Reactions of lead tetraacetate. II. Formation of carbamic acid esters from primary carboxamides

1968 ◽  
Vol 21 (1) ◽  
pp. 197 ◽  
Author(s):  
B Acott ◽  
ALJ Beckwith ◽  
A Hassanali
Keyword(s):  
Reaction Mechanism ◽  
Efficient Method ◽  
Intermediate Formation ◽  
Lead Tetraacetate ◽  
Carbamic Acid ◽  
Structural Types ◽  
Wide Range ◽  
Alcohol Mixtures ◽  
Acid Esters

Treatment of primary carboxamides with lead tetraacetate in benzene-alcohol mixtures or neat alcohol affords a convenient, flexible, and efficient method for the preparation of N-substituted carbamic acid esters. The reaction is applicable to amides and alcohols of a wide range of structural types including compounds containing oleflnic, ester, aromatic, and other reactive functions. The reaction mechanism appears to involve intermediate formation of isocyanates.

Reactions of lead tetraacetate. I. Formation of acylamines from primary carboxamides

1968 ◽  
Vol 21 (1) ◽  
pp. 185 ◽  
Author(s):  
B Acott ◽  
ALJ Beckwith ◽  
A Hassanali
Keyword(s):  
Acetic Acid ◽  
Reaction Mechanism ◽  
Benzoic Acid ◽  
Intermediate Formation ◽  
Lead Tetraacetate ◽  
Acid Mixture ◽  
Curtius Rearrangement ◽  
Alkyl Isocyanate

Pentanamide, when treated with lead tetraacetate in hot benzene, affords a mixture of N-butylacetamide and N,N?-dibutylurea. Examples of similar transformations of a number of primary carboxamides are described. The reaction, which may also be conducted in acetic acid or benzene-acetic acid mixture, is catalysed by pyridine. Cyclohexanecarboxamide, when oxidized by lead tetraacetate in the presence of propionic or benzoic acid, is converted into the appropriate acylcyclohexylamine. The reaction mechanism involves intermediate formation of alkyl isocyanate, possibly via Curtius rearrangement of acylnitrene.

Arylation of enelactams using TIPSOTf: reaction scope and mechanistic insight

2021 ◽  
Author(s):  
Tomasz J. Idzik ◽  
Zofia M. Myk ◽  
Łukasz Struk ◽  
Magdalena Perużyńska ◽  
Gabriela Maciejewska ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Multinuclear Nmr ◽  
Mechanistic Insight ◽  
Nmr Study ◽  
Wide Range

Triisopropylsilyltrifluoromethanesulfonate can be effectively used for the arylation of a wide range of enelactams. The multinuclear NMR study provided deep insights into the reaction mechanism.

Ligand-Enabled γ-C(sp3)–H Olefination of Free Carboxylic Acids

2020 ◽  
Author(s):  
Kiron Kumar Ghosh ◽  
Alexander Uttry ◽  
Francesca Ghiringhelli ◽  
Arup Mondal ◽  
Manuel van Gemmeren
Keyword(s):  
Reaction Mechanism ◽  
Carboxylic Acids ◽  
Michael Addition ◽  
Kinetic Studies ◽  
Wide Range ◽  
Palladium Catalyzed

We report the ligand enabled C(sp3)–H activation/olefination of free carboxylic acids in the γ-position. Through an intramolecular Michael-addition, δ-lactones are obtained as products. Two distinct ligand classes are identified that enable the challenging palladium-catalyzed activation of free carboxylic acids in the γ-position. The developed protocol features a wide range of acid substrates and olefin reaction partners and is shown to be applicable on a preparatively useful scale. Insights into the underlying reaction mechanism obtained through kinetic studies are reported.<br>

scholarly journals Investigating the Enantiodetermining Step of a Chiral Lewis Base Catalyzed Bromocycloetherification of Privileged Alkenes

Synlett ◽  
2017 ◽  
Vol 29 (04) ◽  
pp. 433-439 ◽  
Author(s):  
Scott Denmark ◽  
Dietrich Böse
Keyword(s):  
Reaction Mechanism ◽  
Lewis Base ◽  
Design Criteria ◽  
Significant Progress ◽  
Detailed Understanding ◽  
Wide Range

The development of catalytic, enantioselective halofunctionalizations of unactivated alkenes has made significant progress in recent years. However, the identification of generally applicable catalysts for wide range of substrates has yet to be realized. A detailed understanding of the reaction mechanism is essential to guide the formulation of a truly general catalyst. Herein, we present our investigations on the enantiodetermining step of a Lewis base catalyzed bromocycloetherification that provides important insights and design criteria.

ChemInform Abstract: PRODUCTION OF CARBAMIC ACID ESTERS

1982 ◽  
Vol 13 (51) ◽  
Author(s):  
GORODETSKYL. SH. GORODETSKYL. SH. ◽  
O. N. VOLZHINA ◽  
I. A. KUZNETSOVA ◽  
E. N. ALEKSEEVA
Keyword(s):  
Carbamic Acid ◽  
Acid Esters

Electrocatalytic Oxidative Upgrading of Biomass Platform Chemicals: From the Aspect of Reaction Mechanism

2021 ◽  
Author(s):  
Hua Zhou ◽  
Zhenhua Li ◽  
Lina Ma ◽  
Haohong Duan
Keyword(s):  
Reaction Mechanism ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Oxidation Reactions ◽  
Platform Chemicals ◽  
Wide Range

Oxidation reactions provide a wide range of important chemicals in industry; however, most of them are produced from fossil feedstocks. As a candidate of oxygen evolution reaction (OER), the electrooxidation...

scholarly journals Sequestration of 9-Hydroxystearic Acid in FAHFA (Fatty Acid Esters of Hydroxy Fatty Acids) as a Protective Mechanism for Colon Carcinoma Cells to Avoid Apoptotic Cell Death

Cancers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 524 ◽  
Author(s):  
Juan P. Rodríguez ◽  
Carlos Guijas ◽  
Alma M. Astudillo ◽  
Julio M. Rubio ◽  
María A. Balboa ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Cell Lines ◽  
Hydroxy Fatty Acids ◽  
Fatty Acid Esters ◽  
Protective Mechanism ◽  
Hydroxystearic Acid ◽  
Colorectal Tumors ◽  
Wide Range ◽  
Acid Esters

Hydroxy fatty acids are known to cause cell cycle arrest and apoptosis. The best studied of them, 9-hydroxystearic acid (9-HSA), induces apoptosis in cell lines by acting through mechanisms involving different targets. Using mass spectrometry-based lipidomic approaches, we show in this study that 9-HSA levels in human colorectal tumors are diminished when compared with normal adjacent tissue. Since this decrease could be compatible with an escape mechanism of tumors from 9-HSA-induced apoptosis, we investigated different features of the utilization of this hydroxyfatty acid in colon. We show that in colorectal tumors and related cell lines such as HT-29 and HCT-116, 9-HSA is the only hydroxyfatty acid constituent of branched fatty acid esters of hydroxyfatty acids (FAHFA), a novel family of lipids with anti-inflammatory properties. Importantly, FAHFA levels in tumors are elevated compared with normal tissue and, unlike 9-HSA, they do not induce apoptosis of colorectal cell lines over a wide range of concentrations. Further, the addition of 9-HSA to colon cancer cell lines augments the synthesis of different FAHFA before the cells commit to apoptosis, suggesting that FAHFA formation may function as a buffer system that sequesters the hydroxyacid into an inactive form, thereby restricting apoptosis.

scholarly journals Prediction of Droplet Production Speed by Measuring the Droplet Spacing Fluctuations in a Flow-Focusing Microdroplet Generator

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 812 ◽  
Author(s):  
Wen Zeng ◽  
Dong Xiang ◽  
Hai Fu
Keyword(s):  
Fluid Flow ◽  
Efficient Method ◽  
Immiscible Fluids ◽  
Droplet Generation ◽  
Flow Focusing ◽  
Flow Conditions ◽  
Flow Rates ◽  
Wide Range ◽  
Droplet Production ◽  
Monodisperse Droplets

In a flow-focusing microdroplet generator, by changing the flow rates of the two immiscible fluids, production speed can be increased from tens to thousands of droplets per second. However, because of the nonlinearity of the flow-focusing microdroplet generator, the production speed of droplets is difficult to quantitatively study for the typical flow-focusing geometry. In this paper, we demonstrate an efficient method that can precisely predict the droplet production speed for a wide range of fluid flow rates. While monodisperse droplets are formed in the flow-focusing microchannel, droplet spacing as a function of time was measured experimentally. We discovered that droplet spacing changes periodically with time during each process of droplet generation. By comparing the frequency of droplet spacing fluctuations with the droplet production speed, precise predictions of droplet production speed can be obtained for different flow conditions in the flow-focusing microdroplet generator.

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