- 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
-
-
- Preparation method of tetrahydrofuranacetic acid and ester compounds thereof
-
The invention provides a preparation method of tetrahydrofuranacetic acid and ester compounds thereof. The preparation method comprises the following steps: in a proper solvent, in a reducing atmosphere and under the action of a hydrogenation catalyst, carrying out a reduction reaction on furanacetic acid and ester compounds thereof under the conditions that a pressure is 0.1-10MPa and a temperature is 30-250 DEG C for 0.1-72 hours, separating out the catalyst, and distilling out the solvent to obtain the target products, namely tetrahydrofuranacetic acid and the ester compounds thereof. Under relatively mild and environment-friendly conditions, efficient conversion of bio-based furanacetic acid and esters thereof is achieved, industrial production of the reaction is facilitated, platform molecules can be converted into various important intermediates or terminal products through chemical catalysis upgrading to replace existing petrochemical products, dependence on fossil resources is reduced, and the application range of biomass is expanded.
- -
-
Paragraph 0019; 0025
(2021/05/12)
-
- Cascade conversion of furancarboxylic acid to butanediol diacetate over Pd/C and La(OTf)3 catalytic system
-
The conversion of biomass to a high value-added product 1, 4-butanediol (BDO) and its derivatives is of great economic significance. In this work, furancarboxylic acid (FCA) was adopted as the raw material to prepare BDO. The one-pot synthesis of 1, 4-butanediol diacetate (BDA) has been successfully prepared from FCA with metal triflates and Pd/C catalysts. The effect of reaction conditions was investigated and the reaction routes was systematically studied by 1H-NMR and GC. The tandem catalytic process from FCA to BDA mainly underwent three stages. Firstly, FCA was hydrogenated to tetrahydrofurfuric acid (THFCA) by Pd/C. Afterwards, THFCA was decarbonylated to form oxonium ions with metal triflates. Then the oxonium ions was rapidly hydrogenated to form tetrahydrofuran (THF) by Pd/C. Ultimately, THF was ring-opening esterified to BDA by metal triflates. This novel synthesis method of BDO from FCA provides a promising protocol for broadening the application of common biomass substrates.
- Deng, Jin,Fu, Yao,Gong, Baoxiang,Zhou, Gongyu,Zhu, Rui
-
-
- Selective Hydrogenolysis of α-C-O Bond in Biomass-Derived 2-Furancarboxylic Acid to 5-Hydroxyvaleric Acid on Supported Pt Catalysts at Near-Ambient Temperature
-
Hydrogenolysis of the α-C-O bond in abundantly available biomass-based furfural and its derivatives provides a viable route for sustainable synthesis of valuable C5 compounds, particularly with two terminal oxygen-containing functional groups. However, efficient cleavage of this bond under mild conditions still remains a crucial challenge, primarily because of the competing cleavage of the α-C-O bond and hydrogenation of furan ring. Here, we report that supported Pt catalysts were extremely active for the selective α-C-O cleavage in 2-furancarboxylic acid (FCA) hydrogenolysis to synthesize 5-hydroxyvaleric acid (5-HVA), affording a high yield (～78%) on Pt/SiO2 with a Pt particle size of 4.2 nm at an unprecedentedly low temperature of 313 K. In this reaction, the turnover rate and 5-HVA selectivity sensitively depend on the size of the Pt nanoparticles and the underlying support, as a consequence of their effects on the exposed Pt surfaces. Combined reaction kinetic, infrared spectroscopic, and theoretical assessments reveal that while the exposed high-index Pt surfaces (containing higher fraction of step sites) facilitate the kinetically relevant addition of the first H atom to the unsaturated C atom in furan ring and thus the hydrogenolysis activity, the low-index surfaces (containing higher fraction of terrace sites), together with the electron-withdrawing effect of the carboxylic substituent in FCA, favorably stabilize the dangling C2 atom in the transition states of α-C-O cleavage and lower their activation barriers, leading to the observed high 5-HVA selectivity. Such pivotal roles of the intrinsic properties of metal surfaces and substituents in tuning the reaction pathways will provide a viable strategy for highly selective upgrading of furan derivatives and other biomass-based oxygenates.
- Sun, Qianhui,Wang, Shuai,Liu, Haichao
-
p. 11413 - 11425
(2019/11/21)
-
- Selective hydrogenolysis of 2-furancarboxylic acid to 5-hydroxyvaleric acid derivatives over supported platinum catalysts
-
The conversion of 2-furancarboxylic acid (FCA), which is produced by oxidation of furfural, to 5-hydroxyvaleric acid (5-HVA) and its ester/lactone derivatives with H2 was investigated. Monometallic Pt catalysts were effective, and other noble metals were not effective due to the formation of ring-hydrogenation products. Supports and solvents had a small effect on the performance; however, Pt/Al2O3 was the best catalyst and short chain alcohols such as methanol were better solvents. The optimum reaction temperature was about 373 K, and at higher temperature the catalyst was drastically deactivated by deposition of organic materials on the catalyst. The highest yield of target products (5-HVA, δ-valerolactone (DVL), and methyl 5-hydroxyvalerate) was 62%, mainly obtained as methyl 5-hydroxyvalerate (55% yield). The byproducts were mainly ring-hydrogenation compounds (tetrahydrofuran-2-carboxylic acid and its ester) and undetected ones (loss of carbon balance). The catalyst was gradually deactivated during reuses even at a reaction temperature of 373 K; however, the catalytic activity was recovered by calcination at 573 K. The reactions of various related substrates were carried out, and it was found that the O-C bond in the O-CC structure (1,2,3-position of the furan ring) is dissociated before CC hydrogenation while the presence and position of the carboxyl group (or methoxy carbonyl group) much affect the reactivity.
- Asano, Takehiro,Takagi, Hiroshi,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi
-
supporting information
p. 6133 - 6145
(2019/11/20)
-
- 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)
-
- Method for preparing acid through oxidating alcohols or aldehydes by oxygen
-
The invention provides a method for preparing acid through oxidating alcohols or aldehydes by using oxygen or oxygen in air as an oxidant. The method comprises the steps: oxidating the alcohols or aldehydes to produce the acid at room temperature in an organic solvent in a manner of taking ferric nitrate (Fe(NO3)3.9H2O), 2,2,6,6-tetramethylpiperidyl nitrogen oxide (TEMPO) and an inorganic halide as catalysts and taking the oxygen or air as an oxidant, and oxidating diols to produce lactone; or, carrying out a reaction on the aldehydes, which serve as a raw material, under neutral conditions by taking ferric nitrate as a catalyst, and oxidating the aldehydes to produce the acid and peroxy acid. The method has the advantages that the method is environmentally friendly, the cost is low, the yield is high, the atomic economical efficiency is high, the compatibility of substrate functional groups is good, the reaction conditions are mild, a reaction scale can be enlarged, and the like, so that the method is suitable for being applied to industrial production.
- -
-
Paragraph 0051; 0052; 0053; 0054; 0070; 0071; 0072
(2017/09/29)
-
- Acid-tolerant cyclodextrin-based ruthenium nanoparticles for the hydrogenation of unsaturated compounds in water
-
A water-soluble β-cyclodextrin polymer synthesized by crosslinking β-cyclodextrin with epichlorohydrin and glycidyltrimethylammonium chloride allowed the stabilization of ruthenium nanoparticles not only in basic aqueous medium but also in acidic medium. The aqueous ruthenium colloidal suspensions obtained with this polymer were active as catalysts for the hydrogenation of a large variety of unsaturated compounds including aromatic or fatty acids. The recycling of this catalytic system was attested through ten consecutive runs without loss of stability and activity, demonstrating its robustness.
- No?l, Sébastien,Bourbiaux, Dolorès,Tabary, Nicolas,Ponchel, Anne,Martel, Bernard,Monflier, Eric,Léger, Bastien
-
p. 5982 - 5992
(2017/12/26)
-
- Iron Catalysis for Room-Temperature Aerobic Oxidation of Alcohols to Carboxylic Acids
-
Oxidation from alcohols to carboxylic acids, a class of essential chemicals in daily life, academic laboratories, and industry, is a fundamental reaction, usually using at least a stoichiometric amount of an expensive and toxic oxidant. Here, an efficient and practical sustainable oxidation technology of alcohols to carboxylic acids using pure O2 or even O2 in air as the oxidant has been developed: utilizing a catalytic amount each of Fe(NO3)3·9H2O/TEMPO/MCl, a series of carboxylic acids were obtained from alcohols (also aldehydes) in high yields at room temperature. A 55 g-scale reaction was demonstrated using air. As a synthetic application, the first total synthesis of a naturally occurring allene, i.e., phlomic acid, was accomplished.
- Jiang, Xingguo,Zhang, Jiasheng,Ma, Shengming
-
supporting information
p. 8344 - 8347
(2016/07/26)
-
- Irreversible catalytic ester hydrolysis of allyl esters to give acids and aldehydes by homogeneous ruthenium and ruthenium/palladium dual catalyst systems
-
An irreversible hydrolysis reaction of allyl esters (1) into carboxylic acids (2) and propanal (3) was achieved with a ruthenium/palladium (Ru/Pd) dual catalyst system. The optimized catalysts consists of a 1:1:1 mixture of (cyclopentadienyl)tris(acetonitrile)ruthenium hexafluorophosphate {[RuCp(MeCN)3] PF6}, bis(acetonitrile)palladium dichloride [PdCl2(MeCN)2] and 1,6-bis(diphenylphosphanyl)hexane (DPPHex). The reaction proceeds via isomerization of allyl esters to 1-propenyl esters and hydrolysis of them to give 2 and 3. The first isomerization step was virtually catalyzed by the Ru components and the second hydrolysis step was mainly catalyzed by the Pd components. The optimized bidentate phosphine (DPPHex) which has long alkylene chain effectively generates two vacant sites on the Ru centers by bridging coordination. When a chelating bidentate phosphine such as DPPE was employed, only one vacant site remained on the Ru center and resulted in a low activity. This chelating Ru complex of DPPE formed even in the presence of 2 equivalents of Ru or additional 1 equivalent of Pd. These differences in coordination behaviour between DPPHex and 1,2- bis(diphenylphosphanyl)ethane (DPPE) cause the differences of the catalytic activity in the first step. The phosphine coordination to Pd center slightly decreases the activity of second hydrolysis step but which was compensated by the increasing of the stability of Pd. On the whole, the optimized Ru/Pd dual catalyst system exhibited good performances on the irreversible hydrolysis of allyl esters.
- Nakamura, Asami,Hamasaki, Akiyuki,Goto, Sachihiko,Utsunomiya, Masaru,Tokunaga, Makoto
-
supporting information; experimental part
p. 973 - 984
(2011/06/19)
-
- Green and chemoselective oxidation of alcohols with hydrogen peroxide: A comparative study on Co(II) and Co(III) activity toward oxidation of alcohols
-
Two new cobalt (II) and cobalt (III) complexes of a terpyridine based ligand, (4′-(2-thienyl)-2,2′;6′,2″-terpyridine (L)), were synthesized. Each complex has two units of the tridentate ligand. The complexes were fully characterized by spectroscopic methods as well as CHN analysis. Moreover, their solid state structures were determined by single crystal X-ray diffraction. The cobaltous complex has the formula [Co(L) 2](NO3)2·2CH3OH·H 2O (1), whereas the cobaltic complex shows the formula [Co(L) 2](NO3)3·2CH3OH (2). Both complexes were tested as homogenous catalysts for the oxidation of a variety of aliphatic and aromatic alcohols utilizing aqueous hydrogen peroxide in water media. The Co(II) complex showed more activity in comparison with its isostructural Co(III) species. The results show that the aromatic alcohols were oxidized with higher conversions and selectivity compared to the aliphatic substrates, possibly due to their conjugation systems which thermodynamically stabilized the carbonyl products.
- Nemati Kharat, Ali,Bakhoda, Abolghasem,Tamaddoni Jahromi, Bahareh
-
scheme or table
p. 2768 - 2775
(2011/12/13)
-
- TEMPO-mediated environmentally benign oxidation of primary alcohols to carboxylic acids with poly[4-(diacetoxyiodo)styrene]
-
An operationally simple and environmentally benign oxidation of primary alcohols to the corresponding carboxylic acids with a TEMPO-mediated poly[4-(diacetoxyiodo)styrene] system in acetone and water was carried out.
- Tashino, Yousuke,Togo, Hideo
-
p. 2010 - 2012
(2007/10/03)
-
- CCR5 modulators
-
Compounds of Formula 1[Region α]-[Region β]-[Region γ]-[Region δ]??(I)which are useful as modulators of chemokine activity. The invention also provides pharmaceutical formulations and methods of treatment using these compounds.
- -
-
-
- Enantioselective homogeneous hydrogenation of monosubstituted pyridines and furans
-
The first case of an enantioselective hydrogenation of monosubstituted pyridines and furans with homogeneous rhodium diphosphine catalysts with low but significant enantioselectivities and catalyst activities is reported. Best enantioselectivities (ees of 24-27%) were obtained for the hydrogenation of 2-and 3-pyridine carboxylic acid ethyl ester and 2-furan carboxylic acid with catalysts prepared in situ from [Rh(nbd)2]BF4 and the chiral ligands diop, binap, or ferrocenyl diphosphines of the josiphos type. Turnover numbers (ton) were in the order of 10-20, turnover frequencies (tof) usually 1-2 h-1. Diphosphines giving 6-or 7-ring chelates led to higher ees than 1,2-diphosphines; otherwise, no clear correlation between ligand properties and catalytic performance was found. In some experiments black precipitates were observed at the end of the reaction, indicating the decomposition of the homogeneous catalysts for certain ligand/metal/ substrate combinations.
- Studer, Martin,Wedemeyer-Exl, Christina,Spindler, Felix,Blaser, Hans-Ulrich
-
p. 1335 - 1343
(2007/10/03)
-
- Synthesis, Structure, and Pharmacological Evaluation of the Stereoisomers of Furnidipine
-
The synthesis and pharmacological activities of the four stereoisomers of methyl tetrahydrofuran-2-ylmethyl 2,6-dimethyl-4-(2'-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate (furnidipine) are reported.The four isomers were synthesized by a modified Hantzsch synthesis by reaction of (-)- or (+)-tetrahydrofuran-2-ylmethyl 3-aminocrotonate and methyl 2-acetoacetate or, alternatively, by reaction of (-)- or (+)-tetrahydrofuran-2-ylmethyl 2-acetoacetate and methyl 3-aminocrotonate.The 1:1 diasteromeric mixture thus obtained were separated by chromatography, using poly(D-phenylglycine) as the chiral stationary phase.The enantiomeric purity of the stereoisomers was determined by high-performance liquid chromatography-chiral stationary phase technique (HPLC-CSP).Attempts to obtain crystals of a single stereoisomer failed in different solvent, while methanol crystallization of the product obtained from (+/-)-tetrahydrofuran-2-ylmethyl 2-acetoacetate and methyl 3-aminocrotonate yielded good-quality crystals of the most insoluble racemate which proved to be a mixture of the (SS)/(RR) enantiomers by X-ray crystaloography.Conformational analysis of the stereoisomers, assuming rotation of the aryl substituent and ester groups, shows small energy differences (about 4 kcal*mol-1) between the most and the least favorable conformations.Binding studies were performed using isradipine as a reference ligand.The results showed stereospecificity of the furnidipine isomers in brain, ileum, and cardiac tissues, the (SS) and (SR)-isomers clearly being more potent than their (RR)- and (RS)-enantiomers.The (SS)- and (SR)-isomers were also more selective on cerebral tissue when compared with ileal and cardiac preparations.
- Alajarin, Ramon,Vaguero, Juan J.,Alvarez-Builla, Julio,Pastor, Manuel,Sunkel, Carlos,et al.
-
p. 2830 - 2841
(2007/10/02)
-
- Synthesis of C-Nucleosides via Radical Coupling Reaction
-
Photolysis of O-acyl derivatives of N-hydroxy-2-thiopyridone, prepared from tetrahydrofuran-2-carboxylic acid, D-ribofuranosylmethanoic acid, and D-ribopyranosylmethanoic acid, gave the corresponding C-nucleoside derivatives in the presence of heteroaromatic compounds via radical pathways.The essential step in this method is a radical coupling reaction of D-ribofuranosyl radical or D-ribopyranosyl radical and some heteroaromatic bases.This is a new method for the preparation of C-nucleosides using sugar carboxylic acids.
- Togo, Hideo,Ishigami, Sachiko,Fujii, Misa,Ikuma, Toshihiro,Yokoyama, Masataka
-
p. 2931 - 2942
(2007/10/02)
-
- Process for the preparation of optically active carboxylic acids and amide intermediates
-
The present invention provides a process for the preparation of optically active carboxylic acids of the formula I* or II* STR1 in which X is an oxygen or sulfur atom and n is 1 or 2. The process comprises reacting a racemic carboxylic acid I or II or its derivatives with an optically active 2-amino-carboxylic acid ester to give the diastereomeric carboxylic acid amides, separating the diastereomers and, after cleavage of the amide bond, isolating the optically active carboxylic acids of the general formula I* or II*. The invention also provides certain novel optically active carboxylic acid amides and a tetrahydrothiopyran-2-carboxylic acid.
- -
-
-
- Degenerate Transesterification of 3,5-Dimethylphenolate/3,5-Dimethylphenyl Esters in Weakly Polar, Aprotic Solvents. Reactions of Aggregates and Complex-Induced Proximity Effects
-
The rates of exchange of the 3,5-dimethylphenolate ion between lithium 3,5-dimethylphenolate-d6 and a series of 3,5-dimethylphenyl esters have been determined in the weakly polar, aprotic solvents dioxolane, dimethoxyethane (DME), tetrahydrofuran (THF), and pyridine. The esters include the propionate, butyrate, methoxyacctate, β-methoxypropionate, 4-methoxybutyrate, 2-tetrahydrofuroate, 2-furoate, (N,N-dimethylamino)acetate, (methylthio)acetate, 2- and 4-pyridine-carboxylates, 2-pyridylacetate, 4-pyridylacetate, phenylacetate, andp-methoxy-,p-chloro-, and p-(trifluoromethyl)phenylacetates. The rates and kinetic orders of the reactions of 3,5-dimethylphenyl propionate in various solvents at 35°C gave the following second-order rate constants (104k2, L mol-1 sec-1) for the following major aggregate species: THF tetramer, 6.5; DME tetramer, 3.3 (40°C); dioxolane, 13, hexamer, 71; pyridine tetramer, 2.2, dimer, 29. For 3,5-dimethylphenyl β-methoxypropionate, the order of reactivity is dioxolane > DME > THF. These results are interpreted in terms of a preequilibrium in which a solvent on lithium in the tetramer is replaced by the ester. The rates of transesterification have been compared with the rates of hydrolysis in 30% aqueous ethanol for the above series of esters. Those esters that have a second Lewis base center proximal to the ester function show significantly increased reactivity in transesterification, which is attributed to a complex-induced proximity effect.
- Jackman,Petrei,Smith
-
p. 3451 - 3458
(2007/10/02)
-
- Oxidation of partially protected carbohydrates at the nickel hydroxide electrode
-
Primary hydroxy groups in pyranoses are oxidized in excellent yields to the corresponding carboxylic acids. In furanose 3 the yield of acid is only moderate. Secondary hydroxy groups are inert, aside from lactols. The different reactivity of secondary and primary hydroxy groups allows the chemoselective oxidation of 8 and 10.
- Schaefer, Hans J.,Schneider, Roy
-
p. 715 - 724
(2007/10/02)
-
- Method of racemization of optically active tetrahydrofuran-2-carboxylic acid
-
Disclosed is a method of racemization of optically active tetrahydrofuran-2-carboxylic acid. (+)-Tetrahydrofuran-2-carboxylic acid is useful as a side chain intermediate of the antibiotics of penem series, and is prepared by optical resolution of racemic compound. The remaining (+)-isomer should be racemized and reused as the material for further optical resolution. The racemization can be, in accordance with the present invention, carried out by heating the optically active tetrahydrofuran-2-carboxylic acid to a temperature of 100° C. or higher in the presence of a strong base.
- -
-
-
- Method of racemization of optically active tetrahydrofuran 2-carboxylic acid
-
Disclosed is a method of racemization of optically active tetrahydrofuran-2-carboxylic acid. (+)-Tetrahydro-furan-2-carboxylic acid is useful as a side chain inter-mediate of the antibiotics of penem series, and is prepared by optical resolution of racemic compound. The remaining (-)-isomer should be racemized and reused as the material for further optical resolution. The racemization can be, in accordance with the present invention, carried out by heating the optically active tetrahydrofuran-2-carboxylic acid to a temperature of 100oC or higher in the presence of a strong base.
- -
-
-
- Reactivite du nitrite de sodium. V. Action sur les amino-acides, peptides et proteines
-
The action of sodium nitrite on various amino-acids was re-examined in conditions approximating to a biological medium. 13C-NMR provides evidence of the existence of intramolecular ring closures and the formation of 5-membered rings with ornithine, citrulline and arginine.The reaction of cystine shows the opening of the sulphur bridges, whereas cysteine leads to the formation of carboxy-thiiran and 3-sulpho-lactic acid.The hydrolysis of the amide bonds of asparagine and glutamine is complete whereas the peptides studied - carnosine and aspartam - do not undergo hydrolysis of the peptide linkage.However, the first deamination of glutathion (γ-Glu-Cys-Gly) induces the peptide link to be broken and a cyclization with the formation of lactone to occur.A second deamination takes place on the cysteinyl residue released and allows the formation of a thiiran by intramolecular cyclization with the thiol group.The formation of thiiran was also observed with oxidized glutathion which has an S-S bridge.Finally, the formation of nitrosamines was detected by 15N-NMR during the reaction of sodium nitrite with two commercial products available to the general public.
- Gouesnard, Jean-Paul
-
-
- Enolate Claisen Rearrangement of Esters from Furanoid and Pyranoid Glycals
-
A general method is described for the formation of furanoid and pyranoid glycals.Thus, lithium-ammonia reduction of the corresponding 1-chloro-2,3-O-isopropylidene furanoid and pyranoid carbohydrate derivatives affords the desired glycals in 87-92percent yields.Several examples that reveal the scope of this process are described .The formation of C-glycosides from the glycal esters through application of the ester enolate Claisen rearrangement is explored.The characteristics and stereochemistry of this process in both the acyclic and cyclic series of glycal derivatives are described.
- Ireland, Robert E.,Thaisrivongs, Suvit,Vanier, Noel,Wilcox, C. S.
-
-
