- Tris(pentafluorophenyl)borane-Catalyzed Oxygen Insertion Reaction of α-Diazoesters (α-Diazoamides) with Dimethyl Sulfoxide
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A tris(pentafluorophenyl)borane-catalyzed oxidation reaction of α-diazoesters (α-diazo amides) with dimethyl sulfoxide has been developed. The reaction proceeds under metal free conditions to afford a series α-ketoesters and α-ketoamides. The synthetic utility of this protocol is demonstrated through synthetic transformations and scaled-up synthesis. (Figure presented.).
- Gao, Wen-Xia,Liu, Miao-Chang,Wu, Hua-Yue,Wu, Xiao-Yang,Zhou, Yun-Bing
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supporting information
(2022/01/19)
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- Tandem Photoredox-Chiral Phosphoric Acid Catalyzed Radical-Radical Cross-Coupling for Enantioselective Synthesis of 3-Hydroxyoxindoles
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A photochemical protocol that couples diarylamines and α-ketoesters to afford the chiral 3-hydroxyoxindoles through tandem photoredox and chiral phosphoric acid catalysis is developed. The reaction involves an enantioselective photochemical radical-radical cross-coupling process. The chiral phosphoric acid is discovered to play crucial roles by decreasing the reductive potentials of α-ketoesters and stereocontrolling the downstream asymmetric radical-radical cross-coupling via the formation of pentacoordinate complex.
- Zhang, Yang,Ye, Dan,Shen, Lei,Liang, Kangjiang,Xia, Chengfeng
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supporting information
p. 7112 - 7117
(2021/09/14)
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- Visible-Light-Induced Catalyst-Free Carboxylation of Acylsilanes with Carbon Dioxide
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Intermolecular carbon-carbon bond formation between acylsilanes and carbon dioxide (CO2) was achieved by photoirradiation under catalyst-free conditions. In this reaction, siloxycarbenes generated by photoisomerization of the acylsilanes added to the C═O bond of CO2 to give α-ketocarboxylates, which underwent hydrolysis to afford α-ketocarboxylic derivatives in good yields. Control experiments suggest that the generated siloxycarbene is likely to be from the singlet state (S1) of the acylsilane and the addition to CO2 is not in a concerted manner.
- Fan, Zhengning,Yi, Yaping,Chen, Shenhao,Xi, Chanjuan
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p. 2303 - 2307
(2021/04/05)
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- Preparation method of alpha-ketoester compound
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The invention discloses a preparation method of an alpha-ketone ester compound. The method specifically comprises the following operation steps: adding raw materials alpha-diazo ester and an organic photocatalyst into a reaction flask, then adding an organic solvent, and reacting for 2-12 hours in air at room temperature under the irradiation of a visible light lamp; after the reaction is monitored by thin-layer chromatography (TLC), stopping the reaction, and extracting a reaction solution by using ethyl acetate; concentrating the extracting solution under reduced pressure to obtain a crude product, and performing column chromatography separation on the crude product to obtain the alpha-diazonium ester compound. According to the preparation method, clean visible light is used as reaction energy, cheap organic dye is used as a photocatalyst, air is used as a green oxidizing agent and an oxygen source, and the preparation method has the advantages of simplicity and convenience in operation, no metal residue and mild reaction conditions.
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Paragraph 0110-0113
(2021/04/21)
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- Design, synthesis and evaluation of novel diaryl-1,5-diazoles derivatives bearing morpholine as potent dual COX-2/5-LOX inhibitors and antitumor agents
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In this paper, 41 hybrid compounds containing diaryl-1,5-diazole and morpholine structures acting as dual COX-2/5-LOX inhibitors have been designed, synthesized and biologically evaluated. Most of them showed potent antiproliferative activities and COX-2/5-LOX inhibitory in vitro. Among them, compound A33 displayed the most potency against cancer cell lines (IC50 = 6.43–10.97 μM for F10, HeLa, A549 and MCF-7 cells), lower toxicity to non-cancer cells than celecoxib (A33: IC50 = 194.01 μM vs. celecoxib: IC50 = 97.87 μM for 293T cells), and excellent inhibitory activities on COX-2 (IC50 = 0.17 μM) and 5-LOX (IC50 = 0.68 μM). Meanwhile, the molecular modeling study was performed to position compound A33 into COX-2 and 5-LOX active sites to determine the probable binding models. Mechanistic studies demonstrated that compound A33 could block cell cycle in G2 phase and subsequently induced apoptosis of F10 cells. Furthermore, compound A33 could significantly inhibit tumor growth in F10-xenograft mouse model, and pharmacokinetic study of compound A33 indicated that it showed better stability in vivo. In general, compound A33 could be a promising candidate for cancer therapy.
- Li, Zhang,Wang, Zhong-Chang,Li, Xin,Abbas, Muhammad,Wu, Song-Yu,Ren, Shen-Zhen,Liu, Qi-Xing,Liu, Yi,Chen, Peng-Wen,Duan, Yong-Tao,Lv, Peng-Cheng,Zhu, Hai-Liang
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p. 168 - 184
(2019/03/17)
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- CuO-catalyzed oxidation of aryl acetates with aqueous tert-butyl hydroperoxide for the synthesis of α-ketoesters
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A practical method to access α-ketoesters from readily available aryl acetates is developed. In this approach, aqueous tert-butyl hydroperoxide and CuO are employed. No additional solvents are required and it was found that the peroxide side products in the reaction can be decomposed by pyridine.
- Jiang, Jin
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p. 235 - 240
(2019/07/16)
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- Method for preparing methyl phenylglyoxylate derivative
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The invention provides a method for preparing a methyl phenylglyoxylate derivative. The method comprises the following steps: dissolving alpha-methoxybenzoate or alpha-hydrobenzoate and N-bromosuccinimide into an organic solvent, performing a reaction under the illumination condition, and after the reaction is completed, performing purification to obtain the methyl phenylglyoxylate derivative. Theinvention provides a novel method for preparing the methyl phenylglyoxylate derivative, and the method is simple to operate, and has mild conditions and a higher yield.
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Paragraph 0038; 0039
(2019/01/04)
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- Enantioselective Iridium-Catalyzed Hydrogenation of α-Keto Amides to α-Hydroxy Amides
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A highly enantioselective iridium-catalyzed hydrogenation of α-keto amides to form α-hydroxy amides has been achieved with excellent results (up to >99% conversion and up to >99% ee, TON up to 100?000). As an example, this protocol was applied to the synthesis of (S)-4-(2-amino-1-hydroxyethyl)benzene-1,2-diol, the enantiomer of norepinephrine, which is widely used as an injectable drug for the treatment of critically low blood pressure. Density functional theory (DFT) calculations were also carried out to reveal the reaction mechanism.
- Gu, Guoxian,Yang, Tilong,Yu, Ouran,Qian, Hua,Wang, Jiang,Wen, Jialin,Dang, Li,Zhang, Xumu
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supporting information
p. 5920 - 5923
(2017/11/10)
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- Iridium-Catalyzed Asymmetric Hydrogenation of Unsaturated Piperazin-2-ones
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Two different iridium catalyst systems, generated from the ruthenocene-based phosphine-oxazoline ligand tBu-mono-RuPHOX or the diphosphine ligand BINAP, were developed for the asymmetric hydrogenation of 5,6-dihydropyrazin-2(1H)-ones, affording chiral piperazin-2-ones in good yields and with moderate to good ees. Different catalytic behaviors for the hydrogenation of these types of substrate were observed with these two catalyst systems. Our tBu-mono-RuPHOX ligand, which bears a ruthenocene scaffold with planar chirality, was found to be the best ligand for the [Ir(L)(COD)]BArF catalyst system, affording the desired products with up to 94% ee. (Figure presented.).
- Wang, Yanzhao,Liu, Yuanyuan,Li, Kun,Yang, Guoqiang,Zhang, Wanbin
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supporting information
p. 1933 - 1941
(2017/06/09)
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- Direct asymmetric hydrogenation of α-keto acids by using the highly efficient chiral spiro iridium catalysts
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A new efficient and highly enantioselective direct asymmetric hydrogenation of α-keto acids employing the Ir/SpiroPAP catalyst under mild reaction conditions has been developed. This method might be feasible for the preparation of a series of chiral α-hydroxy acids on a large scale.
- Yan, Pu-Cha,Xie, Jian-Hua,Zhang, Xiang-Dong,Chen, Kang,Li, Yuan-Qiang,Zhou, Qi-Lin,Che, Da-Qing
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supporting information
p. 15987 - 15990
(2015/02/19)
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- One-pot efficient synthesis of aryl α-keto esters from aryl-ketones
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A novel one-pot synthesis of aryl α-keto esters was developed through oxidation of aryl-ketones using selenium dioxide, esterification accompanied by ketalization, and hydrolysis. Both aromatics and heteroaromatics gave good yields by this one-pot method.
- Zhuang, Jing,Wang, Changqing,Xie, Fang,Zhang, Wanbin
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experimental part
p. 9797 - 9800
(2010/02/27)
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- Facile synthesis of aryl α-keto esters via the reaction of aryl diazoacetate with H2O and DEAD
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A facile synthesis of aryl aα-keto esters in high yields is reported involving the reaction of aryl diazoacetate with H2O and diethyl azodicarboxylate (DEAD) catalyzed by dirhodium acetate. Georg Thieme Verlag Stuttgart.
- Guo, Zhenqiu,Huang, Haoxi,Fu, Qingquan,Hu, Wenhao
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p. 2486 - 2488
(2008/02/11)
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- An efficient synthesis of aryl α-keto esters
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A new one-pot approach for the synthesis of aryl α-keto ester based on the diazo transfer and oxidation of diazo group is developed.
- Ma, Ming,Li, Changkun,Peng, Lingling,Xie, Fang,Zhang, Xiu,Wang, Jianbo
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p. 3927 - 3929
(2007/10/03)
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- Facile Synthesis of α-Keto Carbonyl Compounds by Indirect Anodic Oxidation
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Secondary alcohols having a carbonyl group at the neighboring carbon atom were electrochemically oxidized to the corresponding α-keto carbonyl compounds in good yields.Thus, aromatic α-hydroxyl esters were easily transformed to arylglyoxylates in excellent yields using an undivided cell while efficient anodic oxidation of α-hydroxyl ketones and aliphatic α-hydroxyl esters successfully proceeded in a divided cell to give the corresponding α-keto carbonyl compounds.
- Maekawa, Hirofumi,Ishino, Yoshio,Nishiguchi, Ikuzo
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p. 1017 - 1020
(2007/10/02)
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- Kinetics of Pb(IV) Oxidation of Substituted Methyl Mandelates - A L.F.E.R. Study
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Lead tetra acetate (Pb(IV) or LTA) oxidation of the esters X-C6H4-CH(OH)-COOCH3 (X = H, m-NO2, p-NO2, m-Cl, p-Cl, p-Br, p-CH3 and p-C2H5) gives corresponding keto esters.The reaction is first order in and second order in , and is catalysed by pyridine and 2,6-lutidine.The pyridine catalysed reaction is first order each in , and .A kinetic isotope effect is observed in oxidation of methyl mandelate for both uncatalysed reaction (kH/kD = 4.2) and pyridine catalysed reaction (kH/kD = 1.8).Activation parameters for both uncatalysed and pyridine catalysed reactions are evaluated.The results are in accord with Linear Free Energy Relationship (L.F.E.R.) and the reaction constant (ρ = +0.75) obtained supports proton transfer in the α-C-H bond rupture in the rate limiting step.The role of pyridine in catalysis, as a ligand or as a base is discussed. - Keywords: Kinetics of Pb(IV), Substituted Methyl Mandelates
- Banerjee, Sudheer K.,Shanker, R.,Sachdeva, Om P.
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p. 467 - 472
(2007/10/02)
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