Enzymatically cleavable traceless biotin tags for protein PEGylation and purification

2018 ◽  
Vol 54 (15) ◽  
pp. 1913-1916 ◽  
Author(s):  
Adam M. Wawro ◽  
Yusuke Aoki ◽  
Takahiro Muraoka ◽  
Kouhei Tsumoto ◽  
Kazushi Kinbara
Keyword(s):  
Immobilized Lipase ◽  
Mild Conditions ◽  
Rapid Removal ◽  
Protein Pegylation

Immobilized lipase was successfully employed for the rapid removal of a biotin tag from a protein–PEG conjugate under mild conditions.

Ultrastructure of Lymphatic Capillaries in the Transport of Colloidal Particles

1967 ◽  
Vol 25 ◽  
pp. 186-187
Author(s):  
L. V. Leak ◽  
J. F. Burke
Keyword(s):  
Connective Tissue ◽  
Colloidal Particles ◽  
Ultrastructural Level ◽  
Vital Role ◽  
Time Intervals ◽  
Thorium Dioxide ◽  
Lymphatic Capillary ◽  
Tissue Area ◽  
Rapid Removal ◽  
Tissue Fluids

The vital role played by the lymphatic capillaries in the transfer of tissue fluids and particulate materials from the connective tissue area can be demonstrated by the rapid removal of injected vital dyes into the tissue areas. In order to ascertain the mechanisms involved in the transfer of substances from the connective tissue area at the ultrastructural level, we have injected colloidal particles of varying sizes which range from 80 A up to 900-mμ. These colloidal particles (colloidal ferritin 80-100A, thorium dioxide 100-200 A, biological carbon 200-300 and latex spheres 900-mμ) are injected directly into the interstitial spaces of the connective tissue with glass micro-needles mounted in a modified Chambers micromanipulator. The progress of the particles from the interstitial space into the lymphatic capillary lumen is followed by observing tissues from animals (skin of the guinea pig ear) that were injected at various time intervals ranging from 5 minutes up to 6 months.

The Diorgano Dichalcogenides Addition to Benzyne under Mild Conditions

2007 ◽  
Author(s):  
Fabiano Toledo ◽  
Henrique Marques ◽  
João Comasseto ◽  
Cristiano Raminelli
Keyword(s):  
Mild Conditions

Treatment of Axillosubclavian Vein Thrombosis:A Novel Technique for Rapid Removal of Clot Using Low-Dose Thrombolysis

2003 ◽  
Vol 10 (4) ◽  
pp. 733-738 ◽  
Author(s):  
Frank R. Arko ◽  
Paul Cipriano ◽  
Eugene Lee ◽  
Konstantinos A. Filis ◽  
Christopher K. Zarins ◽  
...  
Keyword(s):  
Low Dose ◽  
Novel Technique ◽  
Rapid Removal

Pt-Pd Nanoalloy for the Unprecedented Activation of Carbon-Fluorine Bond at Low Temperature

2019 ◽  
Author(s):  
Raghu Nath Dhital ◽  
keigo nomura ◽  
Yoshinori Sato ◽  
Setsiri Haesuwannakij ◽  
Masahiro Ehara ◽  
...  
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Dft Calculations ◽  
Bond Activation ◽  
Mild Conditions ◽  
Selective Transformation ◽  
Rate Determining Step ◽  
Highly Active ◽  
Harsh Conditions ◽  
Reaction Profile

Carbon-Fluorine (C-F) bonds are considered the most inert organic functionality and their selective transformation under mild conditions remains challenging. Herein, we report a highly active Pt-Pd nanoalloy as a robust catalyst for the transformation of C-F bonds into C-H bonds at low temperature, a reaction that often required harsh conditions. The alloying of Pt with Pd is crucial to activate C-F bond. The reaction profile kinetics revealed that the major source of hydrogen in the defluorinated product is the alcoholic proton of 2-propanol, and the rate-determining step is the reduction of the metal upon transfer of the <i>beta</i>-H from 2-propanol. DFT calculations elucidated that the key step is the selective oxidative addition of the O-H bond of 2-propanol to a Pd center prior to C-F bond activation at a Pt site, which crucially reduces the activation energy of the C-F bond. Therefore, both Pt and Pd work independently but synergistically to promote the overall reaction

Double Ring-Closing Approach for the Synthesis of 2,3,6,7-Substituted Anthracene Derivatives

2020 ◽  
Author(s):  
Birgit Meindl ◽  
Katharina Pfennigbauer ◽  
Berthold Stöger ◽  
Martin Heeney ◽  
Florian Glöcklhofer
Keyword(s):  
Wittig Reaction ◽  
Condensation Reaction ◽  
Synthetic Methods ◽  
Anthracene Derivative ◽  
Double Ring ◽  
Mild Conditions ◽  
Wide Range ◽  
Anthracene Derivatives

Anthracene derivatives have been used for a wide range of applications and many different synthetic methods for their preparation have been developed. However, despite continued synthetic efforts, introducing substituents in some positions has remained difficult. Here we present a method for the synthesis of 2,3,6,7-substituted anthracene derivatives, one of the most challenging anthracene substitution patterns to obtain. The method is exemplified by the preparation of 2,3,6,7-anthracenetetracarbonitrile and employs a newly developed, stable protected 1,2,4,5-benzenetetracarbaldehyde as the precursor. The precursor can be obtained in two scalable synthetic steps from 2,5-dibromoterephthalaldehyde and is converted into the anthracene derivative by a double intermolecular Wittig reaction under very mild conditions followed by a deprotection and intramolecular double ring-closing condensation reaction. Further modification of the precursor is expected to enable the introduction of additional substituents in other positions and may even enable the synthesis of fully substituted anthracene derivatives by the presented approach.<br>

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>

Microwave-Assisted Decarbonylation of Biomass-Derived Aldehydes Using Pd-Doped Hydrotalcites

2019 ◽  
Author(s):  
Nan An ◽  
Diana Ainembabazi ◽  
Kavya Samudrala ◽  
Christopher Reid ◽  
Kare Wilson ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Reaction Times ◽  
Inverse Correlation ◽  
Mulliken Charge ◽  
Metal Leaching ◽  
Carbonyl Carbon ◽  
Mild Conditions ◽  
Microwave Assisted ◽  
Biomass Processing ◽  
Alcohol Dehydrogenation

<p>Here we report the synthesis, characterization and activity of tunable Pd-doped hydrotalcites (Pd-HTs) for the decarbonylation of furfural, hydroxymethylfurfural (HMF), aromatic and aliphatic aldehydes under microwave conditions. The decarbonylation activity reported is a notable improvement over prior heterogeneous catalysts for this process. Furfural decarbonylation is optimized in a benign solvent compatible with biomass processing - ethanol, under relatively mild conditions and short reaction times. HMF selectively affords excellent yields of furfuryl alcohol with no humin formation, but longer reaction can also afford furan via tandem alcohol dehydrogenation and decarbonylation. Yields of substituted benzaldehydes are related to calculated Mulliken charge of the carbonyl carbon. The activity and selectivity differences can be traced to loading-dependent differences in Pd speciation on the catalysts. Poisoning studies show inverse correlation between Pd loading and metal leaching: Pd-HTs with lowest Pd loading, which consist of highly dispersed and oxidized Pd species, operate heterogeneously with negligible metal leaching. Recycling experiments are consistent with this trend, offering potential for further optimization to improve robustness.</p>

Electron Donation by Low-Crystalline Ba-La-Ce Oxygen-Deficient Composite Oxide Accumulating on Ru Nanoparticles for Ammonia Synthesis under Mild Conditions

2019 ◽  
Author(s):  
Katsutoshi Sato ◽  
Shin-ichiro Miyahara ◽  
Yuta Ogura ◽  
Kotoko Tsujimaru ◽  
Yuichiro Wada ◽  
...  
Keyword(s):  
Ammonia Synthesis ◽  
Bond Cleavage ◽  
Synthesis Process ◽  
Strong Electron ◽  
Mild Conditions ◽  
Ru Nanoparticles ◽  
Rate Determining Step ◽  
Highly Active ◽  
Composite Oxides ◽  
Low Crystalline

<p>To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity of Ru/Ba/LaCeO<i><sub>x</sub></i> pre-reduced at 700 °C is the highest reported among oxide-supported Ru catalysts. Our results indicate that low crystalline oxygen-deficient composite oxides, which include Ba<sup>2+</sup>, Ce<sup>3+</sup> and La<sup>3+</sup>, with strong electron-donating ability, accumulate on Ru particles and thus promote N≡N bond cleavage, which is the rate determining step for ammonia synthesis.</p>

Electron Donation by Low-Crystalline Ba-La-Ce Oxygen-Deficient Composite Oxide Accumulating on Ru Nanoparticles for Ammonia Synthesis under Mild Conditions

2019 ◽  
Author(s):  
Katsutoshi Sato ◽  
Shin-ichiro Miyahara ◽  
Yuta Ogura ◽  
Kotoko Tsujimaru ◽  
Yuichiro Wada ◽  
...  
Keyword(s):  
Ammonia Synthesis ◽  
Bond Cleavage ◽  
Synthesis Process ◽  
Strong Electron ◽  
Mild Conditions ◽  
Ru Nanoparticles ◽  
Rate Determining Step ◽  
Highly Active ◽  
Composite Oxides ◽  
Low Crystalline

<p>To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity of Ru/Ba/LaCeO<i><sub>x</sub></i> pre-reduced at 700 °C is the highest reported among oxide-supported Ru catalysts. Our results indicate that low crystalline oxygen-deficient composite oxides, which include Ba<sup>2+</sup>, Ce<sup>3+</sup> and La<sup>3+</sup>, with strong electron-donating ability, accumulate on Ru particles and thus promote N≡N bond cleavage, which is the rate determining step for ammonia synthesis.</p>

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