- Ligand-Enabled Monoselective β-C(sp3)-H Acyloxylation of Free Carboxylic Acids Using a Practical Oxidant
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The development of C-H activation reactions that use inexpensive and practical oxidants remains a significant challenge. Until our recent disclosure of the β-lactonization of free aliphatic acids, the use of peroxides in C-H activation reactions directed by weakly coordinating native functional groups was unreported. Herein, we report C(sp3)-H β-acetoxylation and γ-, δ-, and ?-lactonization reactions of free carboxylic acids enabled by a novel cyclopentane-based mono-N-protected β-amino acid ligand. Notably, tert-butyl hydrogen peroxide is used as the sole oxidant for these reactions. This reaction has several key advantages over other C-H activation protocols: (1) exclusive monoselectivity was observed in the presence of two α-methyl groups; (2) aliphatic carboxylic acids containing α-hydrogens are compatible with this protocol; (3) lactonization of free acids, affording γ-, δ-, or ?-lactones, has been achieved for the first time.
- Fan, Zhoulong,Herron, Alastair N.,Yu, Jin-Quan,Zhuang, Zhe
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supporting information
p. 6769 - 6776
(2020/04/30)
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- A Cooperative Strategy for the Highly Selective Intermolecular Oxycarbonylation Reaction of Alkenes using a Palladium Catalyst
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A novel method for intermolecular functionalization of terminal and internal alkenes has been designed. The electrophilic reagent, hypervalent iodine, plays a key role in this process by activating the alkene C=C bond for nucleophilic addition of the palladium catalyst. This process generates an iodonium-containing palladium species which undergoes CO insertion. The new approach, intermolecular oxycarbonylaton reactions of alkenes, has been achieved and carried out under mild reaction conditions to produce the corresponding β-oxycarbonylic acids with excellent efficiencies and levels of regio- and diastereoselectivity.
- Li, Ming,Yu, Feng,Qi, Xiaoxu,Chen, Pinhong,Liu, Guosheng
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supporting information
p. 13843 - 13848
(2016/10/26)
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- Carbonylation of ethylenically unsaturated compounds
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A process for the carbonylation of ethylenically unsaturated compounds including vinyl esters and a process for the production of 3-hydroxy propanoate esters or acids. The process comprises reacting said compound with carbon monoxide in the presence of a source of hydroxyl groups and of a catalyst system. The catalyst system is obtainable by combining: (a) a metal of Group 8, 9 or 10 or a compound thereof: and (b) a bidentate ligand of general formula (I): X1(X2)-Q2-A-R—B-Q1-X3(X4).
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Page/Page column 47; 48
(2016/06/01)
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- CARBONYLATION OF ETHYLENICALLY UNSATURATED COMPOUNDS
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PROBLEM TO BE SOLVED: To provide a process for the carbonylation of ethylenically unsaturated compounds including vinyl esters and a process for the production of 3-hydroxypropanoate esters or 3-hydroxypropanoic acids. SOLUTION: The process comprises reacting the compound with carbon monoxide in the presence of a source of hydroxyl groups and of a catalyst system. The catalyst system is obtainable by combining: (a) a metal of Group 8, 9 or 10 or a compound thereof: and (b) a bidentate ligand of general formula (I): X1(X2)-Q2-A-R-B-Q1-X3(X4). COPYRIGHT: (C)2015,JPOandINPIT
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Paragraph 0234-0236
(2016/10/09)
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- Gold(I)/copper(II)-cocatalyzed tandem cyclization/semipinacol reaction: Construction of 6-Aza/Oxa-Spiro[4.5]decane skeletons and formal synthesis of (±)-halichlorine
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A simple and efficient strategy for the construction of 6-aza/oxa-spiro[4.5]decane skeletons under the cocatalysis of gold(I)/copper(II) was developed, and its potential utility was demonstrated by a formal synthesis of the biologically active marine alkaloid (±)-halichlorine.
- Zhu, Dao-Yong,Zhang, Zhen,Mou, Xue-Qing,Tu, Yong-Qiang,Zhang, Fu-Min,Peng, Jin-Bao,Wang, Shao-Hua,Zhang, Shu-Yu
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supporting information
p. 747 - 752
(2015/03/18)
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- PYRROLE COMPOUND
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Provided is a highly safe and effective compound represented by the following general formula (1) or a salt thereof which acts on tubulin and has an anticancer effect, wherein Ar represents an aryl group or a heteroaryl group; Z1, Z2
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Paragraph 1271; 1272; 1273
(2014/12/09)
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- Synthesis and antitumour activity of β-hydroxyisovalerylshikonin analogues
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A series of novel β-hydroxyisovalerylshikonin analogues bearing oxygen-containing substituents at the side-chain hydroxyl of shikonin were designed and synthesized. The cytotoxicities of these compounds were evaluated in vitro against multi-drug resistant (MDR) cell lines DU-145 and HeLa. Most compounds exhibited significant inhibitory activity on both cell lines. The structure-activity relationship showed the analogues with ether substituents displayed the most potent antitumour activity and selective cytotoxicity towards DU-145. Among the compounds with ether substituents, increasing the steric hindrance in the carbon bearing β-hydroxyl or replace the β-hydroxyl with acetoxy or methoxy would lead to the decline of cytotoxicity.
- Rao, Zhen,Liu, Xin,Zhou, Wen,Yi, Jing,Li, Shao-Shun
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experimental part
p. 3934 - 3941
(2011/11/12)
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- Characterization of polar compounds and oligomers in secondary organic aerosol using liquid chromatography coupled to mass spectrometry
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A generic method has been developed for the analysis of polar compounds and oligomers in secondary organic aerosol (SOA) formed during atmospheric simulation chamber experiments. The technique has been successfully applied to SOA formed in a variety of systems, ranging from ozonolysis of biogenic volatile organic compounds to aromatic photooxidation. An example application of the method is described for the SOA produced from the reaction of ozone with cis-3-hexenyl acetate, an important biogenic precursor. A range of solvents were tested as extraction media, and water was found to yield the highest recovery. Extracts were analyzed using reversed-phase liquid chromatography coupled to ion trap mass spectrometry. In order to determine correct molecular weight assignments and increase sensitivity for less polar species, a series of low-concentration mobile-phase additives were used (NaCl, LiBr, NH 4OH). Lithium bromide produced better fragmentation patterns, with more structural information than in the other cases with no reduction in sensitivity. The main reaction products identified in the particle-phase were 3-acetoxypropanal, 3-acetoxypropanoic acid, and 3-acetoxypropane peroxoic acid and a series of dimers and trimers up to 500 Da. Structural identification of oligomers indicates the presence of linear polyesters possibly formed via esterfication reactions or decomposition of peroxyhemiacetals.
- Hamilton, Jacqueline F.,Lewis, Alastair C.,Carey, Trevor J.,Wenger, John C.
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p. 474 - 480
(2008/09/17)
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- Synthesis of functionalised nucleosides for incorporation into nucleic acid-based serine protease mimics
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The synthesis of nucleosides modified with an extra imidazole, carboxyl and hydroxyl group is described. These nucleosides can be incorporated into an oligonucleotide duplex, thus generating a novel type of serine protease mimic.
- Catry, Mieke A.,Madder, Annemieke
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p. 114 - 129
(2008/02/04)
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- PROCESS FOR THE PREPARATION OF HYDROXY CARBOXYLIC ACID
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The present invention provides a three step process for the preparation of hydroxy carboxylic acid. The present invention involves the hydroformylation of enol ester (e.g. vinyl acetate) using a cobalt catalyst (e.g. Co2(CO)8), optionally a promoter or a ligand containing O, N, N—O, P, As or Sb atom/s, to obtain a mixture of 2-acetoxy carboxaldehyde (e.g. 2-acetoxy propanal) and 3-acetoxy carboxaldehyde (e.g. 3-acetoxy propanal), oxidizing the product acetoxy carboxyaldehydes to the corresponding acetoxy carboxylic acid, in presence or absence of a Gr. 8 metal catalyst, followed by hydrolyzation of the product acetoxy carboxylic acids to the corresponding desired hydroxy carboxylic acids, in presence of an acidic catalyst and separating the catalyst and reusing it for another hydrolysis step.
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Page/Page column 3
(2008/06/13)
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- Slow reversible inhibitions of rabbit muscle aldolase with substrate analogues: Synthesis, enzymatic kinetics and UV difference spectroscopy studies
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Various dihydroxyacetone-phosphate (DHAP) analogues bearing an aromatic ring or β-dicarbonyl structures were synthesized. Their capacity to form a stabilized iminium ion or conjugated enamine in the reaction catalyzed by rabbit muscle aldolase (EC 4.1.2.1
- Gefflaut,Blonski,Perie
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p. 2043 - 2054
(2007/10/03)
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