Punching a Carbon Atom of C 60 into its Own Cavity to Form an Endohedral Complex CO@C 59 O 6 under Mild Conditions

2013 ◽  
Vol 19 (49) ◽  
pp. 16545-16549 ◽  
Author(s):  
Lijun Shi ◽  
Dazhi Yang ◽  
Francesca Colombo ◽  
Yuming Yu ◽  
Wen‐Xiong Zhang ◽  
...  
Keyword(s):  
Carbon Atom ◽  
Mild Conditions ◽  
Endohedral Complex

Substitutionsreaktionen am N-[1-Chlor-2,2,2-trifluor-1-(trifluormethyl)ethyl]-dimethyIformamidin / Substitution Reactions with N-[1-Chloro-2,2,2-trifluoro-1-(trifluoromethyl)ethyl]-dimethylformamidine

1987 ◽  
Vol 42 (10) ◽  
pp. 1245-1248
Author(s):  
Hansjörg Grützmacher ◽  
Herbert W. Roesky ◽  
Mathias Noltemeyer ◽  
George M. Sheldrick
Keyword(s):  
Reaction Mechanism ◽  
Carbon Atom ◽  
Structure Analysis ◽  
Quantitative Yield ◽  
Nucleophilic Attack ◽  
Substitution Reactions ◽  
X Ray ◽  
Mild Conditions ◽  
Trifluoromethyl Groups

Abstract It is difficult to achieve nucleophilic attack on a carbon atom bonded on two trifluoromethyl groups. However, N-[1-chloro-2,2,2-trifluoro-1-(trifluoromethyl)ethyl]-dimethylformamidine (1) reacts readily with H2O, MeOH, EtSH and P(OMe)3 even under mild conditions to form products 2, 3, 4 and 5. The reaction between 1 and Ph2PH is complex but leads in nearly quantitative yield to N-[2,2,2-trifluoro-1-(trifluoromethyl)ethyl]-dimethylformamidinium chloride 6 which has been characterized by an X-ray structure analysis. A reaction mechanism is proposed.

TERPENOIDS: II. CEANOTHENIC ACID: A C29 A-NORLUPANE DERIVATIVE

1962 ◽  
Vol 40 (8) ◽  
pp. 1632-1641 ◽  
Author(s):  
P. De Mayo ◽  
A. N. Starratt
Keyword(s):  
Carbon Atom ◽  
Dicarboxylic Acid ◽  
Empirical Formula ◽  
The Other ◽  
Carboxyl Group ◽  
Mild Conditions ◽  
Pentacyclic Triterpenoid ◽  
Ceanothus Americanus

Extraction of Ceanothus americanus (Jersey Tea) has afforded a new pentacyclic triterpenoid of the empirical formula C29H42O4. It is a dicarboxylic acid containing two ethylenic linkages. The environment of one carboxyl group and one ethylenic linkage has been shown by diagnostic transformations characteristic of ring E of the lupeol–betulin series. The other ethylenic linkage has been shown to be present in a contracted ring A from which one carbon atom has been lost. The position of the second carboxyl group has been established by introduction of the 11-oxo-12-ene system, when monodecarboxylation occurred under mild conditions. This and other evidence establishes ceanothenic acid to be A-norlupa-1,22-diene-14,17-dicarboxylic acid.

scholarly journals Possibility of using fullerene C240 as the carrier of steroid hormones

2016 ◽  
Author(s):  
Monika K Grudzień ◽  
Izabela Wiśniewska ◽  
Marcin Suskiewicz ◽  
Tomasz Pieńko ◽  
Aleksander P. Mazurek
Keyword(s):  
Molecular Modeling ◽  
Carbon Atom ◽  
Steroid Hormones ◽  
Modeling Technique ◽  
Carbon Cage ◽  
Endohedral Fullerenes ◽  
Endohedral Complex ◽  
The Family ◽  
Formation Heat ◽  
Derivatives Of

Fullerene molecules are created entirely of carbon and form orbicular or ellipsoidal cage shape similar to a hollow tube. The derivatives of fullerenes are classified into the following categories according to their functionalization: endohedral fullerenes with active molecules residing inside the carbon cage, exohedral with wide variety of both inorganic and organic groups existing outside and connected to the fullerenes’ exterior and heterofullerenes when one or more carbon atoms that form the fullerene carbon cage are replaced by a non-carbon atom, i.e. a heteroatom. Fullerene C240belongs to the family of giant fullerenes and is characterized by a greater stability than that of the well-known fullerene C60. This has been proved by observing an increased formation heat that accompanied the decreasing of the carbon cage size.In order to determine the fullerene C240 ability to transport the steroid hormones: estradiol, progesterone, androsterone and their basic structures: estrone, androstane and pregnane, the following parameters, inter alia, have been calculated: energies of stabilization, interaction and deformation of each endohedral complex. The calculations for all chosen structures were carried out with the use of the molecular modeling technique. Based on all available studies, it can be stated that fullerene C240 could be a solution for problems faced by medicine and pharmacy.

scholarly journals Possibility of using fullerene C240 as the carrier of steroid hormones

2016 ◽  
Author(s):  
Monika K Grudzień ◽  
Izabela Wiśniewska ◽  
Marcin Suskiewicz ◽  
Tomasz Pieńko ◽  
Aleksander P. Mazurek
Keyword(s):  
Molecular Modeling ◽  
Carbon Atom ◽  
Steroid Hormones ◽  
Modeling Technique ◽  
Carbon Cage ◽  
Endohedral Fullerenes ◽  
Endohedral Complex ◽  
The Family ◽  
Formation Heat ◽  
Derivatives Of

Fullerene molecules are created entirely of carbon and form orbicular or ellipsoidal cage shape similar to a hollow tube. The derivatives of fullerenes are classified into the following categories according to their functionalization: endohedral fullerenes with active molecules residing inside the carbon cage, exohedral with wide variety of both inorganic and organic groups existing outside and connected to the fullerenes’ exterior and heterofullerenes when one or more carbon atoms that form the fullerene carbon cage are replaced by a non-carbon atom, i.e. a heteroatom. Fullerene C240belongs to the family of giant fullerenes and is characterized by a greater stability than that of the well-known fullerene C60. This has been proved by observing an increased formation heat that accompanied the decreasing of the carbon cage size.In order to determine the fullerene C240 ability to transport the steroid hormones: estradiol, progesterone, androsterone and their basic structures: estrone, androstane and pregnane, the following parameters, inter alia, have been calculated: energies of stabilization, interaction and deformation of each endohedral complex. The calculations for all chosen structures were carried out with the use of the molecular modeling technique. Based on all available studies, it can be stated that fullerene C240 could be a solution for problems faced by medicine and pharmacy.

An atomic resolution study of a carbide phase in platinum

1992 ◽  
Vol 50 (1) ◽  
pp. 20-21
Author(s):  
M.J. Witcomb ◽  
M.A. O'Keefe ◽  
CJ. Echer ◽  
C. Nelson ◽  
J.H. Turner ◽  
...  
Keyword(s):  
Solid Solution ◽  
Carbon Atom ◽  
Carbide Phase ◽  
Structural Changes ◽  
Critical Role ◽  
Alloy System ◽  
Atomic Resolution ◽  
Excess Carbon ◽  
Interstitial Carbon ◽  
Resolution Study

Under normal circumstances, Pt dissolves only a very small amount of interstitial carbon in solid solution. Even so, an appropriate quench/age treatment leads to the formation of stable Pt2C {100} plate precipitates. Excess (quenched-in) vacancies play a critical role in the process by accommodating the volume and structural changes that accompany the transformation. This alloy system exhibits other interesting properties. Due to a large vacancy/carbon atom binding energy, Pt can absorb excess carbon at high temperatures in a carburizing atmosphere. In regions rich in carbon and vacancies, another carbide phase, Pt7C which undergoes an order-disorder reaction was formed. The present study of Pt carburized at 1160°C and aged at 515°C shows that other carbides in the PtxC series can be produced.

The Diorgano Dichalcogenides Addition to Benzyne under Mild Conditions

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

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>

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