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Igor Larrosa - One of the best experts on this subject based on the ideXlab platform.
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ruthenium catalyzed c h arylation of Benzoic Acids and indole carboxylic Acids with aryl halides
Chemistry: A European Journal, 2017Co-Authors: Marco Simonetti, Diego M Cannas, Adyasha Panigrahi, Szymon Kujawa, Michal Kryjewski, Pan Xie, Igor LarrosaAbstract:Herein we report the first Ru-catalyzed C-H arylation of Benzoic Acids with readily available aryl (pseudo)halides. The reaction, which does not require the use of silver salt additives, allows the arylation of previously challenging hindered Benzoic Acids and the use of generally unreactive ortho-substituted halorarenes. Furthermore, our new protocol can efficiently be applied to indole carboxylic Acids, thus allowing access to C7-, C6-, C5- and C4-arylated indole compounds, a departure from the classical enhanced reactivity of the C2 and C3 positions of indole.
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the ortho substituent effect on the ag catalysed decarboxylation of Benzoic Acids
Chemistry: A European Journal, 2014Co-Authors: Rachel Grainger, Igor Larrosa, Josep Cornella, David C Blakemore, Josep M CampaneraAbstract:A combined experimental and computational investigation on the Ag-catalysed decarboxylation of Benzoic Acids is reported herein. The present study demonstrates that a substituent at the ortho position exerts dual effects in the decarboxylation event. On one hand, ortho-substituted Benzoic Acids are inherently destabilised starting materials compared to their meta- and para-substituted counterparts. On the other hand, the presence of an ortho-electron-withdrawing group results in an additional stabilisation of the transition state. The combination of both effects results in an overall reduction of the activation energy barrier associated with the decarboxylation event. Furthermore, the Fujita-Nishioka linear free energy relationship model indicates that steric bulk of the substituent can also exert a negative effect by destabilising the transition state of decarboxylation.
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direct ortho arylation of ortho substituted Benzoic Acids overriding pd catalyzed protodecarboxylation
ChemInform, 2013Co-Authors: Carlos Arroniz, Alan Ironmonger, Gerry Rassias, Igor LarrosaAbstract:The presence of potassium carbonate prevents decarboxylation in Pd-catalyzed ortho-arylations of sterically hindered Benzoic Acids, making 2-aryl-6-substituted Benzoic Acids easily accessible.
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direct ortho arylation of ortho substituted Benzoic Acids overriding pd catalyzed protodecarboxylation
Organic Letters, 2013Co-Authors: Carlos Arroniz, Alan Ironmonger, Gerry Rassias, Igor LarrosaAbstract:ortho-Arylation of ortho-substituted Benzoic Acids is a challenging process due to the tendency of the reaction products toward Pd-catalyzed protodecarboxylation. A simple method for preventing decarboxylation in sterically hindered Benzoic Acids is reported. The method described represents a reliable and broadly applicable entry to 2-aryl-6-substituted Benzoic Acids.
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intermolecular decarboxylative direct c 3 arylation of indoles with Benzoic Acids
ChemInform, 2010Co-Authors: Josep Cornella, Igor LarrosaAbstract:A palladium catalyzed C−H activation of indoles and a silver catalyzed decarboxylative C−C activation of ortho substituted Benzoic Acids are synergistically combined to synthesize indoles arylated exclusively in the C-3 position. This novel decarboxylative C−H arylation methodology is compatible with electron-donating and -withdrawing substituents in both coupling partners.
Igor V Alabugin - One of the best experts on this subject based on the ideXlab platform.
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tuning selectivity of anionic cyclizations competition between 5 exo and 6 endo dig closures of hydrazides of o acetylenyl Benzoic Acids and based catalyzed fragmentation recyclization of the initial 5 exo dig products
Journal of Organic Chemistry, 2009Co-Authors: S. F. Vasilevsky, Tatyana F Mikhailovskaya, Georgy E Salnikov, Georgy A Bogdanchikov, V. I. Mamatyuk, Mariappan Manoharan, Igor V AlabuginAbstract:Depending on the reaction conditions and the nature of substituents at the triple bond, anionic cyclizations of hydrazides of o-acetylenyl Benzoic Acids can be selectively directed along three alternative paths, each of which provides efficient access to a different class of nitrogen heterocycles. The competition between 5-exo and 6-endo cyclizations of the “internal” nitrogen nucleophile is controlled by the nature of alkyne substituents under the kinetic control conditions. In the presence of KOH, the initially formed 5-exo products undergo a new rearrangement that involves a ring-opening followed by recyclization to the formal 6-exo-products and rendered irreversible by a prototropic isomerization. DFT computations provide insight into the nature of factors controlling relative rates of 5-exo, 6-endo, and 6-exo cyclization paths, ascertain the feasibility of direct 6-exo closure and relative stability for the anionic precursor for this process, provide, for the first time, the benchmark data for severa...
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tuning selectivity of anionic cyclizations competition between 5 exo and 6 endo dig closures of hydrazides of o acetylenyl Benzoic Acids and based catalyzed fragmentation recyclization of the initial 5 exo dig products
Journal of Organic Chemistry, 2009Co-Authors: S. F. Vasilevsky, Tatyana F Mikhailovskaya, Georgy E Salnikov, Georgy A Bogdanchikov, V. I. Mamatyuk, Mariappan Manoharan, Igor V AlabuginAbstract:Depending on the reaction conditions and the nature of substituents at the triple bond, anionic cyclizations of hydrazides of o-acetylenyl Benzoic Acids can be selectively directed along three alte...
Masahiro Miura - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of highly substituted isocoumarins by rhodium-catalyzed annulation of readily available Benzoic Acids
Tetrahedron, 2013Co-Authors: Yuto Unoh, Koji Hirano, Tetsuya Satoh, Masahiro MiuraAbstract:Abstract Readily available Benzoic Acids possessing a number of oxygen-containing group(s) efficiently undergo oxidative coupling with alkynes through regioselective C–H bond cleavage under rhodium catalysis to form highly substituted isocoumarin derivatives. Such isocoumarins are of considerable interest due to their unique biological properties.
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synthesis of stilbene and distyrylbenzene derivatives through rhodium catalyzed ortho olefination and decarboxylation of Benzoic Acids
Organic Letters, 2010Co-Authors: Satoshi Mochida, Koji Hirano, Tetsuya Satoh, Masahiro MiuraAbstract:Ortho-substituted Benzoic Acids efficiently undergo precisely ordered ortho-olefination/decarboxylation upon treatment with styrenes in the presence of a rhodium catalyst and silver salt oxidant to afford the corresponding meta-substituted stilbene derivatives. The selective syntheses of 1,3- and 1,4-distyrylbenzenes have also been realized through the reactions of simple Benzoic acid and phthalic acid, respectively, with styrene under similar conditions.
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rhodium and iridium catalyzed oxidative coupling of Benzoic Acids with alkynes and alkenes
ChemInform, 2008Co-Authors: Tetsuya Satoh, Kenji Ueura, Masahiro MiuraAbstract:The oxidative coupling of Benzoic Acids with alkynes and alkenes effectively pro- ceeds in the presence of a Rh catalyst and an appropriate oxidant to produce the correspon- ding isocoumarin and phthalide derivatives, respectively. Interestingly, by using an Ir catalyst in place of Rh, the Acids and alkynes undergo 1:2 coupling accompanied by decarboxylation to afford naphthalene derivatives exclusively.
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rhodium and iridium catalyzed oxidative coupling of Benzoic Acids with alkynes via regioselective c h bond cleavage
Journal of Organic Chemistry, 2007Co-Authors: Kenji Ueura, Tetsuya Satoh, Masahiro MiuraAbstract:The oxidative coupling of Benzoic Acids with internal alkynes effectively proceeds in the presence of [Cp*RhCl2]2 and Cu(OAc)2 x H2O as catalyst and oxidant, respectively, to produce the corresponding isocoumarin derivatives. The copper salt can be reduced to a catalytic quantity under air. Interestingly, by using [Cp*IrCl2]2 in place of [Cp*RhCl2]2, the substrates undergo 1:2 coupling accompanied by decarboxylation to afford naphthalene derivatives exclusively. In this case, Ag2CO3 acts as an effective oxidant.
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an efficient waste free oxidative coupling via regioselective c h bond cleavage rh cu catalyzed reaction of Benzoic Acids with alkynes and acrylates under air
Organic Letters, 2007Co-Authors: Kenji Ueura, And Tetsuya Satoh, Masahiro MiuraAbstract:The direct oxidative coupling of Benzoic Acids with internal alkynes proceeds efficiently in the presence of a rhodium/copper catalyst system under air to afford the corresponding isocoumarin derivatives. The reaction forms no wastes except for water. Under similar conditions, the aerobic coupling with acrylates also takes place smoothly to produce 7-vinylphthalide derivatives via divinylation and subsequent cyclization.
Robert E Mandrell - One of the best experts on this subject based on the ideXlab platform.
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antibacterial activities of phenolic benzaldehydes and Benzoic Acids against campylobacter jejuni escherichia coli listeria monocytogenes and salmonella enterica
Journal of Food Protection, 2003Co-Authors: Mendel Friedman, Philip R Henika, Robert E MandrellAbstract:We evaluated the bactericidal activities of 35 benzaldehydes, 34 Benzoic Acids, and 1 Benzoic acid methyl ester against Campylobacter jejuni, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica when these compounds were substituted on the benzene ring with 0, 1, 2, or 3 hydroxy (OH) and/or methoxy (OCH3) groups in a pH 7.0 buffer. Dose-response plots were used to determine the percentage of the sample that induced a 50% decrease in CFU after 60 min (BA50). Of the 70 compounds tested, 24 were found to be active against all four pathogens, and additional 4, 10, and 12 were found to be active against three, two, and one of the pathogens, respectively. C. jejuni was ~100 times as sensitive as the other three pathogens. The 10 compounds that were most active against the four pathogens (with average BA50 values ranging from 0.026 to 0.166) and are candidates for studies of activity in foods or for disinfections were 2,4,6-trihydroxybenzaldehyde, 2,5-dihydroxybenzaldehyde, 2,3,4-trihydroxyb...
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antibacterial activities of phenolic benzaldehydes and Benzoic Acids against campylobacter jejuni escherichia coli listeria monocytogenes and salmonella enterica
Journal of Food Protection, 2003Co-Authors: Mendel Friedman, Philip R Henika, Robert E MandrellAbstract:We evaluated the bactericidal activities of 35 benzaldehydes, 34 Benzoic Acids, and 1 Benzoic acid methyl ester against Campylobacter jejuni, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica when these compounds were substituted on the benzene ring with 0, 1, 2, or 3 hydroxy (OH) and/or methoxy (OCH3) groups in a pH 7.0 buffer. Dose-response plots were used to determine the percentage of the sample that induced a 50% decrease in CFU after 60 min (BA50). Of the 70 compounds tested, 24 were found to be active against all four pathogens, and additional 4, 10, and 12 were found to be active against three, two, and one of the pathogens, respectively. C. jejuni was approximately 100 times as sensitive as the other three pathogens. The 10 compounds that were most active against the four pathogens (with average BA50 values ranging from 0.026 to 0.166) and are candidates for studies of activity in foods or for disinfections were 2,4,6-trihydroxybenzaldehyde, 2,5-dihydroxybenzaldehyde, 2,3,4-trihydroxybenzaldehyde, 2-hydroxy-5-methoxybenzaldehyde, 2,3-dihydroxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 4-hydroxy-2,6-dimethoxybenzaldehyde, 2,5-dihydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde. and 2-hydroxybenzaldehyde. Comparison of the chemical structures of the test compounds and their activities revealed that (i) the aldehyde (CHO) group was more active than the carboxyl (COOH) group whether or not OH groups were present; (ii) compounds were most active with trisubstituted OH > disubstituted OH > monosubstituted OH; (iii) for disubstituted derivatives, 2-OH enhanced activities were exhibited by benzaldehyde but not by Benzoic acid; (iv) compounds were more active with OH than with OCH3, irrespective of the position of substitution on the benzene ring; (v) compounds with mixed OH and OCH3 groups exhibited variable results, i.e., in some cases OCH3 groups enhanced activity and in other cases they did not; (vi) methoxyBenzoic Acids were largely inactive; and (vii) gallic acid was 20 times as active against S. enterica at pH 7.0 as it was at pH 3.7, suggesting that the ionization of its OH groups may enhance bactericidal activity.
S. F. Vasilevsky - One of the best experts on this subject based on the ideXlab platform.
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tuning selectivity of anionic cyclizations competition between 5 exo and 6 endo dig closures of hydrazides of o acetylenyl Benzoic Acids and based catalyzed fragmentation recyclization of the initial 5 exo dig products
Journal of Organic Chemistry, 2009Co-Authors: S. F. Vasilevsky, Tatyana F Mikhailovskaya, Georgy E Salnikov, Georgy A Bogdanchikov, V. I. Mamatyuk, Mariappan Manoharan, Igor V AlabuginAbstract:Depending on the reaction conditions and the nature of substituents at the triple bond, anionic cyclizations of hydrazides of o-acetylenyl Benzoic Acids can be selectively directed along three alternative paths, each of which provides efficient access to a different class of nitrogen heterocycles. The competition between 5-exo and 6-endo cyclizations of the “internal” nitrogen nucleophile is controlled by the nature of alkyne substituents under the kinetic control conditions. In the presence of KOH, the initially formed 5-exo products undergo a new rearrangement that involves a ring-opening followed by recyclization to the formal 6-exo-products and rendered irreversible by a prototropic isomerization. DFT computations provide insight into the nature of factors controlling relative rates of 5-exo, 6-endo, and 6-exo cyclization paths, ascertain the feasibility of direct 6-exo closure and relative stability for the anionic precursor for this process, provide, for the first time, the benchmark data for severa...
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tuning selectivity of anionic cyclizations competition between 5 exo and 6 endo dig closures of hydrazides of o acetylenyl Benzoic Acids and based catalyzed fragmentation recyclization of the initial 5 exo dig products
Journal of Organic Chemistry, 2009Co-Authors: S. F. Vasilevsky, Tatyana F Mikhailovskaya, Georgy E Salnikov, Georgy A Bogdanchikov, V. I. Mamatyuk, Mariappan Manoharan, Igor V AlabuginAbstract:Depending on the reaction conditions and the nature of substituents at the triple bond, anionic cyclizations of hydrazides of o-acetylenyl Benzoic Acids can be selectively directed along three alte...