First Asymmetry Synthesis and Stereochemistry of Glutinone

Rencently, two new sesquiterpenoids, glutinone 1 and lucinone 2, were isolated from the aerial parts of traditional medicine2 Jasonia glutinosa1 by Castillo and co-workers3. However, Castillo only gave the structure of glutinone, but its absolute configuration is still unknown. Here, we wish to report our stereoselective construction of the four possible diastereoisomers (9a, 9b, 9c & 9d) of glutinone. By comparing the spectrum data with that of the natural product, we outlined the stereoc…     

Dual-parameter Correlation Analysis of the Redox Potential Data of 1-Methyl-2-formyl-5-substituted Pyrroles and their Hydrazones

It has been suggested about forty years ago that the transition states of polarographic potential-determining steps possess free radical character1. However, the dual-parameter correlation analysis [eqn. (1)] have never been successfully applied to the redox potentials until our recent report on five series of aromatic compounds shows that polarographic processes are affected by the polar effect as well as the spin-delocalization effect2. The purpose of this paper is to study the correlation…     

Oxidation of Carbon Monoxide over Cu/CeO_2 Catalysts Prepared by SMAI

Introduction Carbon monoxide is ubiquitous air pollutants emitted by many sources. Total oxidation of carbon monoxide to carbon dioxide is employed to meet environmental regulations in an economic way. Precious metals (Pt, Pd) are well-known oxidation catalysts with high activity and stability, and are widely used for exhaust gas emission control. However, the high cost of precious metals and their sensitivity to sulfur poisoning have long motivated the search for substitute catalysts. …     

A New 24, 30-Dinortriterpenoid from Paeonia delavayi

We reported some constituents from the plant of Paeonia delavayi Franch1. Further investigation on the chemical constituents of the same plant resulted in the isolation and determination of a new triterpenoid, 3(, 4(, 23-trihydroxy-24, 30-dinorolean-12, 20(29)-dien-28-oic acid 1, in addition to five known compounds, 2(, 3(, 23-trihydroxy-12-oleanen-28-oic acid-(-D-glucopyranosyl ester2, palbinone3, 2-hydroxy-benzoic acid4, vanillic acid4, syringic acid5. In this paper we describe the structur…     

Synthesis and ~(183)W NMR Characterization of α-K_7GaW_(11)(TiO_2)O_(39)·11H_2O Heteropolyanion

In recent years, the research of peroxy polyoxometalates (POMs) has attracted increasing attention because of the two reasons. First, peroxy POMs are more active as oxygenation catalysts in some oxygen transfer reactions1~5. Second, recent research from our group and others has established that peroxy POMs are more active antiviral agents and less toxic both in vitro and in vivo than the parent metal-free POMs6. In order to entirely understand the properties and activities of peroxy POMs…     

Direct Electrochemistry of Hemoglobin in Layer-by-layer {PDDA/Hb}_n Films Assembled on Pyrolytic Graphite Electrodes

The principle of alternate adsorption can be used to design and control specific molecular architectures1. Protein-polyion layer-by-layer assembly opens a possibility of organizing proteins with specific molecular architectural plan1 and studying redox proteins with electrochemical methods2. Recently, we reported electrochemistry of layer-by-layer {PSS/Mb}n films grown on PG electrodes1. In this work, layer-by-layer {PDDA/Hb}n films were fabricated on PG electrodes. Electrochemistry and …     

Synthesis, Structure of a Symmetrically Substituted Stilbene with Strong Two-photon Absorption and Up-converted Blue Fluorescence

Symmetric substituted stilbenes have significantly potential application such as fluorescence microscopy, two-photon photodynamic therapy, optical power limiting, and three-dimensional storage1-2. These dyes have strong tendency of symmetric intra-molecular change transfer under the excited state. As a result, they usually exhibit large two-photon absorptivity (TPA), in the meanwhile emit strong up-converted fluorescence. On the other hand, their solutions generally display linear transmis…     

Chitosan-supported Borohydride Reducing Agent

Borohydride exchange resin (BER) a useful reducing reagent has been used in reduction of some carbonyl compounds and acyl halides1. When BER combines with a transition metal catalyst, it can reduce C=C double bonds2, halides2, nitro compounds3, cyano, diazo3 and azide compounds4. The support of BER is the synthetic macromolecule polystyrene. Here, we used chitosan as the support of borohydride. As known, chitosan is a renewable and abundant natural polysaccharide. Scheme 1 Preparat…     

A Concise Approach to the Synthesis of Carnosic Acid Type Diterpenes

AIDS has seriously affected human being's health and about 13.9 million people have been killed by AIDS in the world. So far, A. Paris et al1 found that Carnosic acid and its analogs posses inhibitory effect on HIV-1 protease and HIV virus replication activity. In order to clarify the structure-active relationship of this kind of compounds, a concise approach was designed, which is a convergent synthesis. Best to our knowledge, it is the first successful convergent route in total synthes…     

Synthesis and Characterization of (E)-5-[2-(N-hexylcarbazolyl)vinyl] furan Derivatives with Acceptor Groups

Organic second-order nonlinear optical (NLO) materials have been extensively studied for their potential application involving telecommunications, optical information process and storage1. It has been found that the molecular hyperpolarizability of the NLO chromophores varys dramatically depending upon the donor-acceptor abilities as well as the nature of the conjugated bridge.Carbazole molecule has an isoelectronic structure of diphenylamine, and thus the introduction of electron acceptor (…