- Synthesis and characterization of ZrO2 as acid-basic catalysts: Reactivity of 2-methyl-3-butyn-2-ol
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Two ZrO2-based catalysts have been synthesized by thermal treatment of a gel prepared from ZrOCl2 · 8H2O. The effect of different preparation parameters on the final properties of the solids was studied. Textural characterization was carried out from nitrogen adsorption/desorption isotherms. XRD and FT-Raman spectroscopy have been used to elucidate the physical state of the catalysts. Their acid-base properties were studied following temperature programmed desorption-mass spectrometry and diffuse reflectance infrared Fourier transform techniques, by using pyridine, 2,6-dimethylpyridine and carbon dioxide as probe molecules. Both solids were tested for the 2-methyl-3-butyn-2-ol reaction by using two different procedures: (a) in a microcatalytic pulse reactor and (b) through isotherm and temperature programmed surface reactions in a flow reactor. In addition, temperature programmed oxidation and temperature programmed desorption experiments revealed that catalyst deactivation was caused by carbon deposition on the catalytic surface. Amphoteric selectivity for both solids, leading to 3-hydroxy-3-methyl-2-butanone and 3-methyl-3-buten-2-one, depends on the reaction temperature; thus, it is 92% at 225°C for a catalyst calcined at 400°C (ZrO2-400VAC).
- Aramendia, M. Angeles,Borau, Victoriano,Jimenez, Cesar,Marinas, Jose M.,Marinas, Alberto,Porras, Andres,Urbano, Francisco J.
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- A study of two thermostable NLO chromophores with different π-electron bridges using fluorene as the donor
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Two chromophores C1 and C2 based on a fluorene electron donor with different π-electron bridges and the same electron acceptor have been synthesized and systematically characterized using NMR, MS and UV-vis absorption spectra. The energy gap between the ground state and the excited state and molecular nonlinearity were studied using UV-vis absorption spectroscopy, Density Functional Theory calculations and cyclic voltammetry measurements. The different properties between C1 and C2 were systematically compared. The results showed that C2 had a better performance than C1. The electrooptic coefficient of a poled film containing 25 wt% of C2 doped in amorphous polycarbonate afforded a value of 40 pm V-1 at 1310 nm. In addition, the excellent thermostability of C2 made itself a favourable candidate for practical application.
- Wang, Haoran,Liu, Fenggang,Yang, Yuhui,Zhang, Maolin,Peng, Chengcheng,Bo, Shuhui,Liu, Xinhou,Qiu, Ling,Zhen, Zhen
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- Hydrolysis of methylacetoin ethyl phosphate. competing pathways for carbonyl hydrate participation in a model for biotin carboxylation
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Methylacetoin ethyl phosphate (1) is a phosphodiester with a carbonyl group β to phosphorus. The phosphate ester of a carbonyl hydrate, expected to be generated from an intramolecular reaction of 1 in base, is a model for an enzymic reaction intermediate which would form from the reaction of the tetrahedral addition production of biotin and bicarbonate with ATP. The hydrolysis of 1 is 104-105 times more rapid than that of dimethyl phosphate, extrapolated to common conditions (1 M NaOH, 55°C). Kinetic, product, and isotope labeling studies show that the hydrate of the carbonyl group of 1 serves as an intramolecular nucleophile toward phosphorus, forming the expected phosphate ester of the carbonyl hydrate through cyclic phosphorane intermediates. These adducts decompose by routes which parallel the proposed enzymic mechanism. In addition, solvent isotope incorporation reveals a route not found in reactions of carbonyl-substituted phosphotriesters: the conjugate base of the carbonyl hydrate acts an intramolecular nucleophile at the adjacent carbon atom, forming an unstable hydroxyoxirane (which becomes methylacetoin) and ethyl phosphate. An analogous reaction of ribonucleic acids (and RNAzymes) would have the 2′ hydroxyl group react at the 3′ carbon to form an oxyoxirane, cleaving the 3′ internucleotide bond.
- Taylor, Scott D.,Kluger, Ronald
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- An abnormal reaction of esters of 3-hydroxy-3-methylbutan-2-one. A rapid synthesis of bullatenone and geiparvarin
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A new rapid and facile synthesis of two natural products with the structure of3(2H)furanone is described by a cyclisation catalysed by cesium fluoride.
- Villemin, Didier,Jaffres, Paul-Alain,Hachemi, Messaoud
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- Nonlinear optical chromophores based on Dewar's rules: Enhancement of electro-optic activity by introducing heteroatoms into the donor or bridge
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In this work, we investigated the enhancement of the electro-optic response by introducing electron-rich heteroatoms as additional donors into the donor or bridge of a conventional second-order nonlinear optical chromophore. A series of chromophores C2-C4 based on the same tricyanofuran acceptor (TCF) but with different heteroatoms in the alkylamino phenyl donor (C2 or C3) or thiophene bridge (C4) have been synthesized and systematically investigated. Density functional theory calculations suggested that chromophores C2-C4 had a smaller energy gap and larger first-order hyperpolarizability (β) than traditional chromophore C1 due to the additional heteroatoms. Single crystal structure analyses and optimized configurations indicate that the rationally introduced heteroatom group would bring larger β and weaker intermolecular interactions which were beneficial for translating molecular β into macro-electro-optic activity in electric field poled films. The electro-optic coefficient of poled films containing 25 wt% of these new chromophores doped in amorphous poly-carbonate afforded values of 83 and 91 pm V-1 at 1310 nm for chromophores C3 and C4, respectively, which are two times higher than that of the traditional chromophore C1 (39 pm V-1). High r33 values indicated that introducing heteroatoms to the donor and bridge of a conventional molecular structure can efficiently improve the electron-donating ability, which improves the β. The long-chain on the donor or bridge part, acting as the isolation group, may reduce inter-molecular electrostatic interactions, thus enhancing the macroscopic EO activity. These results, together with good solubility and compatibility with the polymer, show the new chromophore's potential application in electro-optic devices.
- Xu, Huajun,Yang, Dan,Liu, Fenggang,Fu, Mingkai,Bo, Shuhui,Liu, Xinhou,Cao, Yuan
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- Ionic Liquid as an Efficient Promoting Medium for Fixation of CO 2: Clean Synthesis of α-Methylene Cyclic Carbonates from CO2 and Propargyl Alcohols Catalyzed by Metal Salts under Mild Conditions
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Reactions of propargylic alcohols with CO2 in a [BMIm][PhSO 3]/CuCl catalytic system to produce the corresponding α-methylene cyclic carbonates were conducted with high yields. Mild reaction conditions, enhanced rates, improved yields, and recyclable ionic liquid catalyst systems are the remarkable features exhibited in this process. Furthermore, the use of large amounts of tertiary amines as well as nitrogen-containing organic solvent as employed in previously studies was avoided.
- Gu, Yanlong,Shi, Feng,Deng, Youquan
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- α-Oxidation of ketones using n-cation radicals
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Six-membered ring ketones and acyclic ketones were oxidized by stable triarylamminium radical cations in moist acetonitrile at room temperature in the presence of a base to α-hydroxy ketones in good yield. Five-membered ring ketones gave the corresponding αβ-unsaturated compounds.
- Schulz, Manfred,Kluge, Ralph,Sivilai, Li,Kamm, Birgit
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- VOLATILE CONSTITUENTS OF PLUS AND MINUS STRAINS OF BLAKESLEA TRISPORA
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Identification of the predominant constiutents produced by the plus and minus strains of Blakeslea trispora is described.The occurence of xylenes in the volatiles produced by the plus strain is reported.Additionally, production of 3-hydroxy-3-methylbutanal by the plus strain and dimethyl allyl alcohol by the minus strains were confirmed.Isoamyl alcohol, 1-octen-3-ol, 3-octanol and β-phenethyl alcohol were identified in volatiles from both strains. - Key Word Index: Blakeslea trispora; Mucorales, xylene; isoamyl alcohol; 3-hydroxy-3-methylbutanal; dimethyl allyl alcohol.
- Nabeta, K.,Nishimori, I.,Sato, S.,Sugisawa, H.
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- A green and recyclable CuSO4·5H2O/ionic liquid catalytic system for the CO2-promoted hydration of propargyl alcohols: an efficient assembly of α-hydroxy ketones
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α-Hydroxy ketones are important building blocks in biological, pharmaceutical and synthetic chemistry. In this work, diverse α-hydroxy ketones were efficiently constructed through the CO2-promoted hydration process of propargyl alcohols, which was catalyzed by a system consisted of economical CuSO4·5H2O and a green 1-butyl-3-methylimidazolium acetate ionic liquid. Particularly, this catalytic system exhibited excellent activity under atmospheric CO2 or even mimetic flue gas (20 vol% of CO2). Moreover, this system employed the lowest metal loading ever reported (0.004–0.25 mol%) meanwhile reached the highest turnover number (11700) for the target hydration reaction. Additionally, this is the first reported Cu catalytic system with reliable recyclability, which could be easily reused at least 6 times with yields higher than 85%.
- Chen, Cheng,Chen, Yiyun,Hu, Jia,Huang, Leilei,Verpoort, Francis,Wang, Yu,Yuan, Ye,Zhao, Yufeng,Zheng, Jiayun
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- A CO2-mediated base catalysis approach for the hydration of triple bonds in ionic liquids
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Herein, we report a CO2-mediated base catalysis approach for the activation of triple bonds in ionic liquids (ILs) with anions that can chemically capture CO2 (e.g., azolate, phenolate, and acetate), which can achieve hydration of triple bonds to carbonyl chemicals. It is discovered that the anion-complexed CO2 could abstract one proton from proton resources (e.g., IL cation) and transfer it to the CN or CC bonds via a six-membered ring transition state, thus realizing their hydration. In particular, tetrabutylphosphonium 2-hydroxypyridine shows high efficiency for hydration of nitriles and CC bond-containing compounds under a CO2 atmosphere, affording a series of carbonyl compounds in excellent yields. This catalytic protocol is simple, green, and highly efficient and opens a new way to access carbonyl compounds via triple bond hydration under mild and metal-free conditions.
- Han, Buxing,Ke, Zhengang,Li, Ruipeng,Liu, Zhimin,Tang, Minhao,Wang, Yuepeng,Zeng, Wei,Zhang, Fengtao,Zhao, Yanfei
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supporting information
p. 9870 - 9875
(2021/12/27)
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- An efficient and recyclable AgNO3/ionic liquid system catalyzed atmospheric CO2 utilization: Simultaneous synthesis of 2-oxazolidinones and α-hydroxyl ketones
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Oxazolidinones and α-hydroxyl ketones are two series of fine chemicals that have been generally utilized in biological, pharmaceutical, and synthetic chemistry. Herein, a AgNO3/ionic liquid (IL) catalytic system was developed for the simultaneous synthesis of these compounds through the atom-economical three-component reactions of propargyl alcohols, 2-aminoethanols, and CO2. Notably, this system behaved excellent catalytic activity with the lowermost metal loading of 0.25 mol%. Meanwhile, it is the first reported metal-catalyzed system that could efficiently work under atmospheric CO2 pressure and be recycled at least five times. Evaluation of the green metrics proved the AgNO3/IL-catalyzed processes to be relatively more sustainable and greener than the other Ag-catalyzed examples. Further mechanistic investigations revealed the derivative active species of N-heterocyclic carbene (NHC) silver complexes and CO2 adducts generated during the process. Subsequently, their reactivity in this reaction was assessed for the first time, which was finally identified as beneficial for the catalytic activity.
- Bu, Chao,Chaemchuen, Somboon,Chen, Cheng,Du, Minchen,Gong, Yanyan,Hu, Jia,Verpoort, Francis,Yuan, Ye,Zhang, Yongxing
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- Thermodynamic favorable CO2 conversion via vicinal diols and propargylic alcohols: A metal-free catalytic method
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Organocatalysis represents a promising field in chemical fixation of CO2. Herein, a facile metal-free strategy was reported for the one-pot preparation of cyclic carbonates and α-hydroxy ketones from vicinal diols, propargylic alcohols and CO2. Wide scope of vicinal diols and propargylic alcohols was demonstrated to be efficient under the DBU-catalyzed conditions. A plausible mechanism was proposed, which included detailed main and side reactions under the metal-free conditions.
- Han, Li-Hua,Li, Jing-Yuan,Song, Qing-Wen,Zhang, Kan,Zhang, Qian-Xia,Sun, Xiao-Fang,Liu, Ping
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supporting information
p. 341 - 344
(2019/07/04)
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- Photocatalytic Reductive Radical-Polar Crossover for a Base-Free Corey–Seebach Reaction
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A metal-free generation of carbanion nucleophiles is of prime importance in organic synthesis. Herein we report a photocatalytic approach to the Corey–Seebach reaction. The presented method operates under mild redox-neutral and base-free conditions giving the desired product with high functional group tolerance. The reaction is enabled by the combination of photo- and hydrogen atom transfer (HAT) catalysis. This catalytic merger allows a C?H to carbanion activation by the abstraction of a hydrogen atom followed by radical reduction. The generated nucleophilic intermediate is then capable of adding to carbonyl electrophiles. The obtained dithiane can be easily converted to the valuable α-hydroxy carbonyl in a subsequent step. The proposed reaction mechanism is supported by emission quenching, radical–radical homocoupling and deuterium labeling studies as well as by calculated redox-potentials and bond strengths.
- Crespi, Stefano,Donabauer, Karsten,K?nig, Burkhard,Murugesan, Kathiravan,Rozman, Ur?a
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supporting information
p. 12945 - 12950
(2020/09/23)
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- Selective Conversion of CO 2 and Switchable Alcohols into Linear or Cyclic Carbonates via Versatile Zinc Catalysis
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It is promising and challenging to achieve the effective construction of carbonates using CO 2 and a non-noble metal catalyst. Herein, selective catalytic conversion of CO 2 and switchable alcohol candidates to produce linear or cyclic carbonates and α-hydroxy ketones via effective zinc catalyst was developed. A series of primary alcohols and cyclohexanol, 1,2-diols, and water can serve as nucleophiles to give alkyl or aryl 2-substituted-3-oxobutan-2-yl carbonates, substituted 1,3-dioxolan-2-ones, 3-substituted 3-hydroxybutan-2-ones, respectively with excellent selectivity and high yields.
- Song, Qing-Wen,Zhao, Qing-Ning,Li, Jing-Yuan,Zhang, Kan,Liu, Ping
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p. 739 - 746
(2019/01/23)
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- Synthesis of Α-hydroxy ketones by copper(I)-catalyzed hydration of propargylic alcohols: CO2 as a cocatalyst under atmospheric pressure
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Inexpensive and efficient Cu(I) catalysis is reported for the synthesis of α-hydroxy ketones from propargylic alcohols, CO2, and water via tandem carboxylative cyclization and nucleophilic addition reaction. Notably, hydration of propargylic alcohols can be carried out smoothly under atmospheric CO2 pressure, generating a series of α-hydroxy ketones efficiently and selectively. This strategy shows great potential for the preparation of valuable α-hydroxy ketones by using CO2 as a crucial cocatalyst under mild conditions.
- Zhou, Zhi-Hua,Zhang, Xiao,Huang, Yong-Fu,Chen, Kai-Hong,He, Liang-Nian
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p. 1345 - 1351
(2019/08/07)
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- Organic second-order nonlinear optical chromophore modified by flexible isolating group and preparation method and application thereof
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The invention discloses an organic second-order nonlinear optical chromophore modified by a flexible isolating group, It has the following structure described in the description, wherein R1 is an alkyl group of C1 to C20, a hydroxyalkyl group of C1 to C10, a hydroxyalkyl group of C1 to C10 protected by a halogen atom or a hydroxyalkyl group of C1 to C10 protected by a silane; R2 is methyl or trifluoromethyl; R3 is alkyl or phenyl of C1 to C20. The electron donor, the conjugated pi electron bridge and the electron acceptor of the invention are combined to not only well increase the intermolecular steric hindrance, but also inhibit the accumulation between chromophore molecules caused by dipole interaction, improve the intramolecular electron transport ability and effectively improve the conversion of the first-order hyperpolarizability of chromophore molecules to the macroscopic electro-optic coefficients of materials.
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Paragraph 0070; 0074; 0107-0108
(2019/02/21)
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- Highly regio- And stereoselective synthesis of cyclic carbonates from biomass-derived polyols: Via organocatalytic cascade reaction
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The cascade reaction of CO2, vicinal diols, and propargylic alcohol, was firstly achieved by dual Lewis base (LB) organocatalytic systems involving LB-CO2 adducts and commercially available organic amines. This methodology could overcome the chemical inertness of CO2, providing an alternative route to various functionalized five-membered cyclic carbonates in moderate to high yields under mild reaction conditions (25 °C, 1.0 atm of CO2). More importantly, this method could also be applied for facile and efficient synthesis of chiral polycyclic carbonates from biomass-derived polyols with complete configuration retention of chiral centers. This study provides an environment-friendly, scalable and cost effective protocol to construct value-added cyclic carbonates with multi-functional groups and chiral centers.
- Zhou, Hui,Zhang, Hui,Mu, Sen,Zhang, Wen-Zhen,Ren, Wei-Min,Lu, Xiao-Bing
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supporting information
p. 6335 - 6341
(2019/12/03)
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- Microwave synthesis with D - π - A structure of second-order non-linear optical chromophore method
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The invention belongs to a synthesis method of an organic second-order nonlinear optical chromophore with a cyclic polyene structure compound as an electron bridge and especially relates to a second-order nonlinear optical chromophore which is synthesized by microwave heating, contains a high-performance electron donor (D) of an aldehyde group, a cyclic polyene structured electron bridge (pi) and a tricyano-dihydro furan (TCF) or trifluoro-substituted tricyano-dihydro furan (CF3-TCF) electron acceptor (A) and has a D-pi-A structure. The second-order nonlinear optical chromophore has a structure as shown in the specification. By a microwave heating method, the electron donor and the compound with the cyclic polyene structure undergo a chemical reaction in the presence of anhydrous ethanol and sodium ethoxide. Heat energy loss is reduced, reaction molecular collision probability is enhanced, reaction time is greatly shortened, reaction rate is increased, and reaction yield is raised.
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Paragraph 0072; 0075; 0076; 0092; 0093; 0131
(2018/05/24)
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- Alpha-hydroxy-ketone compound synthesis method
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The invention discloses an alpha-hydroxy-ketone compound synthesis method. In the prior art, a noble metal complex, an organophosphorus compound or an iodine elementary substance is always used as a catalyst, the price is high and the recycle cost is higher; used alkali is organic alkali with a complex structure or unusual inorganic alkali such as cesium carbonate which is high in price; a used solvent is always selected from aprotic organic solvents, the post-treatment is complex, and industrialized application is difficult to realize. According to the alpha-hydroxy-ketone compound synthesis method provided by the invention, common inorganic sulfocompounds with low price are adopted as the catalyst, under the alkali and aerobic condition, a carbonyl compound is catalyzed to react to obtain the alpha-hydroxy-ketone compound. The invention has the advantages that the used raw materials are easy to obtain, the price is low, the yield is high, the product purity is high, the waste amount is less and easy to treat, and industrialization is easy to realize.
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Paragraph 0044; 0045; 0046; 0047; 0048
(2017/07/19)
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- Organic second-order nonlinear optical chromophore, synthetic method and application
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The invention discloses an organic second-order nonlinear optical chromophore, a synthetic method and an application. The organic second-order nonlinear optical chromophore is provided with a structure of a Formula (CL) or Formula (HCL): FORMULA, wherein G is H, para-alkoxyphenyl, thienyl, or para-dialkyl aminophenyl; R1 is alkyl, benzyl, and halogenated alkyl; R2 is methyl or trifluoromethyl; R3 is alkyl, phenyl, replaced phenyl, replaced thienyl or hydroxyalkyl. The organic second-order nonlinear optical chromophore with D-Pi-A structure has simple synthetic step and high preparation yield; besides, it has good solubility in the most organic solvent and high thermal stability; the organic second-order nonlinear optical chromophore can be widely applied to the field of optical information material.
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Paragraph 0083; 0096; 0097; 0108; 0120; 0130; 0140
(2017/05/05)
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- Organic second-order nonlinear optical chromophore having Y-type D-pi-A structure, and synthesis method and application thereof
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The invention provides an organic second-order nonlinear optical chromophore having a Y-type D-pi-A structure. The organic second-order nonlinear optical chromophore having the Y-type D-pi-A structure has a structure as shown below in the specification, wherein X is an S or O atom; R1 is methyl or trifluoromethyl; and R2 is alkyl or phenyl. After an electron donor, a conjugate pi electron bridge and an electron acceptor, which are used by the invention, are combined together, the intramolecular electron transmission capability is enhanced, and the electrooptic coefficient can be increased. Besides, the synthesized chromophore molecule has the special Y-type structure, thereby effectively reducing the intermolecular interaction force. The organic second-order nonlinear optical chromophore is doped with amorphous polycarbonate to realize synthesis of a polymer film, and the polymer film can be used as a synthetic optical signal modulation material.
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Paragraph 0057-0058; 0072-0073
(2017/12/02)
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- With D - π - A structure of the organic second-order non-linear optical chromophore and synthetic method and use
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The invention relates to the field of organic second-order nonlinear optical materials and especially relates to an organic second-order nonlinear optical chromophore which has a D-pi-A structure and utilizes julolidine or its derivative as an electron donor, a thiophene ring or a cyclic polyene structure as a conjugate electron bridge and tricyano-dihydro furan or trifluoro-substituted tricyano-dihydro furan as an electron acceptor, and its synthesis method and use. Through combination of the used electron donor, conjugate pi electron bridge and electron acceptor, the organic second-order nonlinear optical chromophore can improve an intramolecular electron transfer capability and improve intermolecular steric hindrance. The organic second-order nonlinear optical chromophore can effectively improve a chromophore molecule first-order hyperpolarization rate (beta) and can effectively reduce intermolecular interaction. The organic second-order nonlinear optical chromophore adopted with amorphous polycarbonate can be used for preparation of a polarized polymer film. The polarized polymer film can be used as a material in the optical signal modulation field. The organic second-order nonlinear optical chromophore has a structure shown in the following description.
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Paragraph 0129; 0145; 0146
(2018/01/05)
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- With double-to the body structure of the organic second-order non-linear optical chromophore and synthetic method and use (by machine translation)
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The present invention has offered a kind of double-to the body structure of the organic second-order non-linear optical chromophore, the with double to the body structure of the organic second-order non-linear optical chromophore has the following structure: Wherein R1 Is methyl or trifluoromethyl; R2 Is alkyl or phenyl. The invention used with a two-to the body structure of the electron donor, conjugated π electronic bridge and electronic receptor are combined together in the molecule after the electronic transmission capacity, can improve the electro-optic coefficient. In addition, the synthesized chromophores with double to the body structure, can effectively reduce the intermolecular interaction force. The said organic second order non-linear optical chromophore with amorphous polycarbonate doped for synthetic polymer film, the polymer film can be used as a synthetic light signal modulation material. (by machine translation)
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Paragraph 0070-0071
(2017/10/13)
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- AgI/TMG-Promoted Cascade Reaction of Propargyl Alcohols, Carbon Dioxide, and 2-Aminoethanols to 2-Oxazolidinones
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Chemical valorization of CO2 to access various value-added compounds has been a long-term and challenging objective from the viewpoint of sustainable chemistry. Herein, a one-pot three-component reaction of terminal propargyl alcohols, CO2, and 2-aminoethanols was developed for the synthesis of 2-oxazolidinones and an equal amount of α-hydroxyl ketones promoted by Ag2O/TMG (1,1,3,3-tetramethylguanidine) with a TON (turnover number) of up to 1260. By addition of terminal propargyl alcohol, the thermodynamic disadvantage of the conventional 2-aminoethanol/CO2 coupling was ameliorated. Mechanistic investigations including control experiments, DFT calculation, kinetic and NMR studies suggest that the reaction proceeds through a cascade pathway and TMG could activate propargyl alcohol and 2-aminoethanol through the formation of hydrogen bonds and also activate CO2.
- Li, Xue-Dong,Song, Qing-Wen,Lang, Xian-Dong,Chang, Yao,He, Liang-Nian
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p. 3182 - 3188
(2017/10/03)
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- Synthesis and characterization of two novel second-order nonlinear optical chromophores based on julolidine donors with excellent electro-optic activity
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Julolidine and its derivatives are excellent electron-rich structures thus two novel second order nonlinear optical (NLO) chromophores based on julolidine donors and tricyanofuran (TCF) acceptors linked via isophorone bridge (zh-1) and modified isophorone bridge (zh-2) have been synthesized. Density functional theory (DFT) was used to optimize the geometrical structures, calculate the HOMO-LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. Besides, to determine the redox properties of these chromophores, cyclic voltammetry (CV) experiments were performed. The optimized structures suggest that chromophore zh-1 possesses better planarity which increases the ability of electron delocalization. These chromophores showed good thermal stability with their decomposition temperatures all above 210 °C. The electro-optic coefficients (r33) of poled films containing 25 wt% of these chromophores doped in amorphous polycarbonate (APC) afforded values of 170 and 101 pm V-1 at 1310 nm for chromophores zh-1 and zh-2, respectively. These properties show the potential use of the new chromophores as advanced material devices.
- Zhang, Hua,Huo, Fuyang,Liu, Fenggang,Chen, Zhuo,Liu, Jialei,Bo, Shuhui,Zhen, Zhen,Qiu, Ling
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p. 99743 - 99751
(2016/11/09)
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- Thermodynamically favorable synthesis of 2-oxazolidinones through silver-catalyzed reaction of propargylic alcohols, CO2, and 2-aminoethanols
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Development of catalytic routes to incorporate CO2 into carbonyl compounds at mild conditions remains attractive and challenging. Herein, a one-pot three-component cascade reaction of terminal propargylic alcohols, CO2, and 2-aminoethanols through AgI-based catalysis is reported for the synthesis of carbonyl compounds through C—O/C—N bond formation. This thermodynamically favorable route can be ingeniously regulated to afford a wide range of 2-oxazolidinones along with concurrent production of α-hydroxyl ketone derivatives in excellent yields and selectivity. Preliminary mechanistic studies indicate that such a process proceeds through successive formation of α-alkylidene cyclic carbonate, β-oxopropylcarbamate, and 2-oxazolidinones.
- Song, Qing-Wen,Zhou, Zhi-Hua,Wang, Mei-Yan,Zhang, Kan,Liu, Ping,Xun, Jia-Yao,He, Liang-Nian
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p. 2054 - 2058
(2017/07/25)
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- Silver(I)-Catalyzed Three-Component Reaction of Propargylic Alcohols, Carbon Dioxide and Monohydric Alcohols: Thermodynamically Feasible Access to β-Oxopropyl Carbonates
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A silver(I)-catalyzed three-component reaction of propargylic alcohols, CO2, and monohydric alcohols was successfully developed for the synthesis of β-oxopropyl carbonates. As such, a series of β-oxopropyl carbonates were exclusively produced in excellent yields (up to 98 %), even under atmospheric pressure of CO2. The silver catalyst works efficiently for both the carboxylative cyclization of propargylic alcohols with CO2 and subsequent transesterification of α-alkylidene cyclic carbonates with monohydric alcohols; thus this tandem process performs smoothly under mild conditions. This work provides a versatile and thermodynamically favorable approach to dissymmetric dialkyl carbonates.
- Zhou, Zhi-Hua,Song, Qing-Wen,Xie, Jia-Ning,Ma, Ran,He, Liang-Nian
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p. 2065 - 2071
(2016/07/28)
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- Water-Soluble Gold-N-Heterocyclic Carbene Complexes for the Catalytic Homogeneous Acid- and Silver-Free Hydration of Hydrophilic Alkynes
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Water-soluble gold(III/I) N-heterocylic carbene complexes behave as efficient catalysts for the hydration of terminal alkynes in neat water. The transformation proceeds in the absence of Bronsted acids or halide scavengers and is suitable for sensitive substrates. Kinetic profiles and DFT studies provide a clear picture of intermediates present during catalysis.
- Ibrahim, Houssein,Defrmont, Pierre,Braunstein, Pierre,Thry, Vincent,Nauton, Lionel,Cisnetti, Federico,Gautier, Arnaud
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p. 3893 - 3900
(2016/01/25)
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- Task-specific ionic liquid and CO2-cocatalysed efficient hydration of propargylic alcohols to α-hydroxy ketones
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The hydration of propargylic alcohols is a green route to synthesize α-hydroxy ketones. Herein a CO2-reactive ionic liquid (IL), [Bu4P][Im], was found to display high performance for catalyzing the hydration of propargylic alcohols in the presence of atmospheric CO2, and a series of propargylic alcohols could be converted into the corresponding α-hydroxy ketones in good to excellent yields. In the IL/CO2 reaction system, CO2 served as a cocatalyst by forming α-alkylidene cyclic carbonates with propargylic alcohols, and was released via the rapid hydrolysis of the carbonates catalysed by the IL. This is the first example of the efficient hydration of propargylic alcohols under metal-free conditions. This journal is
- Zhao, Yanfei,Yang, Zhenzhen,Yu, Bo,Zhang, Hongye,Xu, Huanjun,Hao, Leiduan,Han, Buxing,Liu, Zhimin
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p. 2297 - 2301
(2015/03/30)
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- Highly efficient C-H hydroxylation of carbonyl compounds with oxygen under mild conditions
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A transition-metal-free Cs2CO3-catalyzed α-hydroxylation of carbonyl compounds with O2 as the oxygen source is described. This reaction provides an efficient approach to tertiary α-hydroxycarbonyl compounds, which are highly valued chemicals and widely used in the chemical and pharmaceutical industry. The simple conditions and the use of molecular oxygen as both the oxidant and the oxygen source make this protocol very environmentally friendly and practical. This transformation is highly efficient and highly selective for tertiary C(sp3)-H bond cleavage. OH, so simple! A transition-metal-free Cs2CO 3-catalyzed α-hydroxylation of carbonyl compounds with O 2 provided a variety of tertiary α-hydroxycarbonyl compounds (see scheme; DMSO=dimethyl sulfoxide), which are widely used in the chemical and pharmaceutical industry. The simple conditions and the use of molecular oxygen as both the oxidant and the oxygen source make this protocol very efficient and practical.
- Liang, Yu-Feng,Jiao, Ning
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supporting information
p. 548 - 552
(2014/01/23)
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- AgOTf catalyzed hydration of terminal alkynes
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The silver catalysis towards the hydration of terminal alkynes is explored using Silver(I) triflate (AgOTf). The reaction leads to the formation of only Markovnikov addition product with excellent yield. Copyright
- Das, Rima,Chakraborty, Debashis
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p. 722 - 726
(2013/02/22)
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- Effective guanidine-catalyzed synthesis of carbonate and carbamate derivatives from propargyl alcohols in supercritical carbon dioxide
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The reactions of propargyl alcohols with carbon dioxide in supercritical carbon dioxide or in acetonitrile with gaseous carbon dioxide in the presence of organic bases as catalysts have been examined. Bicyclic guanidines are effective catalysts for the formation of α-methylene cyclic carbonates under mild reaction conditions. Oxoalkyl carbonates, oxoalkyl carbamates or α-methyleneoxazolidinones are obtained in high yields and good selectivities in one-step starting from propargyl alcohols and an external nucleophile (alcohols or amines) using bicyclic guanidines as catalysts in supercritical carbon dioxide. Propargylic diols under the same reaction conditions underwent a rearrangement process instead of carbon dioxide insertion whereas in the presence of an external nucleophile the formation of oxocarbonates, oxocarbamates or cyclic carbamates was achieved in satisfactory yields.
- Ca', Nicola Della,Gabriele, Bartolo,Ruffolo, Giuseppe,Veltri, Lucia,Zanetta, Tito,Costa, Mirco
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experimental part
p. 133 - 146
(2011/04/18)
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- Isolable gold(I) complexes having one low-coordinating ligand as catalysts for the selective hydration of substituted alkynes at room temperature without acidic promoters
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Hydration of a wide range of alkynes to the corresponding ketones has been afforded in high yields at room temperature by using gold(I)-phosphine complexes as catalyst, with no acidic cocatalysts required. Suitable substrates covering alkyl and aryl terminal alkynes, enynes, internal alkynes, and propargylic alcohols, including enantiopure forms, are cleanly transformed to the corresponding ketones in nearly quantitative yields. Acid-labile groups present in the substrates are preserved. The catalytic activity strongly depends on both the nature of the phosphine coordinated to the gold (I) center and the softness of the counteranion, the complex AuSPhOsNTf2 showing the better activity. A plausible mechanism for the hydration of alkynes through ketal intermediates is proposed on the basis of kinetic studies. The described catalytic system should provide an efficient alternative to mercury-based methodologies and be useful in synthetic programs.
- Leyva, Antonio,Corma, Avelino
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scheme or table
p. 2067 - 2074
(2009/08/07)
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- Process for producing carbonyl compound
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The present invention relates to a process which comprises efficiently proceeding a hydration reaction of an alkyne in aspects of turnover numbers of a catalyst, yield and speed to thereby industrially and advantageously produce the corresponding carbonyl compound. The present invention provides a process for producing a carbonyl compound, which comprises reacting an alkyne compound with water in the presence of a gold catalyst which is an organogold complex compound and acid in an organic solvent.
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Page/Page column 8
(2008/06/13)
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- Highly efficient Au1-catalyzed hydration of alkynes
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As good as gold: Hydration of alkynes by using gold - acid catalyst systems with high turnover frequencies provides a greener synthetic route to carbonyl compounds in high yields, as shown.
- Mizushima, Eiichiro,Sato, Kazuhiko,Hayashi, Teruyuki,Tanaka, Masato
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p. 4563 - 4565
(2007/10/03)
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- Structure, texture, acidity and catalytic performance of AlPO4-caesium oxide catalysts in 2-methyl-3-butyn-2-ol conversion
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A series of aluminium orthophosphate-caesium oxide systems with various caesium oxide loadings (5-30 wt%) were prepared by impregnation of ALPO4 with a methanolic solution of caesium acetate and characterized by TG/DTA, XRD, DRIFT, Raman, SEM-EDX, XPS, 27Al and 31P MAS NMR and nitrogen adsorption. Aluminium orthophosphate remained amorphous with caesium oxide incorporation when calcined at 873 K for 3 h. After thermal treatment at 1423 K it crystallized in the tridymite form except for materials containing 30 wt% caesium oxide. DRIFT spectroscopy showed that the P-OH stretching vibration at 3670 cm-1 decreased in intensity with caesium oxide loading. Materials at 20-30 wt% caesium oxide did not exhibit any hydroxyl bands. Besides, Al and P atoms remained in tetrahedral coordination as in unmodified aluminium orthophosphate. Moreover, the incorporation of caesium oxide leads, simultaneously, to a progressive decrease in surface area and pore volume (larger at 30 wt% caesium oxide) as well as to an increase in the most frequently occurring pore radius. On the other hand, caesium oxide reduced both the number and strength of acid sites as the caesium content increased. Consequently, 2-methylbut-3-yn-2-ol (MBOH) underwent almost exclusively dehydration to 3-methyl-3-buten-1-yne (acid activity) on pure AlPO4, whereas its modification with increasing amounts of caesium oxide developed AlPO4- based materials with increased basic properties and hence high selectivities (99 mol%) to the base-catalysed cleavage of MBOH yielding acetone and acetylene.
- Bautista, Felipa M.,Campelo, Juan M.,Garcia, Angel,Leon, Raquel M.,Luna, Diego,Marinas, Jose M.,Romero, Antonio A.,Navio, Jose A.,Macias, Manuel
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p. 827 - 835
(2007/10/03)
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- Mechanisms of carbonyl participation in phosphate ester hydrolysis and their relationship to mechanisms for the carboxylation of biotin
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The enzymic reaction of biotin with bicarbonate and ATP produces N-carboxybiotin, ADP, and phosphate. The intermediates in the reaction are unknown. It has been proposed that the intramolecular reaction of the carbonyl hydrate of methylacetoin diethyl phosphate (1) may serve as a model for the latter part of such a mechanism. In basic solution, 1 reacts rapidly to give two sets of products that can be accounted for by a mechanism involving addition of a hydroxyl group of the carbonyl hydrate to the adjacent phosphate. The rapid reaction of the nonenolizable ester with base rules out earlier mechanistic proposals of the reaction involving an enolization pathway. The course of incorporation of water containing H218O into phosphate ester products was determined by 31P NMR analysis. This reveals that the reversion of the carbonyl hydrate to the ketone occurs at a rate which is competitive with reaction at the phosphate ester since the isotopic enrichment of the phosphate group is less than the content of the solvent (76%). In weakly basic solutions a single set of products is obtained, but in more highly alkaline solutions a second set of products develops. The results are consistent with a competition between a mechanism in which the carbonyl hydrate adduct expels phosphate and one in which ethoxide is expelled to give a cyclic phosphate. Reactions of acetoin diethyl phosphate (2) and acetol diethyl phosphate (3) show a larger degree of solvent incorporation and a smaller variation in product distribution, consistent with expectations based on steric and inductive effects. It is concluded that the reaction mechanism parallels that which was proposed for the carboxylation of biotin.
- Kluger, Ronald,Taylor, Scott D.
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p. 996 - 1001
(2007/10/02)
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- Cetonisation catalytique du methyl-2-butene-3-ol par des complexes du rhodium(III) ou du palladium(II)
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A number of efficient catalytic procedures for the oxidation of acid-sensitive substrate such as 2-methyl-3-buten-2-ol to the corresponding ketone (2-methyl-butan-2-ol-3-one) are compared.Reaction with dioxygen (or quinone) and a palladium precursor (PdCl2 or ) under mild conditions (=35 deg C), gave good conversions (98percent) and good selectivities (=90percent).
- Derdar, Fatma,Martin, Jacques,Martin, Claudine,Bregeault, Jean-Marie,Mercier, Jacqueline
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p. C21 - C26
(2007/10/02)
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- Cobaltocene-Catalyzed Reaction of Carbon Dioxide with Propargyl Alcohols
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The reaction of carbon dioxide with α-ethynyl tertiary alcohols has been catalyzed by cobaltocene to give α-methylene cyclic carbonates in good yields. α-Ethynyl primary or secondary alcohols give noncyclic alkyl carbonates in fair yields.
- Inoue, Yoshio,Ishikawa, Jiro,Taniguchi, Masaaki,Hashimoto, Harukichi
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p. 1204 - 1206
(2007/10/02)
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- FACE SELECTIVITY IN THE (2+2) PHOTOANNELATION OF CHIRAL 3(2H)-FURANONES WITH ALKENES
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The photocycloadditions of a series of chiral 3(2H)-furanones with alkenes show facial selectivities which parallel the steric bulk of the furanone substituents.Selectivities approaching 50:1 are observed in some instances.
- Balbwin, S. W.,Mazzuckelli, T. J.
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p. 5975 - 5978
(2007/10/02)
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- Selectivity in the Oxidation of Aliphatic Ketones by Thallic Sulphate in Aqueous Medium
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The effects of temperature, structure and sulphuric acid concentration on the selectivity of the oxidation of aliphatic ketones (R1COR2) (1a-g) by thallic sulphate have been investigated.With increasing temperature the quantity of internal α-hydroxyketone (3a-d) decreases and the quantity of 1-hydroxyketone (2a-d) increases in the oxidation of methyl alkyl ketone (R2>CH3) (1a-d).The same concerns to the oxidation products of hexan-3-one (1e): 2-hydroxy-hexan-3-one (2e) and 4-hydroxy-hexan-3-one (3e), respectively. "The inverse selectivity temperature" (IST) for oxidation of linear methyl alkyl ketones (1a-c) and hexan-3-one (1e) has been found.With the use of the linear free-energy relationship it has been found that the selectivity of the reaction decreases with increasing the polar and steric effects of substituents R1,R2.With increasing the sulphuric acid concentration the selctivity of the oxidation of methyl alkyl ketones (1a, 1d) increases.
- Pechal, Miroslav,Strasak, Milan
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p. 374 - 380
(2007/10/02)
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- Electrochemical Oxidation of Allenic Hydrocarbons in Acetonitrile
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The anodic oxidation of a variety of alkyl-substituted allenes, terminal and internal ones, has been investigated in acetonitrile. All compounds studied were found to undergo 2e(-) oxidation followed by nucleophilic attack by acetonitrile and water molecules, to form products containing at least two of the following functional groups, C=C, NHCOCH3, C=O, and OH.The effect of various parameters (concentration, electrolyte, oxidation potential, temperature, and anode material) on the electro-oxidation of a model compound (nona-1,2-diene) has been studied and a general mechanistic scheme is presented and discussed.
- Becker, James Y.,Zinger, Baruch
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p. 395 - 402
(2007/10/02)
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- Photolysis of Butane-2,3-dione in Fluorocarbon Solvents; a Chemically Induced Nuclear Polarization (CIDNP) Study
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CIDNP observations of the polarized signals from products of radical reactions in solutions of neat butane-2,3-dione in perfluorocyclohexane and perfluorodecalin, and in solutions with added radical scavenger or hydrogen donor, are consistent with three primary processes.There are symmetric (probably) and unsymmetric fragmentation and hydrogen-abstraction by triplet butane-2,3-dione from the starting material, and each yields free radicals.In all solutions the mechanisms of ensuing reactions are suggested.In the presence of CCl4 and CCl3Br pair substitution effects dominate the CIDNP behaviour.When high concentrations of propan-2-ol are present evidence is given for reaction of the excited singlet state of the parent molecule.
- Broomhead, Eleanor J.,McLauchlan, Keith A.,Roe, Jonathan C.
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p. 796 - 804
(2007/10/02)
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- Peroxygen compounds
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The invention relates to novel ketone peroxides compositions containing them and processes for producing the peroxides and the compositions. The ketone peroxides are those with an alkoxy or hydroxy substituent in the α,β- or γ-position. The compositions contain (1) the peroxides and (2) water which may be in admixture with a hydrophobic or hydrophilic solvent or (3) a hydrophobic solvent. The peroxides are produced by reacting the α,β- or γ-alkoxy or hydroxy ketone with aqueous hydrogen peroxide and a source of hydrogen ions, for example a mineral acid.
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- Process for the synthesis of substituted indolenines
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A process for the preparation of substituted indolenines of the formula: STR1 wherein R is hydrogen, alkyl, aryl or cycloalkyl, halogen, or a functional group selected from among cyano, hydroxyl, alkoxy, nitro or sulphonic groups, and wherein R1, R2 and R3 are the same, or different, and are selected from alkyl, aryl or cycloalkyl radicals, comprising reacting in the presence of an organic solvent an aromatic amine of the formula: STR2 with a tertiary hydroxyketone of the formula: STR3 wherein R, R1, R2 and R3 have the same meanings as defined above, in the presence of a catalyst selected from mineral acids, organic acids, Lewis acids or ionic exchange resins in acid form, and wherein said aromatic amine is slightly in excess, to form first an imine of the formula: STR4 under reaction conditions wherein the solvent is removed by azeotropic distillation, and thereafter continuing the reaction to remove water and cyclizing to the desired indolenines. In a preferred embodiment, 2,3,3-trimethylindolenine is prepared by reacting an excess of aniline with 3-methyl-3-hydroxybutan-2-one in the presence of ZnCl2 as catalyst utilizing benzene as solvent. The substituted indolenines obtained are useful in production of dyes and other compounds useful in the dyeing and photographic industries.
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