Mechanistic study of the Wittig reaction of benzophenone with a nonstabilized ylide

1988 ◽  
Vol 53 (16) ◽  
pp. 3877-3879 ◽  
Author(s):  
Hiroshi Yamataka ◽  
Katsushi Nagareda ◽  
Yoshio Takai ◽  
Masami Sawada ◽  
Terukiyo Hanafusa
Keyword(s):  
Wittig Reaction ◽  
Mechanistic Study

A Mechanistic Study of the Wittig Reaction Between a Cyclic Anhydride and a Stabilized Phosphorane

1988 ◽  
Vol 41 (8) ◽  
pp. 1243 ◽  
Author(s):  
AD Abell ◽  
BM Clark ◽  
WT Robinson
Keyword(s):  
Structure Analysis ◽  
Succinic Anhydride ◽  
Wittig Reaction ◽  
Phosphonium Salt ◽  
Mechanistic Study ◽  
Cyclic Anhydride ◽  
X Ray ◽  
Cyclic Anhydrides

The structure of an isolated acyclic intermediate in the Wittig reaction between succinic anhydride and ethoxycarbonylmethylenetriphenylphosphorane has been shown by X-ray structure analysis and DEPT n.m.r .to be the phosphorane (4a) rather than the alternative phosphonium salt (4b). However, an intermediate was not observed in the Wittig reaction between the phosphorane (1b) and cyclic anhydrides. Both the stabilized phosphoranes (1a,b) react with succinic, phthalic and glutaric anhydrides stereoselectively to produce E enol lactones. Some mechanistic aspects are discussed. The assignment of the enol lactone stereochemistry was achieved by n.O.e. difference n.m.r. methods.

ChemInform Abstract: Mechanistic Study of the Wittig Reaction of Benzophenone with a Nonstabilized Ylide.

ChemInform ◽  
1989 ◽  
Vol 20 (6) ◽  
Author(s):  
H. YAMATAKA ◽  
K. NAGAREDA ◽  
Y. TAKAI ◽  
M. SAWADA ◽  
T. HANAFUSA
Keyword(s):  
Wittig Reaction ◽  
Mechanistic Study

Mechanistic study of proliferation induced by Angelica sinensis in gastric epithelial cells

2001 ◽  
Vol 120 (5) ◽  
pp. A145-A145
Author(s):  
C CHO ◽  
Y YE ◽  
E LIU ◽  
V SHIN ◽  
N SHAM
Keyword(s):  
Epithelial Cells ◽  
Mechanistic Study ◽  
Angelica Sinensis ◽  
Gastric Epithelial Cells

Mechanistic study on the cardioprotective and chemosensitizing effects of a novel danshensu derivative

Planta Medica ◽  
2014 ◽  
Vol 80 (16) ◽  
Author(s):  
L Wang ◽  
L Shan ◽  
G Cui ◽  
Y Chen ◽  
J li ◽  
...  
Keyword(s):  
Mechanistic Study

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>

Mechanistic Study and Development of Catalytic Reactions of Sm(II)

2018 ◽  
Author(s):  
Sandepan Maity ◽  
Robert Flowers
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Proton Donor ◽  
Catalytic Reactions ◽  
Mechanistic Study ◽  
Mechanistic Studies ◽  
Cyclization Reactions ◽  
Mechanistic Approach ◽  
Donor Source

Despite the broad utility and application of SmI<sub>2</sub>in synthesis, the reagent is used in stoichiometric amounts and has a high molecular weight, resulting in a large amount of material being used for reactions requiring one or more equivalents of electrons. We report mechanistic studies on catalytic reactions of Sm(II) employing a terminal magnesium reductant and trimethyl silyl chloride in concert with a non-coordinating proton donor source. Reactions using this approach permitted reductions with as little as 1 mol% Sm. The mechanistic approach enabled catalysis employing HMPA as a ligand, facilitating the development of catalytic Sm(II) 5-<i>exo</i>-<i>trig </i>ketyl olefin cyclization reactions.

Activated carbon from molasses efficiency for Cr(VI), Pb(II) and Cu(II) adsorption: A mechanistic study

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Activated Carbon ◽  
Phosphoric Acid ◽  
Sugar Industry ◽  
Chemical Activation ◽  
High Surface ◽  
High Surface Area ◽  
Mechanistic Study ◽  
Acid Mixture ◽  
Maximum Adsorption Capacity ◽  
Good Potential

Activated carbon was prepared from molasses, which are natural precursors of vegetable origin resulting from the sugar industry. A simple elaboration process, based on chemical activation with phosphoric acid, was proposed. The final product, prepared by activation of molasses/phosphoric acid mixture in air at 500°C, presented high surface area (more than 1400 m2/g) and important maximum adsorption capacity for methylene blue (625 mg/g) and iodine (1660 mg/g). The activated carbon (MP2(500)) showed a good potential for the adsorption of Cr(VI), Cu(II) and Pb(II) from aqueous solutions. The affinity for the three ions was observed in the following order Cu2+ Cr6+ Pb2+. The process is governed by monolayer adsorption following the Langmuir model, with a correlation coefficient close to unity.

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