- Hydration of Cyanohydrins by Highly Active Cationic Pt Catalysts: Mechanism and Scope
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Cyanohydrins (α-hydroxy nitriles) are a special type of nitriles that readily decompose into hydrogen cyanide (HCN) and the corresponding carbonyl compounds. Hydration of cyanohydrins that are readily available through cyanation of aldehydes and ketones provides the most straightforward route to valuable α-hydroxyamides. However, due to low stability of cyanohydrins and deactivation of the catalysts by the released HCN, catalytic direct hydration of cyanohydrins still remains largely unsolved. As a general trend, cyanohydrins containing bulkier substituents, such as α,α-diaryl cyanohydrins, degrade more quickly and thus are more difficult to be hydrated. Here, we report development of cationic platinum catalysts that exhibit high reactivity for hydration of various cyanohydrins. Detailed mechanistic investigations for hydration of nitriles by (PμP)Pt(PR2OH)X(OTf) reveal a catalytic cycle involving the formation of a five-membered metallacyclic intermediate and subsequent hydrolysis via attacking on the phosphorus of the secondary phosphine oxide (PR2OH) ligand by H2O. We discovered that Pt catalyst A bearing the electron-rich, appropriately small-bite-angle bisphosphine ligand provides super reactivity for hydration of cyanohydrins. The hydration reactions catalyzed by A proceed at ambient temperatures and occur with a wide variety of cyanohydrins, including the most difficult α,α-diaryl cyanohydrins, with good turnover numbers.
- Li, Chengcheng,Chang, Xiao-Yong,Huo, Luqiong,Tan, Haibo,Xing, Xiangyou,Xu, Chen
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p. 8716 - 8726
(2021/07/26)
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- Catalyst, preparation method thereof and preparation method of amide compound
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The invention relates to a catalyst, a preparation method thereof, and a preparation method for hydrating nitrile groups into amides. The catalyst is used for catalyzing nitrile groups to be hydratedinto amides, and the structural general formula of the catalyst is shown in the specification. In the formula, a plurality of R are respectively and independently ones selected from aromatic groups, heteroaromatic groups and non-aromatic ring groups; a plurality of R are ones respectively and independently selected from linear alkyl groups and alkane aromatic groups; X is one selected from Cl and Br; and L is one selected from OTf, BF4, PF6 and SbF6. The catalyst can catalyze nitrile groups to be hydrated into amides, and the nitrile groups can be catalyzed to be hydrated into amides even at a low temperature (20-80 DEG C); besides, compared with existing common catalysts for catalyzing nitrile groups to be hydrated into amides, the catalyst has the advantages that the equivalent weight of the catalyst can be obviously reduced, and nitrile groups can reach a relatively high conversion rate when the equivalent weight of the catalyst is only 0.01 mol%-0.5 mol%; and meanwhile, the catalyst is wider in application range and can catalyze various nitrile compounds to be hydrated into amide compounds.
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Paragraph 0142-0146; 0147
(2020/01/12)
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- Highly Efficient Synthesis of Amino Acids by Amination of Bio-Derived Hydroxy Acids with Ammonia over Ru Supported on N-Doped Carbon Nanotubes
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The amino acids have extensive applications, and their productions from biomass-derived feedstocks are very attractive. In this work, the synthesis of amino acids by amination of bio-derived hydroxy acids with ammonia over different metallic nano-catalysts supported on various supports is studied. It is found that Ru nano-catalysts on the nitrogen-doped carbon nanotubes (Ru/N?CNTs) have an outstanding performance for the reaction. Different hydroxy acids can be catalytically converted into the corresponding amino acids with yields up to 70.0 % under mild conditions, which is higher than those reported. The reasons for the high efficiency of the catalyst are investigated, and the reaction pathway is proposed on the basis of control experiments.
- Xie, Zhenbing,Chen, Bingfeng,Peng, Fangfang,Liu, Mingyang,Liu, Huizhen,Yang, Guanying,Han, Buxing
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p. 5683 - 5689
(2020/09/21)
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- Promotion of catalytic properties of vanillin loaded MCM-41 by Cu(I) and Cu(II) for enhanced removal of quinoline contaminants
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In the present study, to enhance removal of quinoline contaminants using natural active component, vanillin was loaded onto the MCM-41 (Mobile Component Material) nanoparticles in a simple way. The product was divided into two parts, which were improved by Copper(I) and Copper(II) salts. Promoted synthetic nanocatalysts (Cu(I)/Van./MCM-41, and Cu(II)/Van./MCM-41) were characterized using X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-Ray Spectroscopy (EDS), Mapping, Fourier-Transform Infrared Spectroscopy (FTIR), and BET/BJH (Brunauer-Emmett-Teller (BET) and Barret-Joyner-Halenda (BJH)) techniques. To reach optimal conditions, experimental design was performed using Response Surface Methodology (RSM). The experiments were done with the aid of nanocomposites, in presence of ultraviolet radiation without any auxiliary oxidants. Degradation percentages were measured by an Ultraviolet (UV) spectrophotometer. The products were identified using Gas Chromatography–Mass (GC-Mass) technique, and some mechanisms for quinoline removal were proposed. The results indicated that Cu (I) showed better performance in enhanced removal of quinoline than Cu(II).
- Arjmand, Mehdi,Fazaeli, Reza,Ghorbani, Mohammad Hossein,Kamani, Mina
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p. 4833 - 4841
(2020/09/16)
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- Catalytic Transfer Hydration of Cyanohydrins to α-Hydroxyamides
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We report the palladium(II)-catalyzed transfer hydration of cyanohydrins to α-hydroxyamides by using carboxamides as water donors. This method enables selective hydration of various aldehyde- and ketone-derived cyanohydrins to afford α-mono- and α,α-disubstituted-α-hydroxyamides, respectively, under mild conditions (50 °C, 10 min). The direct conversion of fenofibrate, a drug bearing a benzophenone moiety, into a functionalized α,α-diaryl-α-hydroxyamide was achieved by means of a hydrocyanation-transfer hydration sequence. Preliminary kinetic studies and the synthesis of a site-specifically 18O-labeled α-hydroxyamide demonstrated the carbonyl oxygen transfer from the carboxamide reagent into the α-hydroxyamide product.
- Kanda, Tomoya,Naraoka, Asuka,Naka, Hiroshi
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supporting information
p. 825 - 830
(2019/01/14)
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- Highly Active Platinum Catalysts for Nitrile and Cyanohydrin Hydration: Catalyst Design and Ligand Screening via High-Throughput Techniques
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Nitrile hydration provides access to amides that are indispensable to researchers in chemical and pharmaceutical industries. Prohibiting the use of this venerable reaction, however, are (1) the dearth of biphasic catalysts that can effectively hydrate nitriles at ambient temperatures with high turnover numbers and (2) the unsolved challenge of hydrating cyanohydrins. Herein, we report the design of new "donor-acceptor"-type platinum catalysts by precisely arranging electron-rich and electron-deficient ligands trans to one other, thereby enhancing both the nucleophilicity of the hydroxyl group and the electrophilicity of the nitrile group. Leveraging a high-throughput, automated workflow and evaluating a library of bidentate ligands, we have discovered that commercially available, inexpensive DPPF [1,1′-ferrocenendiyl-bis(diphenylphosphine)] provides superior reactivity. The corresponding "donor-acceptor"-type catalyst 2a is readily prepared from (DPPF)PtCl2, PMe2OH, and AgOTf. The enhanced activity of 2a permits the hydration of a wide range of nitriles and cyanohydrins to proceed at 40 °C with excellent turnover numbers. Rational reevaluation of the ligand structure has led to the discovery of modified catalyst 2c, harboring the more electron-rich 1,1′-bis[bis(5-methyl-2-furanyl)phosphino] ferrocene ligand, which demonstrates the highest activity toward hydration of nitriles and cyanohydrins at room temperature. Finally, the correlation between the electron-donating ability of the phosphine ligands with catalyst efficiencies of 2a, 2c, 2d, and 2e in the hydration of nitrile 7 are examined, and the results support the "donor-acceptor" hypothesis.
- Xing, Xiangyou,Xu, Chen,Chen, Bo,Li, Chengcheng,Virgil, Scott C.,Grubbs, Robert H.
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supporting information
p. 17782 - 17789
(2019/01/04)
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- Photoiodocarboxylation of Activated C=C Double Bonds with CO2 and Lithium Iodide
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The photolysis at 254 nm of lithium iodide and olefins 1 carrying an electron-withdrawing Z-substituent in CO2-saturated (1 bar) anhydrous acetonitrile at room temperature produces the atom efficient and transition metal-free photoiodocarboxylation of the C=C double bond. The reaction proceeds well for terminal olefins 1 to form the new C-I and C-C σ-bonds at the α and β-positions of the Z-substituent, respectively, and is strongly inhibited by polar protic solvents or additives. The experimental results suggest that the reaction channels through the radical anion [CO2?-] in acetonitrile, yet involves different intermediates in aqueous medium. The stabilizing ion-quadrupole and electron donor-acceptor interactions of CO2 with the iodide anion play a crucial role in the reaction course as they allow CO2 to penetrate the solvation shell of the anion in acetonitrile, but not in water. The reaction paths and the reactive intermediates involved under different conditions are discussed.
- Mello, Rossella,Arango-Daza, Juan Camilo,Varea, Teresa,González-Nú?ez, María Elena
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p. 13381 - 13394
(2018/11/20)
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- Improving the efficiency of Fenton reactions and their application in the degradation of benzimidazole in wastewater
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Reducing the quantity of sludge produced in Fenton reactions can be partly achieved by improving their efficiency. This paper firstly studies the effect of uniform deceleration feeding (ferrous iron and hydrogen peroxide) on the efficiency of a Fenton reaction by measuring the yield of hydroxyl radicals (OH) and chemical oxygen demand (COD) removal rate. The dynamic behavior of OH was also investigated. The results indicated that uniform deceleration feeding was the best feeding method compared with one-time feeding and uniform feeding methods when the same amount of Fenton reagents and the same reaction times were used. Besides, it was found the COD removal rate reached 79.3% when this method was applied to degrade 2-(a-hydroxyethyl)benzimidazole (HEBZ); this COD removal rate is larger than those when the other two modes were used (they reached 60.7% and 72.1%, respectively). The degradation pathway of HEBZ was determined using PL, UV-vis, FTIR, HPLC and GC-MS. Ultimately, HEBZ was decomposed into three small molecules (2-hydroxypropylamine, oxalic acid, and 2-hydroxypropamide). This research is of great significance for the application of Fenton reactions in wastewater treatment.
- Liu, Qinyao,Qian, Kun,Qi, Jinxu,Li, Chenru,Yao, Chen,Song, Wei,Wang, Yihong
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p. 9741 - 9748
(2018/03/23)
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- Condensation of vilsmeier salts, derived from tetraalkylureas, with α-hydroxy amide derivatives: One-pot approach to synthesize 2-dialkylamino-2-oxazolin-4-ones
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A novel and straightforward synthetic protocol was developed to synthesize 2-dialkylamino-2-oxazolin-4-ones from various Vilsmeier salts and α-hydroxy amides derivatives. Notably, thozalinone (3a), as a mild stimulant in tristimania and anorexic, could be synthesized simply and in a high yield using this methodology.
- Liu, Bengen,Su, Dongshan,Wei, Zhonglin,Cao, Jungang,Liang, Dapeng,Lin, Yingjie,Duan, Haifeng
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supporting information
p. 249 - 252
(2017/02/10)
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- Bis(allyl)-ruthenium(IV) complexes with phosphinous acid ligands as catalysts for nitrile hydration reactions
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Several mononuclear ruthenium(iv) complexes with phosphinous acid ligands [RuCl2(η3:η3-C10H16)(PR2OH)] have been synthesized (78-86% yield) by treatment of the dimeric precursor [{RuCl(μ-Cl)(η3:η3-C10H16)}2] (C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl) with 2 equivalents of different aromatic, heteroaromatic and aliphatic secondary phosphine oxides R2P(O)H. The compounds [RuCl2(η3:η3-C10H16)(PR2OH)] could also be prepared, in similar yields, by hydrolysis of the P-Cl bond in the corresponding chlorophosphine-Ru(iv) derivatives [RuCl2(η3:η3-C10H16)(PR2Cl)]. In addition to NMR and IR data, the X-ray crystal structures of representative examples are discussed. Moreover, the catalytic behaviour of complexes [RuCl2(η3:η3-C10H16)(PR2OH)] has been investigated for the selective hydration of organonitriles in water. The best results were achieved with the complex [RuCl2(η3:η3-C10H16)(PMe2OH)], which proved to be active under mild conditions (60 °C), with low metal loadings (1 mol%), and showing good functional group tolerance.
- Tomás-Mendivil, Eder,Francos, Javier,González-Fernández, Rebeca,González-Liste, Pedro J.,Borge, Javier,Cadierno, Victorio
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p. 13590 - 13603
(2016/09/04)
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- Synthesis and biological activity of novel ester derivatives of N3-(4-metoxyfumaroyl)-(S)-2,3-diaminopropanoic acid containing amide and keto function as inhibitors of glucosamine-6-phosphate synthase
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A short series of novel ester derivatives of N3-4-metoxyfumaroyl-(S)-2,3-diaminopropanoic acid (FMDP) containing amide or keto functions have been designed and synthesized. Their antifungal activity and inhibitory properties toward fungal glucosamine-6-phosphate synthase has also been evaluated. The obtained compounds 11–13 and 15–17 demonstrated good antifungal activity against Candida albicans. Compounds 11–13 displayed also potent inhibitory activity against fungal glucosamine-6-phosphate synthase, comparable to that of FMDP.
- Pawlak, Dorota,Schielmann, Marta,Wojciechowski, Marek,Andruszkiewicz, Ryszard
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supporting information
p. 3586 - 3589
(2016/07/21)
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- An efficient ruthenium(iv) catalyst for the selective hydration of nitriles to amides in water under mild conditions
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A Ru(iv) catalyst able to promote the selective hydration of nitriles to amides in water, at low metal loadings and under mild conditions, is presented. This journal is the Partner Organisations 2014.
- Tomás-Mendivil, Eder,Suárez, Francisco J.,Díez, Josefina,Cadierno, Victorio
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supporting information
p. 9661 - 9664
(2014/08/18)
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- Catalytic nitrile hydration with [Ru(η6- p -cymene)Cl 2(PR2R′)] complexes: Secondary coordination sphere effects with phosphine oxide and phosphinite ligands
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The rates of nitrile hydration reactions were investigated using [Ru(η6-p-cymene)Cl2(PR2R′)] complexes as homogeneous catalysts, where PR2R′ = PMe 2(CH2P(O)Me2), PMe2(CH 2CH2P(O)Me2), PPh2(CH 2P(O)Ph2), PPh2(CH2CH 2P(O)Ph2), PMe2OH, P(OEt)2OH. These catalysts were studied because the rate of the nitrile-to-amide hydration reaction was hypothesized to be affected by the position of the hydrogen bond accepting group in the secondary coordination sphere of the catalyst. Experiments showed that the rate of nitrile hydration was fastest when using [Ru(η6-p-cymene)Cl2PMe2OH]: i.e., the catalyst with the hydrogen bond accepting group capable of forming the most stable ring in the transition state of the rate-limiting step. This catalyst is also active at pH 3.5 and at low temperatures - conditions where α-hydroxynitriles (cyanohydrins) produce less cyanide, a known poison for organometallic nitrile hydration catalysts. The [Ru(η6-p-cymene) Cl2PMe2OH] catalyst completely converts the cyanohydrins glycolonitrile and lactonitrile to their corresponding α-hydroxyamides faster than previously investigated catalysts. [Ru(η6-p-cymene) Cl2PMe2OH] is not, however, a good catalyst for acetone cyanohydrin hydration, because it is susceptible to cyanide poisoning. Protecting the -OH group of acetone cyanohydrin was shown to be an effective way to prevent cyanide poisoning, resulting in quantitative hydration of acetone cyanohydrin acetate.
- Knapp, Spring Melody M.,Sherbow, Tobias J.,Yelle, Robert B.,Juliette, J. Jerrick,Tyler, David R.
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supporting information
p. 3744 - 3752
(2013/07/26)
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- Cyanohydrin hydration with [Ru(η6-p-cymene)Cl 2PR3] complexes
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The catalytic hydration of cyanohydrins to their corresponding α-hydroxyamides provides a route to industrially useful α-hydroxy amides, α-hydroxy esters, α-hydroxy carboxylic acids, and their acrylic derivatives. However, until now, no homogeneous nitrile hydration catalyst has been capable of complete conversion of cyanohydrins to their corresponding amides because cyanohydrins degrade to produce cyanide, which poisons the catalyst. Because the cyanohydrin degradation is an equilibrium process, it was hypothesized that a faster nitrile hydration catalyst would be capable of hydrating the cyanohydrin before degradation occurs. Secondary coordination sphere effects were used to develop a faster catalyst based on the [Ru(η6-arene)Cl2(PR3)] scaffold. A series of [Ru(η6-p-cymene)Cl2(PR3)] complexes, where R = NMe2, OMe, Et, was synthesized, and their activity toward cyanohydrin hydration was determined. The complex [Ru(η6-p- cymene)Cl2(P(NMe2)3)] is an excellent catalyst, and the unprecedented complete conversion of a cyanohydrin to its corresponding amide using a homogeneous catalyst was achieved with glycolonitrile and lactonitrile.
- Knapp, Spring Melody M.,Sherbow, Tobias J.,Juliette, J. Jerrick,Tyler, David R.
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experimental part
p. 2941 - 2944
(2012/06/04)
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- PROCESS FOR PRODUCING ORGANIC CARBOXYLIC ACID AMIDES
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The present invention relates to a process for producing organic carboxylic acid amides by nitrile hydrolysis of a nitrile compound at certain temperature and pressure in the presence of a catalyst to produce an organic carboxylic acid amide.
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Page/Page column 5
(2011/01/12)
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- METHOD FOR PRODUCING OPTICALLY ACTIVE 2-HYDROXY ESTER AND NOVEL INTERMEDIATE COMPOUND
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Disclosed is a method for producing an optically active 2-hydroxy ester, comprising selectively esterifying one enantiomer of a racemic 2-hydroxy ester in a solvent containing a catalyst such as tetramisole or benzotetramisole, and a carboxylic acid anhydride, or a carboxylic acid anhydride and a carboxylic acid. In particular, in the case where the solvent contains a carboxylic acid anhydride, but does not contain a carboxylic acid, as the carboxylic acid anhydride, a carboxylic acid anhydride containing a tertiary or quaternary carbon atom in the a-position is used. On the other hand, in the case where the solvent contains a carboxylic acid anhydride and a carboxylic acid, as the carboxylic acid, a carboxylic acid containing a tertiary or quaternary carbon atom in the a-position is used.
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Page/Page column 18
(2012/01/13)
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- Efficient nitrile hydration mediated by RuII catalysts in micellar media
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Efficient nitrile hydration to the corresponding amide derivatives is observed in water using poorly soluble [RuCl2(η6- arene)(PR3)] catalysts 1 with the aid of surfactants to ensure substrate and catalyst solubilization, and enabling ligand effect study on catalytic activity. Amide yields of 40 to 95% can be observed with a variety of aromatic and aliphatic nitriles using the optimized catalyst system, [RuCl 2(p-cymene)(PPh2OEt)]/Triton X-114. Catalyst separation and recycling is possible.
- Cavarzan, Alessandra,Scarso, Alessandro,Strukul, Giorgio
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experimental part
p. 790 - 794
(2010/09/05)
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- Synthesis of α-amino and α-hydroxy acids under volcanic conditions: implications for the origin of life
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Facile synthesis of α-hydroxy and α-amino acids is observed at temperatures from 145 to 280 °C with catalytic Ni2+, with cyano ligands as source for C and N, and with CO as a reductant and as a source for C. Implications for the problem of the origin of life are discussed.
- Huber, Claudia,Eisenreich, Wolfgang,W?chtersh?user, Günter
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scheme or table
p. 1069 - 1071
(2010/04/05)
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- A surprising mechanistic "switch" in Lewis acid activation: A bifunctional, asymmetric approach to α-hydroxy acid derivatives
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We report a detailed synthetic and mechanistic study of an unusual bifunctional, sequential hetero-Diels-Alder/ring-opening reaction in which chiral, metal complexed ketene enolates react with o-quinones to afford highly enantioenriched, α-hydroxylated carbonyl derivatives in excellent yield. A number of Lewis acids were screened in tandem with cinchona alkaloid derivatives; surprisingly, trans-(Ph3P)2PdCl2 was found to afford the most dramatic increase in yield and rate of reaction. A series of Lewis acid binding motifs were explored through molecular modeling, as well as IR, UV, and NMR spectroscopy. Our observations document a fundamental mechanistic "switch", namely the formation of a tandem Lewis base/Lewis acid activated metal enolate in preference to a metal-coordinated quinone species (as observed in other reactions of o-quinone derivatives). This new method was applied to the syntheses of several pharmaceutical targets, each of which was obtained in high yield and enantioselectivity.
- Abraham, Ciby J.,Paull, Daniel H.,Bekele, Tefsit,Scerba, Michael T.,Dudding, Travis,Lectka, Thomas
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supporting information; experimental part
p. 17085 - 17094
(2009/04/13)
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- Synthesis of Peptidosulfinamides and Peptidosulfonamides: Peptidomimetics Containing the Sulfinamide or Sulfonamide Transition-State Isostere
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Synthetic routes are described toward the preparation of α- as well as β-substituted aminoethanesulfinyl chlorides, starting from either an aldehyde or from an amino acid derivative.The sulfinyl chlorides are used as building blocks for the preparation of homochiral α- or β-substituted sulfinamide and sulfonamide transition-state isosteres.The methodology has been applied to the synthesis of peptidosulfonamide peptidomimetics such as a hapten needed for the generation of antibodies and potential HIV protease inhibitors.In addition, the β-substituted aminoethanesulfinyl chlorides were used as building blocks for the preparation of a tetrapeptidosulfonamide, which can be considered as a biopolymer mimetic, employing a repetition of a cycle of three reactions: coupling of the sulfinyl chloride to the N-terminus of the growing peptidosulfonamide, oxidation to the sulfonamide, and deprotection of the N-terminus.
- Moree, Wilna J.,Marel, Gijs A. van der,Liskamp, Rob J.
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p. 5157 - 5169
(2007/10/02)
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- HYDRATION OF CYANOHYDRINS IN WEEKLY ALKALINE SOLUTIONS OF BORIC ACID SALTS
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α-Hydroxyamides and α-hydroxyacids were prepared in satisfactory yield by heating aldehyde-derived cyanohydrins in aqueous solution in the presence of borax or alkaline borates.
- Jammot, Jacqueline,Pascal, Robert,Commeyras, Auguste
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p. 563 - 564
(2007/10/02)
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- 11a-Methano-TXA compounds
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The present invention provides novel 11a-methano-TXA compounds and intermediates and processs for their preparation. Further provided are methods for using these novel TXA analogs as inhibitors of thromboxane synthetase, rendering these analogs useful for a variety of pharmacological purposes. These pharmacological uses include anti-inflammatory, anti-thromobitc, and anti-asthma indications.
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