Boronic Acids:  New Coupling Partners in Room-Temperature Suzuki Reactions of Alkyl Bromides. Crystallographic Characterization of an Oxidative-Addition Adduct Generated under Remarkably Mild Conditions

2002 ◽  
Vol 124 (46) ◽  
pp. 13662-13663 ◽  
Author(s):  
Jan H. Kirchhoff ◽  
Matthew R. Netherton ◽  
Ivory D. Hills ◽  
Gregory C. Fu
Keyword(s):  
Room Temperature ◽  
Oxidative Addition ◽  
Boronic Acids ◽  
Suzuki Reactions ◽  
Mild Conditions ◽  
Alkyl Bromides

scholarly journals H/D Exchange Under Mild Conditions in Arenes and Unactivated Alkanes with C6D6 and D2O Using Rigid, Electron-rich Iridium PCP Pincer Complexes

2020 ◽  
Author(s):  
Joel D. Smith ◽  
George Durrant ◽  
Daniel Ess ◽  
Warren Piers
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Room Temperature ◽  
Pincer Complexes ◽  
Synthesis And Characterization ◽  
Hydrogen Isotope Exchange ◽  
Mild Conditions ◽  
Highly Active ◽  
Pcp Pincer

<div>The synthesis and characterization of an iridium polyhydride complex (Ir-H4)</div><div>supported by an electron-rich PCP framework is described. This complex readily loses molecular</div><div>hydrogen allowing for rapid room temperature hydrogen isotope exchange (HIE) at the hydridic</div><div>positions and the α-C-H site of the ligand with deuterated solvents such as benzene-d6, toluene-d8</div><div>and THF-d8. The removal of 1-2 equivalents of molecular H2 forms unsaturated iridium carbene</div><div>trihydride (Ir-H3) or monohydride (Ir-H) compounds that are able to create further unsaturation</div><div>by reversibly transferring a hydride to the ligand carbene carbon. These species are highly active</div><div>hydrogen isotope exchange (HIE) catalysts using C6D6 or D2O as deuterium sources for the</div><div>deuteration of a variety of substrates. By modifying conditions to influence the Ir-Hn speciation,</div><div>deuteration levels can range from near exhaustive to selective only for sterically accessible sites.</div><div>Preparative level deuterations of select substrates were performed allowing for procurement of</div><div>>95% deuterated compounds in excellent isolated yields; the catalyst can be regenerated by</div><div>treatment of residues with H2 and is still active for further reactions.</div>

Palladium-Catalysed Cross-Coupling of Benzylammonium Salts with Boronic Acids under Mild Conditions

Synthesis ◽  
2017 ◽  
Vol 50 (04) ◽  
pp. 793-802 ◽  
Author(s):  
Robert Phipps ◽  
Paul Türtscher ◽  
Holly Davis
Keyword(s):  
Quaternary Ammonium ◽  
Good Yield ◽  
Oxidative Addition ◽  
Cross Coupling ◽  
Boronic Acids ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Full Account ◽  
Mild Conditions

Herein, we give a full account of the development of the palladium­-catalysed cross-coupling of benzylammonium salts with boronic acids. A range of benzylamine-derived quaternary ammonium salts can be coupled with boronic acids under relatively mild conditions. Our optimization has identified ligands that can be used to chemoselectively cross-couple at the ammonium in the presence of chlorides. We demonstrate that intramolecular palladium-catalysed C–H activation is also a viable pathway for the putative benzyl-Pd(II) intermediate obtained upon oxidative addition and have optimised this to obtain fluorene in good yield.

scholarly journals Characterization of Chitosan Extracted from Fish Scales of the Colombian Endemic Species Prochilodus magdalenae as a Novel Source for Antibacterial Starch-Based Films

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2079
Author(s):  
Carlos Molina-Ramírez ◽  
Paulina Mazo ◽  
Robin Zuluaga ◽  
Piedad Gañán ◽  
Juan Álvarez-Caballero
Keyword(s):  
Molecular Weight ◽  
Antibacterial Activity ◽  
Room Temperature ◽  
Low Molecular Weight ◽  
Fish Scales ◽  
Molecular Weight Characteristic ◽  
Mild Conditions ◽  
And Staphylococcus Aureus ◽  
Positive Results

Scales of Prochilodus magdalenae, a Colombian endemic fish species, were used to obtain chitosan for application as an antibacterial agent integrated into starch-based films. Analysis of its composition during the demineralization and deproteinization process indicated that minerals and protein were both removed successfully. At this point, mild conditions for the deacetylation process were employed, namely, 2, 4, and 6 wt.% NaOH at room temperature for 16 h. Chitosan processed under 2 wt.% NaOH had low molecular weight, with the lowest value of 107.18 ± 24.99 kDa, which was closely related to its antibacterial activity. Finally, this chitosan was integrated into a banana starch-based film, and its antibacterial activity was assayed in Escherichia coli and Staphylococcus aureus cultures, with positive results in the former culture, especially due to the low-molecular-weight characteristic of chitosan.

Some new diphosphine-bridged nickel carbonyl and cyclopentadienyl compounds

1969 ◽  
Vol 47 (8) ◽  
pp. 1429-1431 ◽  
Author(s):  
A. J. Carty ◽  
A. Efraty ◽  
T. W. Ng
Keyword(s):  
Room Temperature ◽  
Direct Reaction ◽  
Nickel Carbonyl ◽  
Mild Conditions ◽  
Nickel Phosphine

The binuclear diphosphine bridged monocarbonyl compound [Ni(CO)]2(DPPA)3 has been obtained by reaction of Ni(CO)4 with bis(diphenylphosphino)acetylene (DPPA) under mild conditions and by displacement of π-cyclopentadienyl groups from [π-C5H5Ni(CO)]2 at room temperature. The latter reaction suggests a possible route to other monocarbonyl nickel phosphine compounds not available by direct reaction of Ni(CO)4 with phosphines. The preparation and characterization of the binuclear compounds [Ni(CO)2]2(DPPA)2, [Ni(CO)3]2(DPPA), and (π-C5H5NiI)2(DPPA) are also described.

Copper-Catalyzed N-Arylation of Sulfoximines with Arylboronic Acids under Mild Conditions

Synthesis ◽  
2019 ◽  
Vol 51 (10) ◽  
pp. 2171-2182 ◽  
Author(s):  
Surabhi Gupta ◽  
Siddharth Baranwal ◽  
Nalluchamy Muniyappan ◽  
Shahulhameed Sabiah ◽  
Jeyakumar Kandasamy
Keyword(s):  
Room Temperature ◽  
Boronic Acids ◽  
Methionine Sulfoximine ◽  
Reaction Conditions ◽  
Biologically Relevant ◽  
Arylboronic Acids ◽  
Mild Conditions ◽  
Short Span ◽  
Sterically Hindered ◽  
First Time

N-Arylation of sulfoximines with different arylboronic acids, including sterically hindered boronic acids, is achieved using copper(I) iodide and 4-DMAP at room temperature. Moreover, N-arylation of biologically relevant l-methionine sulfoximine is demonstrated for the first time. All these reactions provided the desired products in excellent yields within a short span of time. The optimized reaction conditions are well suited to the task of N-vinylation of sulfoximine with trans-2-phenylvinylboronic acid.

scholarly journals H/D Exchange Under Mild Conditions in Arenes and Unactivated Alkanes with C6D6 and D2O Using Rigid, Electron-rich Iridium PCP Pincer Complexes

2020 ◽  
Author(s):  
Joel D. Smith ◽  
George Durrant ◽  
Daniel Ess ◽  
Warren Piers
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Room Temperature ◽  
Pincer Complexes ◽  
Synthesis And Characterization ◽  
Hydrogen Isotope Exchange ◽  
Mild Conditions ◽  
Highly Active ◽  
Pcp Pincer

<div>The synthesis and characterization of an iridium polyhydride complex (Ir-H4)</div><div>supported by an electron-rich PCP framework is described. This complex readily loses molecular</div><div>hydrogen allowing for rapid room temperature hydrogen isotope exchange (HIE) at the hydridic</div><div>positions and the α-C-H site of the ligand with deuterated solvents such as benzene-d6, toluene-d8</div><div>and THF-d8. The removal of 1-2 equivalents of molecular H2 forms unsaturated iridium carbene</div><div>trihydride (Ir-H3) or monohydride (Ir-H) compounds that are able to create further unsaturation</div><div>by reversibly transferring a hydride to the ligand carbene carbon. These species are highly active</div><div>hydrogen isotope exchange (HIE) catalysts using C6D6 or D2O as deuterium sources for the</div><div>deuteration of a variety of substrates. By modifying conditions to influence the Ir-Hn speciation,</div><div>deuteration levels can range from near exhaustive to selective only for sterically accessible sites.</div><div>Preparative level deuterations of select substrates were performed allowing for procurement of</div><div>>95% deuterated compounds in excellent isolated yields; the catalyst can be regenerated by</div><div>treatment of residues with H2 and is still active for further reactions.</div>

Characterization of intergranular cuprous oxide in polycrystalline YBa2Cu3O7-x

1988 ◽  
Vol 46 ◽  
pp. 880-881
Author(s):  
Bradley L. Thiel ◽  
Chan Han R. P. ◽  
Kurosky L. C. Hutter ◽  
I. A. Aksay ◽  
Mehmet Sarikaya
Keyword(s):  
Grain Boundary ◽  
Cuprous Oxide ◽  
Room Temperature ◽  
Boundary Phase ◽  
Spectroscopic Techniques ◽  
Transition Width ◽  
Practical Applications ◽  
Thin Foils ◽  
Superconducting Oxides

The identification of extraneous phases is important in understanding of high Tc superconducting oxides. The spectroscopic techniques commonly used in determining the origin of superconductivity (such as RAMAN, XPS, AES, and EXAFS) are surface-sensitive. Hence a grain boundary phase several nanometers thick could produce irrelevant spectroscopic results and cause erroneous conclusions. The intergranular phases present a major technological consideration for practical applications. In this communication we report the identification of a Cu2O grain boundary phase which forms during the sintering of YBa2Cu3O7-x (1:2:3 compound).Samples are prepared using a mixture of Y2O3. CuO, and BaO2 powders dispersed in ethanol for complete mixing. The pellets pressed at 20,000 psi are heated to 950°C at a rate of 5°C per min, held for 1 hr, and cooled at 1°C per min to room temperature. The samples show a Tc of 91K with a transition width of 2K. In order to prevent damage, a low temperature stage is used in milling to prepare thin foils which are then observed, using a liquid nitrogen holder, in a Philips 430T at 300 kV.

SuFEx Activation with Ca(NTf2)2: A Unified Strategy to Access Sulfamides, Sulfamates and Sulfonamides from S(VI) Fluorides

2020 ◽  
Author(s):  
Subham Mahapatra ◽  
Cristian P. Woroch ◽  
Todd W. Butler ◽  
Sabrina N. Carneiro ◽  
Sabrina C. Kwan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Medicinal Chemistry ◽  
Mild Conditions ◽  
Broad Array

<p><br></p> <p>A method to activate sulfamoyl fluorides, fluorosulfates, and sulfonyl fluorides with calcium triflimide, and DABCO for SuFEx with amines is described. The reaction was applied to a diverse set of sulfamides, sulfamates, and sulfonamides at room temperature under mild conditions. Additionally, we highlight the application of this transformation to parallel medicinal chemistry to generate a broad array of nitrogen-based S(VI) compounds. </p>

SuFEx Activation with Ca(NTf2)2: A Unified Strategy to Access Sulfamides, Sulfamates and Sulfonamides from S(VI) Fluorides

2020 ◽  
Author(s):  
Subham Mahapatra ◽  
Cristian P. Woroch ◽  
Todd W. Butler ◽  
Sabrina N. Carneiro ◽  
Sabrina C. Kwan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Medicinal Chemistry ◽  
Mild Conditions ◽  
Broad Array

<p><br></p> <p>A method to activate sulfamoyl fluorides, fluorosulfates, and sulfonyl fluorides with calcium triflimide, and DABCO for SuFEx with amines is described. The reaction was applied to a diverse set of sulfamides, sulfamates, and sulfonamides at room temperature under mild conditions. Additionally, we highlight the application of this transformation to parallel medicinal chemistry to generate a broad array of nitrogen-based S(VI) compounds. </p>

Sign in / Sign up

Export Citation Format

Share Document