Synthesis and Bioactivity of Novel Fluorinated Heteroaromatic Ureas

In order to find new urea cytokinins, a series of novel fluorinated heteroaromatic ureas have been designed and synthesized, The crystal structure of 3g was further determined by single crystal X-ray diffraction to obtain the structural feature of this class of urea compounds. The preliminary bioassay showed that some title compounds have good cytokinin activity.

Studies on Intramolecular Stacking Interaction of Ternary Complexes M（Ⅱ）（ATP）￣（2－） with Heteroaromatic N－Base Ligands

o understand the driving forces leading to mixed-ligand complexes in biologi-cal systenis.ternary complexes of M (ATP(L￣(2-) type, where M = Cu￣(2+), Ni￣(2+) orCo￣(2+) , and L= pyridine(Py) , 4-picoline, 3, 5-lutidine, isoquinoline (lq) or benzimi-dazole(Bi) in aqueous solution were studied by spectropliotometry, some of them(M=Cu￣(2+), L = isoquinoline or benzimidazole) were also separately studied hy po-tentiometric pH titration. The results show that an intramolecular stacking interac-tion exists between the heteroaromatic ring of the ligands and the purine moiety ofATP.

Synthesis, Characterization and Properties of Bis{oxo-bis[heteroaromatic carboxylatodibenzyltin(Ⅳ)]} and Crystal Structure of Bis{oxo-bis[2-furylcarboxylatodibenzyltin(Ⅳ)]}

A series of bis{oxo bis[heteroaromatic carboxylatodibenzyltin(Ⅳ)]} complexes {[(PhCH 2) 2Sn· (O 2CR)] 2O} 2[where R=2 furyl, 2 (2 furyl)vinyl, 2 (5 tert butyl)furyl, 2 thiophenyl, 2 pyridinyl, 3 pyridinyl , 4 pyridinyl, 3 indolyl, 3 indolylmethyl, 3 indolylpropyl] was synthesized by the reactions of heteroaromatic carboxylic acids with dibenzyltin(Ⅳ) oxide. All the complexes were characterized by elemental analysis, IR, and NMR spectra. The complexes were tested against two human tumour cell lines: MCF 7 and WiDr. The results show that they have higher activities in vitro . The crystal structure of bis{oxo bis[2 furylcarboxylatodibenzyltin(Ⅳ)]}(1) was determined by X ray diffraction. The crystal belongs to monoclinic space group P2 1/n, a =1 6641(2) nm, b =1 25073(18) nm, c =1 7193(3) nm, β= 101 951(2)° , Z=2, R 1=0 0446, wR 2=0 1100. Complex 1 is of a centrosymmetric dimer structure with a four membered central endo cyclic Sn 2O 2 unit in which the bridged oxygen atoms are tri coordinated. Each bridged oxygen atom also connects with an exo cyclic tin atom. The tin atoms are six coordinated and have a coordination geometry of a distorted octahedron. The exo cyclic tin atoms are five coordinated and have a coordination geometry of a monocapped trigonal bipyramid with a very similarly distorted mode. Four carboxylate ligands are divided into two types. The two of the four carboxylate ligands are bidentate and bridged to each pair of exo and endo cyclic tin atoms by using both the oxygen atoms. The other two are monodentate and bridged to each pair of exo and endo cyclic tin atoms but each utilizes one O atom only.

TERNARY Cu(Ⅱ)(ATP)AND HETEROAROMATIC N BASE COMPLEXES IN SOLUTION:STABILITY CONSTANTS AND ANTITUMOR MECHANISM EXPLORATION

The stability of the complexes of four pyridine-like ligands with Cu(ATP)^(2-) was studied and by comparing the stability constants of the ternary complexes[Cu(ATP)L]^(2-) with those of the binary complexes[CuL]^(2+),a stacking interaction between the pyridine ring and the purine ring of ATP is indicated.It is possible to interpret the antitumor mechanism of[Pt(NH_3)_8 (N-het)Cl]Cl in terms of this stacking interaction.

Removal of Heteroaromatic Sulfur Compounds by a Non-noble Metal Fe Single-atom Adsorbent

Sulfur-containing compounds(SCCs)must be removed from fuels before use.In this study,a novel non-noble metal Fe single-atom adsorbent(SA-Fe/CN)was synthesized using a core-shell strategy and applied for the adsorptive removal of benzothiophene(BT)and dibenzothiophene(DBT).The adsorption isotherms,thermodynamics,kinetics,and adsorption-regeneration cycles of DBT and BT on SA-Fe/CN were studied.SA-Fe/CN exhibited a significant capacity to adsorb DBT,and the isothermal equilibrium was well described by the Langmuir isotherm.The Gibbs free energy values were negative(ΔG^(0)<0),indicating that the adsorption of DBT and BT was favored and spontaneous.The adsorption process conformed to the pseudo-second-order kinetic model with high R^(2) values(0.9994,0.9987).The adsorption capacity of SA-Fe/CN for DBT and BT reached 163.21 mg/g and 90.35 mg/g,respectively,due to the highly active sites of the single atom and electrostatic interaction with the sulfide.Therefore,SA-Fe/CN may be a promising adsorbent for SCC removal.

TERNARY COMPLEXES OF Cu(ATP)AND HETEROAROMATIC N BASE-ISOQUINOLINE AND BENZIMIDAZOLE:STABILITY CONSTANT AND STACKING EFFECT

The stability constants of the binary complexes of Cu^(2+) with isoquinoline and benzimidazole as well as the ternary complexes of Cu(ATP)with the same ligands have been measured in aqueous solution spectrophotometrically and a strong stacking interaction between the heteroaromatic ring of the ligands and the purine moiety of ATP has been found.The fact of this stacking interaction is much stronger than that in the systems of Cu(ATP)with pyridine and imidazole shows that the stacking interaction increases with the size of the heteroaromatic ring of the ligands.

A NEW ROUTE FROM HETEROAROMATIC BORON COMPOUNDS TO CORRESPONDING KETONES VIA DICHLOROCARBENE INSERTION UNDER PHASE TRANSFER CONDITIONS

The reactions of tri-2-benzofuranylborane or aminoethyl di-2-thienylborinate and 2-thienylphenylborinate with dichlorocarbene generated in situ from chloroform under phase transfer conditions were explored as a new route for the preparation of heteroaromatic ketones. It was found that a good yield of the ketones can be obtained by solid-liquid system.

Stacking interaction in metal complexes with compositions of DNA and heteroaromatic N-bases

The current development in the intramolecular aromatic-ring stacking interactions in the complexes with compositions of DNA and heteroaromatic N-bases has been reviewed to a great extent, especially the significant contributions in several important systems about ternary mixed-ligand complexes, including nucleotide-metal ion-po-lyaromatic amine, amino acid-metal ion-polyaromatic amine, nucleotide-metal ion-pyridine-like aromatic amine, nucleo-tide-metal ion-amino acid, nucleotide-metal ion-nucleic acid base, nucleic acid base-metal ion, and the important factors affecting the intramolecular aromatic-ring stacking interac-tions in the complexes. Based on the study of stacking inter-action in the complexes, the mechanism of interaction be-tween DNA molecules and complexes of heteroaromatic N-bases has been established, which is crucial for the design and synthesis of the complexes acting as molecular devices of DNA.

Hypervalent iodine mediated C-H amination of quinoxalinones with heteroaromatic amines under metal-free conditions

An efficient and facile method for C-H amination of quinoxalinones with heteroaromatic amines under metal-free conditions has been described.In the presence of hypervalent PIDA reagent,the desired products with various groups were obtained with moderate to high yields.

In Situ Generation of N-Heteroaromatic Polymers:Metal-Free Multicomponent Polymerization for Photopatterning,Morphological Imaging,and Cr(Ⅵ)Sensing

Electron-deficient N-heteroaromatic polymers are crucial for the high-tech applications of organicmaterials,especially in the electronic and optoelectronic fields.Thus,the development of new polymerizations to afford adaptable electron-donating-accepting scaffolds in N-heteroaromatic polymers is in high demand.Herein,we have developed metal-free multicomponent polymerizations of diynes,diamines,and glyoxylates successfully for in situ generation of poly(quinoline)s with high molecular weights(Mw up to 16,900)in nearly quantitative yields.By tuning the electron distributions of the polymer backbones,the resulting poly(quinoline)s showed various aggregation-induced behaviors and photoresponsive abilities:The thin films of the poly(quinoline)s could be fabricated readily intowell-resolved photopatterns by photolithography techniques.They could be utilized as fluorescent probes to visualize themorphologies of polymer materials directly;these include spherulites and microphase separation of polymer blends.Their nanoparticles demonstrated sensitive and highly selective fluorescence quenching to hexavalent chromium ion Cr(Ⅵ),thereby providing access for biological imaging of Cr(Ⅵ)in unicellular algae.

Synthesis and Characterization of Novel Polyimides Based on Pyridine-containing Diamine

A new aromatic diamine monomer containing pyridine unit, 2,6-bis （4-aminophenoxy- 4＇-benzoyl）pyridine（BABP）, was synthesized in three steps, starting from 2,6-pyridinedicarboxyl chloride. A series of novel pyridine-containing polyimides were prepared v/a the polycondensation of BABP with various aromatic dianhydrides through poly（amic acid） precursors, and thermal or chemical imidization of the precursors. The polyimides exhibit desirable properties, e.g., good solubility in N-methyl-2-pyrrolidone and m-cresol, excellent thermal stability and film-forming capability, as well as high inherent viscosity, indicating high molecular weight.

Synthesis, Spectroscopic Properties and Structural Characterization of Tri（o-chlorobenzyl）tin Ester of 4-Pyridinecarboxylic Acid

The title complex, tri(o-chlorobenzyl)tin ester of 4-pyridinecarboxylic acid, has been synthesized by the reaction of bis[tri(2-chlorobenzyl)tin] oxide with 4-pyridinyl carboxylic acid and characterized by elemental analysis, IR and H NMR, and its crystal structure was 1 determined by X-ray single-crystal diffraction. The crystal belongs to triclinic, space group P21/n with a = 8.821(7), b = 18.888(15), c = 15.333(12) ?, β = 92.390(12)°, Z = 4, V = 2552(3) ?3, Dc= 1.607 g/cm3, μ = 1.340 mm-1, F(000) = 1232, R = 0.0408 and wR = 0.0962. In the molecular structure of the title complex, the tin atoms are five-coordinated into a trigonal bipyramidal geometry by coordinating to the intermolecular pyridine N atoms of carboxylate groups. The resulting structure is a one-dimensional linear polymer containing Sn–O (2.150(4) ?) and Sn–N (2.522(4) ?) bonds.

Some Ferrocene Derivatives of Acylhydrazones

The title organometallic compounds were synthesized by the condensation of formyl and acetyl ferrocene with cyanoacetyl, propionyl, butyryl, o furoyl, o thiofuroyl and m pyridinecarboxy hydrazine in anhydrous ethanol under reflux. The IR, 1H NMR, MS, and Mssbauer spectra for these compounds were recorded and are discussed.

General radical difluoromethylation using difluoroacetic anhydride via photoredox catalysis

CF_(2)H-containing molecules play pivotal roles in diverse fields from medicinal chemistry to materials science. However, the application of existing CF_(2)H reagents as a source of CF_(2)H radical is limited by their reactivity and preparation. Herein, we develop a simple and general visible-light-catalyzed radical difluoromethylation reaction of alkenes, dienes, and heteroaromatics using commercially available, easy-to-handle, and low-cost difluoroacetic anhydride as the CF_(2)H reagent. This scalable protocol enables the convenient synthesis of a range of CF_(2)H-containing compounds under mild conditions, exhibiting a broad substrate scope and functional group tolerance. Potential applications are further demonstrated by gram-scale synthesis, sunlight experiments, derivatization experiments as well as the synthesis of bioactive molecules.

Intramolecular aromatic-ring stacking interaction of ternary Zn(UTP)L^(2-) complexes

THE mechanism of the action of the classic platinum antitumor drugs can be interpreted accord-ing to their bidentate, bifunctional interaction with the DNA of the tumor cell, resulting in in-hibition of the DNA replication. Recently, it was found that a new class of compounds withthe general formula cis-[Pt（NH3）2（N-het）Cl]Cl（N-het is a heteroaromatic N-base like pyri-dine） show effective antitumor activities. However, two possible mechanisms of action

Divergent Syntheses of Pyridoacridine Alkaloids via Palladium-Catalyzed Reductive Cyclization with Nitro-Biarenes

Main observation and conclusion A divergent and novel protocol for the preparation of both pyrido[2,3,4-kl]acridine and pyrido[4,3,2-kl]acridine alkaloids was developed.This method featured the remote palladium-catalyzed reductive cyclization with Mo(CO)_(6) as reductant.A wide range of substrates including three types of nitro arenes were tolerated and afforded corresponding products in good to excellent yields.