scholarly journals TfOH-Promoted Reaction of 2,4-Diaryl-1,1,1-Trifluorobut-3-yn-2-oles with Arenes: Synthesis of 1,3-Diaryl-1-CF3-Indenes and Versatility of the Reaction Mechanisms

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3079 ◽  
Author(s):  
Aleksey V. Zerov ◽  
Anna N. Kazakova ◽  
Irina A. Boyarskaya ◽  
Taras L. Panikorovskii ◽  
Vitalii V. Suslonov ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Reaction Mechanisms ◽  
Room Temperature ◽  
Ring Closure ◽  
Nucleophilic Attack ◽  
New Process ◽  
Intramolecular Ring ◽  
Propargyl Alcohols

The TfOH-mediated reactions of 2,4-diaryl-1,1,1-trifluorobut-3-yn-2-oles (CF3-substituted diaryl propargyl alcohols) with arenes in CH2Cl2 afford 1,3-diaryl-1-CF3-indenes in yields up to 84%. This new process for synthesis of such CF3-indenes is complete at room temperature within one hour. The synthetic potential, scope, and limitations of this reaction were illustrated by more than 70 examples. The proposed reaction mechanism invokes the formation of highly reactive CF3-propargyl cation intermediates that can be trapped at the two mesomeric positions by the intermolecular nucleophilic attack of an arene partner with a subsequent intramolecular ring closure.

scholarly journals 1,3-Dimethyl-3′,5-diphenyl-1,5-dihydro-2H,5′H-spiro[furo[2,3-d]pyrimidine-6,4′-isoxazole]-2,4,5′(3H)-trione

Molbank ◽  
10.3390/m1317 ◽  
2022 ◽  
Vol 2022 (1) ◽  
pp. M1317
Author(s):  
Yuliya E. Ryzhkova ◽  
Varvara M. Kalashnikova ◽  
Fedor V. Ryzhkov ◽  
Michail N. Elinson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Infrared Spectroscopy ◽  
Magnetic Resonance ◽  
Elemental Analysis ◽  
Sodium Acetate ◽  
Room Temperature ◽  
Halogen Atom ◽  
Ring Closure ◽  
Leaving Group ◽  
Intramolecular Ring

Michael addition–halogenation–intramolecular ring-closing (MHIRC) reactions are processes in which a halogen atom as a leaving group can attach to substrates or reactants during the reaction, which then undergoes intramolecular ring closure. In this communication the MHIRC transformation of 4-benzylidene-3-phenylisoxazol-5(4H)-one and 1,3-dimethylbarbituric acid in the presence of N-bromosuccinimide and sodium acetate in EtOH at room temperature was carefully investigated to give novel 1,3-dimethyl-3′,5-diphenyl-1,5-dihydro-2H,5′H-spiro[furo[2,3-d]pyrimi- dine-6,4′-isoxazole]-2,4,5′(3H)-trione in a good yield. The structure of the new compound was confirmed by the results of elemental analysis as well as mass, nuclear magnetic resonance, and infrared spectroscopy.

DFT studies on the diastereoselectivity of four-component Ugi reaction

2018 ◽  
Vol 17 (06) ◽  
pp. 1850039 ◽  
Author(s):  
Elaheh Sadat Sharifzadeh ◽  
Nader Zabarjad Shiraz
Keyword(s):  
Reaction Mechanism ◽  
Ring Opening ◽  
Transition States ◽  
Ugi Reaction ◽  
Ring Closure ◽  
Nucleophilic Attack ◽  
Dft Studies ◽  
Acid Base ◽  
Bond Rotation ◽  
Iminium Ion

In this study, mechanism and stereochemistry of four-component Ugi reaction was investigated theoretically. Structures of reagents, products, intermediates, and transition states were optimized at B3LYP/6-31[Formula: see text]G(d,p) level of theory. Mechanism and stereoselectivity of the reaction depended on several processes, including bond rotation, ring closure ring opening, acid-base, nucleophile-electrophile competitions, and rearrangements. These diverse phenomena were studied to provide a clearer picture of the mechanism of this valuable reaction, especially in terms of stereochemistry considerations. According to the results, (E)-oxazolidinols were considered as proper intermediates in Ugi reaction mechanism. In addition, the key point of diastereoselectivity of the reaction was under kinetic and thermodynamic controls of nucleophilic attack of isocyanide to less hindered re-face (E[Formula: see text] compared to 10.19[Formula: see text]kcal/mol for si-face) of chiral (E)-iminium ion.

Replacement of the carboxylic acid function with fluorine

1986 ◽  
Vol 64 (1) ◽  
pp. 138-141 ◽  
Author(s):  
Timothy B. Patrick ◽  
Kamalesh K. Johri ◽  
David H. White ◽  
William S. Bertrand ◽  
Rodziah Mokhtar ◽  
...  
Keyword(s):  
Free Radicals ◽  
Reaction Mechanism ◽  
Room Temperature ◽  
Methylene Chloride ◽  
Chloroform Solution ◽  
Xenon Difluoride ◽  
Nucleophilic Displacement ◽  
New Process ◽  
Alkanoic Acids ◽  
Acid Function

Replacement of a carboxyl function by fluorine, fluorodecarboxylation, is a new process that can be accomplished by the reaction of alkanoic acids with xenon difluoride. Primary, tertiary, and benzylic acids perform best in the reaction, which is conducted at room temperature in methylene chloride or chloroform solution. A reaction mechanism is proposed in which the acid is initially converted to a fluoroxenon ester, RCO2XeF. The esters of the primary and secondary acids react by nucleophilic displacement by fluoride, as evidenced by incorporation of 18F− and no reactions common to free radicals or carbocations. The esters of the tertiary and benzylic acids react by converting to free radicals that can be further oxidized to carbocations. Thus incorporation of 18F− and racemization are observed with α-methoxy-α-trifluoromethylphenylacetic acid. Hydroxyl and amino functions inhibit the reaction. Aromatic and vinylic acids do not react.

A Paramedic Treatment for Modeling Explicitly Solvated Chemical Reaction Mechanisms

2018 ◽  
Author(s):  
Yasemin Basdogan ◽  
John Keith
Keyword(s):  
Reaction Mechanism ◽  
Chemical Reaction ◽  
Reaction Mechanisms ◽  
Reaction Pathway ◽  
Optimization Procedure ◽  
Cost Effective ◽  
Chemical Reaction Mechanisms ◽  
Solvent Molecules ◽  
Dynamics Simulations ◽  
Mbh Reaction

<div> <div> <div> <p>We report a static quantum chemistry modeling treatment to study how solvent molecules affect chemical reaction mechanisms without dynamics simulations. This modeling scheme uses a global optimization procedure to identify low energy intermediate states with different numbers of explicit solvent molecules and then the growing string method to locate sequential transition states along a reaction pathway. Testing this approach on the acid-catalyzed Morita-Baylis-Hillman (MBH) reaction in methanol, we found a reaction mechanism that is consistent with both recent experiments and computationally intensive dynamics simulations with explicit solvation. In doing so, we explain unphysical pitfalls that obfuscate computational modeling that uses microsolvated reaction intermediates. This new paramedic approach can promisingly capture essential physical chemistry of the complicated and multistep MBH reaction mechanism, and the energy profiles found with this model appear reasonably insensitive to the level of theory used for energy calculations. Thus, it should be a useful and computationally cost-effective approach for modeling solvent mediated reaction mechanisms when dynamics simulations are not possible. </p> </div> </div> </div>

Determination of Complex Reaction Mechanisms

2006 ◽  
Author(s):  
John Ross ◽  
Igor Schreiber ◽  
Marcel O. Vlad
Keyword(s):  
Reaction Mechanism ◽  
Reaction Mechanisms ◽  
Reaction Pathway ◽  
Chemical Species ◽  
Rate Coefficients ◽  
Chemical System ◽  
Evolutionary Development ◽  
Complex Reaction ◽  
Oscillatory Reactions

In a chemical system with many chemical species several questions can be asked: what species react with other species: in what temporal order: and with what results? These questions have been asked for over one hundred years about simple and complex chemical systems, and the answers constitute the macroscopic reaction mechanism. In Determination of Complex Reaction Mechanisms authors John Ross, Igor Schreiber, and Marcel Vlad present several systematic approaches for obtaining information on the causal connectivity of chemical species, on correlations of chemical species, on the reaction pathway, and on the reaction mechanism. Basic pulse theory is demonstrated and tested in an experiment on glycolysis. In a second approach, measurements on time series of concentrations are used to construct correlation functions and a theory is developed which shows that from these functions information may be inferred on the reaction pathway, the reaction mechanism, and the centers of control in that mechanism. A third approach is based on application of genetic algorithm methods to the study of the evolutionary development of a reaction mechanism, to the attainment given goals in a mechanism, and to the determination of a reaction mechanism and rate coefficients by comparison with experiment. Responses of non-linear systems to pulses or other perturbations are analyzed, and mechanisms of oscillatory reactions are presented in detail. The concluding chapters give an introduction to bioinformatics and statistical methods for determining reaction mechanisms.

scholarly journals Recent advances in understanding oxygen evolution reaction mechanisms over iridium oxide

2021 ◽  
Author(s):  
Takahiro Naito ◽  
Tatsuya Shinagawa ◽  
Takeshi Nishimoto ◽  
Kazuhiro Takanabe
Keyword(s):  
Reaction Mechanism ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Reaction Mechanisms ◽  
State Of The Art ◽  
Iridium Oxide ◽  
The State ◽  
Computational Studies ◽  
Recent Advances ◽  
Iridium Oxides

Recent spectroscopic and computational studies concerning the oxygen evolution reaction over iridium oxides are reviewed to provide the state-of-the-art understanding of its reaction mechanism.

scholarly journals Mechanically induced solvent-free esterification method at room temperature

RSC Advances ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 5080-5085
Author(s):  
Lei Zheng ◽  
Chen Sun ◽  
Wenhao Xu ◽  
Alexandr V. Dushkin ◽  
Nikolay Polyakov ◽  
...  
Keyword(s):  
Natural Products ◽  
Carboxylic Acids ◽  
Late Stage ◽  
Reaction Mechanisms ◽  
Room Temperature ◽  
Solvent Free ◽  
Mild Conditions

We have developed I2/KH2PO2 and KI/P(OEt)3 strategy syntheses of esters from carboxylic acids and alcohols through different reaction mechanisms. The advantages of present protocol: mild conditions and late-stage diversification of natural products.

scholarly journals Experimental validation of the reaction mechanism models of dechlorination and [Zn] reclaiming in the roasting steelmaking zinc-rich dust process

2020 ◽  
Vol 39 (1) ◽  
pp. 107-116
Author(s):  
Hongyang Wang ◽  
Kai Dong ◽  
Rong Zhu
Keyword(s):  
Reaction Mechanism ◽  
Dust Particle ◽  
Chemical Reaction ◽  
Reaction Mechanisms ◽  
Experimental Validation ◽  
Step Process ◽  
Mass Percent ◽  
Mechanism Model ◽  
Air Atmosphere ◽  
Almost All

AbstractThe reaction mechanism models of dechlorination and [Zn] reclaiming in the roasting steelmaking zincrich dust process are studied. The dust collected from a steelwork contains 63.8% zinc and 3.18% chlorine (mass percent), of which, almost all zinc elements exist in ZnO and ZnCl2 forms, and all the chlorine elements are stored in ZnCl2. When the dust is roasted at above 732∘C in an air atmosphere, the ZnCl2 in the steelmaking zinc-rich dust is volatilized into steam and then oxidized into ZnO. Finding the position where the chemical reaction occurs is the key to determining the reaction mechanisms of dechlorination and [Zn] reclaiming. In this study, two groups of thermal experiments are designed and executed for roasting in different atmosphere environments and at different roasting temperatures. Based on the experiment results, the mechanism model is discussed and built, and the reaction of dechlorination and [Zn] reclaiming is shown to be a multi-step process. Because O2 from the air cannot transmit into the dust particle interior or dust bed effectively, the chemical reaction of [Zn] reclaiming occurs in the external gas environment outside of the dust, where the [Zn] recalcining reaction should be limited by the dynamics of new nucleation of ZnO solids.

Room Temperature Solvent-Free Synthesis of Monodisperse Magnetite Nanocrystals

2006 ◽  
Vol 6 (3) ◽  
pp. 852-856 ◽  
Author(s):  
X. R. Ye ◽  
C. Daraio ◽  
C. Wang ◽  
J. B. Talbot ◽  
S. Jin
Keyword(s):  
Oleic Acid ◽  
Solid State ◽  
Large Scale ◽  
Room Temperature ◽  
Solvent Free ◽  
Two Dimensional ◽  
New Process ◽  
High Boiling Point ◽  
Magnetite Nanocrystals ◽  
Solvent Free Synthesis

We have successfully demonstrated a facile, solvent-free synthesis of highly crystalline and monodisperse Fe3O4 nanocrystallites at ambient temperature avoiding any heating. Solid state reaction of inorganic Fe(II) and Fe(III) salts with NaOH was found to produce highly crystalline Fe3O4 nanoparticles. The reaction, if carried out in the presence of surfactant such as oleic acid–oleylamine adduct, generated monodisperse Fe3O4 nanocrystals extractable directly from the reaction mixture. The extracted nanoparticles were capable of forming self-assembled, two-dimensional and uniform periodic array. The new process utilizes inexpensive and nontoxic starting materials, and does not require a use of high boiling point and toxic solvents, thus is amenable to an environmentally desirable, large-scale synthesis of nanocrystals.

scholarly journals Synthesis of spiro[dihydropyridine-oxindoles] via three-component reaction of arylamine, isatin and cyclopentane-1,3-dione

2013 ◽  
Vol 9 ◽  
pp. 8-14 ◽  
Author(s):  
Yan Sun ◽  
Jing Sun ◽  
Chao-Guo Yan
Keyword(s):  
Acetic Acid ◽  
Reaction Mechanism ◽  
Room Temperature ◽  
The Other ◽  
Other Hand ◽  
Three Component Reaction ◽  
High Yields

A fast and convenient protocol for the synthesis of novel spiro[dihydropyridine-oxindole] derivatives in satisfactory yields was developed by the three-component reactions of arylamine, isatin and cyclopentane-1,3-dione in acetic acid at room temperature. On the other hand the condensation of isatin with two equivalents of cyclopentane-1,3-dione gave 3,3-bis(2-hydroxy-5-oxo-cyclopent-1-enyl)oxindole in high yields. The reaction mechanism and substrate scope of this novel reaction is briefly discussed.

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