- Simultaneous Kinetic Resolution and Asymmetric Induction within a Borrowing Hydrogen Cascade Mediated by a Single Catalyst
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The mechanistic uniqueness and versatility of borrowing hydrogen catalysis provides an opportunity to investigate the controllability of a cascade reaction, and more importantly, to realize either one or both of chiral recognition and chiral induction simultaneously. Here we report that, in a borrowing hydrogen cascade starting from racemic allylic alcohols, one of the enantiomers could be kinetically resolved, while the other enantiomer could be purposely converted to various targeted products, including α,β-unsaturated ketones, β-functionalized ketones and γ-functionalized alcohols. By employing a robust Ru-catalyst, both kinetic resolution and asymmetric induction were achieved with remarkable levels of efficiency and enantioselectivity. Density functional theory (DFT) calculations suggest that corresponding catalyst–substrate π–π interactions are pivotal to realize the observed stereochemical diversity.
- Jin, Ming Yu,Tao, Guanyu,Xiao, Dengmengfei,Xing, Xiangyou,You, Yipeng,Yu, Peiyuan,Zhen, Qianqian,Zhou, Yali
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supporting information
(2021/11/18)
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- Ruthenium-Catalyzed Redox Isomerizations inside Living Cells
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Tailored ruthenium(IV) complexes can catalyze the isomerization of allylic alcohols into saturated carbonyl derivatives under physiologically relevant conditions, and even inside living mammalian cells. The reaction, which involves ruthenium-hydride intermediates, is bioorthogonal and biocompatible, and can be used for the "in cellulo" generation of fluorescent and bioactive probes. Overall, our research reveals a novel metal-based tool for cellular intervention, and comes to further demonstrate the compatibility of organometallic mechanisms with the complex environment of cells.
- Vidal, Cristian,Tomás-Gamasa, María,Gutiérrez-González, Alejandro,Mascarenas, José L.
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supporting information
p. 5125 - 5129
(2019/03/29)
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- Synthesis method of D,L-naproxen
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The invention provides a synthesis method of D,L-naproxen. The synthesis method is characterized by comprising the step of removing bromine: taking D,L-2-(5-bromo-6-methoxyl-naphthyl)-sodium propionate as a raw material, and taking water and dioxane as solvents, adding a catalyst under alkaline conditions and nitrogen protection, reacting under 80-90 DEG C, filtering after the reaction is completed, and regulating the pH (Potential of hydrogen) of filtrate by acid to obtain a final product, wherein the catalyst is one of tetrakis(triphenylphosphine)palladium or diacetatobis(triphenylphosphine)palladium(II) or palladium chloride taking triphenylphosphine as a ligand. According to the synthesis method, through optimizing the synthesis method of naproxen, the tetrakis(triphenylphosphine)palladium and the diacetatobis(triphenylphosphine) palladium(II) as well as the palladium chloride taking the triphenylphosphine as the ligand are adopted as the catalyst to remove the bromine on a benzene ring; hydrogenation and high pressure are not needed; the reaction is safe and reliable; the yield is high; the synthesis method is suitable for industrial production.
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Paragraph 0047-0050
(2019/10/01)
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- Synthetic method of naproxendrug intermediate namely 6-methoxy-2-propionyl naphthalene
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The invention discloses a synthetic method of a naproxendrug intermediate namely 6-methoxy-2-propionyl naphthalene. The synthetic method comprises the following steps: adding 300-310ml of triethylamine and 0.61-0.65mol of stannous chloride into a reaction vessel provided with an agitator, a reflux condenser, a thermometer and a dropping funnel, controlling the agitation rate at 160-190rpm, and lowering the solution temperature to be 3 to -5 DEG C; slowly adding 0.5-0.65mol of beta-naphthylmethyl ether, dropwise adding 0.47mol of propionamide, controlling the dropwise adding time to be 50-80min, keeping the temperature of the solution for reaction for 8-9h, and raising the temperature of the solution to be 17 to -19 DEG C; standing for 20-22h, pouring reactants into 1.8L of sodium hydrogen sulfite solution, and controlling the temperature of the solution to be 2 to -5 DEG C; performing steam distillation until triethylamine is completely distilled out; controlling the agitation rate at 110-130rpm; naturally cooling the solution to solidify oily substances; performing suction filtration; performing washing with a saline solution; performing dehydration with a dehydrating agent; and performing recrystallization in cyclohexane solution to obtain yellow solids namely 6-methoxy-2-propionyl naphthalene, wherein the mass percentage of the sodium hydrogen sulfite solution used in the step is 20-25%.
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Paragraph 0015; 0016
(2016/10/17)
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- Stereoselective Ketone Rearrangements with Hypervalent Iodine Reagents
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The first stereoselective version of an iodine(III)-mediated rearrangement of arylketones in the presence of orthoesters is described. The reaction products, α-arylated esters, are very useful intermediates in the synthesis of bioactive compounds such as ibuprofen. With chiral lactic acid-based iodine(III) reagents product selectivities of up to 73 % ee have been achieved.
- Malmedy, Florence,Wirth, Thomas
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supporting information
p. 16072 - 16077
(2016/10/30)
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- Fluorescence-Based Kinetic Assay for High-Throughput Discovery and Engineering of Stereoselective ω-Transaminases
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ω-Transaminases are a valuable class of enzymes for the production of chiral amines with either (R)- or (S)-configuration in high optical purity and 100% yield by the biocatalytic reductive amination of prochiral ketones. A versatile new assay was developed to quantify ω-transaminase activity for the kinetic characterization and enantioselectivity typing of novel or engineered enzymes based on the conversion of 1-(6-methoxynaphth-2-yl)alkylamines. The associated release of the acetonaphthone product can be monitored by the development of its bright fluorescence at 450 nm with very high sensitivity and selectivity. The assay principle can be used to quantify ω-transaminase catalysis over a very broad range of enzyme activity. Because of its simplicity and low substrate consumption in microtiter plate format the assay seems suitable for liquid screening campaigns with large library sizes in the directed evolution of optimized transaminases. For assay substrates that incorporate structural variations, an efficient modular synthetic route was developed. This includes racemate resolution by lipase-catalyzed transacylation to furnish enantiomerically pure (R)- and (S)-configured amines. The latter are instrumental for the rapid enantioselectivity typing of ω-transaminases. This method was used to characterize two novel (S)-selective taurine-pyruvate transaminases of the subtype 6a from thermophilic Geobacillus thermodenitrificans and G. thermoleovorans.
- Scheidt, Thomas,Land, Henrik,Anderson, Mattias,Chen, Yujie,Berglund, Per,Yi, Dong,Fessner, Wolf-Dieter
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p. 1721 - 1731
(2015/06/02)
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- 3-[6-(2-Dimethylamino-1-imidazol-1-yl-butyl)-naphthalen-2-yloxy]-2,2-dimethyl-propionic acid as a highly potent and selective retinoic acid metabolic blocking agent
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3-[6-(2-Dimethylamino-1-imidazol-1-yl-butyl)-naphthalen-2-yloxy]-2,2-dimethyl-propionic acid and analogs were designed and synthesized as highly potent and selective CYP26 inhibitors, serving as retinoic acid metabolic blocking agents (RAMBAs), with demonstrated in vivo efficacy to increase the half-life of exogenous atRA.
- Mulvihill, Mark J.,Kan, Julie L.C.,Cooke, Andrew,Bhagwat, Shripad,Beck, Patricia,Bittner, Mark,Cesario, Cara,Keane, David,Lazarescu, Viorica,Nigro, Anthony,Nillson, Christy,Panicker, Bijoy,Smith, Vanessa,Srebernak, Mary,Sun, Feng-Lei,O'Connor, Matthew,Russo, Suzanne,Fischetti, Gia,Vrkljan, Michael,Winski, Shannon,Castelhano, Arlindo L.,Emerson, David,Gibson, Neil W.
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p. 2729 - 2733
(2007/10/03)
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- Photochemical Rearrangement of α-Chloro-Propiophenones to α-Arylpropanoic Acids: Studies on Chirality Transfer and Synthesis of (S)-(+)-Ibuprofen and (S)-(+)-Ketoprofen
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A new single-step efficient photochemical approach for α-arylpropanoic acids (4) from α-chloro-propiophenones (5) is described.It involves carbonyl triplet excited state directed 1,2-aryl migration of the aryl group which has been found to be highly dependent upon the nature of the aryl substituent.The mode of the rearrangement is probed by the study of the photobehaviour of a set of optically active α-chloro-propiophenones.The results suggest that the nature of the carbonyl triplets (n, ?*/ ?, ?*) plays an important role in the chirality transfer.This method finds application in the synthesis of optically active ibuprofen (4e) and ketoprofen (26), though in moderate optical yields.
- Sonawane, Harikisan,Bellur, Nanjundiah S.,Kulkarni, Dilip G.,Ayyangar, Nagaraj R.
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p. 1243 - 1260
(2007/10/02)
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- Process for the debromination of 2-substituted-5-bromo-6-methoxynaphthalenes
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Naphthalenes of formula STR1 wherein X represents COCH3, COC2 H5, CH(CH3)COOH, CH(CH3)COOR, CH(CH3)CN and CH(CH3)CONHR1, R represents alkyl and R1 represents hydrogen, alkyl or hydroxyalkyl, are debrominated by means of acceptors of bromine, like alkylarenes and alkoxyarenes, in the presence of Lewis acids.
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- Process for the debromination of 2-substituted-5-bromo-6-methoxynaphthalenes
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Naphthalenes of formula wherein X represents COCH3, COC2H5, CH(CH3)COOH, CH(CH3)COOR, CH(CH3)CN and CH(CH3)CONHR1, R represents alkyl and R1 represents hydrogen, alkyl or hydroxyalkyl, are debrominated by means of acceptors of bromine, like alkylarenes and alkoxyarenes, in the presence of Lewis acids.
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- Process for preparing an organic synthesis intermediate
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A process is described for the preparation of 2-methoxy-6-propionyl-naphthalene, an intermediate in the synthesis of naproxen. The process consists of Friedel-Crafts acylation of 2-methoxy-naphthalene, and obviates the drawbacks related to the use of nitrobenzene as solvent.
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- Mild and Reversible Friedel-Crafts Acylation: Synthesis of 6-Acyl-2-methoxynaphthalenes
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A new practical method for large scale preparation of 2-acyl-6-methoxynaphthalenes 3 is reported.The selectivity toward 3 is due to reversibility of the Friedel-Crafts acylation and to the termodynamic stability of 3.
- Giordano, Claudio,Villa, Marco
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p. 383 - 392
(2007/10/02)
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- Process for the preparation of aryl alkyl ketones
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Preparation of aryl alkyl ketones by reaction of an aryl compound with an aliphatic acid and/or a functional derivative thereof in anhydrous hydrofluoric acid.
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