Thiolsulfonate functionalized polystyrene resin:Preparation and application in the isolation and identification of electrophilic mutagens

A new approach for isolation and identification of elecrtophilic mutagens from complex matrix was developed. Thiosulforfic anion was immobilized onto polystyrene beads and used as separation media. Potassium polystyryl-thiosulfonate, prepared from polystyryl- sulfonyl chloride and KHS, was observed to selectively react with model electrophilic mutagens such as alkyl halides, ct-chloroketones and α-chloroesters to produce polystyryl-thiosulfonlc esters. After separation from other nonreactive organic compounds, the beads then reacted with ethanethiol to produce unsymmetrical ethyl disulfides which are easily detected by GC/MS. For one mutagenic compound, only one unsymmetrical disulfide was found to contain its structure part. Thus, the structure of the parent mutagens could be deduced from that of the unsymmetrical disulfides. The degree of functionalization of the potassium polystyryl-thiosulfonate resin was 1.11 mmol/g. Its reactivity was discussed and its recycling method was reported here.

Quantitative Electrophilicity Measures

Quantitative correlation of several theoretical electrophilicity measures over different families of organic compounds are examined relative to the experimental values of Mayr et al.Notably,the ability to predict these values accurately will help to elucidate the reactivity and selectivity trends observed in charge-transfer reactions.A crucial advantage of this theoretical approach is that itprovides this information without the need of experiments,which are often demanding and time-consuming.Here,two different types of electrophilicity measures were analyzed.First,models derived from conceptual density functional theory(c-DFT),including Parr's original proposal and further generalizations of this index,are investigated.For instance,the approaches of Gázquez et al.and Chamorro et al.are considered,whereby it is possible to distinguish between processes in which a molecule gains or loses electrons.Further,we also explored two novel electrophilicity definitions.On one hand,the potential of environmental perturbations to affect electron incorporation into a system is analyzed in terms of recent developments in c-DFT.These studies highlight the importance of considering the molecular surroundings when a consistent description of chemical reactivity is needed.On the other hand,we test a new definition of electrophilicity that is free from inconsistencies(so-called thermodynamic electrophilicity).This approach is based on Parr's pioneering insights,though it corrects issues present in the standard working expression for the calculation of electrophilicity.Additionally,we use machine-learning tools(i.e.,symbolic regression) to identify the models that best fit the experimental values.In this way,the best possible description of the electrophilicity values in terms of different electronic structure quantities is obtained.Overall,this straightforward approach enables one to obtain good correlations between the theoretical and experimental quantities by using the simple,yet powerful,interpretative advantage of c-DFT methods.In general,we observed that the correlations found at the HF/6-31 G(d) level of theory are of semi-quantitative value.To obtain more accurate results,we showed that working with families of compounds with similar functional groups is indispensable.

Polymer-support Selenium-induced Electrophilic Cyclization:Solid-phase Synthesis of Flavonoids

The Lewis acid mediated polystyrene supported selenium cyclization of chalcones and oxidative cleavage of selenium resins flavonoids in good yields and purities have been reported. induced intramolecular gave the corresponding

Studies on Electrophilic Substitution of Quasi-Aromatic Metal Ion Complexes

The electrophilic substitution reaction occurring to the chelate ring of the complexes could be regarded as an indication of quasi-aromaticity of the ring systems, no catalyst was used and only triethylamine was employed, implying that the aroylating agents with different p-substituents are polarized enough to be effective electrophiles to attack the methine carbon of the electron-rich substrate 1. This property is probably the clue to polarization of the ligand electrons by the nickel( Ⅱ ) ion and to the participation of the nickel( Ⅱ ) in the π-bond systems of the two coordinated conjugated rings. The linearity relationship between vd-d maxima, E1/2OX(1) and σp are obtained, respectively. The electronic environment of central metal ion as well as the aromaticity of the ring system are affected by the electronic properties of the p-substituents. A comparison of the electrochemical results with each other showed .that when the electronegativity of the substituent was higher, the oxidation(Ni2+/Ni3+) becomes more difficult.

THE ELECTRIC PROPERTY OF SINGLET CARBENE AND ITS ISOELECTRONIC SYSTEM^1——Electrophilic and Nucleophilic Directions of an Atom in the Molecule

The electrostatic potential of carbene and nitrene,have been calculated by AB INITIO method with 6-31G** basis set,there are positive potential regions in the directions of vacant P orbitals,and negative regions in the directions of lone-pair electrons. Therefore,atoms in these molecules have different electric properties in different directions.The idea of electrophilic and nucleophilic directions of an atom in molecules should be introduced.

THE RELATIONSHIPS BETWEEN THE POLARIZING FORCE OF CATIONS AND THE ELECTROPHILIC CHARACTER AND CATALYTIC PERFORMANCES OF PROMOTED Pt-Al_2O_3 CATALYST

The electronic modification effect of various metal oxides over Pt-Al;O;catalyst andthe relationships between the polarizing force of cations（PFC）and the electrophiliccharacter（EC）and catalytic performances（CP）of promoted Pt catalyst have been studiecby competitive hydrogenation reaction method（CHRM）and test reaction,i.e.hydrogena-tion of benzene and hydrogenolysis of cyclopentane.

THE PSEUDO ORBITAL STUDIES ON ELECTROPHILIC AROMATIC SUBSTITUTION

The electrophilic aromatic substitution reactions have been studied by using the con- cept of pseudo orbital proposed by authors,Because the unoccupied orbitals of electrophilic reagents have been.taken into account,the present results are better than ones given by superdelocalizability,S,.

Density Functional Theory Study of Exohedral Carbon Atoms Effect on Electrophilicity of Nicotine: Comparative Analysis

In recent years, many studies have been done on the structure of fullerene as medicine nano carrier compounds. On this basis, Quantum mechanical calculations have been done and the effect of the nicotine compound in structure of Nanofullerene C12 was studied. Density Functional Theory (DFT) can be used to calculate an accurate electronic structure, HOMO and LUMO energies, Mulliken charge of atoms, energetic orbital levels, global hardness, chemical potential and electrophilicity of systems, and finally chemical, physical properties of fullerene and fullerene derivatives. Theoretical calculations such as Natural Bond Orbital (NBO) are very important to understand the pathways of electron transfer in assemblies. Consequently, the obtained results showed that energy orbital levels decreased considerably by linking structure of Nanofullerene to the structure of Nicotine. The intramolecular interaction is formed by the orbital overlap between C-C, C-N, C-H anti bonding orbital which results an intermolecular charge transfer (ICT) from a Lewis valence orbital (donor), with a decreasing of its occupancy, to a non-Lewis orbital (acceptor). The interacting effect is also discussed in terms of the change in the C-C bond lengths, net atomic charge distribution, total dipole moment. The obtained results indicate that the C-C distances are enlarged interaction. Furthermore, there is a complete change in the net atomic charge distribution, as well as a corresponding increase in the value of the total dipole moment. On the basis of fully optimized ground-state structure, TDDFT//B3LYP/3-21G* calculations have been performed to determine the low-lying excited states of nanofullerene interacting with nicotine (NFN).

S-(1,3-Dioxoisoindolin-2-yl)O,O-diethyl phosphorothioate (SDDP): A practical electrophilic reagent for the phosphorothiolation of electron-rich compounds

An efficient synthesis of the electrophilic reagent,S-(1,3-dioxoisoindolin-2-yl)O,O-diethyl phosphorothioate(SDDP)is described.Moreover,the synthetic applications of SDDP wherein the transfer of the SP(O)(OEt)_(2) moiety occurs were investigated.In this manner,SDDP underwent facile SP(O)(OEt)_(2) transfer with electron-rich substrates such as ketones,indoles,and thiols to formα-phosphorothiolated ketones,3-phosphorothiolated indoles and S-phosphorothiolated thioethers,respectively.

Enriched electrophilic oxygen species facilitate acidic oxygen evolution on Ru-Mo binary oxide catalysts

The polymer electrolyte membrane(PEM)electrolyzers are burdened with costly iridium(Ir)-based catalysts and high operation overpotentials for the oxygen evolution reaction(OER).The development of earth-abundant,highly active,and durable electrocatalysts to replace Ir is a critical step in reducing the cost of green hydrogen production.Here we develop a Ru5Mo4Ox binary oxide catalyst that exhibits high activity and stability in acidic OER.The electron-withdrawing property of Mo enriches the electrophilic surface oxygen species,which promotes acidic OER to proceed via the adsorbate evolution pathway.As a result,we achieve a 189 mV overpotential at 10 mA·cm^(-2) and a Tafel slope of 48.8 mV·dec^(-1).Our catalyst demonstrates a substantial 18-fold increase in intrinsic activity,as evaluated by turnover frequency,compared to commercially available RuO_(2) and IrO_(2) catalysts.Moreover,we report a stable OER operation at 10 mA·cm^(-2) for 100 h with a low degradation rate of 2.05 mV·h^(-1).

Studies on the Activities of Electrophilic Sites on Benzene Ring of 4-Substituted Anilines and Their Acyl Compounds with Multiphilicity Descriptor

In this paper, the activities of electrophilic sites on benzene ring of 4-substituted anilines and their acyl compounds were studied with the quantitative indicator of multiphilicity descriptor. Four substituents were synthe- sized with microwave irradiation in good yields to verify the quantitative analysis data. Friedel-Crafts acylation was carried out by the microwave method for the first time.

State-of-the-Art in Electrophilic Trifluoromethylthiolation Reagents

The trifluoromethylthio group （SCF3） is a fluorine chemotype that has experienced a strong acceleration of in- terest in the recent years. It is particularly true of the construction of new fluorinated architectures by electrophilic trifluoromethylthiolation. The spread of knowledge was already very active in this research domain in the sixties; however, gaseous and highly toxic trifluoromethanesulfenyl chloride （CF3SC1） was the only reagent available at that time. Nowadays, one really can speak of a revival in the field thanks to the rapid development of a wide pano- ply of reagents that are stable and easy to handle. This review provides a historical perspective of the development of shelf-stable electrophilic trifluoromethylthiolation reagents.

Rational Design and Development of Low-Price, Scalable, Shelf-Stable and Broadly Applicable Electrophilic Sulfonium Ylide-Based Trifluoromethylating Reagents

The development of two highly reactive electrophilic trifluoromethylating reagents(trifluoromethyl)(4-nitrophenyl)bis(carbometh-oxy)methylide(1g)and(trifluoromethyl)(3-chlorophenyl)bis(carbomethoxy)methylide(1j)through structure-activity study was described.Under mild conditions,reagent 1g reacted with β-ketoesters and silyl enol ethers to give α-trifluoromethylated-β-ketoesters or α-trifluoromethylated ketones in high yields.In addition,reagent 1g could serve as a trifluoromethyl radical for a variety of trifluo-romethylative transformations under visible light irradiation,including radical trifluoromethylation of electron-rich indoles and pyrroles and sodium aryl sulfinates as well as trifluoromethylative difunctionalization with styrene derivatives.On the other hand,as a complimentary,under reductive coupling conditions,reagent 1j reacted with a variety of(hetero)aryl iodides for the formation of tri-fluoromethylated(hetero)arenes.

EHMO QUANTITATIVE VERIFICATION OF QUANTUM THEORY MECHANISM FOR ELECTROPHILIC ADDITIONS

Most of the electrophilic additions on carbon-carbon multiply bond can be summarized as: where Y are certain atoms on the fight of the periodic table; Z may be null, atom or group. Regardless of the rate law of Ad_E2 Ad_E3 or the more complex kinetics, the micromechanisms of transition state of electrophilic addition can be divided into two sorts, i.e. open ion and bridged ion mechanisms. The former one allows free rotation of

Direct Double Electrophilic Fluorination of Allenoic Acids and Tosylamides to Give 1,1-Difluoroallylic Heterocyclic Compounds

A novel and facile preparation of l,l-difluoroallyl substituted five-membered lactones or pyrrolidines in mod- erate yields through direct double electrophilic fluorination of 4,5-allenoic acids or tosylamides with SelectfluorTM F-TEAD-BF4 is described.

A Versatile,Electrophilic Reagent for Monofluoromethylthiolation

Comprehensive Summary,A new electrophilic monofluoromethylthiolating reagent N-fluoromethylthiophthalimide PhthSCH2F 1 was developed.Reagent 1 could be readily synthesized from easily available starting materials benzyl mercaptan and CH_(2)FCl in three steps.N-Fluoromethylthiophthalimide 1 is a powerful electrophilic monofluoromethylthiolating reagent that allows the monofluoromethylthiolation of a wide range of nucleophiles including alkynes,aryl/vinyl boronic acids,electron-rich heteroarenes,β-ketoesters and oxindoles,as well as thiols under mild conditions.

Efficient Synthesis of P-Chirogenic Compounds Enabled by Chiral Selenide-Catalyzed Enantioselective Electrophilic Aromatic Halogenation

P-chirogenic compounds have been applied in different fields,especially in asymmetric catalysis as ligands and organocatalysts.However,broader applicability has been severely restricted by the lack of efficient synthetic methods.Consequently,developing efficient methods to access these compounds is of high synthetic value.Herein,we report a convenient,efficient,and unprecedented pathway to construct valuable P-chirogenic compounds via chiral selenide-catalyzed enantioselective electrophilic aromatic halogenation.Using a new chiral bifunctional selenide as the catalyst,a variety of bis(2-hydroxyaryl)aryl phosphine oxides were efficiently converted to the corresponding chlorinated and brominated P-chirogenic compounds with good to excellent enantioselectivities.By slightly adjusting the catalyst and solvent,this method is also able to prepare chiral alkyl diaryl phosphine oxides and diaryl phosphinates.Furthermore,control experiments revealed the decomposition pathways of catalysts and the possible reasons why chiral selenide catalyst was more effective than chiral sulfide catalyst.The effect of hydrogen bonding was studied,and the reason why the chlorination took place on the various aromatic rings was elucidated when the substrates were switched from triaryl phosphine oxides to alkyl diaryl phosphine oxides and diaryl phosphinates.

Is There a Minimum Electrophilicity Principle in Chemical Reactions？

For 25 simple reactions, the changes of the hardness （△η）, polarizability （△α） and electrophilicity index （△ω） and their cube-roots （△η^1/3, △α^1/3, △ω^1/3） were calculated. It is shown that although the Maximum Hardness and Minimum Polarizability Principles are not valid for all reactions, but in most cases △ω^1/3〈0, whereas we always find △ω〈0. Our observation implies to this fact that for those chemical reactions in which the number of moles decreases or at least remains constant, the most stable species （reactants or products） have the lowest sum of electrophilicities. In other words ＂the natural direction of a chemical reaction is toward a state of minimum electrophilicity＂. This fact may be called Minimum Electrophilicity Principle （MEP）.

Isokinetic correlation analysis of the series of electrophilic substitution reactions of o-substituted phenylmercurials

Isokinetic relationships of the series of electrophilic substitution reactions of o-substi- tuted phenylmercurials are studied, and the results show, for the first time, that isokinetic correlation analysis can reveal the dominant factor in the system of the reactions. The analysis of SE2 of o-substituted phenylmercuric chlorides indicates that the steric effect of o-substituents is the pre-dominant factor when I2 is used as electrophilic agent, however, the electronic effect of o-substituents would become the predominant factor when HCl is used as the electrophilic agent. In SE1 of o-substituted phenylmercuric chlorides, the results of the analysis display that the predomi-nant factor is the field effects of o-substituents. The determination of predominant factors in those reactions would provide further scientific basis for those reaction mechanisms.

TEMPO-Regulated Regio-and Stereoselective Cross-Dihalogenation with Dual Electrophilic X^(+) Reagents

A TEMPO catalyzed cross-dihalogenation reaction was established via redox-regulation of the otherwise complex system of dual electrophilic X+reagents.Formally,the ICl,BrCl,I_(2) and Br_(2) were generated in-situ,which enabled high regio-or stereoselective access to a myriad of iodochlorination,bromochlorination and homo-dihalogenation products with a wide spectrum of functionalities.With its mild conditions and operational simplicity,this method could enable wide applications in organic synthesis,which was exemplified by divergent synthesis of two pharmaceuticals.Detailed mechanistic investigations via radical clock reaction,pinacol ring expansion and Hammett experiments were conducted,which confirmed the intermediacy of halonium ion.In addition,a dynamic catalytic model based on the versatile catalytic role of TEMPO was proposed to explain the selective outcomes.