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.

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.