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 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,.

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.

Synthesis of Isoquinoline-1, 3-Dicarboxylic Acid

Two new compounds, isoquinoline-1, 3-dicarboxyaldehyde and (IDA) were synthesized via 6 or 7 steps starting from benzaldehyde, or prepared via 4 steps starting from allylbenzene.

Study on Synthesis of Azo-Coupling Products of 3-Aminotropolone

3-Acetamidotropolone 1 reacted with p-substitutedbenzenediazonium chloride in pyridine to afford 3-acetamido-5-(4-substitutedphenylazo)tropolones 2a~f. Hydrolysis of compounds 2a~f gave 3-amino-5-(4-substitutedphenylazo)tropolones 3a~f which could not be obtained directly from reactions of 3-aminotropolone with p-substitutedbenzenediazonium chloride. The structures of these new compounds 2a, 2c~f, 3a, 3c~f were confirmed from the elemental analysis and spectral data.

Radiolabeling, docking studies, in silico ADME and biological evaluation of serotonin with 125I for 5-HTRs imaging

Serotonin is one of the significant signaling molecules used by several neural systems in the gut and brain. This study aimed to develop a novel and potent tracer for targeting, detecting, and imaging serotonin receptors(5-HTRs), which is a promising tool in the determination of the receptor’s function and relationship with the diseases related to serotonin and its receptor dysfunction. Serotonin was effectively labeled via a direct electrophilic substitutional reaction using an oxidizing agent such as iodogen with 125I in a neutral medium, and 125I-serotonin was achieved with a maximum labeling yield of 91 ± 0.63% with in vitro stability up to 24 h. Molecular modeling was conducted to signify 125I-serotonin structure and confirm that the radiolabeling process did not affect serotonin binding ability to its receptors. Biodistribution studies show that the maximum gastro intestinal tract uptake of 125I-serotonin was 17.8 ± 0.93% ID/organ after 30 min postinjection and the tracer’s ability to pass the blood–brain barrier. Thus, 125I-serotonin is a promising single photon emission computed tomography tracer in the detection of 5 HTRs.

Chiral Lewis Base/Achiral Acid Co-Catalyzed Atroposelective Sulfenylation of Pyrrole Derivatives: Construction of C-N Axially Chiral Sulfides

Chiral BINAM-derived selenide/achiral acid co-catalyzed atroposelective electrophilic sulfenylation of pyrrole derivatives has been realized for the first time.A variety of C-N axially chiral sulfur-containing pyrrole derivatives were readily obtained in moderate to good yields with moderate to excellent enantioselectivities.This catalytic system involves sequential desymmetrization and kinetic resolution.

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.

Formal[2+1]Cycloadditions of a Metallacyclopentadiene Unit with Alkynes:Constructing Tetracyclic Conjugated Frameworks with Bridgehead Metals

Comprehensive Summary Metallacyclopentadienes play a vital role in transition-metal mediated and catalyzed cycloaddition reactions of alkynes.Though versatile reactions of metallacyclopentadienes with alkynes have been disclosed,[2+1]cycloadditions of metallacyclopentadienes and alkynes have never been discovered.In present work,we report the formal[2+1]cycloadditions of a metallacyclopentadiene unit with a broad scope of commercial alkynes,providing a facile strategy to construct tetracyclic conjugated compounds.The deuterated experiment indicates a metal vinylidene intermediate has been involved in[2+1]cycloaddition.Moreover,the electrophilic substitution reaction of the tetracyclic conjugated compound with the aid of density functional theory(DFT)calculated Fukui functions is investigated.

Simple and Efficient Aromatic C−H Oxazolination

Aromatic oxazolines are versatile in organic synthesis as directing groups,ligands,and protected carboxylic acids.Developing efficient approaches to oxazoline from an aromatic C−H bond is more desirable compared to the established protocols from carboxylic acid and its equivalents.Herein,a simple and efficient aromatic C−H oxazolination with broad substrate scope is described.By employing this transformation as an enabling step,diversity-oriented synthesis of functionalized arenes and target-oriented synthesis of four drugs were accomplished.Mechanistic experiments suggest that this aromatic oxazolination is an electrophilic aromatic substitution.It is anticipated that this transformation will find applications in aromatic C−H functionalization with oxazoline either as a removable directing group or as a masked carboxylic acid.

Study of the Reaction of 5-Aryl-7-hydrazino-2-phenylpyra- zolo[1,5-c]pyrimidines with 1,3-Dicarbonyl Compounds

A novel synthetic method for the preparation of 5-aryl-7-（3,5-dimethyl-lH-pyrazol-l-yl）-2-phenylpyra- zolo[1,5-c]-pyrimidines and 1-（5-aryl-2-phenylpyrazolo[1,5-c]pyrimidin-7-yl）-3-methyl-lH-pyrazol-5-ols is provided by condensative cyclization of 5-aryl-7-hydrazino-2-phenylpyrazolo[1,5-c]pyrimidines with 1,3-dicarbonyl compounds. The study of the more reactive position for electrophilic substitusion reactions on such ring system was also achieved.