- Kinetic and mechanistic studies on quinuclidinolysis of Y-substituted-phenyl picolinates: Effect of amine nature on reactivity and transition- state structure
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Second-order rate constants (kN) have been measured spectrophotometrically for reactions of Y-substitutedphenyl picolinates (7a-7i) with a series of quinuclidines in 80 mol% H2O/20 mol% DMSO at 25.0 ± 0.1 °C. The Bronsted-type plot f
- Um, Ik-Hwan,Kim, Min-Young,Kang, Yeseul
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- Copper-Catalyzed Electrochemical C-H Amination of Arenes with Secondary Amines
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Electrochemical oxidation represents an environmentally friendly solution to conventional methods that require caustic stoichiometric chemical oxidants. However, C-H functionalizations merging transition-metal catalysis and electrochemical techniques are, to date, largely confined to the use of precious metals and divided cells. Herein, we report the first examples of copper-catalyzed electrochemical C-H aminations of arenes at room temperature using undivided electrochemical cells, thereby providing a practical solution for the construction of arylamines. The use of n-Bu4NI as a redox mediator is crucial for this transformation. On the basis of mechanistic studies including kinetic profiles, isotope effects, cyclic voltammetric analyses, and radical inhibition experiments, the reaction appears to proceed via a single-electron-transfer (SET) process, and a high valent Cu(III) species is likely involved. These findings provide a new avenue for transition-metal-catalyzed electrochemical C-H functionalization reactions using redox mediators.
- Yang, Qi-Liang,Wang, Xiang-Yang,Lu, Jia-Yan,Zhang, Li-Pu,Fang, Ping,Mei, Tian-Sheng
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p. 11487 - 11494
(2018/09/13)
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- Method of coupling, and the coupling method using the aromatic group-substituted heterocyclic compound
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Provided is an easy method (coupling method) capable of easily synthesizing a compound group in which aromatic molecules and aromatic molecules are coupled, a compound group in which aromatic molecules and alkene molecules are coupled, and the like without producing halogen waste and without the need to use scarce and expensive palladium. A compound (A) shown by general formula (A): Ar-H and a compound (B1) shown by general formula (B1): RaOCO-Ar', a compound (B2) shown by general formula (B2): RbCH=C(Ar")2, or a compound (B3) shown by general formula (B3): RcOCOCH=C(Ar")2 are reacted in the presence of a nickel compound.
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Paragraph 0202-0207
(2020/09/17)
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- Mechanistic Insight into Weak Base-Catalyzed Generation of Carbon Monoxide from Phenyl Formate and Its Application to Catalytic Carbonylation at Room Temperature without Use of External Carbon Monoxide Gas
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The mechanisms of the weak base-catalyzed generation of carbon monoxide (CO) and phenol from phenyl formate were investigated by experimental and theoretical methods. Kinetic studies revealed a first-order reaction in both phenyl formate and the base. The reaction was found to proceed by an E2 α-elimination pathway, which involves the abstraction of the formyl proton of phenyl formate, simultaneously generating CO and phenoxide. The reaction rate was affected by the substituents on phenyl formate, the polarity of solvents, and the basicity of bases. The mechanistic insight obtained from these studies permitted the chemical control of the rate of CO generation, which was the key to the development of the external CO-free Pd-catalyzed phenoxycarbonylation of haloarenes at room temperature. Because of the mild reaction conditions and wide substrate scope, this phenoxycarbonylation constitutes a general, safe, and practical method to synthesize arenecarboxylic acid esters. (Figure presented.).
- Konishi, Hideyuki,Matsubara, Mika,Mori, Keisuke,Tokiwa, Takaki,Arulmozhiraja, Sundaram,Yamamoto, Yuta,Ishikawa, Yoshinobu,Hashimoto, Hiroshi,Shigeta, Yasuteru,Tokiwa, Hiroaki,Manabe, Kei
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supporting information
p. 3592 - 3601
(2017/10/24)
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- Metal-Free O-Arylation of Carboxylic Acid by Active Diaryliodonium(III) Intermediates Generated in situ from Iodosoarenes
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The metal-free arylative coupling of carboxylic acids using iodosoarenes without the use of a catalyst and base, which is applicable to even a highly-polar molecule bearing multiple alcohol groups, is reported. The in situ preparation of the reactive diaryliodonium(III) carboxylates is the important key to this approach, and the introduction of the trimethoxybenzene auxiliary enables both the smooth salt formations and the selective aryl transfer events during the couplings. (Figure presented.).
- Dohi, Toshifumi,Koseki, Daichi,Sumida, Kohei,Okada, Kana,Mizuno, Serina,Kato, Asami,Morimoto, Koji,Kita, Yasuyuki
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supporting information
p. 3503 - 3508
(2017/09/13)
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- Method of converting amide and urea into ester
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The invention provides a method of converting amide and urea into ester. In the method, different types of amide and urea are used as substrate, alcohol or phenol is used as nucleophile, iron salt is used as catalyst, and acid is used as additive, the conversion of amide and urea into ester is achieved under a mild condition. The method is characterized in that cheap iron salt is used as the catalyst, the commercialized amide, urea, and alcohol are used as the substrate, and the conversion of amide to ester is achieved in one step. The method has the advantages that the reaction condition is mild, the raw materials are cheap and easy to obtain, the reaction substrate is wide in adaptability, the selectivity and yield of the product are very high, the product is green and environmentally friendly and the like, and the method has good prospects for industrial applications.
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Paragraph 0060-0062
(2017/08/30)
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- N-(3,5-dimethyladamantane-1-yl)-N'-substituted phenylurea compound as well as preparation method and application thereof
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The invention belongs to the technical field of medicinal chemistry, in particular to N-(3,5-dimethyladamantane-1-yl)-N'-substituted phenylurea compounds as well as preparation methods and application thereof. The compounds have the structure shown in the formula I. The compounds are proved that the compounds can improve the image recognition memory, the working and learning memory, the spatial learning and memory ability of model rats and has good anti-alzheimer effects by the new object discrimination experiments, Y-maze experiments, positioning navigation and space exploration experiments in mats. The formula I is shown in the description.
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Paragraph 0072; 0073; 0120; 0121
(2017/12/28)
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- The light-emitting compound and use this light-emitting compound of the organic light emitting diode device
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An embodiment of the present invention provides an emitting compound of following formula: wherein “A” is represented by and “B” is represented by
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Paragraph 0078-0081
(2017/04/11)
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- Kinetic study on alkaline hydrolysis of Y-substituted phenyl picolinates: Effects of modification of nonleaving group from benzoyl to picolinyl on reactivity and reaction mechanism
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Second-order rate constants (kOH-) for alkaline hydrolysis of Y-substituted phenyl picolinates (6a-6i) have been measured spectrophotometrically. A linear Bronsted-type plot is obtained with βlg = -0.34, which is typical for reactions reported previously to proceed through a stepwise mechanism with formation of an addition intermediate being the rate-determining step (RDS). However, σYo constants result in a much poorer Hammett correlation than σY- constants. Furthermore, the Yukawa-Tsuno plot exhibits an excellent linear correlation with ρY = 0.82 and r = 0.72, indicating that a negative charge develops partially on the O atom of the leaving group in the RDS. Thus, the reactions have been concluded to proceed through a forced concerted mechanism with a highly unstable intermediate 7. Comparison of the current kinetic data with those reported previously for the corresponding reactions of Y-substituted phenyl benzoates has revealed that modification of the nonleaving group from benzoyl to picolinyl causes not only an increase in reactivity but also a change in the reaction mechanism (i.e., from a stepwise mechanism to a forced concerted pathway).
- Kim, Myung-Joo,Kim, Min-Young,Um, Ik-Hwan
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p. 1138 - 1142
(2015/07/15)
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- Nickel-Catalyzed Decarbonylative Coupling of Aryl Esters and Arylboronic Acids
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A variety of functionalized biaryls can be accessed by coupling aryl and heteroaryl esters with boronic acids in Suzuki-Miyaura-type decarbonylative cross-coupling catalyzed by an affordable catalyst system composed of Ni(cod)2 and PCy3. The methodology is tolerant of a variety of functional groups and presents an attractive alternative to the use of palladium catalysis currently used in industry to acquire such bis(hetero)aryls, but also reveals challenges associated with nickel catalysis of esters in cross-coupling chemistry.
- Laberge, Nicole A.,Love, Jennifer A.
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supporting information
p. 5546 - 5553
(2015/09/01)
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- Chiral magnesium(ii)-catalyzed asymmetric ring-opening of meso-aziridines with primary alcohols
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The asymmetric ring-opening of meso-aziridines with primary alcohols is realized using an N,N′-dioxide-Mg(OTf)2 complex as the catalyst. The desired vicinal trans-β-amino ethers are afforded in good yields and enantioselectivities. Aniline and
- Li, Jun,Liao, Yuting,Zhang, Yulong,Liu, Xiaohua,Lin, Lili,Feng, Xiaoming
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supporting information
p. 6672 - 6674
(2014/06/10)
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- Aminolysis of aryl ester using tertiary amine as amino donor via c-o and c-n bond activations
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An aminolysis reaction between various aryl esters and inert tertiary amines by C-O and C-N bond activations has been developed for the selective synthesis of a broad scope of tertiary amides under neutral and mild conditions. The mechanism may undergo the two key steps of oxidative addition of acyl C-O bond in parent ester and C-N bond cleavage of tertiary amine via an iminium-type intermediate.
- Bao, Yong-Sheng,Zhaorigetu, Bao,Agula, Bao,Baiyin, Menghe,Jia, Meilin
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p. 803 - 808
(2014/04/03)
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- Kinetic study on aminolysis of y-substituted-phenyl picolinates: Effect of h-bonding interaction on reactivity and transition-state structure
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A kinetic study is reported on nucleophilic substitution reactions of Y-substituted-phenyl picolinates (7a-7h) with a series of cyclic secondary amines in 80 mol % H2O/20 mol % DMSO at 25.0 ± 0.1 °C. Comparison of the kinetic results with those reported previously for the corresponding reactions of Y-substituted-phenyl benzoates (1a-1f) reveals that 7a-7h are significantly more reactive than 1a-1f. The Bronsted-type plot for the aminolysis of 4-nitrophenyl picolinate (7a) is linear with βnuc = 0.78, which is typical for reactions proceeding through a stepwise mechanism with expulsion of the leaving group being the rate-determining step. The Bronsted-type plots for the piperidinolysis of 7a-7h and 1a-1f are also linear with βlg = -1.04 and -1.39, respectively, indicating that the more reactive 7a-7h are less selective than the less reactive 1a-1f to the leavinggroup basicity. One might suggest that the enhanced reactivity of 7a-7h is due to the inductive effect exerted by the electronegative N atom in the picolinyl moiety, while the decreased selectivity of the more reactive substrates is in accord with the reactivity-selectivity principle. However, the nature of intermediate (e.g., a stabilized cyclic intermediate through the intramolecular H-bonding interaction for the reactions of 7a-7h, which is structurally not possible for the reactions of 1a-1f) is also responsible for the enhanced reactivity with a decreased selectivity.
- Kim, Min-Young,Kang, Tae-Ah,Yoon, Jung Hwan,Um, Ik-Hwan
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p. 2410 - 2414
(2014/11/08)
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- A hetero Diels-Alder approach to the synthesis of chromans (3,4-dihydrobenzopyrans) using oxonium ion chemistry: The oxa-Povarov reaction
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An oxa analogue of the well-known Povarov reaction has been developed for the synthesis of 3,4-dihydrobenzopyrans (chromans). The reaction involves the formal inverse electron demand [4 + 2] cycloaddition reaction of in situ-generated cationic aryl 2-oxadiene oxocarbenium ions with alkenes. The oxonium ion intermediates are generated through Lewis acid (SnCl 4)-promoted reactions of phenol-derived Rychnovsky-type mixed acetals. The yield and diastereoselectivity of the chroman products are found to depend upon the substitution pattern of the precursor alkene (i.e., monosubstituted, trans- or cis-disubstituted and cyclic alkenes). Generally, the reactions afford the endo-diastereomers as the major products, except for the reactions of trans-β-methylstyrene, which afford exo-chromans. A comparison of the product distributions from the reactions of trans- and cis-β-methylstyrene reveal that the reaction proceeds, at least in part, by a nonconcerted ionic pathway. Just as for the aza-Povarov reaction, there are two potential mechanisms for the reaction. The first mechanism involves a direct asynchronous [4 + 2] cycloaddition pathway, while the second occurs through the stepwise Prins addition of the alkene to the aryl 2-oxadiene oxonium ion, followed by an intramolecular aromatic substitution reaction of the resultant cation (i.e., a domino Prins/intramolecular Friedel-Crafts reaction).
- Taylor, Rivka R. R.,Batey, Robert A.
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p. 1404 - 1420
(2013/03/28)
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- Transesterification for synthesis of carboxylates using aldehydes as acyl donors via C-H and C-O bond activations
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A new type of transesterification between aryl, heteroaryl, alkyl N-heteroarene-2-carboxylates and various aldehydes by C-H and C-O bond activations has been developed for the synthesis of versatile carboxylates. A possible mechanism containing oxidative addition of acyl-O bond in parent ester and radical cleavage of sp2 C-H bond in aldehyde is proposed.
- Bao, Yong-Sheng,Chen, Chao-Yue,Huang, Zhi-Zhen
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p. 8344 - 8349,6
(2020/10/15)
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- Palladium-catalyzed carbonylation of aryl, alkenyl, and allyl halides with phenyl formate
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Highly efficient palladium-catalyzed carbonylation of aryl, alkenyl, and allyl halides with phenyl formate is reported. This procedure does not use carbon monoxide and affords one-carbon-elongated carboxylic acid phenyl esters in excellent yields. The reaction proceeds smoothly under mild conditions and tolerates a wide range of functional groups including aldehyde, ether, ketone, ester, and cyano groups. Furthermore, a variety of heteroaromatic bromides can be converted to the corresponding phenyl esters in high yields.
- Ueda, Tsuyoshi,Konishi, Hideyuki,Manabe, Kei
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p. 3100 - 3103
(2012/07/27)
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- Decarbonylative C-H coupling of azoles and aryl esters: Unprecedented nickel catalysis and application to the synthesis of muscoride A
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A nickel-catalyzed decarbonylative C-H biaryl coupling of azoles and aryl esters is described. The newly developed catalytic system does not require the use of expensive metal catalysts or silver- or copper-based stoichiometric oxidants. We have successfully applied this new C-H arylation reaction to a convergent formal synthesis of muscoride A.
- Amaike, Kazuma,Muto, Kei,Yamaguchi, Junichiro,Itami, Kenichiro
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p. 13573 - 13576
(2012/10/08)
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- Synthesis of triphenylmethane derivative: Bisacodyl
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A new method for the synthesis of bisacodyl 1 is described. The key step involves migration of 2-pyridacyl group of phenyl pyridine-2-carboxylate 4 in AlCl3 at 160 °C to yield the intermediate 4-hydroxyphenyl (2-pyridyl) ketone 5a. The reaction of 5a with phenol using H3PO 4 gives 1. This method has advantage over the existing literature methods because easily available pyridine-2-carboxylic acid is used as a starting material instead of the less stable pyridine-2-carboxaldehyde.
- Mereyala, Hari Babu,Sambaru, Kalyani
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p. 615 - 617
(2007/10/03)
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