- Transformation of Thioacids into Carboxylic Acids via a Visible-Light-Promoted Atomic Substitution Process
-
A visible-light-promoted atomic substitution reaction for transforming thiocacids into carboxylic acids with dimethyl sulfoxide (DMSO) as the oxygen source has been developed, affording various alkyl and aryl carboxylic acids in over 90% yields. The atomic substitution process proceeds smoothly through the photochemical reactivity of the formed hydrogen-bonding adduct between thioacids and DMSO. A DMSO-involved proton-coupled electron transfer (PCET) and the simultaneous generation of thiyl and hydroxyl radicals are proposed to be key steps for realizing the transformation.
- Fu, Qiang,Liang, Fu-Shun,Lou, Da-Wei,Pan, Gao-Feng,Wang, Rui,Wu, Min,Xie, Kai-Jun
-
supporting information
p. 2020 - 2024
(2022/03/31)
-
- Gram-scale synthesis of carboxylic acids via catalytic acceptorless dehydrogenative coupling of alcohols and hydroxides at an ultralow Ru loading
-
Acceptorless dehydrogenative coupling (ADC) of alcohols and water/hydroxides is an emergent and graceful approach to produce carboxylic acids. Therefore, it is of high demand to develop active and practical catalysts/catalytic systems for this attractive transformation. Herein, we designed and fabricated a series of cyclometallated N-heterocyclic carbene-Ru (NHC-Ru) complexes via ligand tuning of [Ru-1], the superior complex in our previous work. Gratifyingly, gram-scale synthesis of carboxylic acids was efficiently enabled at an ultralow Ru loading (62.5 ppm) in open air. Moreover, effects of distinct ancillary NHC ligands and other parameters on this catalytic process were thoroughly studied, while further systematic studies were carried out to provide rationales for the activity trend of [Ru-1]-[Ru-7]. Finally, determination of quantitative green metrics illustrated that the present work exhibited superiority over representative literature reports. Hopefully, this study could provide valuable input for researchers who are engaging in metal-catalyzed ADC reactions.
- Chen, Cheng,Cheng, Hua,Verpoort, Francis,Wang, Zhi-Qin,Wu, Zhe,Yuan, Ye,Zheng, Zhong-Hui
-
-
- Time-Dependent Self-Assembly of Copper(II) Coordination Polymers and Tetranuclear Rings: Catalysts for Oxidative Functionalization of Saturated Hydrocarbons
-
This study describes a time-dependent self-assembly generation of new copper(II) coordination compounds from an aqueous-medium reaction mixture composed of copper(II) nitrate, H3bes biobuffer (N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid), ammonium hydroxide, and benzenecarboxylic acid, namely, 4-methoxybenzoic (Hfmba) or 4-chlorobenzoic (Hfcba) acid. Two products were isolated from each reaction, namely, 1D coordination polymers [Cu3(μ3-OH)2(μ-fmba)2(fmba)2(H2O)2]n (1) or [Cu2(μ-OH)2(μ-fcba)2]n (2) and discrete tetracopper(II) rings [Cu4(μ-Hbes)3(μ-H2bes)(μ-fmba)]·2H2O (3) or [Cu4(μ-Hbes)3(μ-H2bes)(μ-fcba)]·4H2O (4), respectively. These four compounds were obtained as microcrystalline air-stable solids and characterized by standard methods, including the single-crystal X-ray diffraction. The structures of 1 and 2 feature distinct types of metal-organic chains driven by the μ3- or μ-OH- ligands along with the μ-benzenecarboxylate linkers. The structures of 3 and 4 disclose the chairlike Cu4 rings assembled from four μ-bridging and chelating aminoalcoholate ligands along with μ-benzenecarboxylate moieties playing a core-stabilizing role. Catalytic activity of 1-4 was investigated in two model reactions, namely, (a) the mild oxidation of saturated hydrocarbons with hydrogen peroxide to form alcohols and ketones and (b) the mild carboxylation of alkanes with carbon monoxide, water, and peroxodisulfate to generate carboxylic acids. Cyclohexane and propane were used as model cyclic and gaseous alkanes, while the substrate scope also included cyclopentane, cycloheptane, and cyclooctane. Different reaction parameters were investigated, including an effect of the acid cocatalyst and various selectivity parameters. The obtained total product yields (up to 34% based on C3H8 or up to 47% based on C6H12) in the carboxylation of propane and cyclohexane are remarkable taking into account an inertness of these saturated hydrocarbons and low reaction temperatures (50-60 °C). Apart from notable catalytic activity, this study showcases a novel time-dependent synthetic strategy for the self-assembly of two different Cu(II) compounds from the same reaction mixture.
- Costa, Ines F. M.,Kirillova, Marina V.,André, Vania,Fernandes, Tiago A.,Kirillov, Alexander M.
-
supporting information
p. 14491 - 14503
(2021/07/19)
-
- Mild oxidative functionalization of cycloalkanes catalyzed by novel dicopper(II) cores
-
The search for new transition metal based catalytic systems that are active in the oxidative functionalization of such inert substrates as saturated hydrocarbons continues to be an important research direction in molecular catalysis. In the present study, two new copper(II) coordination compounds, namely a discrete dimer [Cu2(μ-H2tea)2(nfa)2]·2H2O (1) and a 1D coordination polymer [Cu2(μ-H2tea)2(μ-Htma)]n·4nH2O (2) were synthesized and applied as homogeneous catalysts for the mild oxidative functionalization of cycloalkanes (cyclopentane, cyclohexane, cycloheptane, and cyclooctane). Both products 1 and 2 were self-assembled in aqueous medium from copper(II) nitrate, triethanolamine (H3tea), sodium hydroxide, and 2-naphthoic (Hnfa) or trimesic (H3tma) acids, isolated as stable crystalline solids, and fully characterized by standard methods including single-crystal X-ray diffraction. Their structures feature a similar type of dicopper(II) triethanolaminate cores that are decorated by terminal or bridging aromatic carboxylate ligands. Two model catalytic reactions were investigated, namely the oxidation of cycloalkanes by H2O2 to produce cycloalkyl hydroperoxides as intermediate products and then a mixture of cyclic alcohols and ketones as final products, and the carboxylation of cycloalkanes with CO/S2O82?/H2O to form cycloalkanecarboxylic acids as main products. These model reactions undergo under very mild conditions (50?60 °C) and show good efficiency. Substrate scope, selectivity features, and the effects of reaction parameters were investigated and discussed in detail. This study widens the family of multicopper(II) cores capable of catalyzing the oxidative functionalization of saturated hydrocarbons under mild conditions.
- Trusau, Kiryl I.,Kirillova, Marina V.,André, Vania,Usevich, Andrew I.,Kirillov, Alexander M.
-
-
- Oxidation of Primary Alcohols and Aldehydes to Carboxylic Acids via Hydrogen Atom Transfer
-
The oxidation of primary alcohols and aldehydes to the corresponding carboxylic acids is a fundamental reaction in organic synthesis. In this paper, we report a new chemoselective process for the oxidation of primary alcohols and aldehydes. This metal-free reaction features a new oxidant, an easy to handle procedure, high isolated yields, and good to excellent functional group tolerance even in the presence of vulnerable secondary alcohols and tert-butanesulfinamides.
- Tan, Wen-Yun,Lu, Yi,Zhao, Jing-Feng,Chen, Wen,Zhang, Hongbin
-
supporting information
p. 6648 - 6653
(2021/09/08)
-
- An efficient and ultrastable single-Rh-site catalyst on a porous organic polymer for heterogeneous hydrocarboxylation of olefins
-
A heterogeneous hydrocarboxylation process of olefins to obtain carboxylic acids with one more carbon was first realized using a single-Rh-site catalyst formed on porous organic polymer (Rh1/POPs). The in situ formation of hydrophilic porous ionic polymer from hydrophobic POPs with the help of CH3I led to high activity and superb stability.
- Yuan, Qiao,Song, Xiangen,Feng, Siquan,Jiang, Miao,Yan, Li,Li, Jingwei,Ding, Yunjie
-
supporting information
p. 472 - 475
(2021/01/25)
-
- An Anionic, Chelating C(sp3)/NHC ligand from the Combination of an N-heterobicyclic Carbene and Barbituric Heterocycle
-
The coordination chemistry of the anionic NHC1-based on an imidazo[1,5-a]pyridin-3-ylidene (IPy) platform substituted at the C5 position by an anionic barbituric heterocycle was studied with d6(Ru(II), Mn(I)) and d8(Pd(II), Rh(I), Ir(I), Au(III)) transition-metal centers. While the anionic barbituric heterocycle is planar in the zwitterionic NHC precursor 1·H, NMR spectroscopic analyses supplemented by X-ray diffraction studies evidenced the chelating behavior of ligand 1-through the carbenic and the malonic carbon atoms in all of the complexes, resulting from a deformation of the lateral barbituric heterocycle. The complexes were obtained by reaction of the free carbene with the appropriate metal precursor, except for the Au(III) complex 10, which was obtained by oxidation of the antecedent gold(I) complex [AuCl(1)]?with PhICl2as an external oxidant. During the course of the process, the kinetic gold(I) intermediate 9 resulting from the oxidation of the malonic carbon of the barbituric moiety was isolated upon crystallization from the reaction mixture. The νCOstretching frequencies recorded for complex [Rh(1)(CO)2] (5) demonstrated the strong donating character of the malonate-C(sp3)/NHC ligand 1-. The ruthenium complex [Ru(1)Cl(p-cymene)] (11) was implemented as a precatalyst in the dehydrogenative synthesis of carboxylic acid derivatives from primary alcohols and exhibited high activities at low catalyst loadings (25-250 ppm) and a large tolerance toward functional groups.
- Benaissa, Idir,Gajda, Katarzyna,Vendier, Laure,Lugan, No?l,Kajetanowicz, Anna,Grela, Karol,Michelet, Véronique,César, Vincent,Bastin, Stéphanie
-
supporting information
p. 3223 - 3234
(2021/09/30)
-
- Hydroxycarbonylation of alkenes with formic acid using a rhodium iodide complex and alkyl ammonium iodide
-
Hydroxycarbonylation of alkenes using formic acid (HCOOH) is ideal for the synthesis of various carboxylic acids as a means to develop a sustainable reaction system with lower environmental impact. In this study, we developed a new catalytic system for hydroxycarbonylation of alkenes with HCOOH using a Vaska-type Rh complex with an iodide ligand, RhI(CO)(PPh3)2(1), as the catalyst, and a quaternary ammonium iodide salt as the promoter for the catalyst. In comparison with similar reaction systems using Rh catalysts, our reaction system is safer and more environmentally friendly since it does not require high-pressure conditions, explosive gases, or environmentally unfriendly CH3I and extra PPh3promoters. In addition, we also experimentally clarified that the catalytic reaction proceedsviaRhHI2(CO)(PPh3)2(2), which is formed by the reaction of1with a quaternary ammonium iodide salt andp-TsOH. Furthermore, the Rh(iii) complex2can catalyze hydroxycarbonylation of alkenes with HCOOH without any promoters.
- Okada, Masaki,Takeuchi, Katsuhiko,Matsumoto, Kazuhiro,Oku, Tomoharu,Choi, Jun-Chul
-
supporting information
p. 8727 - 8734
(2021/10/22)
-
- Enantioselective Enzymatic Reduction of Acrylic Acids
-
An ene-reductase (ERED 36) with broad substrate specificity was identified, and optimization studies led to the development of an enzymatic protocol for the reduction of α,β-unsaturated acids under mild, aqueous conditions. The substrate scope includes aromatic- A nd aliphatic-substituted acrylic acids, as well as cyclic α,β-substituted acrylic acids, yielding chiral α-substituted acids with exquisite levels of enantioselectivity (>99% ee).
- An, Chihui,Shaw, Megan H.,Tharp, Annika,Verma, Deeptak,Li, Hongming,Wang, Heather,Wang, Xiao
-
supporting information
p. 8320 - 8325
(2020/11/03)
-
- Activated charcoal as an effective additive for alkaline and acidic hydrolysis of esters in water
-
Activated charcoal largely enhanced the rates of the alkaline hydrolysis of methyl, ethyl, and n-propyl esters in aqueous 1.5 M NaOH solution to give the corresponding carboxylic acids in excellent yields. The acidic hydrolysis of methyl, ethyl, and n-propyl esters in aqueous 3 M H2SO4 solution was accelerated by the addition of activated charcoal to afford the corresponding carboxylic acids in good yields.
- Rohand, Taoufik,Tanemura, Kiyoshi
-
supporting information
(2020/10/08)
-
- Hydrogenation reaction method
-
The invention relates to a hydrogenation reaction method, and belongs to the technical field of organic synthesis. The hydrogenation reaction method provided by the invention comprises the following steps: carrying out a hydrogen transfer reaction on a hydrogen acceptor compound, pinacol borane and a catalyst in a solvent in the presence of proton hydrogen, so that the hydrogen acceptor compound is subjected to a hydrogenation reaction; the catalyst is one or more than two of a palladium catalyst, an iridium catalyst and a rhodium catalyst; the hydrogen acceptor compound comprises one or morethan two functional groups of carbon-carbon double bonds, carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogentriple bonds and epoxy. The method is mild in reaction condition, easy to operate, high in yield, short in reaction time, wide in substrate application range, suitable for carbon-carbon double bonds,carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogen triple bonds and epoxy functional groups, good in selectivity and high in reaction specificity.
- -
-
Paragraph 0034; 0073-0076
(2020/05/14)
-
- Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration
-
A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H2 combination, are tolerated. The activity of the reactants was studied and the trends are as follows: styrene'diphenylmethanimine'benzaldehyde'azobenzene'nitrobenzene'quinoline'acetophenone'benzonitrile. Substrates bearing two or more different unsaturated bonds were also investigated and transfer hydrogenation occurred with excellent chemoselectivity. Nano-palladium catalyst in situ generated from Pd(OAc)2 and HBPin extremely improved the TH efficiency. Furthermore, chemoselective anti-Markovnikov hydrodeuteration of terminal aromatic olefins was achieved using D2O and HBPin via in situ HD generation and discrimination. (Figure presented.).
- Wang, Yong,Cao, Xinyi,Zhao, Leyao,Pi, Chao,Ji, Jingfei,Cui, Xiuling,Wu, Yangjie
-
supporting information
p. 4119 - 4129
(2020/08/10)
-
- Mild C-H functionalization of alkanes catalyzed by bioinspired copper(ii) cores
-
Three new copper(ii) coordination compounds formulated as [Cu(H1.5bdea)2](hba)·2H2O (1), [Cu2(μ-Hbdea)2(aca)2]·4H2O (2), and [Cu2(μ-Hbdea)2(μ-bdca)]n (3) were generated by aqueous medium self-assembly synthesis from Cu(NO3)2, N-butyldiethanolamine (H2bdea) as a main N,O-chelating building block and different carboxylic acids [4-hydroxybenzoic (Hhba), 9-anthracenecarboxylic (Haca), or 4,4′-biphenyldicarboxylic (H2bdca) acid] as supporting carboxylate ligands. The structures of products range from discrete mono- (1) or dicopper(ii) (2) cores to a 1D coordination polymer (3), and widen a family of copper(ii) coordination compounds derived from H2bdea. The obtained compounds were applied as bioinspired homogeneous catalysts for the mild C-H functionalization of saturated hydrocarbons (cyclic and linear C5-C8 alkanes). Two model catalytic reactions were explored, namely the oxidation of hydrocarbons with H2O2 to a mixture of alcohols and ketones, and the carboxylation of alkanes with CO/S2O82- to carboxylic acids. Both processes proceed under mild conditions with a high efficiency and the effects of different parameters (e.g., reaction time and presence of acid promoter, amount of catalyst and solvent composition, substrate scope and selectivity features) were studied and discussed in detail. In particular, an interesting promoting effect of water was unveiled in the oxidation of cyclohexane that is especially remarkable in the reaction catalyzed by 3, thus allowing a potential use of diluted, in situ generated solutions of hydrogen peroxide. Moreover, the obtained values of product yields (up to 41% based on alkane substrate) are very high when dealing with the C-H functionalization of saturated hydrocarbons and the mild conditions of these catalytic reactions (50-60 °C, H2O/CH3CN medium). This study thus contributes to an important field of alkane functionalization and provides a notable example of new Cu-based catalytic systems that can be easily generated by self-assembly from simple and low-cost chemicals.
- Kirillova, Marina V.,Fernandes, Tiago A.,André, Vania,Kirillov, Alexander M.
-
supporting information
p. 7706 - 7714
(2019/08/30)
-
- Organocatalyzed Aerobic Oxidation of Aldehydes to Acids
-
The first example organocatalyzed aerobic oxidation of aldehydes to carboxylic acids in both organic solvent and water under mild conditions is developed. As low as 5 mol % N-hydroxyphthalimide was used as the organocatalyst, and molecular O2 was used as the sole oxidant. No transition metals or hazardous oxidants or cocatalysts were involved. A wide range of carboxylic acids bearing diverse functional groups were obtained from aldehydes, even from alcohols, in high yields.
- Dai, Peng-Fei,Qu, Jian-Ping,Kang, Yan-Biao
-
supporting information
p. 1393 - 1396
(2019/02/26)
-
- Carboxylation of benzylic and aliphatic C-H bonds with CO2 induced by light/ketone/nickel
-
A photoinduced carboxylation reaction of benzylic and aliphatic C-H bonds with CO2 is developed. Toluene derivatives capture gaseous CO2 at the benzylic position to produce phenylacetic acid derivatives when irradiated with UV light in the presence of an aromatic ketone, a nickel complex, and potassium tert-butoxide. Cyclohexane reacts with CO2 to furnish cyclohexanecar-boxylic acid under analogous reaction conditions. The present photoinduced carboxylation reaction provides a direct access from readily available hydrocarbons to the corresponding carboxylic acids with one carbon extension.
- Ishida, Naoki,Masuda, Yusuke,Imamura, Yuuya,Yamazaki, Katsushi,Murakami, Masahiro
-
supporting information
p. 19611 - 19615
(2019/12/24)
-
- Synthesis of Carboxylic Acids by Palladium-Catalyzed Hydroxycarbonylation
-
The synthesis of carboxylic acids is of fundamental importance in the chemical industry and the corresponding products find numerous applications for polymers, cosmetics, pharmaceuticals, agrochemicals, and other manufactured chemicals. Although hydroxycarbonylations of olefins have been known for more than 60 years, currently known catalyst systems for this transformation do not fulfill industrial requirements, for example, stability. Presented herein for the first time is an aqueous-phase protocol that allows conversion of various olefins, including sterically hindered and demanding tetra-, tri-, and 1,1-disubstituted systems, as well as terminal alkenes, into the corresponding carboxylic acids in excellent yields. The outstanding stability of the catalyst system (26 recycling runs in 32 days without measurable loss of activity), is showcased in the preparation of an industrially relevant fatty acid. Key-to-success is the use of a built-in-base ligand under acidic aqueous conditions. This catalytic system is expected to provide a basis for new cost-competitive processes for the industrial production of carboxylic acids.
- Sang, Rui,Kucmierczyk, Peter,Dühren, Ricarda,Razzaq, Rauf,Dong, Kaiwu,Liu, Jie,Franke, Robert,Jackstell, Ralf,Beller, Matthias
-
supporting information
p. 14365 - 14373
(2019/09/06)
-
- Highly active bidentate N-heterocyclic carbene/ruthenium complexes performing dehydrogenative coupling of alcohols and hydroxides in open air
-
Eight bidentate NHC/Ru complexes, namely [Ru]-1-[Ru]-8, were designed and prepared. In particular, [Ru]-2 displayed extraordinary performance even in open air for the dehydrogenative coupling of alcohols and hydroxides. Notably, an unprecedentedly low catalyst loading of 250 ppm and the highest TON of 32 800 and TOF of 3200 until now were obtained.
- Wang, Zhi-Qin,Tang, Xiao-Sheng,Yang, Zhao-Qi,Yu, Bao-Yi,Wang, Hua-Jing,Sang, Wei,Yuan, Ye,Chen, Cheng,Verpoort, Francis
-
supporting information
p. 8591 - 8594
(2019/07/25)
-
- Three-Component Copper-Phosphonate-Auxiliary Ligand Systems: Proton Conductors and Efficient Catalysts in Mild Oxidative Functionalization of Cycloalkanes
-
The synthesis, structural characterization, topological analysis, proton conductivity, and catalytic properties are reported of two Cu(II)-based compounds, namely a dinuclear Cu(II) complex [Cu2(μ-VPA)2(phen)2(H2O)2]·8H2O (1) (H2VPA = vinylphosphonic acid, phen = 1,10-phenanthroline) and a 1D coordination polymer [Cu(μ-SO4)(phen)(H2O)2]∞ (2). Their structural features and H-bonding interactions were investigated in detail, showing that the metal-organic structures of 1 and 2 are extended by multiple hydrogen bonds to more complex 2D or 1D H-bonded architectures with the kgd [Shubnikov plane net (3.6.3.6)/dual] and SP 1-periodic net (4,4)(0,2) topology, respectively. These nets are primarily driven by the H-bonding interactions involving water ligands and H2O molecules of crystallization; besides, the (H2O)4/(H2O)5 clusters were identified in 1. Both 1 and 2 are moderate proton conductors, with proton conductivity values, σ = 3.65 × 10-6 and 3.94 × 10-6 S·cm-1, respectively (measured at 80 °C and 95% relative humidity). Compounds 1 and 2 are also efficient homogeneous catalysts for the mild oxidative functionalization of C5-C8 cycloalkanes (cyclopentane, cyclohexane, cycloheptane, and cyclooctane), namely for the oxidation by H2O2 to give cyclic alcohols and ketones and the hydrocarboxylation by CO/H2O and S2O82- to the corresponding cycloalkanecarboxylic acids as major products. The catalytic reactions proceed under mild conditions (50-60 °C) in aqueous acetonitrile medium, resulting in up to 34% product yields based on cycloalkane substrate.
- Armakola, Eirini,Colodrero, Rosario M. P.,Bazaga-García, Montse,Salcedo, Inés R.,Choquesillo-Lazarte, Duane,Cabeza, Aurelio,Kirillova, Marina V.,Kirillov, Alexander M.,Demadis, Konstantinos D.
-
p. 10656 - 10666
(2018/09/13)
-
- Interplay between H-bonding and interpenetration in an aqueous copper(ii)-aminoalcohol-pyromellitic acid system: self-assembly synthesis, structural features and catalysis
-
Two new copper(ii) coordination compounds, [Cu(H1.5mdea)2]2(H2pma) (1a) and [{Cu2(μ-Hmdea)2}2(μ4-pma)]n·2nH2O (1b), were self-assembled at different temperatures from the same multicomponent reaction system, comprising copper(ii) nitrate, N-methyldiethanolamine (H2mdea), pyromellitic acid (H4pma), and potassium hydroxide. Products 1a and 1b were isolated as microcrystalline solids and fully characterized and their structures were established by single-crystal X-ray diffraction. Compound 1a features the bis-aminoalcohol(ate) monocopper(ii) units and H2pma2? anions that are multiply interconnected by strong H-bonds into a firm 2D H-bonded layer. Compound 1b reveals the bis-aminoalcoholate dicopper(ii) motifs that are interlinked by the μ4-pma4? spacers into a 3D + 3D interpenetrated metal-organic framework. From a topological perspective, both networks of 1a and 1b are uninodal and driven by similar 4-connected H2pma2? or pma4? nodes, but result in distinct sql and dia topologies, respectively. Compound 1a was applied as an efficient catalyst for two model cycloalkane functionalization reactions: (1) oxidation by H2O2 to form cyclic alcohols and ketones and (2) hydrocarboxylation by CO/H2O and S2O82? to form cycloalkanecarboxylic acids. The substrate scope, effects of various reaction parameters, selectivity and mechanistic features were also investigated.
- Fernandes, Tiago A.,Kirillova, Marina V.,André, Vania,Kirillov, Alexander M.
-
supporting information
p. 16674 - 16683
(2018/12/05)
-
- A aldehyde or mellow directly converted into the carboxylic acid (by machine translation)
-
The invention discloses a aldehyde or mellow oxidation can be directly transformed into carboxylic acid, is characterized in that the pure oxygen environment, in N - hydroxy imide compound under the catalysis of the imide compound or N - hydroxy and nitrous acid ester compound common under the catalysis, the CH2 OH and CHO oxidation directly converted into the carboxylic acid compounds. The invention using oxygen as the oxidizing agent, does not add any metal catalyst, environment-friendly, high catalytic efficiency, simple and convenient operation. With the previous metal catalytic system complex and different catalytic system, has some metal catalytic system in the process, the use of transition metal will cause the transition metal of the residual, the invention adopts the non-metallic catalytic system, environmental protection, preventing the metal residue problem, this to the solution of the drug in the synthesis of transition metal residue problem and provides a new method of thinking. (by machine translation)
- -
-
Paragraph 0035; 0036
(2018/08/03)
-
- Electrochemical Oxidation of Alcohols and Aldehydes to Carboxylic Acids Catalyzed by 4-Acetamido-TEMPO: An Alternative to "anelli" and "pinnick" Oxidations
-
An electrocatalytic method has been developed to oxidize primary alcohols and aldehydes to the corresponding carboxylic acids using 4-acetamido-2,2,6,6-tetramethylpiperidin-1-oxyl (ACT) as a mediator. The method successfully converts benzylic, aliphatic, heterocyclic, and other heteroatom-containing substrates to the corresponding carboxylic acids in aqueous solution at room temperature. The mild conditions enable retention of stereochemistry adjacent to the site of oxidation, as demonstrated in a 40 g-scale synthesis of a precursor to levetiracetam, a medication used to treat epilepsy.
- Rafiee, Mohammad,Konz, Zachary M.,Graaf, Matthew D.,Koolman, Hannes F.,Stahl, Shannon S.
-
p. 6738 - 6744
(2018/06/19)
-
- Production technology of cyclopentanecarboxylic acid
-
The invention discloses a production technology of cyclopentanecarboxylic acid, and belongs to the field of chemical synthesis. The production technology comprises the following steps: with epoxycyclopentane as a starting material, performing a reaction on the epoxycyclopentane, carbon dioxide, Mg powder and TMSCl to produce 2-hydroxycyclohexanecarboxylic acid, and then performing catalytic hydrogenation by Pd/C in the presence of an acid to obtain the cyclopentanecarboxylic acid. By the production technology, used raw materials are cheap and easy to obtain, the whole technology is easy and convenient to operate, a catalyst can be recycled repeatedly, and a new idea is provided for synthesis of the cyclopentanecarboxylic acid.
- -
-
Paragraph 0016; 0019; 0020; 0023; 0024; 0027
(2018/11/03)
-
- Mild homogeneous oxidation and hydrocarboxylation of cycloalkanes catalyzed by novel dicopper(II) aminoalcohol-driven cores
-
N-benzylethanolamine (Hbea) and triisopropanolamine (H3tipa) were applied as unexplored aminoalcohol N,O-building blocks for the self-assembly generation of two novel dicopper(II) compounds, [Cu2(μ-bea)2(Hbea)2](NO3)2 (1) and [Cu2(H3tipa)2(μ-pma)]·7H2O (2) {H4pma = pyromellitic acid}. These were isolated as stable and aqua-soluble microcrystalline products and were fully characterized by IR spectroscopy, ESI–MS(±), and single-crystal X-ray diffraction, the latter revealing distinct Cu2 cores containing the five-coordinate copper(II) centers with the {CuN2O3} or {CuNO4} environments. Compounds 1 and 2 were used as homogeneous catalysts for the mild oxidation of C5–C8 cycloalkanes to give the corresponding cyclic alcohols and ketones in up to 23% overall yields based on cycloalkane. The reactions proceed in aqueous acetonitrile medium at 50 °C using H2O2 as an oxidant. The effects of different reaction conditions were studied, including the type and loading of catalyst, amount and kind of acid promoter, and water concentration. Despite the fact that different acids (HNO3, H2SO4, HCl, or CF3COOH) promote the oxidation of alkanes, the reaction is exceptionally fast in the presence of a catalytic amount of HCl, resulting in the TOF values of up to 430 h?1. Although water typically strongly inhibits alkane oxidations due to the reduction of H2O2 concentration and lowering of the alkane solubility, in the systems comprising 1 and 2 we observed a significant growth (up to 5-fold) of an initial reaction rate in the cyclohexane oxidation on increasing the amount of H2O in the reaction mixture. The bond-, regio- and stereo-selectivity parameters were investigated in oxidation of different linear, branched, and cyclic alkane substrates. Both compounds 1 and 2 also catalyze the hydrocarboxylation of C5–C8 cycloalkanes, by CO, K2S2O8, and H2O in a water/acetonitrile medium at 60 °C, to give the corresponding cycloalkanecarboxylic acids in up to 38% yields based on cycloalkanes.
- Fernandes, Tiago A.,André, Vania,Kirillov, Alexander M.,Kirillova, Marina V.
-
p. 357 - 367
(2016/12/16)
-
- Three-component 1D and 2D metal phosphonates: structural variability, topological analysis and catalytic hydrocarboxylation of alkanes
-
Herein, we report the use of diphosphonate building blocks and chelating auxiliary N,N-ligands to generate novel polymeric architectures. Specifically, we report new 1D and 2D coordination polymers incorporating three components: transition metal ions (Co2+, Cu2+, Mn2+ or Zn2+), diphosphonate ligands (methane-diphosphonate, MDPA, or 1,2-ethanediphosphonate, EDPA) and N,N-heterocyclic chelators (1,10-phenanthroline, phen, or 2,2′-bipyridine, bpy). Six compounds were isolated under mild synthesis (ambient temperature) conditions: [Cu2(phen)2(EDPA)2(H2O)4]∞ (1), [Co(phen)(EDPA)(H2O)2]∞ (1a), {[Cu(phen)(MDPA)]·H2O]}∞ (2), [Mn(bpy)(EDPA)(H2O)2]∞ (3), [Zn(bpy)(EDPA)]∞ (4), and, lastly, a discrete Ni2+ molecular derivative [Ni(phen)(H2O)4](EDPA) (5). Synthetic details, crystal structures, and intermolecular interactions (π-π stacking and hydrogen bonding) in 1-5 are discussed. Topological analyses and classification of the underlying metal-organic networks in 1-4 were performed, revealing the uninodal 1D chains with the 2C1 topology in 1-3 and the binodal 2D layers with the 3,4L13 topology in 4. In 1-3 and 5, multiple hydrogen bonds lead to the extension of the structures to give 3D H-bonded nets with the seh-4,6-C2/c topology in 1 and 3, 2D H-bonded layers with the 3,5L52 topology in 2, and a 3D H-bonded net with the 6,6T1 topology in 5. The catalytic activity of compounds 1 and 1a was evaluated in a single-step hydrocarboxylation of cyclic and linear C5-C8 alkanes to furnish the carboxylic acids with one more carbon atom. These reactions proceed in the presence of CO, K2S2O8, and H2O at 60 °C in MeCN/H2O medium. Compound 1 showed higher activity than 1a and was studied in detail. Substrate scope was investigated, revealing that cyclohexane and n-pentane are the most reactive among the cyclic and linear C5-C8 alkanes, and resulting in the total yields of carboxylic acids (based on substrate) of up to 43 and 36%, respectively. In the case of cycloalkane substrates, only one cycloalkanecarboxylic acid is produced, whereas a series of isomeric monocarboxylic acids is generated when using linear alkanes; an increased regioselectivity at the C(2) position of the hydrocarbon chain was also observed.
- Demadis, Konstantinos D.,Anagnostou, Zafeiria,Panera, Aggeliki,Mezei, Gellert,Kirillova, Marina V.,Kirillov, Alexander M.
-
p. 17788 - 17799
(2017/03/30)
-
- Site-Selective Catalytic Carboxylation of Unsaturated Hydrocarbons with CO2 and Water
-
A catalytic protocol that reliably predicts and controls the site-selective incorporation of CO2 to a wide range of unsaturated hydrocarbons utilizing water as formal hydride source is described. This platform unlocks an opportunity to catalytically repurpose three abundant, orthogonal feedstocks under mild conditions.
- Gaydou, Morgane,Moragas, Toni,Juliá-Hernández, Francisco,Martin, Ruben
-
supporting information
p. 12161 - 12164
(2017/09/12)
-
- New Strategy for Forging Contiguous Quaternary Carbon Centers via H 2 O 2 -Mediated Ring Contraction
-
Stereospecific construction of contiguous quaternary carbon centers constitutes a major challenge in natural product synthesis. A general protocol that enables stereospecific construction of all stereoisomers of such a moiety remains elusive. In this article, we will discuss the oxidative ring contraction of all-substituted cyclic α-formyl ketones mediated by H 2 O 2, which provides a facile access to the stereospecific construction of contiguous quaternary carbon centers.
- Hu, Jiadong,Yu, Xin,Xie, Weiqing
-
p. 2517 - 2524
(2017/09/28)
-
- Silver-Catalyzed Dehydrogenative Synthesis of Carboxylic Acids from Primary Alcohols
-
A simple silver-catalyzed protocol has been developed for the acceptorless dehydrogenation of primary alcohols into carboxylic acids and hydrogen gas. The procedure uses 2.5 % Ag2CO3 and 2.5–3 equiv of KOH in refluxing mesitylene to afford the potassium carboxylate which is then converted into the acid with HCl. The reaction can be applied to a variety of benzylic and aliphatic primary alcohols with alkyl and ether substituents, and in some cases halide, olefin, and ester functionalities are also compatible with the reaction conditions. The dehydrogenation is believed to be catalyzed by silver nanoparticles that are formed in situ under the reaction conditions.
- Ghalehshahi, Hajar Golshadi,Madsen, Robert
-
p. 11920 - 11926
(2017/09/07)
-
- Structurally well-characterized new multinuclear Cu(II) and Zn(II) clusters: X-ray crystallography, theoretical studies, and applications in catalysis
-
Two new trinuclear Cu(ii) and dinuclear Zn(ii) clusters are crystallized out by reacting the metal salts with the triethanolamine (H3tea) ligand in the presence of benzoic acid (Hba). The complexes are characterized by elemental, thermal, magnetic, spectral (FTIR, UV-Visible, EPR, and photoluminescence) and single crystal X-ray studies. Single crystal X-ray crystallography reveals the composition of the complexes to be [Cu3(H2tea)2(ba)2(NO3)2] (1) and [Zn2(H2tea)(ba)3]H2O (2). FTIR ascertains the binding modes of H2tea-, ba- and NO3-. Triethanolamine binds in both the complexes in the monoanionic (H2tea-) mode. ba- is present as an anchoring auxiliary to generate di- and trinuclear clusters. The Cu(ii) ion is present as a distorted octahedral center in the Cu3 cluster (1), while the two Zn(ii) ions in 2 have been reported for the first time to possess distorted octahedral as well as tetrahedral geometry in the same molecule. The intriguing features of the non-covalent supramolecular interactions have been investigated and supported theoretically by using Hirshfeld surface analysis and ab initio methods. The solid state photoluminescence (PL) spectra of 1 and 2 disclose the luminescence property of the complexes. Due to the closed or nearly closed shell configuration (d9 or d10), the present complexes are screened for catalytic properties in the hydrocarboxylation of alkanes and cycloalkanes. The catalytic activity data are indicative of the potential catalytic properties of 1 and 2.
- Ansari, Istikhar A.,Sama, Farasha,Raizada, Mukul,Shahid,Ahmad, Musheer,Siddiqi, Zafar A.
-
supporting information
p. 9840 - 9852
(2016/11/11)
-
- Dehydrogenative Synthesis of Carboxylic Acids from Primary Alcohols and Hydroxide Catalyzed by a Ruthenium N-Heterocyclic Carbene Complex
-
Primary alcohols have been reacted with hydroxide and the ruthenium complex [RuCl2(IiPr)(p-cymene)] to afford carboxylic acids and dihydrogen. The dehydrogenative reaction is performed in toluene, which allows for a simple isolation of the products by precipitation and extraction. The transformation can be applied to a range of benzylic and saturated aliphatic alcohols containing halide and (thio)ether substituents, while olefins and ester groups are not compatible with the reaction conditions. Benzylic alcohols undergo faster conversion than other substrates, and a competing Cannizzaro reaction is most likely involved in this case. The kinetic isotope effect was determined to be 0.67 using 1-butanol as the substrate. A plausible catalytic cycle was characterized by DFT/B3LYP-D3 and involved coordination of the alcohol to the metal, β-hydride elimination, hydroxide attack on the coordinated aldehyde, and a second β-hydride elimination to furnish the carboxylate.
- Santilli, Carola,Makarov, Ilya S.,Fristrup, Peter,Madsen, Robert
-
p. 9931 - 9938
(2016/11/02)
-
- Efficient and convenient oxidation of aldehydes and ketones to carboxylic acids and esters with H2O2 catalyzed by Co4HP2Mo15V3O62 in ionic liquid [TEBSA][BF4]
-
A simple, efficient, and eco-friendly procedure for the oxidation of aldehydes and ketones to carboxylic acids and esters with H2O2 catalyzed by Co4HP2Mo15V3O62 in ionic liquid [TEBSA][BF4] has been developed. This atom-economical protocol affords the target products in good to high yields. The products can be separated by a simple extraction with organic solvent, and the catalytic system can be recycled and reused without loss of catalytic activity. Additionally, the possible mechanism of oxidation in the catalytic system is proposed. This journal is
- Hu, Yu-Lin,Li, De-Jiang,Li, Dong-Sheng
-
p. 24936 - 24943
(2015/03/30)
-
- An atom-economic approach to carboxylic acids via Pd-catalyzed direct addition of formic acid to olefins with acetic anhydride as a co-catalyst
-
An effective Pd-catalyzed hydrocarboxylation of olefins using formic acid with acetic anhydride as a co-catalyst is described. A variety of carboxylic acids are obtained in good yields with high regioselectivities under mild reaction conditions without the use of toxic CO gas.
- Wang, Yang,Ren, Wenlong,Shi, Yian
-
supporting information
p. 8416 - 8419
(2015/08/06)
-
- How to force a classical chelating ligand to a metal non-chelating bridge: The observation of a rare coordination mode of diethanolamine in the 1D complex {[Cu2(Piv)4(H3tBuDea)](Piv)}n
-
The novel chain coordination polymer {[Cu2(Piv) 4(H3tBuDea)](Piv)}n (1) has been prepared through the self-assembly reaction of copper(ii) nitrate with pivalic acid (HPiv) and N-tert-butyldiethanolamine (H2tBuDea) in acetonitrile solution. Crystallographic analysis revealed the extremely rare non-chelating bridging coordination mode of diethanolamine ligand in 1, observed for the first time in transition metal complexes, as well as in complexes of diethanolamine having a non-coordinating aliphatic group at the N atom. Possible reasons for such a coordination and analysis of the main coordination modes of diethanolamine-based ligands are discussed. Variableerature (1.8-300 K) magnetic susceptibility measurements showed that 1 represents a rare example of dicopper(ii) tetracarboxylate that is a diamagnetic solid at room temperature. This behaviour is compared with literature examples and discussed on the basis of DFT calculations. Furthermore, 1 acts as an efficient catalyst for the mild hydrocarboxylation of linear and cyclic C5-C8 alkanes into the corresponding carboxylic acids.
- Nesterova, Oksana V.,Kirillova, Marina V.,Guedes Da Silva, M. Fatima C.,Boca, Roman,Pombeiro, Armando J. L.
-
p. 775 - 783
(2014/01/17)
-
- Facile palladium-catalyzed hydrocarboxylation of olefins without external CO gas
-
An effective Pd-catalyzed hydrocarboxylation of olefins with phenyl formate and formic acid is described. A variety of carboxylic acids are obtained in good yields with high regioselectivities under operationally simple conditions without the use of toxic CO gas.
- Wang, Yang,Ren, Wenlong,Li, Jingfu,Wang, Haining,Shi, Yian
-
supporting information
p. 5960 - 5963
(2015/02/19)
-
- Tautomeric effect of hydrazone Schiff bases in tetranuclear Cu(ii) complexes: Magnetism and catalytic activity towards mild hydrocarboxylation of alkanes
-
Three new tetranuclear copper(ii) complexes [Cu(HL1)] 4·4EtOH (1·4EtOH), [Cu(HL2)]4 (2) and [Cu(H2L3)]4(NO3) 4·2H2O (3·2H2O) have been synthesized using three different hydrazone Schiff base ligands derived from the condensation of the aromatic acid hydrazides 2-hydroxybenzo-, 2-aminobenzo- or benzo-hydrazide, with 2,3-dihydroxybenzaldehyde. Complexes 1 and 3 have been characterized by single crystal X-ray diffraction analysis. The coordinating behaviour of the ligand depends on the nature of the ortho substituent present in the hydrazide moiety. The ligands bearing a strong electron donating group (by resonance) in the ortho position undergo complexation via enolization and deprotonation, whereas the absence of such an effect leads to complexation via the keto form, and two different types of tetranuclear Cu(ii) clusters, viz. open-cubane and cubane, are obtained. Variable temperature magnetic susceptibility measurements of complexes 1 and 3 have been carried out to examine the nature of magnetic interaction between the Cu(ii) centres. All the three complexes (1-3) act as good catalyst precursors towards mild hydrocarboxylation of linear and cyclic alkanes into carboxylic acids in water-acetonitrile medium.
- Sutradhar, Manas,Kirillova, Marina V.,Guedes Da Silva, M. Fatima C.,Liu, Cai-Ming,Pombeiro, Armando J. L.
-
p. 16578 - 16587
(2013/12/04)
-
- Cooperative N-Heterocyclic Carbene (NHC) and Ruthenium Redox Catalysis: Oxidative Esterification of Aldehydes with Air as the Terminal Oxidant
-
The paper describes a cooperative NHC (N-heterocyclic carbene) and ruthenium-based redox catalysis for the mild aerobic oxidative esterification of various aromatic and heteroaromatic aldehydes. The ruthenium(II) complex Ru(bpz)3(PF6)2 (bpz=2,2′-bipyrazine) as catalyst is shown to be compatible with free NHCs. The NHC is used in these cascade reactions for the umpolung of the aldehyde to form the corresponding Breslow intermediate which in turn gets oxidized to an acylazolium ion by the ruthenium redox catalyst. Air is used as a terminal oxidant for oxidation (regeneration) of the ruthenium catalyst. In addition, we will show that in the absence of the ruthenium redox catalyst and alcohol, NHC-catalyzed aerobic oxidation of aldehydes delivers the corresponding acids in good to excellent yields. Mechanistic studies and DFT calculations supporting our suggested mechanisms are provided. Copyright
- Zhao, Junfeng,Mueck-Lichtenfeld, Christian,Studer, Armido
-
supporting information
p. 1098 - 1106
(2013/05/21)
-
- Carbon dioxide as a C1 building block for the formation of carboxylic acids by formal catalytic hydrocarboxylation
-
A happy marriage of two processes: An effective catalytic system was identified for the direct synthesis of carboxylic acids from non-activated olefins or alcohols, CO2, and H2. Detailed analysis together with labeling studies indicated that the overall hydrocarboxylation of simple olefins results from a combination of the reverse water-gas shift (rWGS) reaction and a hydroxycarbonylation step, each promoted by a rhodium catalyst (see scheme). Copyright
- Ostapowicz, Thomas G.,Schmitz, Marc,Krystof, Monika,Klankermayer, Juergen,Leitner, Walter
-
p. 12119 - 12123
(2013/12/04)
-
- Topologically unique 2D heterometallic CuII/Mg coordination polymer: Synthesis, structural features, and catalytic use in alkane hydrocarboxylation
-
The new two-dimensional (2D) heterometallic CuII/Mg coordination polymer [Cu2Mg2(μ-Htea)2(μ6- pma)(H2O)6]n?6nH2O (1) with an unprecedented [Cu2Mg(μ-O)2(μ-COO)2] - core has been easily generated by aqueous medium self-assembly from copper(II) nitrate, triethanolamine (H3tea), magnesium hydroxide, and pyromellitic acid (H4pma). The crystal structure of 1 is composed of infinite interdigitated 2D metal-organic layers that extend via H-bonds into an intricate 3D supramolecular framework. The topological analysis of 1 discloses a binodal 2,4-connected underlying 2D net with the unique topology described by the point symbol of (64?8?10)(6), further simplification of which leads to an uninodal 4-connected net with the sql topology. Apart from representing a very rare example of the heterometallic Cu/Mg coordination network, compound 1 also acts as an efficient catalyst precursor for the mild single-pot hydrocarboxylation of linear and cyclic C n (n = 5-9) alkanes into the corresponding Cn+1 carboxylic acids.
- Kirillov, Alexander M.,Karabach, Yauhen Y.,Kirillova, Marina V.,Haukka, Matti,Pombeiro, Armando J. L.
-
scheme or table
p. 1069 - 1074
(2012/06/18)
-
- New diamondoid-like [Cu3B(μ-O)6] core self-assembled from Bis-Tris biobuffer for mild hydrocarboxylation of alkanes to carboxylic acids
-
The new tricopper(ii) complex [Cu3(μ3-BO)(H 3L)3][BF4]·2H2O (1) with an unprecedented diamondoid-like [Cu3B(μ-O)6] core has been easily generated by self-assembly in an aqueous medium from Cu(NO 3)2, NaBF4, NaOH and Bis-Tris (H5L) biobuffer, (HOCH2)3CN(CH2CH2OH) 2. Compound 1 efficiently promotes the mild single-pot hydrocarboxylation, by CO and H2O, of various linear and cyclic Cn (n = 2-8) alkanes into the corresponding Cn+1 carboxylic acids.
- Kirillov, Alexander M.,Karabach, Yauhen Y.,Kirillova, Marina V.,Haukka, Matti,Pombeiro, Armando J. L.
-
supporting information; experimental part
p. 6378 - 6381
(2011/08/06)
-
- Mild oxidative functionalization of alkanes and alcohols catalyzed by new mono- and dicopper(II) aminopolyalcoholates
-
The new mono- and dicopper(II) complexes [Cu(H3L 1)(NCS)] (1) and [Cu2(μ-HL2) 2(NCS)2] (2) were easily self-assembled from Cu(CH 3COO)2·H2O, NaNCS, NaOH and N,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine (H 4L1) or N-ethyldiethanolamine (H2L 2), respectively. They were fully characterized by IR spectroscopy, ESI-MS(±), elemental and single-crystal X-ray diffraction analyses, and applied as homogeneous catalysts for (i) the oxidation of alkanes by t-BuOOH in air to alkyl peroxides, alcohols and ketones, and in turn the oxidation of alcohols to ketones, and (ii) the single-pot aqueous medium hydrocarboxylation, by CO, H2O and K2S2O8, of various linear and cyclic Cn (n = 5-8) alkanes into the corresponding C n+1 carboxylic acids. Compound 1 was significantly more active in the oxygenation of alkanes and oxidation of alcohols, allowing to achieve 18% yield (TON = 800) of oxygenates in the oxidation of cyclohexane, and 78% yield (TON = 780) of cyclohexanone in the oxidation of cyclohexanol. In alkane hydrocarboxylations, 1 and 2 exhibited comparable activities with the total yields (based on alkane) of carboxylic acids attaining 39%. The selectivity parameters for oxidative transformations were measured and discussed, supporting free-radical mechanisms.
- Kirillov, Alexander M.,Kirillova, Marina V.,Shul'Pina, Lidia S.,Figiel, Pawe? J.,Gruenwald, Katrin R.,Guedes Da Silva, M. Fátima C.,Haukka, Matti,Pombeiro, Armando J.L.,Shul'Pin, Georgiy B.
-
experimental part
p. 26 - 34
(2012/01/14)
-
- Efficient CuCl-catalyzed selective and direct oxidation of β- And γ-substituted aliphatic primary alcohols to carboxylic acids
-
A new procedure for the selective and direct oxidation of aliphatic primary alcohols having substitution at - and -positions to corresponding carboxylic acids was developed using a catalytic amount of ligand and additive-free CuCl with anhydrous tBuOOH in acetonitrile solvent under very mild reaction conditions. This procedure is very simple and mild and works efficiently without any additives at room temperature.
- Mannam, Sreedevi,Sekar, Govindasamy
-
experimental part
p. 2822 - 2829
(2010/10/20)
-
- Alkanes to carboxylic acids in aqueous medium: Metal-free and metal-promoted highly efficient and mild conversions
-
A convenient and clean route to transform, in aqueous medium, various alkanes to carboxylic acids via single-pot carboxylation with CO and water, under mild conditions, has been achieved, proceeding efficiently and selectively even without any metal catalyst and any acid additive, at low temperatures; the relevant hydroxylating role of H2O and radical mechanisms are disclosed by radical-trap, H218O and DFT studies. The Royal Society of Chemistry 2009.
- Kirillova, Marina V.,Kirillov, Alexander M.,Kuznetsov, Maxim L.,Silva, Jose A. L.,Frausto Da Silva, Joao J. R.,Pombeiro, Armando J. L.
-
supporting information; experimental part
p. 2353 - 2355
(2009/09/06)
-
- Metal-free and copper-promoted single-pot hydrocarboxylation of cycloalkanes to carboxylic acids in aqueous medium
-
A simple and effective method for the transformation, under mild conditions and in aqueous medium, of various cycloalkanes (cyclopentane, cyclohexane, methylcyclohexane, cis- and trans-1,2dimethylcyclohexane, cycloheptane, cyclooctane and adamantane) into the corresponding cycloalkanecarboxylic acids bearing one more carbon atom, is achieved. This method is characterized by a singlepot, low-temperature hydrocarboxylation reaction of the cycloalkane with carbon monoxide, water and potassium peroxodisulfate in water/acetonitrile medium, proceeding either in the absence or in the presence of a metal promoter. The influence of various reaction parameters, such as type and amount of metal promoter, solvent composition, temperature, time, carbon monoxide pressure, oxidant and cycloalkane, is investigated, leading to an optimization of the cyclohexane and cyclopentane carboxylations. The highest efficiency is observed in the systems promoted by a tetracopper(II) triethanolaminate-de rived complex, which also shows different bond and stereoselectivity parameters (compared to the metalfree systems) in the carboxylations of methylcyclohexane and stereoisomeric 1,2-dimethylcyclohexanes. A free radical mechanism is proposed for the carboxylation of cyclohexane as a model substrate, involving the formation of an acyl radical, its oxidation and consequent hydroxylation by water. Relevant features of the present hydrocarboxylation method, besides the operation in aqueous medium, include the exceptional metal-free and acid-solvent-free reaction conditions, a rare hydroxylating role of water, substrate versatility, low temperatures (ca. 50°C) and a rather high efficiency (up to 72% carboxylic acid yields based on cycloalkane).
- Kirillova, Marina V.,Kirillov, Alexander M.,Pombeiro, Armando J. L.
-
experimental part
p. 2936 - 2948
(2010/04/03)
-
- ABCA-1 ELEVATING COMPOUNDS AND METHODS
-
Disclosed are novel compounds of Formula I useful for treating various disease states, in particular, insulin resistance, diabetes, dyslipidemia, coronary artery disease, and inflammation. The compounds of the present invention elevate cellular expression of the ABCA-1 gene as well as increasing the level of ABCA-1 protein, which may result in an increase in HDL levels in the plasma of a mammal, in particular humans.
- -
-
-
- A convenient titanium-mediated intermolecular alkyne-carbonate coupling reaction
-
A direct diastereoselective titanium-mediated intermolecular coupling of internal alkynes with dialkyl carbonates under Kulinkovich-type reaction conditions is presented. The influence of the structures of the coupling partners on the yields and regioselectivities of this transformation is described.
- Wolan, Andrzej,Cadoret, Frédéric,Six, Yvan
-
experimental part
p. 7429 - 7439
(2009/12/06)
-
- METHOD FOR THE CONVERSION, UNDER MILD CONDITIONS AND IN AQUEOUS MEDIUM, OF GASEOUS AND LIQUID ALKANES INTO CARBOXYLIC ACIDS
-
The present invention concerns a new efficient method for the selective transformation, under mild conditions and in aqueous medium, of gaseous (ethane, propane and n-butane) and liquid (n-pentane, n-hexane, cyclopentane and cyclohexane) alkanes into carboxylic acids bearing one more carbon atom, characterized by a single-pot low- temperature (25-60 °C) reaction of the alkane with carbon monoxide in water/acetonitrile liquid medium, either in the absence or in the presence of a metal catalyst, in systems containing also an oxidant (a peroxodisulphate salt).
- -
-
Page/Page column 7-13
(2008/12/07)
-
- PROCESS FOR PRODUCING OXYGENIC COMPOUND
-
An oxidation catalyst composition is obtained by mixing a selenium compound, a nitrogen-containing aromatic compound and an acid, and if necessary, in the presence of a solvent. The oxidation catalyst composition shows an oxidation catalyst activity in the oxidation reaction of an organic compound. For example, at least one oxygen-containing compound selected from an alcohol compound, an aldehyde compound, a ketone compound and a carboxylic acid compound is obtained by reacting the olefin compound having two or more hydrogen atoms on the carbon atom at α-position of a carbon-carbon double bond with an organic hydroperoxide compound in the presence of the oxidation catalyst composition.
- -
-
-
- Structure activity studies with xenobiotic substrates using carboxylesterases isolated from Arabidopsis thaliana
-
Carboxylesterases (CXEs) catalyse the hydrolysis of xenobiotics and natural products radically altering their biological activities. Whereas the substrate selectivity of animal CXEs, such as porcine liver esterase (PLE) have been well studied, the respective enzymes in plants have yet to be defined and their activities determined. Using Arabidopsis thaliana (At) as a source, five representative members of the α/β hydrolase AtCXE family of proteins have been cloned, expressed and the purified recombinant proteins assayed for esterase activity with xenobiotic substrates. Two members, AtCXE5 and AtCXE18 were found to be active carboxylesterases, though AtCXE5 proved to be highly unstable as a soluble protein. AtCXE18 and the previously characterised S-formylglutathione hydrolase from Arabidopsis (AtSFGH) were assayed against a series of esters based on methylumbelliferone in which the acyl moiety was varied with respect to size and conformation. The same series was used to assay crude esterase preparation from Arabidopsis plants and the results compared with those obtained with the commonly used PLE. With straight chain esters, AtCXE18 behaved like PLE, but the Arabidopsis hydrolases proved less tolerant of branched chain acyl components than the mammalian enzyme. While none of the enzyme preparations accurately reflected all the activities determined with crude Arabidopsis protein extracts, the plant enzymes proved more useful than PLE in predicting the hydrolysis of the more sterically constrained esters.
- Cummins, Ian,Landrum, Marie,Steel, Patrick G.,Edwards, Robert
-
p. 811 - 818
(2008/03/13)
-
- Diisopropyloxy(η2-cyclopentene)titanium for the diastereoselective synthesis of various 1,2-disubstituted cyclopentanes
-
The reaction of 3 equiv of cyclopentylmagnesium chloride with 2 equiv of titanium(IV) isopropoxide at low temperature (-70 to -50 °C) leads to the formation of 1 equiv of diisopropyloxy(η2-cyclopentene)titanium containing low amounts of the starting Grignard reagent. The sequential addition of two electrophiles onto this titanium complex involved as an intermediate in Kulinkovich-type reactions delivers various 1,2-disubstituted cyclopentane rings with generally high diastereoselectivity. Mechanistic considerations and possible extensions of this method are discussed.
- Cadoret, Frédéric,Retailleau, Pascal,Six, Yvan
-
p. 7749 - 7753
(2007/10/03)
-
- PIPERIDINE DERIVATIVES AND THEIR USE AS GLYCINE TRANSPORTER INHIBITORS
-
The invention provides a compound of formula (1), or a salt or solvate thereof: wherein R, R5, R6, R7, R8, R9, X, n and Ar are as defined in the specification, and uses of such compounds. The compounds inhibit GlyT1 transporters and are useful in the treatment of certain neurological and neuropsychiatric disorders, including schizophrenia.
- -
-
Page/Page column 33
(2010/02/15)
-
- Partial and full agonists of A1 adenosine receptors
-
Disclosed are novel compounds that are partial and full A1 adenosine receptor agonists, useful for treating various disease states, in particular tachycardia and atrial flutter, angina, and myocardial infarction.
- -
-
-