- Design of multifaceted antioxidants: Shifting towards anti-inflammatory and antihyperlipidemic activity
-
Oxidative stress and inflammation are two conditions that coexist in many multifactorial diseases such as atherosclerosis and neurodegeneration. Thus, the design of multifunctional compounds that can concurrently tackle two or more therapeutic targets is an appealing approach. In this study, the basic NSAID structure was fused with the antioxidant moieties 3,5-di-tert-butyl-4-hydroxybenzoic acid (BHB), its reduced alcohol 3,5-di-tert-butyl- 4-hydroxybenzyl alcohol (BHBA), or 6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox), a hydrophilic analogue of α-tocopherol. Machine learning algorithms were utilized to validate the potential dual effect (anti-inflammatory and antioxidant) of the designed analogues. Derivatives 1-17 were synthesized by known esterification methods, with good to excellent yields, and were pharmacologically evaluated both in vitro and in vivo for their antioxidant and anti-inflammatory activity, whereas selected compounds were also tested in an in vivo hyperlipidemia protocol. Furthermore, the activity/binding affinity of the new compounds for lipoxygenase-3 (LOX-3) was studied not only in vitro but also via molecular docking simulations. Experimental results demonstrated that the antioxidant and anti-inflammatory activities of the new fused molecules were increased compared to the parent molecules, while molecular docking simulations validated the improved activity and revealed the binding mode of the most potent inhibitors. The purpose of their design was justified by providing a potentially safer and more efficient therapeutic approach for multifactorial diseases.
- Kourounakis, Angeliki,Lambrinidis, George,Tzara, Ariadni
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- Redox-active ligand based Mn(i)-catalyst for hydrosilylative ester reduction
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Herein a Mn(i) catalyst bearing a redox-active phenalenyl (PLY) based ligand is reported for the efficient hydrosilylation of esters to alcohols using the inexpensive silane source polymethylhydrosiloxane (PMHS) under mild conditions. Mechanistic investigations suggest a strong ligand-metal cooperation where a ligand-based single electron transfer (SET) process initiates the reaction through Si-H bond activation.
- Chakraborty, Soumi,Das, Arpan,Mandal, Swadhin K.
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supporting information
p. 12671 - 12674
(2021/12/04)
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- Radical Carbonyl Umpolung Arylation via Dual Nickel Catalysis
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The formation of carbon-carbon bonds lies at the heart of synthetic organic chemistry and is widely applied to construct complex drugs, polymers, and materials. Despite its importance, catalytic carbonyl arylation remains comparatively underdeveloped, due
- Bellotti, Peter,Erchinger, Johannes E.,Glorius, Frank,Huang, Huan-Ming,Paulisch, Tiffany O.
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supporting information
(2022/02/01)
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- Carbon monoxide and hydrogen (syngas) as a C1-building block for selective catalytic methylation
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A catalytic reaction using syngas (CO/H2) as feedstock for the selective β-methylation of alcohols was developed whereby carbon monoxide acts as a C1 source and hydrogen gas as a reducing agent. The overall transformation occurs through an intricate network of metal-catalyzed and base-mediated reactions. The molecular complex [Mn(CO)2Br[HN(C2H4PiPr2)2]]1comprising earth-abundant manganese acts as the metal component in the catalytic system enabling the generation of formaldehyde from syngas in a synthetically useful reaction. This new syngas conversion opens pathways to install methyl branches at sp3carbon centers utilizing renewable feedstocks and energy for the synthesis of biologically active compounds, fine chemicals, and advanced biofuels.
- Kaithal, Akash,H?lscher, Markus,Leitner, Walter
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p. 976 - 982
(2021/02/06)
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- Highly efficient NHC-iridium-catalyzed β-methylation of alcohols with methanol at low catalyst loadings
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The methylation of alcohols is of great importance since a broad number of bioactive and pharmaceutical alcohols contain methyl groups. Here, a highly efficient β-methylation of primary and secondary alcohols with methanol has been achieved by using bis-N-heterocyclic carbene iridium (bis-NHC-Ir) complexes. Broad substrate scope and up to quantitative yields were achieved at low catalyst loadings with only hydrogen and water as by-products. The protocol was readily extended to the β-alkylation of alcohols with several primary alcohols. Control experiments, along with DFT calculations and crystallographic studies, revealed that the ligand effect is critical to their excellent catalytic performance, shedding light on more challenging Guerbet reactions with simple alcohols. [Figure not available: see fulltext.].
- Lu, Zeye,Zheng, Qingshu,Zeng, Guangkuo,Kuang, Yunyan,Clark, James H.,Tu, Tao
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p. 1361 - 1366
(2021/06/30)
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- Design and Scalable Synthesis of N-Alkylhydroxylamine Reagents for the Direct Iron-Catalyzed Installation of Medicinally Relevant Amines**
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Secondary and tertiary alkylamines are privileged substance classes that are often found in pharmaceuticals and other biologically active small molecules. Herein, we report their direct synthesis from alkenes through an aminative difunctionalization reaction enabled by iron catalysis. A family of ten novel hydroxylamine-derived aminating reagents were designed for the installation of several medicinally relevant amine groups, such as methylamine, morpholine and piperazine, through the aminochlorination of alkenes. The method has excellent functional group tolerance and a broad scope of alkenes was converted to the corresponding products, including several drug-like molecules. Besides aminochlorination, the installation of other functionalities through aminoazidation, aminohydroxylation and even intramolecular carboamination reactions, was demonstrated, further highlighting the broad potential of these new reagents for the discovery of novel amination reactions.
- Delcaillau, Tristan,Falk, Eric,Gürtler, Laura,Makai, Szabolcs,Morandi, Bill
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supporting information
p. 21064 - 21071
(2020/09/21)
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- Manganese(I)-Catalyzed β-Methylation of Alcohols Using Methanol as C1 Source
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Highly selective β-methylation of alcohols was achieved using an earth-abundant first row transition metal in the air stable molecular manganese complex [Mn(CO)2Br[HN(C2H4PiPr2)2]] 1 ([HN(C2H4PiPr2)2]=MACHO-iPr). The reaction requires only low loadings of 1 (0.5 mol %), methanolate as base and MeOH as methylation reagent as well as solvent. Various alcohols were β-methylated with very good selectivity (>99 %) and excellent yield (up to 94 %). Biomass derived aliphatic alcohols and diols were also selectively methylated on the β-position, opening a pathway to “biohybrid” molecules constructed entirely from non-fossil carbon. Mechanistic studies indicate that the reaction proceeds through a borrowing hydrogen pathway involving metal–ligand cooperation at the Mn-pincer complex. This transformation provides a convenient, economical, and environmentally benign pathway for the selective C?C bond formation with potential applications for the preparation of advanced biofuels, fine chemicals, and biologically active molecules.
- Kaithal, Akash,van Bonn, Pit,H?lscher, Markus,Leitner, Walter
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supporting information
p. 215 - 220
(2019/12/03)
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- Selective Hydroboration of Carboxylic Acids with a Homogeneous Manganese Catalyst
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Catalytic reduction of carboxylic acid to the corresponding alcohol is a challenging task of great importance for the production of a variety of value-added chemicals. Herein, a manganese-catalyzed chemoselective hydroboration of carboxylic acids has been developed with a high turnover number (>99?000) and turnover frequency (>2000 h-1) at 25 °C. This method displayed tolerance of electronically and sterically differentiated substrates with high chemoselectivity. Importantly, aliphatic long-chain fatty acids, including biomass-derived compounds, can efficiently be reduced. Mechanistic studies revealed that the reaction occurs through the formation of active manganese-hydride species via an insertion and bond metathesis type mechanism.
- Barman, Milan K.,Das, Kuhali,Maji, Biplab
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p. 1570 - 1579
(2019/01/30)
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- Method used for reduction of tertiary amide into alcohols and/or amines
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The invention discloses a method used for reduction of tertiary amide into alcohols and/or amines. The method comprises following steps: tertiary amide, an alkali metal reagent, and a proton donor agent are added into an organic solvent for a following reaction selectively: when the proton donor agent is a raw material alcohol and/or inorganic salt aqueous solution, the reaction product is an alcohol compound and/or tertiary amine compound. The method is capable of realizing selective reduction of tertiary amide into alcohols and tertiary amine compounds, the yield is high, the suitable rangeis wide, operation is safe and simple, the adopted raw materials are cheap and easily available; no precious metal catalyst, toxic silanes, and flammable and combustible metal hydrides are adopted; notoxic by product is generated; reaction is more friendly to the environment; problems in the prior art that amide compound reducing method operation is complex, conditions are strict, and control ofproducts is difficult are solved.
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-
Paragraph 0239-0242
(2019/08/07)
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- Ruthenium(II)-Catalyzed β-Methylation of Alcohols using Methanol as C1 Source
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Selective introduction of methyl branches into the carbon chains of alcohols can be achieved with low loadings of ruthenium precatalyst [RuH(CO)(BH4)(HN(C2H4PPh2)2)] (Ru-MACHO-BH) using methanol both as methylating reagent and as reaction medium. A wide range of structurally divers alcohols was β-methylated with excellent selectivity (>99 %) in fair to high yields (up to 94 %) under standard conditions, and turnover numbers up to 18,000 could be established. The overall reaction rate of the complex catalytic network appears to be governed by interconnection of the individual subcycles through availability of the reactive intermediates. The synthetic procedure opens pathways to important structural motifs following the Green Chemistry principles.
- Kaithal, Akash,Schmitz, Marc,H?lscher, Markus,Leitner, Walter
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p. 5287 - 5291
(2019/05/28)
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- Palladium-Catalyzed Regioselective Aerobic Allylic C?H Oxygenation: Direct Synthesis of α,β-Unsaturated Aldehydes and Allylic Alcohols
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A protocol for the synthesis of α,β-unsaturated aldehydes and allylic alcohols from simple allylic hydrocarbons with water via palladium-catalyzed functionalization of allylic C?H bonds was described. Molecular oxygen is utilized as the sole oxidant in this oxygenation of terminal alkenes. This protocol features good functional group compatibility, broad substrate scope, and high atom- and step-economy. Moreover, the synthetic utility of this method can be highlighted by its application to the synthesis of ibuprofen, which is a highly potent analgesic. (Figure presented.).
- Li, Chunsheng,Chen, Huoji,Li, Jianxiao,Li, Meng,Liao, Jianhua,Wu, Wanqing,Jiang, Huanfeng
-
supporting information
p. 1600 - 1604
(2018/03/05)
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- Biocatalytic Parallel Interconnected Dynamic Asymmetric Disproportionation of α-Substituted Aldehydes: Atom-Efficient Access to Enantiopure (S)-Profens and Profenols
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The biocatalytic asymmetric disproportionation of aldehydes catalyzed by horse liver alcohol dehydrogenase (HLADH) was assessed in detail on a series of racemic 2-arylpropanals. Statistical optimization by means of design of experiments (DoE) allowed the identification of critical interdependencies between several reaction parameters and revealed a specific experimental window for reaching an ′optimal compromise′ in the reaction outcome. The biocatalytic system could be applied to a variety of 2-arylpropanals and granted access in a redox-neutral manner to enantioenriched (S)-profens and profenols following a parallel interconnected dynamic asymmetric transformation (PIDAT). The reaction can be performed in aqueous buffer at ambient conditions, does not rely on a sacrificial co-substrate, and requires only catalytic amounts of cofactor and a single enzyme. The high atom-efficiency was exemplified by the conversion of 75 mM of rac-2-phenylpropanal with 0.03 mol% of HLADH in the presence of ~0.013 eq. of oxidized nicotinamide adenine dinucleotide (NAD+), yielding 28.1 mM of (S)-2-phenylpropanol in 96% ee and 26.5 mM of (S)-2-phenylpropionic acid in 89% ee, in 73% overall conversion. Isolated yield of 62% was obtained on 100 mg-scale, with intact enantiopurities. (Figure presented.).
- Tassano, Erika,Faber, Kurt,Hall, Mélanie
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supporting information
p. 2742 - 2751
(2018/07/29)
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- Reduction and Reductive Deuteration of Tertiary Amides Mediated by Sodium Dispersions with Distinct Proton Donor-Dependent Chemoselectivity
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A practical and scalable single electron transfer reduction mediated by sodium dispersions has been developed for the reduction and reductive deuteration of tertiary amides. The chemoselectivity of this method highly depends on the nature of the proton donor. The challenging reduction via C-N bond cleavage has been achieved using Na/EtOH, affording alcohol products, while the use of Na/NaOH/H2O leads to the formation of amines via selective C-O scission. Sodium dispersions with high specific surface areas are crucial to obtain high yields and good chemoselectivity. This new method tolerates a range of tertiary amides. Moreover, the corresponding reductive deuterations mediated by Na/EtOD-d1 and Na/NaOH/D2O afford useful α,α-dideuterio alcohols and α,α-dideuterio amines with an excellent deuterium content.
- Zhang, Bin,Li, Hengzhao,Ding, Yuxuan,Yan, Yuhao,An, Jie
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p. 6006 - 6014
(2018/05/24)
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- Directed β C-H Amination of Alcohols via Radical Relay Chaperones
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A radical-mediated strategy for β C-H amination of alcohols has been developed. This approach employs a radical relay chaperone, which serves as a traceless director that facilitates selective C-H functionalization via 1,5-hydrogen atom transfer (HAT) and enables net incorporation of ammonia at the β carbon of alcohols. The chaperones presented herein enable direct access to imidate radicals, allowing their first use for H atom abstraction. A streamlined protocol enables rapid conversion of alcohols to their β-amino analogs (via in situ conversion of alcohols to imidates, directed C-H amination, and hydrolysis to NH2). Mechanistic experiments indicate HAT is rate-limiting, whereas intramolecular amination is product- and stereo-determining.
- Wappes, Ethan A.,Nakafuku, Kohki M.,Nagib, David A.
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supporting information
p. 10204 - 10207
(2017/08/10)
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- En Route to a Practical Primary Alcohol Deoxygenation
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A long-standing scientific challenge in the field of alcohol deoxygenation has been direct catalytic sp3 C-O defunctionalization with high selectivity and efficiency, in the presence of other functionalities, such as free hydroxyl groups and amines widely present in biological molecules. Previously, the selectivity issue had been only addressed by classic multistep deoxygenation strategies with stoichiometric reagents. Herein, we propose a catalytic late-transition-metal-catalyzed redox design, on the basis of dehydrogenation/Wolff-Kishner (WK) reduction, to simultaneously tackle the challenges regarding step economy and selectivity. The early development of our hypothesis focuses on an iridium-catalyzed process efficient mainly with activated alcohols, which dictates harsh reaction conditions and thus limits its synthetic utility. Later, a significant advancement has been made on aliphatic primary alcohol deoxygenation by employing a ruthenium complex, with good functional group tolerance and exclusive selectivity under practical reaction conditions. Its synthetic utility is further illustrated by excellent efficiency as well as complete chemo- and regio-selectivity in both simple and complex molecular settings. Mechanistic discussion is also included with experimental supports. Overall, our current method successfully addresses the aforementioned challenges in the pertinent field, providing a practical redox-based approach to the direct sp3 C-O defunctionalization of aliphatic primary alcohols.
- Dai, Xi-Jie,Li, Chao-Jun
-
supporting information
p. 5433 - 5440
(2016/05/19)
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- METHOD FOR MANUFACTURING ALCOHOL BY HYDROGENATION OF CARBOXYLIC ACID COMPOUND AND ESTER COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for obtaining alcohol by hydrogenation of carboxylic acid compound efficiently by using a homogeneous system catalyst, especially a method for obtaining alcohol by hydrogenation of various carboxylic acid compound and ester compound by the homogeneous system catalyst efficiently even under alleviation condition. SOLUTION: A carboxylic acid compound and/or an ester compound is hydrogenated in a presence of a rhenium complex represented by ReXmYnZp, where X is a halogen atom, Y is same or different and each a ligand containing one or more phosphorus atom, Z is a ligand other than X and Y, m is an integer of 1 to 6, p is an integer of 0 to 2 and the sum of m, n and p is an integer of 2 to 6, and a specific alkali metal salt. COPYRIGHT: (C)2015,JPOandINPIT
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-
Paragraph 0117; 0118; 0127; 0129; 0131
(2016/10/10)
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- Direct Ruthenium-Catalyzed Hydrogenation of Carboxylic Acids to Alcohols
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The "green" reduction of carboxylic acids to alcohols is a challenging task in organic chemistry. Herein, we describe a general protocol for generation of alcohols by catalytic hydrogenation of carboxylic acids. Key to success is the use of a combination of Ru(acac)3, triphos and Lewis acids. The novel method showed broad substrate tolerance and a variety of aliphatic carboxylic acids including biomass-derived compounds can be smoothly reduced.
- Cui, Xinjiang,Li, Yuehui,Topf, Christoph,Junge, Kathrin,Beller, Matthias
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supporting information
p. 10596 - 10599
(2015/09/02)
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- Accessible protocol for asymmetric hydroformylation of vinylarenes using formaldehyde
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We report herein on an accessible protocol for the asymmetric hydroformylation of vinylarenes using formaldehyde as a substitute for syngas. The regioselectivity (branched/linear = up to 96/4) and enantioselectivity (up to 95% ee) can be attributed to the use of chiral Ph-bpe as a ligand. This journal is
- Morimoto, Tsumoru,Fujii, Tetsuji,Miyoshi, Kota,Makado, Gouki,Tanimoto, Hiroki,Nishiyama, Yasuhiro,Kakiuchi, Kiyomi
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supporting information
p. 4632 - 4636
(2015/04/27)
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- Simultaneous identification of Fenton degradation by-products of diclofenac, ibuprofen and ketoprofen in aquatic media by comprehensive two-dimensional gas chromatography coupled with mass spectrometry
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Diclofenac, ibuprofen and ketoprofen are anti-inflammatory drugs intensively used both in human and animal treatment. Due to their high stability these compounds are partially removed by wastewater treatment plants and from this reason the development of some alternative treatments such as advanced oxidative processes are necessary. The main problems in the optimization of an advanced oxidative process rise from the difficulties which appear in the identification of degradation by-products necessary for the establishment of degradation pathway. In this paper a developed method for the simultaneous identification of Fenton degradation by-products of the three above mentioned pharmaceuticals is presented. The obtained results show the comprehensive two-dimensional gas chromatography coupled with mass spectrometry as a proper method for the analysis of the complex mixture of compounds resulted from the Fenton degradation process. Moreover, some compounds never mentioned in the scientific literature were identified. (Chemical Equation Presented).
- Beldean-Galea, Mihail Simion,Coman, Virginia,Copaciu, Florina,Thiébaut, Didier,Vial, Jér?me
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p. 1021 - 1027
(2015/07/15)
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- Evaluating a sodium dispersion reagent for the Bouveault-Blanc reduction of esters
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A new sodium dispersion reagent has been evaluated for the reduction of esters. Na-D15, a sodium dispersion with sodium particle size of 5-15 μm, is a nonpyrophoric reagent that can be handled in air. In this study, a broad range of aliphatic ester substrates were reduced to primary alcohols by Na-D15/i-PrOH with good yields. The method compares favorably with modern metal hydride reductions and is much safer and efficient than the traditional Bouveault-Blanc reduction.
- An, Jie,Work, D. Neil,Kenyon, Craig,Procter, David J.
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p. 6743 - 6747
(2014/08/05)
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- Laccase-Mediator System for Alcohol Oxidation to Carbonyls or Carboxylic Acids: Toward a Sustainable Synthesis of Profens
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By combining two green and efficient catalysts, such as the commercially available enzyme laccase from Trametes versicolor and the stable free radical 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), the oxidation in water of some primary alcohols to the corresponding carboxylic acids or aldehydes and of selected secondary alcohols to ketones can be accomplished. The range of applicability of bio-oxidation is widened by applying the optimized protocol to the oxidation of enantiomerically pure 2-arylpropanols (profenols) into the corresponding 2-arylpropionic acids (profens), in high yields and with complete retention of configuration.
- Galletti, Paola,Pori, Matteo,Funiciello, Federica,Soldati, Roberto,Ballardini, Alberto,Giacomini, Daria
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p. 2684 - 2689
(2016/12/23)
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- Uncovering the importance of proton donors in TmI2-promoted electron transfer: Facile C-N bond cleavage in unactivated amides
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Nonclassical lanthanide(II) iodides are modern reagents for the development of challenging electron-transfer processes. It was demonstrated that alcohols are critical for the formation of a thermodynamically more powerful reductant from TmI2 (thulium diiodide), the first nonclassical lanthanide(II) iodide in the series (TmI2, DyI2, NdI2). The TmI2(ROH)n reagent promotes an unprecedented cleavage of the σ C-N bond in amides. Copyright
- Szostak, Michal,Spain, Malcolm,Procter, David J.
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supporting information
p. 7237 - 7241
(2013/07/26)
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- Electron transfer reduction of carboxylic acids using SmI 2-H2O-Et3N
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The first general method for efficient electron transfer reduction of carboxylic acids has been developed. The protocol using SmI2 - H 2O - Et3N allows for reduction of a variety of carboxylic acids in excellent yields and provides an attractive alternative to processes mediated by reactive alkali metals, lithium aluminum hydride, and boron hydrides. Of broader significance, the method allows acyl radical equivalents to be generated from carboxylic acids under mild reaction conditions.
- Szostak, Michal,Spain, Malcolm,Procter, David J.
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supporting information; experimental part
p. 840 - 843
(2012/04/11)
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- Electron transfer reduction of unactivated esters using SmI 2-H2O
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The reduction of unactivated esters using samarium diiodide is reported for the first time. The optimised protocol allows for the reduction of primary, secondary and tertiary alkyl esters in excellent yields and is competitive with reductions mediated by metal hydrides and alkali metals.
- Szostak, Michal,Spain, Malcolm,Procter, David J.
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supporting information; experimental part
p. 10254 - 10256
(2011/10/31)
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- Use of a robust dehydrogenase from an archael hyperthermophile in asymmetric catalysis-dynamic reductive kinetic resolution entry into (s)-profens
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Described is an efficient heterologous expression system for Sulfolobus solfataricus ADH-10 (Alcohol Dehydrogenase isozyme 10) and its use in the dynamic reductive kinetic resolution (DYRKR) of 2-arylpropanal (Profen-type) substrates. Importantly, among the 12 aldehydes tested, a general preference for the (S)-antipode was observed, with high ee's for substrates corresponding to the NSAIDs (nonsteroidal anti-inflammatory drugs) naproxen, ibuprofen, flurbiprofen, ketoprofen, and fenoprofen. To our knowledge, this is the first application of a dehydrogenase from this Sulfolobus hyperthermophile to asymmetric synthesis and the first example of a DYRKR with such an enzyme. The requisite aldehydes are generated by Buchwald-Hartwig-type Pd(0)-mediated α-arylation of tert-butyl propionate. This is followed by reduction to the aldehyde in one [lithium diisobutyl tert-butoxyaluminum hydride (LDBBA)] or two steps [LAH/Dess-Martin periodinane]. Treatment of the profenal substrates with SsADH in 5% EtOH/phosphate buffer, pH 9, with catalytic NADH at 80 °C leads to efficient DYRKR, with ee's exceeding 90% for 9 aryl side chains, including those of the aforementioned NSAIDs. An in silico model, consistent with the observed broad side chain tolerance, is presented. Importantly, the SsADH-10 enzyme could be conveniently recycled by exploiting the differential solubility of the organic substrate/product at 80 °C and at rt. Pleasingly, SsADH-10 could be taken through several thermal cycles, without erosion of ee, suggesting this as a generalizable approach to enzyme recycling for hyperthermophilic enzymes. Moreover, the robustness of this hyperthermophilic DH, in terms of both catalytic activity and stereochemical fidelity, speaks for greater examination of such archaeal enzymes in asymmetric synthesis.
- Friest, Jacob A.,Maezato, Yukari,Broussy, Sylvain,Blum, Paul,Berkowitz, David B.
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supporting information; experimental part
p. 5930 - 5931
(2010/07/05)
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- Chemoenzymatic synthesis of (2S)-2-arylpropanols through a dynamic kinetic resolution of 2-arylpropanals with alcohol dehydrogenases
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We applied Horse Liver Alcohol Dehydrogenase (HLADH) to the enantioselective synthesis of six (2S)-2-arylpropanols, useful intermediates in the synthesis of Profens. The influence of substrate structure and reaction conditions on yields and enantioselectivity were investigated. The high yields and high enantioselectivity towards the (S)-enantiomer obtained in the bioreduction of 2-arylpropionic aldehydes, clearly indicate the achievement of a DKR process through a combination of an enzyme-catalyzed kinetic reduction with a chemical base-catalyzed racemization of the unreacted aldehydes. The racemization step is represented by the keto-enol equilibrium of the aldehyde and can be controlled by modulating pH and reaction conditions.
- Galletti, Paola,Emer, Enrico,Gucciardo, Gabriele,Quintavalla, Arianna,Pori, Matteo,Giacomini, Daria
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supporting information; experimental part
p. 4117 - 4123
(2010/10/03)
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- An improved bouveault-blanc ester reduction with stabilized alkali metals
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Significantly improved Bouveault-Blanc conditions for ester reduction have been developed using sodium in silica gel (Na-SG), a free-flowing powder that can be easily handled in the open atmosphere. Primary alcohols were prepared in excellent yield from a variety of aliphatic esters under mild reaction conditions. The chemistry presented here is far safer than the classic Bouveault-Blanc reduction and is competitive with more modern hydride reduction methods.
- Bodnar, Brian S.,Vogt, Paul F.
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supporting information; experimental part
p. 2598 - 2600
(2009/08/07)
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- Highly efficient asymmetric reduction of arylpropionic aldehydes by Horse Liver Alcohol Dehydrogenase through dynamic kinetic resolution
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The enantioselective synthesis of (2S)-2-phenylpropanol and (2S)-2-(4-iso-butylphenyl)propanol ((S)-Ibuprofenol) has been achieved by means of Horse Liver Alcohol Dehydrogenase (HLADH) in buffered aqueous solution or buffered organic solvent mixtures; under the reaction conditions, a dynamic kinetic resolution (DKR) process was realized with good reaction yields and enantiomeric ratios. The Royal Society of Chemistry.
- Giacomini, Daria,Galletti, Paola,Quintavalla, Arianna,Gucciardo, Gabriele,Paradisi, Francesca
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p. 4038 - 4040
(2008/03/27)
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- Chemoenzymatic synthesis of antiinflammatory drugs in enantiomerically pure form
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A novel chemoenzymatic route to chiral antiinflammatory drugs in enantiomerically pure form is described. Copyright (C) 2000 Elsevier Science Ltd.
- Basak, Amit,Nag, Ahindra,Bhattacharya, Gautam,Mandal, Subrata,Nag, Sikha
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p. 2403 - 2407
(2007/10/03)
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- Compounds having one or more aminosulfaonyloxy radicals useful as pharmaceuticals
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Methods of treating chronic arthritis and osteoporosis which utilize both known and novel compounds which would fall under the general formula:(HO)p--A--[--OS(O) 2 NR 1 R 2 ] zwherein A encompasses a wide range of values including but not limited to aryl, loweralkyl, cycloalkyl, and carbohydrates including sucrose and fructose; p is equal to the number of unreacted hydroxy groups contained on the molecule and may be zero; z is the number of --OS(O) 2 NR 1 R 2 groups and is always at least one; R 1 and R 2 are selected from hydrogen, loweralkyl, carboxy and the like; a novel process for preparing the compounds is provided wherein an appropriate sulfamic acid aryl ester is reacted with a hydroxy substituted A radical which may or may not contain thereon protected carboxyl, amino or hydroxy substituents, in an aprotic solvent containing a tertiary amine base. Pharmaceutical compositions for the treatment of chronic arthritis and osteoporosis are also provided.
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- IBUPROFEN AND NAPROXEN VIA ORGANOBORANES
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The sequential Pd-catalyzed couplings of aryl bromides and triflates with the appropriate organoboranes provide the key steps in new synthetic routes to both ibuprofen and naproxen in racemic form.
- Rivera, Isaac,Colberg, Juan C.,Soderquist, John A.
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p. 6919 - 6922
(2007/10/02)
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- Reductive Carbonylation of Alkenes using Zwitterionic Rhodium Complexes as Catalysts
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Alkenes react with carbon monoxide, sodium borohydride, propan-2-ol and a catalytic amount of Rh(cod)(η6-PhBPh3) (cod = cyclooctadiene) to give alcohols in fine yields; high regioselectivity for the branched or linear alcohol is usually observed, depending on the organic substrate.
- Zhou, Jian-Qiang,Alper, Howard
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p. 233 - 234
(2007/10/02)
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- Synthesis and in solution behaviour of new 2-substituted-4-thiazolidinecarboxylic acid derivatives
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A number of 2-substituted-4-thiazolidinecarboxylic acid derivatives were synthesized by cyclocondensation of L-cysteine or its esters with various aldehydes, resulting from acids provided with antiinflammatory properties. In the cyclocondensation a new chiral center at C-2 position of thiazolidine ring is formed giving rise to a mixture of diastereoisomers which can be partially separated. These diastereoisomers show in solution a fast epimerisation at the same chiral center as evidenced by 1H-nmr studies.
- Chiarino,Ferrario,Pellacini,Sala
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p. 589 - 593
(2007/10/02)
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- Synthesis of 2-Arylpropionaldehydes through Hydroformylation
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The rhodium-phospholes and rhodium-phosphanorbornadienes-catalyzed hydroformylation of the readily available vinylarenes 1-3 gives rise to arylpropionaldehydes 4-6 in good yields.
- Neibecker, Denis,Reau, Regis,Lecolier, Serge
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p. 5208 - 5210
(2007/10/02)
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