scholarly journals Pyran-2-one-6-carboxylic acid under Meerwein reaction conditions

2018 ◽  
Vol 59 (2) ◽  
pp. 311
Author(s):  
Kh. Pitkovych ◽  
R. Lytvyn ◽  
Y. Horak ◽  
V. Kinzhybalo
Keyword(s):  
Carboxylic Acid ◽  
Reaction Conditions ◽  
Meerwein Reaction

Ketones from Nickel-Catalyzed Decarboxylative, Non-Symmetric Cross-Electrophile Coupling of Carboxylic Acid Esters

2019 ◽  
Author(s):  
Jiang Wang ◽  
Brian P. Cary ◽  
Peyton Beyer ◽  
Samuel H. Gellman ◽  
Daniel Weix
Keyword(s):  
Carboxylic Acid ◽  
Solid Support ◽  
Reaction Conditions ◽  
Decarboxylative Coupling ◽  
New Strategy ◽  
The Cross ◽  
Acyl Donors ◽  
Acid Esters

A new strategy for the synthesis of ketones is presented based upon the decarboxylative coupling of N-hydroxyphthalimide (NHP) esters with S-2-pyridyl thioesters. The reactions are selective for the cross-coupled product because NHP esters act as radical donors and the thioesters act as acyl donors. The reaction conditions are general and mild, with over 40 examples presented, including larger fragments and the 20-mer peptide Exendin(9-39) on solid support.

Synthesis of Optically Active Hydroxyalkyl Cycloheptatrienes: A Key Step in the Total Synthesis of 6,11-Methylene-LXB4

Synlett ◽  
2020 ◽  
Vol 32 (01) ◽  
pp. 45-50
Author(s):  
Udo Nubbemeyer ◽  
Analuisa Nava ◽  
Lukas Trippe ◽  
Andrea Frank ◽  
Lars Andernach ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Total Synthesis ◽  
Structure Elucidation ◽  
Butyl Ester ◽  
Optically Active ◽  
Chiral Hplc ◽  
Reaction Conditions ◽  
Acid Product ◽  
Tert Butyl ◽  
Nabh4 Reduction

AbstractStarting from methyl cycloheptatrienyl-1-carboxylate, 6-acylation was successfully achieved employing glutaryl chloride in the presence of AlCl3 under controlled reaction conditions to furnish keto carboxylic acid product. After protection of this keto carboxylic acid as tert-butyl ester, reagent-controlled enantioselective reductions delivered configuration-defined methyl-6-hydroxylalkyl cycloheptatriene-1-carboxylates with up to 80% ee. Whereas simple NaBH4 reduction of the keto carboxylic acid and subsequent lactonization afforded a methyl-6-tetrahydropyranonyl cycloheptatriene-1-carboxylate. Resolution using chiral HPLC delivered the product enantiomers with up to >99% ee Finally, ECD analyses enabled structure elucidation. The products are used as key intermediates in enantioselective 6,11-methylene-lipoxin B4 syntheses.

scholarly journals Derivatives of the triaminoguanidinium ion, 5. Acylation of triaminoguanidines leading to symmetrical tris(acylamino)guanidines and mesoionic 1,2,4-triazolium-3-aminides

2017 ◽  
Vol 13 ◽  
pp. 579-588 ◽  
Author(s):  
Jan Szabo ◽  
Julian Greiner ◽  
Gerhard Maas
Keyword(s):  
Crystal Structure ◽  
Carboxylic Acid ◽  
Nitrogen Atom ◽  
Catalytic Hydrogenation ◽  
Acid Chlorides ◽  
Reaction Conditions ◽  
Derivatives Of ◽  
Guanidinium Salts ◽  
Triazolium Salts

Depending on the reaction conditions, N,N’,N’’-tris(benzylamino)guanidinium salts can react with carboxylic acid chlorides to form either symmetrical N,N’,N’’-tris(N-acyl-N-benzylamido)guanidines 6 or mesoionic 4-amino-1,2,4-triazolium-3-hydrazinides 7. The latter were converted into 1,2,4-triazolium salts by protonation or methylation at the hydrazinide nitrogen atom. Neutral 1,2,4-triazoles 10 were obtained by catalytic hydrogenation of an N-benzyl derivative. Crystal structure analyses of a 4-benzylamino-1,2,4-triazolium-3-hydrazinide and of two derived 1,2,4-triazolium salts are presented.

Crown ether catalysis of decarboxylation: a general survey of reactivity and detailed analysis of the triphenylacetate anion

1978 ◽  
Vol 56 (1) ◽  
pp. 104-113 ◽  
Author(s):  
D. H. Hunter ◽  
M. Hamity ◽  
V. Patel ◽  
R. A. Perry
Keyword(s):  
Carboxylic Acid ◽  
Crown Ether ◽  
Water Concentration ◽  
Solvent Polarity ◽  
General Survey ◽  
Reaction Conditions ◽  
Diphenylacetic Acid ◽  
Decarboxylation Rate ◽  
Optimum Reaction ◽  
Triphenylacetic Acid

The effect of 18-crown-6 ether 3 on the decarboxylation rate in THF of sodium salts of carboxylic acids formally derived from hydrocarbons has been investigated and these acids include 9-phenylfluorene-9-carboxylic acid, fluorene-9-carboxylic acid, phenylacetylene carboxylic acid, triphenylacetic acid, and diphenylacetic acid. Addition of equimolar 3 resulted in an increase in decarboxylation rate of 13- to 500-fold and there was a correlation between the decarboxylation rate and the pKa value of the product hydrocarbon.The decarboxylation of triphenylacetate was investigated in detail. The effect on reaction rate of cation (Li+, Na+, K+), crown ether concentration, water concentration, and solvent polarity has provided information as to optimum reaction conditions and has helped to clarify the reaction mechanism.

scholarly journals A Novel, One-Step Palladium and Phenylsilane Activated Amidation from Allyl Ester on Solid Support

2008 ◽  
Vol 2008 ◽  
pp. 1-4
Author(s):  
Zheming Ruan ◽  
Katy Van Kirk ◽  
Christopher B. Cooper ◽  
R. Michael Lawrence
Keyword(s):  
Carboxylic Acid ◽  
Solid Phase ◽  
Direct Conversion ◽  
Solid Support ◽  
Phase Array ◽  
Reaction Conditions ◽  
Allyl Ester ◽  
One Step ◽  
Allyl Esters

The direct conversion of solid-supported carboxylic acid allyl esters to carboxamides through the use of phenylsilane and catalytic Pd under mild reaction conditions is reported. The use of this methodology for the generation of a 48 compound solid-phase array is described herein.

scholarly journals Comportamiento de agregación de noveles surfactantes de par iónico

2018 ◽  
Vol 3 (2) ◽  
pp. 1
Author(s):  
Belgica Bravo ◽  
Gerson Chávez ◽  
Nelson Márquez ◽  
Nacarid Delgado ◽  
Ana Cáceres ◽  
...  
Keyword(s):  
Surface Tension ◽  
Carboxylic Acid ◽  
Key Words ◽  
Alkyl Chain ◽  
Ionic Species ◽  
Ion Pair ◽  
Aggregation Behavior ◽  
Reaction Conditions ◽  
Palabras Clave ◽  
Fundamental Paper

Los ácidos alquilcarboxílicos pueden dar origen a la formación de una especie iónica con características anfifílicas que disminuye la tensión superficial de un sistema agua/aire. El tipo de contraión de estas especies juega un papel fundamental en las propiedades superficiales del compuesto. Se preparó una novedosa clase de surfactantes de par iónico (SPI) por neutralización de cantidades equimolares del ácido carboxílico con una base de tipo ciclohexilamina (cHACn) bajo condiciones suaves de reacción. Se estudió el comportamiento de agregación por tensión superficial. Los compuestos obtenidos disminuyeron la tensión superficial presentando baja concentración micelar crítica (CMC) y por tanto una mayor actividad superficial. La CMC de todos los compuestos estudiados disminuyó con la longitud de la cadena alquílica aniónica (n).  Palabras clave: ácidos alquilcarboxílicos, surfactantes de par iónico, comportamiento de agregación, tensión superficial. ABSTRACT The alkylcarboxylic acids can give origin to the formation of ionic species with amphiphilic characteristics that decreases the surface tension of a water/air system. The type of counterion of these species plays a fundamental paper in the surface properties of the compound. Novel class ion pair surfactants (IPS) were prepared by neutralization of equimolar amounts of carboxylic acid with a base of type cyclohexylamine (cHACn) though mild reaction conditions. The aggregation behavior through surface tension was studied. The compounds obtained reduced the surface tension presenting low critical micelar concentration (CMC) and therefore a greater surface activity. The CMC of all compounds studied decreased with the length of the anionic alkyl chain (n).  Key words: Alkylcarboxylic acids, ion pair surfactant, aggregation behavior, surface tension.

Acid-Catalyzed Intramolecular Ring-Opening Reactions of Cyclopropanated Oxabenzonorbornadienes with Carboxylic Acid Nucleophiles

Synthesis ◽  
2021 ◽  
Author(s):  
Angel Ho ◽  
Austin Pounder ◽  
Samuel Koh ◽  
Matthew Macleod ◽  
Emily Carlson ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Ring Opening ◽  
Reaction Conditions ◽  
Ring Opening Reactions ◽  
Acidic Conditions ◽  
Acid Catalyzed ◽  
Type 3 ◽  
Intramolecular Ring

The present work demonstrates the ability of carboxylic acid-tethered cyclopropanated oxabenzonorbornadienes (CPOBDs) to undergo ring-opening reactions in mild acidic conditions. The optimized reaction conditions involve the use of pTsOH in DCE at 90 °C. Two regioisomers are formed but the reactions are highly regioselective towards type 3 ring-opened products. It was observed that substitution at the C-5 and aryl positions of CPOBD significantly hinders the ring opening reactions leading to decreased yields of ring-opened product, although high regioselectivity for the Type 3 ring-opened product is still maintained. Herein, we report the first examples of acid-catalyzed intramolecular ring-opening reactions of CPOBD with carboxylic acid nucleophiles.

Comportamiento de agregación de noveles surfactantes de par iónico

2018 ◽  
Vol 3 (2) ◽  
pp. 1
Author(s):  
Bélgica Bravo ◽  
Gerson Chávez ◽  
Nelson Márquez ◽  
Nacarid Delgado ◽  
Ana Cáceres ◽  
...  
Keyword(s):  
Surface Tension ◽  
Carboxylic Acid ◽  
Key Words ◽  
Alkyl Chain ◽  
Ionic Species ◽  
Ion Pair ◽  
Aggregation Behavior ◽  
Reaction Conditions ◽  
Palabras Clave ◽  
Fundamental Paper

Los ácidos alquilcarboxílicos pueden dar origen a la formación de una especie iónica con características anfifílicas que disminuye la tensión superficial de un sistema agua/aire. El tipo de contraión de estas especies juega un papel fundamental en las propiedades superficiales del compuesto. Se preparó una novedosa clase de surfactantes de par iónico (SPI) por neutralización de cantidades equimolares del ácido carboxílico con una base de tipo ciclohexilamina (cHACn) bajo condiciones suaves de reacción. Se estudió el comportamiento de agregación por tensión superficial. Los compuestos obtenidos disminuyeron la tensión superficial presentando baja concentración micelar crítica (CMC) y por tanto una mayor actividad superficial. La CMC de todos los compuestos estudiados disminuyó con la longitud de la cadena alquílica aniónica (n).  Palabras clave: ácidos alquilcarboxílicos, surfactantes de par iónico, comportamiento de agregación, tensión superficial. ABSTRACT The alkylcarboxylic acids can give origin to the formation of ionic species with amphiphilic characteristics that decreases the surface tension of a water/air system. The type of counterion of these species plays a fundamental paper in the surface properties of the compound. Novel class ion pair surfactants (IPS) were prepared by neutralization of equimolar amounts of carboxylic acid with a base of type cyclohexylamine (cHACn) though mild reaction conditions. The aggregation behavior through surface tension was studied. The compounds obtained reduced the surface tension presenting low critical micelar concentration (CMC) and therefore a greater surface activity. The CMC of all compounds studied decreased with the length of the anionic alkyl chain (n).  Key words: Alkylcarboxylic acids, ion pair surfactant, aggregation behavior, surface tension.

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