Efficient and Facile Synthesis of ( ± )-Salvirecognine

Salvirecognine (7) is a diterpene isolated from Salvia recognita[1] which has been the subject of continued and growing interest, due to the range of biological activities shown by many members of this family. [2] In order to study further relationships between the structure and biological activity of the diterpene compounds and as an extension of diterpenoid synthesis in our laboratory, [3,4] the first total synthesis of the title compound was achieved by an efficient and facile route (Scheme 1).     

Two-photon-excited fluorescence of zinc(II), cadmium(II) complexes containing phenothiazine ligand

Shortly after the experimental verification of two-photon absorption by Kaiser et al.[1] with aCaF2:Eu2+ crystal in 1961, two-photon processes have been used to create a number of chemical or physical processes including optical data storage[2], lithographic fabrication[3], and fluorescence imaging[4]. In fluorescence imaging, two-photon excitation (TPE) has developed as an importantalternative to the traditional one-photon excitation (OPE) in the fluorescence microscopy and spectroscopy[5,…     

Synthesis of Fulleropyrrolidines under Microwave Irradiation

In recent years, considerable efforts have been devoted to the development of systems in which C60 is covalently linked to an electron donor.[1] Studies[2] on intermolecular photoinduced electron transfer between C60 and triphenyl amine show that triphenyl amine is a good donor. It is envisaged that the use of donor segments consisting of either pyrrole/aniline may extend the lifetime of charge-separated state.[3] Since Gedye[4] demonstrated that many organic reactions can be conducted rapidly under microwave irradiation, here we have successfully synthesized five new fulleropyrrolidines containing triphenyl amine or thiophene dyads under microwave irradiation, which are different from traditional heating. The determination of structures of these fulleropyrrolidines is in progress. On the other hand, we have studied the geometry, electronic structures and frontier orbitals of these N-methyl-pyrrolo[3,4]C60 derivatives by using AM1semiempirical quantum calculation method. The results indicate that there exists strong intramolecular electron transfer in them.     

Highly Enantioselective Diels-Alder Reactions Promoted by Non C2-Symmetric Chiral Ligands

Ligand design and synthesis occupy a central theme in asymmetric catalysis. [1] In developing chiral ligands, their design should provide an opportunity for tuning through easy modification of substituents. In a large number of cases, this means starting from a new chiral source. We have been interested in design/synthesis of novel chiral ligands that allow for diversity to be introduced with ease. We have designed a new ligand system containing a core dihydropyrazole moiety with chiraliuy residing remotely to the fluxional group as shown in Scheme 1. There are three points of diversity and these are indicated on the structure.     

BrΦnsted acid-promoted ‘on-water’ C(sp^3)-H functionalization fot the synthesis of isoindolinone/[1,2,4]triazolo[1,5-a]pyrimidine derivatives targeting the SKP2-CKS1 interaction

The isoindolinone and biaryl scaffolds are prevalent in natural products and drug molecules,which have showed broad and interesting biological activities.The efficient construction of such hybridized molecules and biological evaluation are of great interest to medicinal chemistry community.In this communication,we report an efficient BrΦnsted acid-promoted C(sp^3)-H functionalization approach that enables the rapid construction of biologically important isoindolinone/[1,2,4]triazolo[1,5-a]pyrimidine hybrids from 5-methyl-7-(2,4,6-trimethoxyphenyl)-[1,2,4]triazolo[1,5-a]pyrimidine,2-formylbenzoic acid and various anilines.The title compounds were generated in high to excellent yields(up to 96%)regardless of the electronic nature and steric effects of the substituents.In this reaction,an isoindolinone scaffold,one C-C single bond,and two C-N bonds were formed simultaneously with high atom economy.In this work,we have envisioned that the methyl group linked to the electron-deficient Nheterocycles could be used as a new synthetic handle for late-state diversification and may have broad applications in the field of organic and medicinal chemistry.Besides,the title compounds have exhibited promising activity against the SKP2-CKS1 interaction.     

Design and Synthesis of 1-Benzyl-3-(a-hydroxy-(un)substituted benzylidene)pyrrolidine-2,4-diones as Potential Herbicides

The inhibitors of 4-hydroxyphenylpyruvate dioxygenase (HPPD, EC 1.13.11.27) are an new kind of herbicides.[1]Generally, in structure, potent herbicides of this kind must possess: (1) a tricarbonyl methane structure and one of the three carbonyl groups must be a subustituted benzoyl group; (2) the compound must be able to enolise so that the enolate is capable of inhibiting HPPD enzyme by competitive combination with Fe2+, the reaction center of HPPD enzyme.[2]Recently, we noticed that the 3-acyltetramic acids form an expanding group of antibiotics and pigments from micro-organisms,[3] they display a range of biological activities[4] and all of this kind compounds possess all of the characters mentioned above. Tests of their antimicrobial activities indicated that the structure of the acyl substituent at the 3-position was important to many typical antibiotics.[4～6] These characters stimulated us to study this kind of compounds so as to discover new herbicides. In this report, we synthesized a series of compounds 3 and tested their herbicidal activities to investigate their structure-activity relationships.     

Relationship between Coordination Structure and Biological Activity of Copper(II) Nicotinate

1 INTRODUCTION In 1945, Braude[1] found for the first time that adding copper (Cu) ten times the normal requisite amount into the feed can improve the production property of the animal obviously. Therefore, from then on copper has been widely applied in pig- breeding industry as an effective growth-promoting agent, especially in the process of intensive culture, which plays an important part in improving the growth of animal and the production property. However, at the same time, the high…     

Novel Synthesis of 1-Oxo-10-epi-α-cyperone

In the sesquiterpenic family, β-dihydroagarofuran and a large number of eudesmanes have an oxygenated func tional group at C1. [1] Although considerable efforts have been devoted to the total synthesis of eudesmane β-dihydroagarofuran and some germacrane sesquiterpenoids starting from the corresponding eudesmane over the pastdecades, the introduction of C1 oxygenated functional group still represents significant challenge.     

Effect of Supercritical Fluids on the Biological Activity of Absidia coerulea for the Hydroxylation of Reichsterin’s Substance Acetate

In a number of fermentation processes, organic solvents are often used due to the poorsolubility of many substrates and/or products in water. However, the interface betweenwater and organic phases may lead to the diffusion-limited bioconversion. Supercriticalfluid technology can be employed to eliminate the mass transfer resistance existed in thebiphasic system1-6. Hydrocortisone is an effective anti-inflammatory drug and an important precursor ofother steroid drugs. The C11β-hydroxylati…     

Synthesis and Structural Characterization of {[Mn(phen)_2(OAc)(H_2O)]ClO_4}_2H_2O

1 INTRODUCTION Chemistry of manganese cluster has become an attractive research field because of the involvement of manganese in several biological redox-active sys- tems[1,2], especially in the oxygen-evolving complex (OEC) of photosystem Ⅱ (PSⅡ) in green plants[3]. It was thought that the coordination environment of Mn in OEC contains O and N donors, and the bind- ing of aqua to the Mn site may be important to the oxidation of aqua for the evolution of dioxygen[4, 5]. In recent …     

Synthesis and Crystal Structure of Bis[2-[2-(diethylamino)ethyliminomethyl]-4-nitrophenolato]dimethanolcobalt(II) Dinitrate

1 INTRODUCTION The significance of cobalt coordination com- pounds in biological systems is recognized[1～3]. In many instances the cobalt coordination compounds of Schiff bases have been suggested as models to describe energy transfer in naturally occurring systems. In such cases the coordination sphere about the metal ion is believed to play an important role in determining the nature of the model system[4, 5]. In order to investigate the structures of such complexes, we report herein t…     

Electrochemical behavior of [UO_2Cl_4]~(2-) in 1-ethyl-3-methylimidazolium based ionic liquids

In order to examine the chemical form of uranyl species in 1-ethyl-3-methylimidazolium(EMI) based ionic liquids,UV-visible absorption spectra of solutions prepared by dissolving [EMI] 2 [UO2Cl4] into a mixture of EMICl and EMIBF 4(50:50 mol%) were measured.As a result,it was confirmed that uranyl species in the mixture of EMICl and EMIBF 4 existed as [UO2Cl4]2-.Cyclic voltammograms(CVs) of [UO2Cl4]2-in the mixture were measured at 25 ℃ using a Pt working electrode,a Pt wire counter electrode,and an Ag/Ag + reference electrode(0.01 M AgNO 3,0.1 M tetrabutylammonium perchlorate in acetonitrile) in a glove box under an Ar atmosphere.Peaks corresponding to one redox couple were observed around-1.05 V(Epc) and-0.92 V(Epa) vs.ferrocene/ferrocenium ion(Fc/Fc +).The potential differences between two peaks(Ep) increased from 101 to 152 mV with an increase in the scan rate from 50 to 300 mV s-1,while the(Epc+Epa)/2 value was constant,-0.989 V vs.Fc/Fc + regardless of the scan rate.Furthermore,the diffusion coefficient of [UO2Cl4]2-and the standard rate constant were estimated to be 3.7 × 10-8 cm 2 s-1 and(2.7-2.8) × 10-4 cm s-1 at 25 oC.By using the diffusion coefficient and the standard rate constant,the simulation of CVs was performed based on the reaction,[UO2Cl4]2-+ e = [UO2Cl4]3-.The simulated CVs were found to be consistent with the experimental ones.From these results,it is concluded that [UO2Cl4]2-in the mixture of EMICl and EMIBF 4 is reduced to [UO2Cl4]3-quasi-reversibly at-0.989 V vs.Fc/Fc +.     

Theoretical Study of the Molecular and Electronic Structures of CPDT-TCNQ and Its Difluoro and Dimethyl Derivatives

1 INTRODUCTION Since the discovery of one-dimensional metallic behavior of tetrathiafulvalene (TTF) with tetracyano- quinodimethane (TCNQ)[1], organic charge-transfer (CT) complexes and CT salts have been intensively studied in search of electrically conducting and superconducting properties[2 ～ 6] which are most unusual for an organic material. The most intriguing property is that it is excellent metal with conducti- vity similar to that of metals at room temperature[7, 8]. In these…     

Solid Phase Catalytic Oxidation of Alcohols by Polymer Supported Rare Earth Catalysts

Oxidation of alcohols to the corresponding aldehydes or ketones is one of the most fundamental reactions in organic chemistry [1, . Some of the products of the oxidation exhibit an 2] important role in the organic synthesis as well as pharmaceutical synthesis. In most reactions, the lanthanide complexes show satisfied catalytic activities for some compounds. Furthermore, there has been increasing interest in the lanthanide complexes and several reports have appeared in the literature[3, 4] …     

Synthesis of 2- [ (4-Hydroxylcarbomylphenyl) -methylamino ] - N- ( 2- aminophenyl ) acetamide

Early studies revealed that the hybrid polar/apolar compound N, N′-hexamethylene bisacetaamide (HMBA) was a very effective inducer of differentiation in a transformed cell lines. [1] The use of this polar/apolar compound to induce murine erythroleukemia cells (MELC) to undergo erythoid differentiation with suppression of oncogenicity has proved a useful model to study inducer-mediated differentiation of transformed cell. [2] To search more effective inducers, we utilized the computer to design a new target compound. Herein, we reported the synthesis of title compound.     

Electrochemical Studies on the Interactions of Dipyridophenazine Complex of Ruthenium and Herring Sperm DNA

Cyclic voltammetry (CV) and single-step chronocoulometry were used to study the interaction of [Ru(phen)2dppz]2 (phen=l,10-phenanthroline; dppz=dipyrido[3,2-a:2‘,3‘-c]phen-azine) with herring sperm DNA. The addition of DNA caused a diminution in the peak current and a positive shift in the peak potential of the complex of [Ru(phen)2dppz]2 . The 12 mV positive shift in the peak potential of [Ru(phen)2dppz]^2 indicates that [Ru(phen)2dppz]^2 binds 2.6 times more strongly to DNA than its reductive form. In addition, by using fluorimetric and UV-spectrophotometric methods and studies of denatured DNA and the effect of NaC1 solution, it was also found that the binding mode was intercalation. The decrease of peak current is proportional to the concentration of DNA, which can be applied to estimate DNA concentration.     

QCM Detection of Adhesion, Spreading and Proliferation of Human Breast Cancer Cells （MCF-7） on a Gold Surface

The quartz crystal microbalance (QCM) was used to monitor the one-day incubation of human breast cancer cells (MCF-7) on the gold electrode. In combination with an optical microscope simulation experiment, the cell-population pictures at various stages, the QCM responses to the cells' adhesion, spreading and proliferation on the electrode surface were discussed. The △f0 and △R1 responses were found mainly from mixed effects of viscodensity and surface stress, and in proportion to the cell coverage, rather than to the number of cells at the electrode. The significant fore-and-aft changes in cyclic voltammetry and electrochemical impedance spectroscopy of the ferri-ferrocyanide redox couple also proved that the cells were adhesion to the gold surface.     

Self-assembly of Bis[2-(2-hydroxyphenyl)-pyridine]Copper(Ⅱ) Induced by C-H…π and π…π Stacking Interaction

Introduction The control of molecular assembly in the solid state is an important theme of modern chemistry.It is in this regard that there is an activity in the area of supramolecular structures at present.The self-assembly of molecules can form well-defined supramolecular structures under the influence of drive forces such as hydrogen bonds[1-3],metal-ligand coordination bonds[4-6] and π…π stacking interactions[7-10].Word et al.have described the co-ordination chemistry of polydentate chelating ligands which contain mixed pyridine-phenol donor sets[11].Some unusual structures of transition metal pyridine-phenol complexes have been established in which non-covalent interactions such as hydrogen bonding and π…π stacking appear to play a dominant part.These observations suggest that it might be possible to construct supramolecular structures with a metal pyridine-phenol system.To explore this idea we have begun to investigate the self-assembly properties of metal pyridine-phenol complexes.Herein we present the self-assembly properties of Cu(pp)2[pp=2-(2-hydroxyphenol)-pyridine] under different conditions.     

Preparation of Ionic Liquids and Their Application in Hydrogenation of Aromatic Nitriles

On the basis of their characteristic polar nature, phase behavior and lack of vapour pressure, ionic liquids are considered as green solvents and have attracted significant attention as an alternative reaction medium for homogeneous catalysis.[1] However, the "greenness" of typical ionic liquids used in the literature consisted of halogen-containing anions (such as [AlCl4]-, [BF4]- and [PF6]-) was limited in some sense, due to the serious environment concerns if the hydrolysis stability of the anion is poor (e.g. for [AlCl4]-and [PF6]-) or thermal stability of used ionic liquid is undesired. In both cases, the additional effort is needed to avoid the liberation of toxic and corrosive HF or HCl into the environment.     

Revising Space Groups from Simulated SHELXfcf Structure Factors. More Examples of Incorrect Space Groups, an Example of a Chemically-Incorrect Structure and the Special Case of Pgl to PRevisions

1 INTRODUCTION Although the incorrect assignment of the space groups of crystal structures has been addressed in a number of reports, instances of crystal structures refined in incorrect symmetry turn up even in the recent literature[1～4]. A simple method of space group revision makes use of the published atomic coordinates and temperature factors to simulate the diffraction intensities; the structure is then 搒olved?in the correct space group from the simulated hkl-F2 data[5] and an O…