- Visible-Light-Enabled Carboxylation of Benzyl Alcohol Derivatives with CO2 Using a Palladium/Iridium Dual Catalyst
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A highly efficient carboxylation of benzyl alcohol derivatives with CO2 using a palladium/iridium dual catalyst under visible-light irradiation was developed. A wide range of benzyl alcohol derivatives could be employed to provide benzylic carboxylic acids in moderate to high yields. Mechanistic studies indicated that the oxidative addition of benzyl alcohol derivatives was possibly the rate-determining-step. It was also found that a switchable site-selective carboxylation between benzylic C?O and aryl C?Cl moieties could be achieved simply by changing the palladium catalyst.
- Iwasawa, Nobuharu,Jin, Yushu,Toriumi, Naoyuki
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- Method for preparing carboxylic acid by one-pot method
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The invention discloses a method for preparing carboxylic acid by a one-pot method, which comprises the steps of carrying out a Corey-Fuchs process on 1,1-dibromo olefin under the action of n-butyllithium, reacting with isopropanol pinacol borate, quenching with hydrogen chloride, oxidizing with an oxidant, separating and purifying to obtain carboxylic acid. The method disclosed by the invention is a one-pot preparation method, is simple and convenient to operate, does not need to use metal catalysis, uses cheap and easily available reagents for reaction, is green and environment-friendly, hasmild reaction conditions and wide substrate applicability, and provides a new way for rapidly preparing a series of carboxylic acids containing different functional groups.
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Paragraph 0056-0060
(2021/01/29)
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- Visible-Light-Driven External-Reductant-Free Cross-Electrophile Couplings of Tetraalkyl Ammonium Salts
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Cross-electrophile couplings between two electrophiles are powerful and economic methods to generate C-C bonds in the presence of stoichiometric external reductants. Herein, we report a novel strategy to realize the first external-reductant-free cross-electrophile coupling via visible-light photoredox catalysis. A variety of tetraalkyl ammonium salts, bearing primary, secondary, and tertiary C-N bonds, undergo selective couplings with aldehydes/ketone and CO2. Notably, the in situ generated byproduct, trimethylamine, is efficiently utilized as the electron donor. Moreover, this protocol exhibits mild reaction conditions, low catalyst loading, broad substrate scope, good functional group tolerance, and facile scalability. Mechanistic studies indicate that benzyl radicals and anions might be generated as the key intermediates via photocatalysis, providing a new direction for cross-electrophile couplings.
- Liao, Li-Li,Cao, Guang-Mei,Ye, Jian-Heng,Sun, Guo-Quan,Zhou, Wen-Jun,Gui, Yong-Yuan,Yan, Si-Shun,Shen, Guo,Yu, Da-Gang
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p. 17338 - 17342
(2019/01/04)
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- FENFLURAMINE COMPOSITIONS AND METHODS OF PREPARING THE SAME
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Methods of preparing a fenfluramine active pharmaceutical ingredient are provided. Aspects of the method include (a) hydrolyzing a 2-(3-(trifluoromethyl)phenyl)acetonitrile composition to produce a 2-(3-(trifluoromethyl)phenyl)acetic acid composition; (b) reacting the 2-(3-(trifluoromethyl)phenyl)acetic acid composition with acetic anhydride and a catalyst to produce a 1-(3-(trifluoromethyl)phenyl)propan-2-one composition; and (c) reductively aminating the 1-(3-(trifluoromethyl)phenyl)propan-2-one composition with ethylamine using a borohydride reducing agent to produce a fenfluramine composition. Also provided are compositions and pharmaceutical ingredients prepared according to the subject methods including a pharmaceutically acceptable salt of fenfluramine and having less than 0.2% by weight in total of trifluoromethyl regioisomers.
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Paragraph 0153
(2017/07/14)
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- An efficiently cobalt-catalyzed carbonylative approach to phenylacetic acid derivatives
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A highly efficient cobalt-catalyzed carbonylative approach to phenylacetic acid derivatives under one atmosphere pressure is reported. This methodology represents a useful extension of benzimidazole used as ligand in metal catalysis, and the catalytic mechanism has been proved by computer simulation. Notably, this new cobalt precatalyst, which promotes the carbonylation reaction dramatically and has already been used for scale-up experiment of phenylacetic acid derivatives.
- She, Meng-Yao,Xiao, Da-Wei,Yin, Bing,Yang, Zheng,Liu, Ping,Li, Jian-Li,Shi, Zhen
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p. 7264 - 7268
(2013/08/23)
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- MgCl2-accelerated addition of functionalized organozinc reagents to aldehydes, ketones, and carbon dioxide
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Figure Presented Pump it up! The sluggish reactivity of organozinc reagents in additions to aldehydes, ketones, and CO2 can be increased by MgCl2, which is usually generated in the preparation of the zinc reagent. The direct reaction with CO2, in particular, opens an expeditious route to phenylacetic acid derivatives, as demonstrated in a short synthesis of ibuprofen (see scheme).
- Metzger, Albrecht,Bernhardt, Sebastian,Manolikakes, Georg,Knochel, Paul
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supporting information; experimental part
p. 4665 - 4668
(2010/08/19)
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- THIADIAZOLE DERIVATIVES, INHIBITORS OF STEAROYL-COA DESATURASE
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The present invention relates to substituted thiadiazole compounds of the formula (I) and pharmaceutically acceptable salts thereof, to pharmaceutical compositions containing them and their use in medicine. In particular, the invention relates to compounds for modulating SCD activity.
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Page/Page column 49
(2008/12/07)
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- Aryl sulfonamide and sulfonyl compounds as modulators of PPAR and methods of treating metabolic disorders
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Aryl sulfonamide and sulfonyl compounds as modulators of peroxisome proliferator activated receptors, pharmaceutical compositions comprising the same, and methods of treating disease using the same are disclosed.
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Page/Page column 97
(2010/02/14)
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- Photolysis of the 1-naphthylmethyl ester of substituted phenylacetic acids: intramolecular charge transfer and rates of decarboxylation of arylacyl radicals
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The photolysis of esters 6 and 8 in methanol leads to products resulting from both naphthylmethyl cations and radicals.The product distribution is nearly independent of X for the esters 6 except when X equals methoxy.A mechanism involving initial homolytic cleavage of the carbon-oxygen bond in the excited singlet state of the ester is proposed.Competition between electron transfer in the radical pair to form the ion pair and decarboxylation of the arylacyloxy radical allows calculations of the rates of this decarboxylation process.The ρ values versus ? is close to zero.When X equals methoxy, intramolecular electron transfer occurs with the naphthalene ring serving as the acceptor and the methoxyaromatic as the donor.This exciplex fragments to carbon dioxide and 1-(1-naphthyl)-2-arylethane. Key words: acyloxy radical, decarboxylation, photolysis of benzylic esters.
- Hilborn, James W.,Pincock, James A.
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p. 992 - 999
(2007/10/02)
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- General Base Catalysis, Structure-Reactivity interactions, and Merging of Mechanisms for Elimination Reactions of (2-Arylethyl)quinuclidinium Ions
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Structure-reactivity parameters and interaction coefficients are reported for elimination reactions of N-(2-arylethyl)quinuclidinium ions and for 2-arylethyl halides and tosylates in 60percent Me2SO/wares at 40 deg C, based on direct measurements of Bronsted β values for general base catalysis by oxyanion buffers, Hammet ρ values, and β1g for substituted quinuclidines.The Bronsted slopes increase from β - 0.67 for N-(2-(p-nitrophenyl)ethyl)quinuclidinium ions, which react by an E1cBirr mechanism, to β ca. 0.9 for the reactions of other N-(2-arylethyl)quinuclidinium ions by a concerted E2 elimination.There is no detectable interaction between the base catalyst and the leaving group for E1cB elimination, so that the interaction coefficient pxy = dβ1g/dpKBH = dβ/dpK1g is ca.0 for the N-(2-(p-nitrophenyl)ethyl)quinuclidinium ions.In contrast, values of β1g become less negative with increasing pKa of the base catalyst for the p-cyano and other N-(2-arylethyl)quinuclidinium ions, giving a constant value of pxy = 0.018 for the E2 elimination reactions of these compounds.The positive pxy coefficient for the N-(2-phenylethyl)quinuclidinium ions is confirmed by the observation of less negative values of β1g as the effective basicity of aqueous tetramethylammonium hydroxyde is increased by the addition of Me2SO.An increase in β with poorer leaving groups in the series of 2-(p-nitrophenyl)ethyl halides also corresponds to a positive pxy coefficient and an E2 mechanism.The interaction between the leaving group and central atoms is shown by the less negative values of β1g with electron-withdrawing substituents on the β-phenyl group, which corresponds to a negative coefficient pyy' = -dβ1g/d?- = -dρ/dpK1g = -0.09.A small decrease in β with electron-withdrawing substituents on the β-phenyl group suggests an interaction between the base catalyst and the central atoms that is described by a negative coefficient pxy' = dβ/d?- = dρ/dpKBH = -0.07.The sign of the pyy' and pxy' coefficient are consistent with an important component of proton transfer in the transition state.These properties of the E2 elimination reactions of N-(2-arylethyl)quinuclidinium ions can be described by a reaction coordinate that is rotated 24 deg counterclockwise from the x coordinate (for proton transfer) on a reaction coordinate-energy diagram that is defined by the observed structure-reactivity parameters.In contrast, β increases with increasing ? for elimination reactions of 2-arylethyl bromides with a positive value of pxy' = 0.07.This suggests more diagonal character to the transition state on the reaction coordinate diagram.The change from E1cB to an E2 mechanism is more easily described as a transformation of mechanism than as a change between two coexisting mechanisms.
- Gandler, Joseph R.,Jencks, William P.
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p. 1937 - 1951
(2007/10/02)
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- Micellar Catalysis of the Basic Hydrolysis of Anilides. III α-Substituted N-Methyl-N-p-nitrophenylacetamides
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The basic hydrolysis of a number of α-substituted N-methyl-N-p-nitrophenylacetamides has been studied both in the presence and absence of micelles of cetyltrimethylammonium bromide (ctab).Unlike the related p-nitrophenyl esters of α-substituted acetic acids, no evidence for the operation of the E1cb mechanism in the basic hydrolysis has been detected.Reasons for the differences between the amides and esters are discussed.Substituent effects on the hydrolysis of the amides have been studied both by single-parameter and dual-parameter analysis.
- Broxton, Trevor J.,Duddy, Neil W.
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p. 1771 - 1781
(2007/10/02)
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