A New Quinolizidine Alkaloid from Boehmeria siamensis

Boehmeria siamensis Craib is distributed in China, Vietnam, Laos and Thailand1. The whole plants of B. siamensis were used in folk medicine2,3. Previous studies on the plants of this genus led to the isolation of different compounds such as alkaloids, flavones, lignans, triterpenoids and its glycosides4-9. Some antimicrobial alkaloids were obtained from B. cylindrical4. In the investigation of the whole plant of B. siamensis, a new alkaloid, 3-(4-hydroxyphenyl)-4-(3-methoxy -4-hydroxypheny…     

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…     

New Diterpenoid Alkaloids from Spiraea japonica var. Ovalifolia

In the investigation of the chemical constituents of Spireae japonica L. f. var. ovalifolia (Rosaceae), a shrub originated in Songming, Yunnan, five new diterpenoid alkaloids, 19-O-deethylspiramine N (1), deacetylspiramine S (2), spiramidine A (3), spiramidine B (4) and deacetylspiramine F (5), were isolated from aerial parts of the plant and structurally elucidated. Compound 1, a white amorphous powder with [(]+17.99 (c, 0.26, MeOH ), was determined to have the molecular formula of C20H…     

Separation of Six Pyridoncarboylxic Acid Derivatives by Micellar and Microemulsion Electrokinetic Chromatography

Micellar electrokinetic chromatography (MEKC) and microemulsion electrokinetic chromatography (MEEKC) are two kinds of electrokinetic capillary chromatography (EKC), which are characterized of high solubilization capacity and separation efficiency. In our previous work, some polar organic compounds and hydrophobic neutral compounds were separated successfully by EKC1-3. In this paper, these methods were used for separating six pyridoncarboylxic acid derivatives with similar structures. T…     

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 (…