based polymers, paints and coatings are cornerstones of modern industry but our future sustainable society demands greener processes and renewable feedstock materials. A challenge is to access platform monomers from biomass resources while integrating the principles of green chemistry in their chemical synthesis. We present a synthesis route starting from biomass-derived furfural towards the commonly used monomers maleic anhydride and acrylic acid, implementing environmentally benign photooxygenation, aerobic oxidation and ethenolysis reactions. Maleic anhydride and acrylic acid, transformed into sodium acrylate, were isolated in yields of 85 % (2 steps) and 81 % (4 steps), respectively. With minimal waste and high atom efficiency, this biobased route provides a viable alternative to access key monomers.
- Feringa, Ben L.,Hermens, Johannes G. H.,Jensma, Andries
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supporting information
(2021/12/16)
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- Photocatalytic valorization of furfural to value-added chemicals via mesoporous carbon nitride: a possibility through a metal-free pathway
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Strategizing the exploitation of renewable solar light could undoubtedly provide new insight into the field of biomass valorization. Therefore, for the first time, we reported a heterogeneous photocatalytic oxidation route of renewable furfural (FUR) to produce industrial feedstocks maleic anhydride (MAN) and 5-hydroxy-2(5H)-furanone (HFO) under simulated solar light (AM 1.5G) using molecular oxygen (O2) as a terminal oxidant and mesoporous graphitic carbon nitride (SGCN) as a photocatalyst. SGCN showed an excellent photoconversion (>95%) of FUR with 42% and 33% selectivity to MAN and HFO, respectively. Moreover, an excellent selectivity towards MAN (66%) under natural sunlight indicates a pioneering route for the sustainable production of MAN. In addition, the underlying mechanistic route of the FUR photo-oxidation was investigated via various experiments including scavenger studies, substrate studies, and electron spin resonance (ESR) studies which constructively proved the pivotal role of singlet oxygen (1O2) and holes (h+) in FUR photo-oxidation.
- Battula, Venugopala R.,Chauhan, Deepak K.,Giri, Arkaprabha,Kailasam, Kamalakannan,Patra, Abhijit
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p. 144 - 153
(2022/01/19)
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- Cyanine-based near infra-red organic photoredox catalysis
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Direct metal-free near infra-red photoredox catalysis is applied to organic oxidation, photosensitization and reduction, involving cyanines as photocatalysts. This photocatalyst is competitive with conventional reactions catalyzed under visible light. Kin
- Baralle, Alexandre,Cormier, Morgan,Goddard, Jean-Philippe,Obah Kosso, Anne Roly,Sellet, Nicolas
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p. 6964 - 6968
(2021/06/02)
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- A plug-and-play chemobiocatalytic route for the one-pot controllable synthesis of biobased C4 chemicals from furfural
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Chemobiocatalytic selective transformation is an attractive yet challenging task, due to the incompatibility issues between different types of catalysts. In this work, one-pot, multi-step cascades integrating biocatalysis with organo-, base- and photocatalysis in a plug-and-play fashion were constructed for the controllable synthesis of eight C4 chemicals from furfural. Furfural was converted to 5-hydroxy-2(5H)-furanone (HFO) by sequential biocatalytic oxidation and photooxygenation in phosphate buffer, in >90% yields. Ring opening and concurrent isomerization of HFO to fumaric semialdehyde (FSA) were readily realized under mild conditions by a weakly basic resin (e.g., DVB resin). The versatile intermediate FSA could be oxidized to fumaric acid (FA) using a laccase-2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO) system, which was further upgraded to amino acids including l-aspartic acid (l-Asp) and β-alanine (β-Ala) by whole-cell catalysis. Notably, amino acids were obtained from biobased furfural in a one-pot, four-step process with yields of up to 75%, without the isolation of any intermediates. Besides, the scale-up synthesis of l-Asp was demonstrated. This work demonstrates the great potential of the combination of chemo- and biocatalysis for selective furfural valorization.
- Huang, Yi-Min,Lu, Guang-Hui,Zong, Min-Hua,Cui, Wen-Jing,Li, Ning
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supporting information
p. 8604 - 8610
(2021/11/16)
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- Metal Sub-nanoclusters Confined within Hierarchical Porous Carbons with High Oxidation Activity
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Metal sub-nanoclusters (SNCs) have shown great promise for a variety of catalytic reactions. However, the fabrication of stable metal SNCs simultaneously with high dispersion and high metal contents remains a challenge. Herein, we report a novel and versatile strategy for the synthesis of various bimetal SNCs stabilized within hierarchical porous carbons (HPC). This facile synthesis only involves the self-assembly of a metal-organic framework (MOF) as the precursor, a molten salt assisted pyrolysis process and the final metal replacement. The metal SNCs (mostly less than 0.8 nm) derived from the metal nodes of the MOF are exclusively confined and homogeneously dispersed throughout the organic ligands derived HPC at high loadings (up to 11.2 wt %). The obtained Cu-Pd@HPC composite exhibits superior catalytic activity and recycling durability in the selective transformation of furfural to maleic acid, achieving 97.8 % yield of maleic acid with a TOF value as high as 20.1 h?1 under mild conditions. DFT calculations reveal that the introduction of Pd shifts the partial density of states of Cu toward the Fermi level, leading to stronger chemisorption of furfural to enhance the catalytic activity.
- Zhao, Xin,Kong, Xiangpeng,Wang, Fengliang,Fang, Ruiqi,Li, Yingwei
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supporting information
p. 10842 - 10849
(2021/03/16)
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- The oligomer approach: An effective strategy to assess phenylene vinylene systems as organic heterogeneous photocatalysts in the degradation of aqueous indigo carmine dye
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Four oligo-phenylenevinylenes (OPVs) were synthesized by the Mizoroki-Heck cross-coupling reaction to provide a deeper understanding of the mechanism and fate of phenylenevinylene systems when applied to the heterogeneous photocatalytic degradation of indigo carmine (IC) dye in aqueous media. OPVs displayed visible light absorption near 500 nm and appreciable emission properties. The stability, mechanism, and photodegradation activity of the OPV systems over aqueous indigo carmine were investigated using radical scavengers, a singlet oxygen (1O2) trap, and ESI-IT-MS. It was confirmed that superoxide radical (O2??), 1O2, and direct oxidation are responsible for dye degradation. Hydroxide radical formation, under neutral pH conditions, does not occur, and it was corroborated by the HOMO and LUMO levels of the photocatalysts. Additionally, the use of oxalic acid as an electron sacrificial donor was demonstrated as an effective approach to enhance the OPVs photocatalytic activity. However, a significant decrease in activity during the first three irradiation cycles was observed, indicating that the enhancement in photo- and chemical stability is required for further dye-contaminated water treatment applications.
- Acelas, Mauricio,Sierra, César A.
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- β-Cyclodextrin-conjugated phthalocyanines as water-soluble and recyclable sensitisers for photocatalytic applications
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Two zinc(ii) phthalocyanines substituted with two and four permethylated β-cyclodextrin moieties at the α positions have been synthesised and immobilised on the surface of adamantane-modified silica nanoparticles through host-guest interactions. These molecular and supramolecular systems can catalyse the photooxygenation of 1-naphthol and 2-furoic acid in organic and aqueous media with high conversion efficiency and reaction yield, and photodegradation of 2-chlorophenol in water. Having a higher photostability and recyclability, the supramolecular nanosystems are particularly promising for these photocatalytic applications.
- Chen, Xiao-Fei,Ng, Dennis K. P.
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supporting information
p. 3567 - 3570
(2021/04/14)
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- Heavy-Atom Free spiro Organoboron Complexes As Triplet Excited States Photosensitizers for Singlet Oxygen Activation
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Herein, we present a new strategy for the development of efficient heavy-atom free singlet oxygen photosensitizers based on rigid borafluorene scaffolds. Physicochemical properties of borafluorene complexes can be easily tuned through the choice of ligand, thus allowing exploration of numerous organoboron structures as potent 1O2 sensitizers. The singlet oxygen generation quantum yields of studied complexes vary in the range of 0.55-0.78. Theoretical calculations reveal that the introduction of the borafluorene moiety is crucial for the stabilization of a singlet charge transfer state, while intersystem crossing to a local triplet state is facilitated by orthogonal donor-acceptor molecular architecture. Our study shows that quantitative oxidation of selected organic substrates can be achieved in 20-120 min of irradiation with only 0.05 mol % loading of a photocatalyst.
- Marek-Urban, Paulina H.,Urban, Mateusz,Wiklińska, Magdalena,Paplińska, Klaudia,Wo?niak, Krzysztof,Blacha-Grzechnik, Agata,Durka, Krzysztof
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supporting information
p. 12714 - 12722
(2021/09/18)
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- OXIDATION OF 5-HYDROXY-2-FURANONE TO MALEATES
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The invention is directed to a process for preparing maleic acid or a derivative thereof, said process comprising a step b) of oxidizing 5-hydroxy-2(5H)-furanone and/or cis-β-formylacrylic acid to maleic acid thereof by contacting 5-hydroxy-2(5H)-furanone and/or cis-β-formylacrylic acid with molecular oxygen (O2) in the presence of a catalyst. In a particular embodiment, step b) is preceded by a step a) of oxidizing a furanic compound according to formula (I) into 5-hydroxy-2(5H)-furanone and/or cis-β-formylacrylic acid, or a derivative wherein R1 is H, CH2OH, CO2H or CHO and R2 is H, OH, C1-C6 alkyl or O(C1-C6 alkyl), or esters, ethers, amides, acid halides, anhydrides, carboximidates, nitriles, and salts thereof.
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(2020/07/14)
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- METHOD FOR PREPARING MALEIC ACID
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The present invention pertains to a method for the preparation of maleic acid from 5-hydroxy-2(5H)-furanone or a tautomer thereof, said method comprising the step of subjecting 5-hydroxy-2(5H)-furanone or a tautomer thereof to an oxidation reaction selected from the group consisting of enzymatic oxidation, and electrochemical oxidation; wherein said oxidation reaction is carried out at a pH of at least 2, preferably at a pH of at least 3.
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Page/Page column 20
(2021/01/22)
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- Electrochemistry Broadens the Scope of Flavin Photocatalysis: Photoelectrocatalytic Oxidation of Unactivated Alcohols
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Riboflavin-derived photocatalysts have been extensively studied in the context of alcohol oxidation. However, to date, the scope of this catalytic methodology has been limited to benzyl alcohols. In this work, mechanistic understanding of flavin-catalyzed oxidation reactions, in either the absence or presence of thiourea as a cocatalyst, was obtained. The mechanistic insights enabled development of an electrochemically driven photochemical oxidation of primary and secondary aliphatic alcohols using a pair of flavin and dialkylthiourea catalysts. Electrochemistry makes it possible to avoid using O2 and an oxidant and generating H2O2 as a byproduct, both of which oxidatively degrade thiourea under the reaction conditions. This modification unlocks a new mechanistic pathway in which the oxidation of unactivated alcohols is achieved by thiyl radical mediated hydrogen-atom abstraction.
- Zhang, Wen,Carpenter, Keith L.,Lin, Song
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supporting information
p. 409 - 417
(2019/11/25)
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- Four Stereoisomers of 2-Aminomethyl-1-cyclopropanecarboxylic Acid: Synthesis and biological evaluation
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Here, we report a practical method for asymmetric synthesis of cyclopropane-fused GABA analogs. Starting from 2-furaldehyde, the cis-isomer (CAMP) was synthesized over 10 steps; (1)- and (+)-CAMP￠HCl were synthesized by employing d- and l-menth
- Oikawa, Masato,Sugeno, Yuka,Tukada, Hideyuki,Takasaki, Yuichi,Takamizawa, Satoshi,Irie, Raku
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supporting information
p. 1816 - 1823
(2019/11/13)
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- Eco-efficient synthesis of 2-quinaldic acids from furfural
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Quinaldic acids are important fine chemicals. Nowadays, industrial methods to synthesize quinaldic acids rely heavily on a three-step process established based on the Reissert reaction, which involves however the use of highly toxic potassium cyanide. In this paper, a novel cyclization of aniline with ethyl 4,4-diethoxycrotonate was realized, which offered ethyl quinaldate in good yield. Based on this reaction, an eco-efficient method to prepare quinaldic acids was developed, which involves the following three steps: (i) synthesis of ethyl 4,4-diethoxycrotonate through photooxidation of furfural and a consecutive ring-opening alcoholysis; (ii) cyclization of ethyl 4,4-diethoxycrotonate with aniline, and (iii) hydrolysis of the generated ethyl quinaldate. This new method not only avoids the use of toxic potassium cyanide but also meets many salient features of green chemistry, such as the use of bio-based feedstocks, environmentally benign metal-free conditions and good reaction yields.
- Li, Minghao,Dong, Xiaohan,Zhang, Na,Jér?me, Fran?ois,Gu, Yanlong
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p. 4650 - 4655
(2019/09/09)
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- An electrocatalytic route for transformation of biomass-derived furfural into 5-hydroxy-2(5H)-furanone
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Development of efficient strategies for biomass valorization is a highly attractive topic. Herein, we conducted the first work on electrocatalytic oxidation of renewable furfural to produce the key bioactive intermediate 5-hydroxy-2(5H)-furanone (HFO). It was demonstrated that using H2O as the oxygen source and metal chalcogenides (CuS, ZnS, PbS, etc.) as electrocatalysts, the reaction could proceed efficiently, and the CuS nanosheets prepared in this work showed the best performance and provided high HFO selectivity (83.6%) and high conversion (70.2%) of furfural. In addition, the CuS electrocatalyst showed long-term stability. Mechanism investigation showed that furfural was oxidized to HFO via multistep reactions, including C-C cleavage, subsequent ring opening and oxidation, and intramolecular isomerization.
- Wu, Haoran,Song, Jinliang,Liu, Huizhen,Xie, Zhenbing,Xie, Chao,Hu, Yue,Huang, Xin,Hua, Manli,Han, Buxing
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p. 4692 - 4698
(2019/05/14)
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- Furan-Derived Chiral Bicycloaziridino Lactone Synthon: Collective Syntheses of Oseltamivir Phosphate (Tamiflu), (S)-Pipecolic acid and its 3-Hydroxy Derivatives
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A unified synthetic strategy for oseltamivir phosphate (tamiflu), (S)-pipecolic acid, and its 3-hydroxy derivatives from furan derived common chiral bicycloaziridino lactone synthon is described here. Key features are the short (4-steps), enantiopure, and decagram-scale synthesis of common chiral synthon from furan and its first-ever application in the total synthesis of biologically active compounds by taking the advantages of high functionalization ability of chiral synthon.
- Chavan, Subhash P.,Gonnade, Rajesh G.,Kadam, Appasaheb L.,Shinde, Shrikrishna S.
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- A quinoline -2 - formic acid and quinoline -2 - carboxylic acid derivatives of the preparation method (by machine translation)
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The invention discloses a quinoline - 2 - carboxylic acid and quinoline - 2 - carboxylic acid derivatives of the preparation method, the preparation method comprises the following steps: (1) 2 - furan formaldehyde after photolysis reaction to produce 5 - hydroxy furan - 2 (5 H) - one; (2) 5 - hydroxy furan - 2 (5 H) - ketone after acid hydrolysis reaction to produce 4, 4 - diethoxy - 2 - butene thiourethane; (3) 4, 4 - diethoxy - 2 - butenoic acid ethyl ester and aniline or an aniline derivative reaction, get the quinoline - 2 - carboxylic acid ethyl ester or the quinoline - 2 - carboxylic acid ethyl ester derivatives; (4) quinoline - 2 - carboxylic acid ethyl ester or the quinoline - 2 - carboxylic acid ethyl ester derivatives ester is hydrolyzed to generate quinoline - 2 - carboxylic acid or quinoline - 2 - carboxylic acid derivatives. The invention has the easy availability of raw materials, environmental pollution is small, high reaction selectivity, industrial application value is large and the like. (by machine translation)
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Paragraph 0028; 0036; 0038; 0039; 0046
(2018/08/03)
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- Rearrangements and Tautomeric Transformations of Heterocyclic Compounds in Homogeneous Reaction Systems Furfural–Н2О2–Solvent
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General information on the reactions of furfurals with hydrogen peroxide is given. We have discussed the Baeyer–Villiger rearrangement of furan 2-hydroxyhydroperoxides and tautomeric transformations with proton transfer of 2-hydroxyfuran and β-formylacrylic acid formed in a homogeneous reaction system furfural–Н2О2–solvent under the catalysis with the formed acids. The factors affecting these rearrangements and tautomeric transformations as well as their specificity in comparison with benzene type compounds, and the pathway of the reactions of furan aldehydes with Н2О2 in water have been analyzed. Ketoenol tautomerism of cyclic hemiacetal form of β-formylacrylic acid leading to its transformation into succinic anhydride has been described for the first time.
- Badovskaya,Poskonin
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p. 1568 - 1579
(2018/11/10)
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- Continuous Photo-Oxidation in a Vortex Reactor: Efficient Operations Using Air Drawn from the Laboratory
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We report the construction and use of a vortex reactor which uses a rapidly rotating cylinder to generate Taylor vortices for continuous flow thermal and photochemical reactions. The reactor is designed to operate under conditions required for vortex generation. The flow pattern of the vortices has been represented using computational fluid dynamics, and the presence of the vortices can be easily visualized by observing streams of bubbles within the reactor. This approach presents certain advantages for reactions with added gases. For reactions with oxygen, the reactor offers an alternative to traditional setups as it efficiently draws in air from the lab without the need specifically to pressurize with oxygen. The rapid mixing generated by the vortices enables rapid mass transfer between the gas and the liquid phases allowing for a high efficiency dissolution of gases. The reactor has been applied to several photochemical reactions involving singlet oxygen (1O2) including the photo-oxidations of α-terpinene and furfuryl alcohol and the photodeborylation of phenyl boronic acid. The rotation speed of the cylinder proved to be key for reaction efficiency, and in the operation we found that the uptake of air was highest at 4000 rpm. The reactor has also been successfully applied to the synthesis of artemisinin, a potent antimalarial compound; and this three-step synthesis involving a Schenk-ene reaction with 1O2, Hock cleavage with H+, and an oxidative cyclization cascade with triplet oxygen (3O2), from dihydroartemisinic acid was carried out as a single process in the vortex reactor.
- Lee, Darren S.,Amara, Zacharias,Clark, Charlotte A.,Xu, Zeyuan,Kakimpa, Bruce,Morvan, Herve P.,Pickering, Stephen J.,Poliakoff, Martyn,George, Michael W.
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supporting information
p. 1042 - 1050
(2017/07/26)
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- Visible-light-mediated achmatowicz rearrangement
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Visible-light-mediated photoredox catalysis is a viable method to access highly reactive intermediates from cheap, readily available, and shelfstable reagents to perform clean chemical transformations. Here, we report the first photoredox-catalyzed Achmatowicz reaction of furfuryl alcohol derivatives to produce functionalized dihydropyranones while only forming easily separable NaHSO4 as a byproduct. The water solubility of the byproduct facilitates direct Boc-protection of the resulting hemiacetal without the need for column purification. The reaction is very robust and permits the use of various aqueous solutions and light sources including sunlight.
- Plutschack, Matthew B.,Seeberger, Peter H.,Gilmore, Kerry
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- Conjugated microporous polymer nanoparticles with enhanced dispersibility and water compatibility for photocatalytic applications
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Here we report the design of well-dispersible conjugated microporous polymer nanoparticles as highly stable heterogeneous organic photocatalysts in aqueous medium. This class of materials combines two different heterogeneous catalytic model systems: (i) nanostructured catalysts and (ii) highly porous materials. By incorporating different electron donor and acceptor moieties, the nanoparticle shape can be controlled ranging from nanospheres via nanorods to nanorings. The high photocatalytic activity, stability and reusability of the materials were demonstrated in the reductive activation of molecular oxygen and photooxidation of amines under irradiation of a household energy-saving light bulb.
- Ma, Beatriz Chiyin,Ghasimi, Saman,Landfester, Katharina,Vilela, Filipe,Zhang, Kai A.I.
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supporting information
p. 16064 - 16071
(2015/08/06)
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- Practical evaluation of compact fluorescent lamps for dye-sensitized photooxidation reactions
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Energy-efficient compact fluorescent lamps (CFL) have been evaluated as a light source for the sensitized generation of singlet oxygen used in the oxidation of 1,3-butadienes and furfural derivatives using a range of dyes including rose bengal, methylene
- Stockton, Kieran P.,May, Joseph P.,Taylor, Dennis K.,Greatrex, Ben W.
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p. 1168 - 1172
(2014/05/20)
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- Aqueous-phase catalytic oxidation of furfural with H2O2: High yield of maleic acid by using titanium silicalite-1
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This investigation explores the selective liquid-phase oxidation of furfural to maleic acid (MA) using hydrogen peroxide as an oxidant and titanium silicalite (TS-1) as a catalyst. The effect of temperature and of the concentration of H2O2, furfural and catalyst on the MA yield was studied. The highest yield, 78 mol%, was obtained under the following reaction conditions: 4.6 wt% of furfural, 4.6 wt% of catalyst, a H2O2/furfural mol ratio of 7.5, corresponding to 12.3 wt% of H2O2, 323 K and 24 hours of reaction. To reduce the amount of H2O2 employed, a two-step sequence of reactions was conducted using TS-1 and Amberlyst 70 consecutively as catalysts in the first and second steps, respectively. In this case, a H2O2/furfural mol ratio = 4.4 was required, which is quite close to the stoichiometric ratio (3.0), and a maleic acid yield close to 80% was obtained under 4.6 wt% of furfural, 4.6 wt% of catalyst and 28 h of reaction at 323 K; after 52 h of reaction, the MA yield reached 92%. Fresh and used catalysts were characterised by X-ray diffraction (XRD), Raman spectroscopy, total reflection X-ray fluorescence (TXRF), X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption isotherms and thermogravimetric analysis. Ti was largely incorporated within the silicalite framework, but the presence of some TiO2 anatase was also confirmed. Ti leaching was observed, especially during the first run but became much less important in successive cycles. Leaching affects both anatase and Ti species within the silicalite framework. Notwithstanding the leaching, when using pure furfural, TS-1 could be reused for six runs without noticeable deactivation, whereas when using furfural directly derived from biomass, weak but visible deactivation occurred upon reutilisation; this deterioration must be related to the presence of some organic products other than furfural.
- Alonso-Fagndez,Agirrezabal-Telleria,Arias,Fierro,Mariscal,Granados, M. Lpez
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p. 54960 - 54972
(2015/02/19)
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- Effect of acid-base properties of the medium on the reactions in the 2-furaldehyde-H2O2-H2O system with and without VOSO4
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Data on the effect of acid-base properties of the medium in the pH range 0-9 on the intensity of transformation of 2-furaldehyde and the direction of the multi-stage reactions in the 2-furaldehyde-H2O2-H 2O system in the presence of VOSO4 and without it are presented. Significant influence of the medium pH value on the reaction pathway in the system under investigation hase been found. Mechanism of these reactions considering the effect of acid-base properties of the medium has been suggested.
- Badovskaya,Poskonin,Ponomarenko
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p. 1133 - 1140
(2014/08/05)
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- Poly-(styrene sulphonic acid): An acid catalyst from polystyrene waste for reactions of interest in biomass valorization
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This article reports on the use of poly-(styrene sulphonic acid) (PSSA) prepared by sulphonation of polystryrene waste as catalyst in reactions demanding acid sites. Two different waste derived catalysts (waste to catalyst, WTC) were studied: soluble PSSA (WTC-PSSA) and solid SiO2-PSSA nanocomposite (WTC-SiO2-PSSA). The catalytic properties of these waste derived acid catalysts have been explored in three different reactions of interest in biomass valorization: biodiesel synthesis, xylose dehydration to furfural and furfural oxidation to maleic and succinic acids. The results show that both soluble and nanocomposite WTC catalysts present promising catalytic properties. The WTC-PSSA requires ultrafiltration for reutilization whereas the WTC-SiO2-PSSA can be separated from the reaction mixtures by more usual techniques (centrifugation or conventional filtration). Further research is required for improving the hydrothermal stability of WTC-SiO2-PSSA in order to substantially reduce the leaching of polymer that takes place during the catalytic runs.
- Alonso-Fagúndez,Laserna,Alba-Rubio,Mengibar,Heras,Mariscal,Granados, M. López
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p. 285 - 294
(2014/07/07)
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- Sulfonated surfactants obtained from furfural
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Furfural obtained from pentose containing biomass such as hemicelluloses is subjected to photooxygenation. The resulting hydroxyfuranone obtained in high yields undergoes acetalization with fatty alcohols. Using NaHSO3, surfactants are obtained by addition of a sulfonate group to α,β-unsaturated carboxyl or carbonyl compounds. Addition occurred either at the CC double bond (6) or at the aldehyde function (7). Compared to conventional surfactants of this type, the resulting compounds possess similar good detergent properties. In the case of compound family 6 and when compared to the corresponding alkylsulfate and alkylsulfonate surfactants, even lower critical micelle concentrations (CMC) are observed. Biodegradation of the new surfactants was determined according to the OECD Test guideline 301 F. Compounds of family 6 are biodegradable. Biodegradation of compounds of family 7 stopped after 10 days.
- Gassama, Abdoulaye,Ernenwein, Cedric,Youssef, Ali,Agach, Mickael,Riguet, Emmanuel,Marinkovic, Sinisa,Estrine, Boris,Hoffmann, Norbert
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p. 1558 - 1566
(2013/09/24)
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- Total synthesis of a novel oxa-bowl natural product paracaseolide A via a 'putative' biomimetic pathway
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A total synthesis of bioactive tetracyclic natural product paracaseolide A, embodying an architecturally unusual oxa-bowl framework, has been accomplished from commercially available 5-methyl-2-furfural. The key step involving a thermal [4+2]-dimerization of an appropriately crafted 5-methyl-3- alkenylbutenolide is shown to proceed in a stepwise manner.
- Vasamsetty, Laxmaiah,Khan, Faiz Ahmed,Mehta, Goverdhan
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p. 3522 - 3525
(2013/07/05)
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- A self-organizing chemical assembly line
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Chemical syntheses generally involve a series of discrete transformations whereby a simple set of starting materials are progressively rendered more complex. In contrast, living systems accomplish their syntheses within complex chemical mixtures, wherein the self-organization of biomolecules allows them to form assembly lines that transform simple starting materials into more complex products. Here we demonstrate the functioning of an abiological chemical system whose simple parts self-organize into a complex system capable of directing the multistep transformation of the small molecules furan, dioxygen, and nitromethane into a more complex and information-rich product. The novel use of a self-assembling container molecule to catalytically transform a high-energy intermediate is central to the system's functioning.
- Salles, Airton G.,Zarra, Salvatore,Turner, Richard M.,Nitschke, Jonathan R.
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supporting information
p. 19143 - 19146
(2014/01/17)
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- Microphotochemistry using 5-mm light-emitting diodes: Energy-efficient photooxidations
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Commercial, inexpensive 5-mm milliwatt light-emitting diodes are effective sources for batch microphotochemical oxidations. Using limited quantities of singlet oxygen, these oxidations are atom economical and therefore useful for labeling experiments with rare isotopes. Georg Thieme Verlag Stuttgart · New York.
- Carney, John M.,Hammer, Reagan J.,Hulce, Martin,Lomas, Chad M.,Miyashiro, Dayna
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experimental part
p. 2560 - 2566
(2012/09/07)
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- Photooxygenations in a bubble column reactor
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A novel column reactor was constructed and successfully applied to dye-sensitized photooxygenation reactions in aqueous alcohol solutions. The air flow pattern within the narrow glass column could be controlled via the size of the air inlet capillary. Using a 500 μm capillary, a slug flow pattern was realized which allowed for superior mass transfer and light transparency within a thin solvent layer. These features subsequently gave higher conversion rates and isolated yields.
- Yavorskyy, Alexander,Shvydkiv, Oksana,Limburg, Carolin,Nolan, Kieran,Delaure, Yan M. C.,Oelgemoeller, Michael
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experimental part
p. 888 - 892
(2012/06/18)
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- Synthesis and phytotoxicity of 4,5 functionalized tetrahydrofuran-2-ones
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In this work we report a versatile synthesis of fourteen γ-lactones all structurally related, nine of which are novel compounds, accomplished from the readily available furfural. The phytotoxic activity of the synthesized compounds was evaluated in vitro by the influence on the growth of wheat coleoptiles. The percentages of inhibition were mostly small and not statistically different from control after the third dilution (100 μmol L-1). In general, α,β-unsaturated lactones presented better activities than the saturated ones. The most active compounds presented 51, 68 and 76percent of inhibition in 1000 μmol L-1. The results indicate that regardless of saturation, the presence of the γ-lactone moiety is important for the bioactivity, but their presence has no implications with potency. ?2012 Sociedade Brasileira de Qui?mica.
- Resende, Gabriela C.,Alvarenga, Elson S.,Galindo, Juan C.G.,MacIas, Francisco A.
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p. 2266 - 2270
(2013/04/24)
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- Using water, light, air and spirulina to access a wide variety of polyoxygenated compounds
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A new set of completely green methods utilising air, light, water and spirulina to transform readily accessible furan substrates into a diverse range of synthetically useful polyoxygenated motifs commonly found in natural products is presented herein. The Royal Society of Chemistry 2012.
- Noutsias, Dimitris,Alexopoulou, Ioanna,Montagnon, Tamsyn,Vassilikogiannakis, Georgios
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supporting information; experimental part
p. 601 - 604
(2012/04/23)
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- Scope and limitations of the photooxidations of 2-(α-Hydroxyalkyl) furans: Synthesis of 2-hydroxy-exo -brevicomin
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Photooxygenation of 2-(α-hydroxyalkyl)furans at 5 °C in MeOH followed by in situ reduction affords, in one synthetic operation, 6-hydroxy-3(2H)-pyranones and/or 5-hydroxy-2(5H)-furanones. The relative ratio of the final products is highly dependent on the substitution of the starting furan substrate. Photooxygenation of 2-(α,β-dihydroxyalkyl)furans followed by in situ reduction and ketalization with acid rapidly provides the 6,8-dioxabicyclo[3.2.1]oct-3-en-2-one framework. This new methodology was successfully applied to the synthesis of 2-hydroxy-exo-brevicomin.(Figure Presented)
- Noutsias, Dimitris,Kouridaki, Antonia,Vassilikogiannakis, Georgios
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supporting information; experimental part
p. 1166 - 1169
(2011/05/06)
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- Photooxygenation of furans in water and ionic liquid solutions
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Photooxygenation of differently functionalized furans is investigated in aqueous solutions and in ionic liquids [emim]Br and [bmim]BF4. The reaction is generally selective and the final products derive from rearrangement of the intermediate endoperoxides, depending mainly on the polarity and/or nucleophilic nature of the solvent.
- Astarita, Anna,Cermola, Flavio,Dellagreca, Marina,Iesce, Maria Rosaria,Previtera, Lucio,Rubino, Maria
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scheme or table
p. 2030 - 2033
(2010/06/15)
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- Efficient and recyclable phthalocyanine-based sensitizers for photooxygenation reactions
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Treatment of 4,5-bis(4-methoxycarbonylphenoxy) phthalonitrile with Zn(OAc)2·2H2O and 1,8-diazabicyclo[5.4.0]undec-7- ene in octan-1-ol or dodecan-1-ol led to base-promoted cyclotetramerization. Under these conditions, transesterification also occurred to give the corresponding zinc(II) octakis(4-alkoxycarbonylphenoxyphthalocyanines. These two macrocycles, together with another two pegylated silicon(IV) phthalocyanines, were found to be highly efficient sensitizers for the photooxygenation of a series of alkenes and 1-naphthol. In general, the zinc(II) analogues exhibit a higher photostability and can be recycled at least four times without a significant loss of activity. Georg Thieme Verlag Stuttgart.
- Xu, Hu,Chan, Wing-Kin,Ng, Dennis K. P.
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scheme or table
p. 1791 - 1796
(2010/01/15)
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- Catalytic oxidation reactions of furan and hydrofuran compounds 9. Characteristics and synthetic possibilities of the reaction of furan with aqueous hydrogen peroxide in the presence of compounds of niobium(II) and (V)
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The effect of the catalytic characteristics of compounds of niobium(II) and (V) on the duration and the composition of the products during the oxidation of furfural by aqueous hydrogen peroxide was studied. It was established that the process is intermediate in its main characteristics between reactions of the compounds taking place under the conditions of autocatalysis by the acids that are formed and in the presence of the vanadium compounds. The main product of the reaction is 2(5H)-furanone. A method is proposed for its production with yields of up to 60%.
- Poskonin
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experimental part
p. 1177 - 1183
(2010/05/02)
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- Stereocontrolled total synthesis of (-)-kainic acid. Regio- and stereoselective lithiation of pyrrolidine ring with the (+)-sparteine surrogate
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(Chemical Equation Presented) A stereocontrolled total synthesis of (-)-kainic acid is described. cis-3,4-Disubstituted pyrrolidine ring was constructed by [3 + 2] cycloaddition of azomethine ylide with chiral butenolide. The crucial introduction of carboxyl group at the C-2 position was executed by regio- and stereoselective lithiation of the pyrrolidine ring in the presence of a (+)-sparteine surrogate followed by trapping with carbon dioxide.
- Morita, Yasuhiro,Tokuyama, Hidetoshi,Fukuyama, Tohru
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p. 4337 - 4340
(2007/10/03)
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- Highly enantioselective synthesis and potential biological activity of chiral novel nucleoside analogues containing adenine and naturally phenol derivatives
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This paper described an efficient synthetic strategy for chiral acyclic nucleoside analogues containing both the phenoxy components of some bioactive natural compounds and a heterocyclic base. The phenoxy components with adenine moiety were incorporated into the chiral acyclic nucleoside analogues through two key synthetic tactics. Chiron 5-(R)-menthyloxy-2(5H)-furanone 5 was obtained in good yield from the cheap starting material furfural via a valuable synthetic route. The asymmetric Michael addition of 5 with adenine and the subsequent reduction reaction afforded the key chiral intermediate, 2-(R)-(9′-adeninyl)-1,4-butanediol 8. The absolute configuration of 8 was established by X-ray crystallography. The intermolecular dehydration reaction between 2-(9′-adeninyl)-1,4-butanediol 8 and phenoxy components 9 on treatment with diethyl azodicarboxylate and triphenylphosphine was carried out to give the chiral acyclic nucleoside analogues 1a-1e. The regioselectivity of the reaction was established by NMR methods, especially through 13C NMR shifts and NOE effect observed in the target molecule 1c, as well as by HMBC/HMQC experiments. The target compounds were tested for inhibition of cytopathogenicity against different cancer cells and exhibited potential anticancer activity.
- He, Lan,Liu, Yumei,Zhang, Wei,Li, Ming,Chen, Qinghua
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p. 8505 - 8511
(2007/10/03)
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- Origin of Chiral Induction in Radical Reactions with the Diastereoisomers (5R)- and (5S)-5-l-Menthyloxyfuran-2[5H]-one
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Acetalization of 5-hydroxyfuran-2[5H]-one with l-menthol yields (5R)-(1) and (5S)-5-l-menthyloxyfuran-2[5H]-one (2) in equal amounts. The diastereomer 1 crystallizes preferentially. For the first time, the isolation of pure diastereoisomer 2 is reported. Different diastereoselectivities were observed in the radical tandem reaction of 1 and 2 with N,N-dimethylaniline. The privileged conformations in solution of the substrates and the products of the radical reaction were then determined, and X-ray crystal structure analyses were carried out on the reaction products. The different stereoselectivities in both cases are explained by different orientations of the menthyloxy substituent.
- Marinkovic, Sinisa,Brule, Cedric,Hoffmann, Norbert,Prost, Elise,Nuzillard, Jean-Marc,Bulach, Veronique
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p. 1646 - 1651
(2007/10/03)
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- Titanium silicalite 1 (TS-1) catalyzed oxidative transformations of furan derivatives with hydrogen peroxide
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The oxidation of furan derivatives with titanium silicalite 1 (TS-1) and hydrogen peroxide is described. Oxidation products are identified and possible reaction pathways are discussed. It is shown that the oxidation of these compounds occurs via epoxidation of one of the furan double bonds. The initially formed epoxides immediately undergo rearrangement, furans yielding unsaturated 1,4-dicarbonyl compounds and furfuryl alcohols yielding 6-hydroxy-2H-pyran-3(6H) -ones. The latter compounds originate from cyclization of intermediate enedione alcohols. The presented method is particularly useful for the oxidation of 2,5-dimethylfuran to 3-hexene-2,5-dione and the conversion of furfuryl alcohol to 6-hydroxy-2H-pyran-3(6H)-one, a versatile synthon in organic synthesis.
- Wahlen, Joos,Moens, Bart,De Vos, Dirk E.,Alsters, Paul L.,Jacobs, Pierre A.
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p. 333 - 338
(2007/10/03)
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- Diastereoselectivity in the epoxidation of γ-hydroxy α,β-unsaturated esters: Temperature and solvent effect
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The diastereoselectivity in the nucleophilic epoxidation of γ-hydroxy α,β-unsaturated compounds using lithium-tert-butylperoxide is highly dependent on the reaction solvent but not influenced by the temperature. The free hydroxyl is key for stereoselection.
- Rodríguez, Santiago,Vidal, Alberto,Monroig, Juan J.,González, Florenci V.
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p. 5359 - 5361
(2007/10/03)
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- Photooxygenation of olefins, phenol, and sulfide using fullerodendrimer as catalyst
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Fullerodendrimer acts as a new catalyst that uses oxygen and light to generate singlet oxygen (1O2)- The dendrimer facilitates various types of singlet oxygenation reactions including ene reaction, the Diels-Alder reaction, and oxidation of phenol and sulfide.
- Takaguchi, Yutaka,Yanagimoto, Yasushi,Fujima, Shohoko,Tsuboi, Sadao
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p. 1142 - 1143
(2007/10/03)
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