Fangshi Li

Synthesis, Crystal Structure, Vibration Spectral, and DFT Studies of 4-Aminoantipyrine and Its Derivatives

Three compounds derived from 4-aminoantipyrine (AA) were synthesized and their structures confirmed by melting point, elemental analysis, FT-IR, and 1H-NMR. The molecular structures of the four compounds were characterized by single-crystal X-ray diffraction and calculated by using the density functional theory (DFT) method with 6-31G (d) basis set. The calculated molecular geometries and the vibration frequencies of the AA derivatives in the ground state have been compared with the experimental data. The results show that the optimized geometries can reproduce well the crystal structural parameters, and the theoretical vibration frequencies show good agreement with the experimental data, although the experimental data are different from the theoretical ones due to the intermolecular forces. Besides, the molecular electrostatic potential (MEP) and the frontier molecular orbital (FMO) analysis of the compounds were investigated by theoretical calculations.

Synthesis, Spectroscopic Characterization, X-Ray Structure, and DFT Calculations of Some New 1,4-Dihydro-2,6-Dimethyl-3,5 -Pyridinedicarboxamides

A series of novel 1,4-dihydro-2,6- dimethyl-3,5-pyridinedicarboxamides were synthesized and characterized by infrared absorption spectrum (IR), proton nuclear magnetic resonance (1H NMR), elemental analysis, ultraviolet spectrum (UV), and fluorescence techniques, together with X-ray single crystal diffraction. The results of density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations provided a reasonable explanation on the molecular structures, the molecular frontier orbital, and the spectra of electronic absorption and emission. The present work will be helpful to systematically understanding of the structures and the optical properties of 1,4-dihydropyridines for studying the structure-activity relationship and to develop new drugs and their analytical methods.

Synthesis and Fungicidal Activity of Novel Chloro-Containing 1-Aryl-3-oxypyrazoles with an Oximino Ester or Oximino Amide Moiety

Six novel chloro-containing 1-aryl-3-oxypyrazoles TMa–TMf with an oximino ester or an oximino amide moiety were prepared by the reaction of 1-aryl-1H-pyrazol-3-ols with benzyl bromide. Their structures were characterized by 1H-NMR, 13C-NMR, IR, MS, and elemental analysis. A preliminary in vitro bioassay indicated that compounds TMa, TMe and TMf displayed excellent fungicidal activity against Rhizoctonia solani and could be used as potential lead compounds for further development of novel fungicides.

N-{[2,5-Dichloro-4-(1,1,2,3,3,3-hexa-fluoro-prop-oxy)phen-yl]amino-carbon-yl}-2,6-difluoro-benzamide.

In the molecule of the title compound, C17H8Cl2F8N2O3, the two aromatic rings are oriented at a dihedral angle of 50.12 (3)°. Intramolecular N—H⋯O, C—H⋯O and N—H⋯Cl hydrogen bonds result in the formation of two six- and one five-membered rings. The six-membered rings have flattened-boat conformations, while the five-membered ring adopts an envelope conformation. In the crystal structure, intermolecular N—H⋯O hydrogen bonds link the molecules into centrosymmetric dimers.

Fluorescent Determination of Mercury(II) Using Rhodamine B Immobilized on Polystyrene Microspheres

ABSTRACT A novel microsphere-based fluorescent sensor 1 for determination of Hg(II) in food samples has been successfully synthesized and its fluorescent sensing properties were investigated in detail. Polystyrene microsphere was innovatively surface modified by a rhodamine derivative; therefore sensor 1 was a fluorescent sensor with high polymer material properties of polystyrene and the optical properties of a fluorescent probe. Sensor 1 displayed high selectivity, good anti-interference performance, and instantaneous response to Hg(II). The fluorescence intensity of sensor 1 showed a linear response to Hg(II) in the concentration range of 0 µM to 8 µM with a detection limit of 0.439 µM. The most valuable advantage was that sensor 1 was recyclable and environmentally-friendly. This proposed sensor 1 was applied to monitor the content of Hg(II) in real food samples, such as tap water, rice, and anglerfish. The recovery range of tap water was from 92.60 to 105.80%, the recovery range of rice was from 90.45 to 106.10%, and the recovery range of anglerfish was from 91.30 to 105.84%. The relative error was below 10% in spiked recovery studies, suggesting that fluorescent sensor 1 provides a simple, efficient, and promising method for determination of Hg(II) in complex matrices.

N-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)formamide

In the title compound, C12H13N3O2, the dihedral angle between the pyrazole and benzene rings is 50.0 (3)°. In the crystal, molecules are linked by intermolecular N—H⋯O hydrogen bonds to form a three-dimensional network. Two weak C—H⋯π interactions reinforce the crystal packing.

1-(2-Chloro-benzo-yl)-3-[4-(trifluoro-meth-oxy)phen-yl]urea.

The title compound, C15H10ClF3N2O3, is considered to belong to a fourth generation of insecticides with properties such as high selectivity, low acute toxicity for mammals and high biological activity. The dihedral angle between the two benzene rings is 59.3 (2)°. Intramolecular C—H⋯O and N—H⋯O hydrogen bonds are observed. Intermolecular N—H⋯O hydrogen bonding generates a centrosymmetric dimer. The F atoms are disordered over two positions; the site occupancy factors are 0.52 and 0.48.

Bis(3-nitro-phen-yl) sulfone.

The asymmetric unit of the title compound, C12H8N2O6S, an important diphenyl sulfone derivative, contains one half-molecule; a mirror plane passes through the SO2 group. The dihedral angle between the two symmetry-related benzene rings is 40.10 (13)°. An intramolecular C—H⋯O hydrogen bond results in the formation of a five-membered ring, which adopts an envelope conformation.

Methyl 2-{[3-(4,6-dimethoxy-pyrimidin-2-yl)ureido]sulfonyl-meth-yl}benzoate.

In the title compound, C16H18N4O7S, a synthetic sulfonylurea herbicide, there are intramolecular N—H⋯N and C—H⋯O hydrogen bonds. Intermolecular N—H⋯O and C—H⋯O hydrogen bonds form centrosymmetric dimers. The dihedral angle between the two rings is 50.00 (15)°.

Synthesis and Identification of Artificial Antigens for an Antibody of Anthracene

To detect the residue of polycyclic aromatic hydrocarbons (PAHs)in the environment quickly by immune method, preparation of high quality antibody against PAHs is the most critical step of the project. As the first step toward developing sensitive enzyme linked immunosorbent assays (ELISAs) for selective detection of anthracene in environment, a new hapten was synthesized by the Friedel-Crafts acylation reaction from anthracene. It bears a carboxylic group with four carbon length spacer at the position 1of anthracene. The hapten was characterized by 1H NMR, IR, and element analysis. The hapten was coupled with bovine serum albumin (BSA) to raise an antibody or with ovalbumin (OVA) to form competitor conjugate. The artificial antigents were verified by their spectral characteristics using ultra violets pectrophotometry. The resultant immunogen was fabricated and used to stimulate immune responses in rabbits to survey the characteristics of the hapten. The obtained antiserum exhibited relatively high antibody titer (1:110000) in indirect ELISA.