顺丁烯二酸酐封端的新颖聚酰亚胺的合成及其结构性能研究Ⅰ．酰胺酸的合成及亚胺化动力学研究

报道合顺丁烯二酸酐基团的二苯甲酮四羧酸二酐双对氨基二苯醚酰胺酸（ＭＰＷ）的合成．该产物可用来制备具有优良性能的新颖聚酰亚胺。产物结构通过红外光谱、元素分析等进行表征。本文建立了用单谱ＤＳＣ法研究酰胺酸亚胺化动力学的新方法。结果表明其亚胺化反应级数ｎ＝３，在亚胺化过程中反应活化能及频率因子不随亚胺化程度增加而变化，数值亦保持不变。     

Podospermic acid, 1,3,5-tri-O-(7,8-dihydrocaffeoyl)quinic acid from Podospermum laciniatum (Asteraceae)

A phytochemical investigation of Podospermum laciniatum (L.) DC. (Asteraceae) yielded the new quinic acid derivative podospermic acid (1,3,5-tridihydrocaffeoylquinic acid), which was named after the genus it was isolated from. The structure was established by HR mass spectrometry and extensive 1D and 2D NMR spectroscopy. Podospermic acid is the first naturally occurring dihydrocaffeoylquinic acid derivative. The chemosystematic impact and the radical scavenging activity of the new compound are discussed briefly.     

Seimatoric acid and colletonoic acid:Two new compounds from the endophytic fungi,Seimatosporium sp.and Colletotrichum sp.

A new metabolite,named seimatoric acid(1),representing a new oxobutanoic acid derivative has been isolated from Seimatosporium sp., in addition to four known compounds viz.,2-hydroxymethyl-4β,5α,6β-trihydroxycyclohex-2-enone(2),(-)-phyllostine(3),(+)-epiepoxydon(4) and(+)-epoxydon monoacetate(5).Similarly one new benzoic acid derivative,named colletonoic acid(6) was isolated from the ethyl acetate fraction of Colletotrichum sp.The structures of the new compounds were elucidated by detailed ~1 H NMR,~(13)C NMR,COSY,HMQC.HMBC spectroscopic analysis,and HR-E1-MS.Seimatoric acid(1)was also isolated from another taxonomical unidentified fungal strain 4295 in ourgroup.The structures of the known compounds were elucidated by their spectral data comparison to literature data.Preliminary studies showed that colletonoic acid(6) showed good antibacterial,antifungal,and antialgal activities.     

4,5-咪唑双酰腙的合成与表征

以酒石酸为原料，经成环制酸、酯化、肼解、与芳香醛缩合，制备了7个4，5－咪唑双酰腙，并用元素分析，IR，^1H NMR,^13C NMR对它们的结构进行了表征。实验结果表明，酰肼与芳香醛在冰醋酸中进行缩合酰腙化一步，具有反应快速、产率高、条件温和、操作简便等优点。     

Epicoccamide,a novel secondary metabolite from a jellyfish-derived culture of Epicoccum purpurascens

From the inner tissue of the jellyfish Aurelia aurita a marine strain of the fungus Epicoccum purpurascens was obtained. After mass cultivation the fungus was investigated for its secondary metabolite content and found to contain the new, and most unusual tetramic acid derivative, epicoccamide (1). Epicoccamide is quite unusual since it is composed of three biosynthetically distinct subunits; glycosidic, fatty acid and tetramic acid (amino acid). The structure of the new compound was elucidated using spectroscopic methods, mainly 1D and 2D NMR, ESI-MS, and chemical degradations.     

A new triterpenoid acid from <Emphasis Type="Italic">Schisandra henryi</Emphasis>

A new lanostane triterpenoid acid, nigranoic acid 3-ethyl ester (1), together with two known lanostane triterpenoid acids, isoschizandronic acid (2) and anwuweizic acid (3), was isolated from the stems of Schisandra henryi Clarke. The new compound was identified based on extensive spectroscopic studies including HR-ESI-MS and 2D NMR spectra, and the known compounds were identified by their spectroscopic data analysis and comparison with reports in the literature. Compounds 2 and 3 were isolated from the plant for the first time.     

gamma-Aminobutyric acid, catecholamine and indoleamine determinations from the same brain region by high-performance liquid chromatography with electrochemical detection.

A new procedure for the measurement of gamma-aminobutyric acid, norepinephrine, dopamine, serotonin and 5-hydroxyindoleacetic acid from the same brain region was developed. In general, two separate high-performance liquid chromatographic runs were performed, one for the gamma-aminobutyric acid determination and one for the determination of the monoamines. The electrochemical detection of gamma-aminobutyric acid was determined by a new procedure that utilized a small aliquot of the brain sample prepared for monoamine measurement. This assay was linear and parallel between 6 and 200 ng per 20-microliters injection with 5-aminovaleric acid utilized as an internal standard. Inter-assay variability averaged 5% throughout the assay with gamma-aminobutyric acid values in the gerbil hypothalamus of 344 micrograms/g. The catecholamine assay has been characterized previously and utilizes 3,4-dihydroxybenzylamine as an internal standard with less than 5% variability. Norepinephrine, dopamine, serotonin and 5-hydroxyindoleacetic acid levels in the gerbil hypothalamus averaged 2922, 729, 797 and 272 ng/g, respectively. This new protocol allows a wide range of neurochemicals to be determined and evaluated from the same brain region.     

Highly active catalyst for vinyl acetate synthesis by modified activated carbon

A new zinc acetate catalyst which was prepared from modified activated carbon exhibited extreme activity towards the synthesis of vinyl acetate.The activated carbon was modified by nitric acid,vitriol and peroxyacetic acid(PAA).The effect on specific area, structure,pH and surface acidity groups of carriers by modification was discussed.Amount of carbonyl and carboxyl groups in activated carbon was increased by peroxyacetic acid treatment.The productivity of the new catalyst was 14.58%higher than that of...     

A new nor-lignan from the seeds of Descurainia sophia

A new aryldihydronaphthoic acid, descuraic acid (1), was isolated from the seeds of Descurainia sophia (L.) Webb ex Prantl. The structure of 1 was elucidated by means of physico-chemical properties and spectroscopic methods (1D and 2D NMR, MS). 1 was a new nor-lignan.     

Preparation and Analytical Application of a New Chelating Ion Exchange Resin Containing Thioglycolic Acid

Starting from copolymerization of acrylonitrile and divinylbenzene by emulsion polymerization technique, a macroporous, crosslinked polyacrylonitrile copolymer was synthesized. The nitrile groups on the copolymer resin were converted into carboxylic acid groups by hydrolysis with strong alkaline solution of sodium hydroxide to obtain the resin matrix with carboxylic acid groups. A new chelating ion exchange resin containing alkylthioglycolate was prepared by esterification of carboxylic acid groups on the resin matrix and thioglycolic acid with 1,6-hexanediol as binding part. After studies of the basic characters, ion exchange ability, exchange rate and acidity of the medium, it was found that the new resin obtaind was highly selective for silver(I), mercury(II), gold(III) and bismuth(III) in acidic-aqueous solution. Separation of these metal ions from each other and concentration of these metal ions from very dilute solution were studied by liquid chromatography using a short column of this new resin. The analytical applications of this new resin are reported.     

The role of pyruvic acid as starting material in some organic reactions in the presence of SBA-Pr-SO<Subscript>3</Subscript>H nanocatalyst

Pyruvic acid contains three different reactive positions: –COOH, ketone carbonyl and methyl groups. Correspondingly, pyruvic acid was applied as starting material in the modified Niementowski reaction and Aldol condensation using SBA-Pr-SO₃H as an efficient nanocatalyst. Aldol condensation of pyruvic acid and oxindole provided a new oxindol-based carboxylic acid which was subsequently used in the Ugi four-component reaction. Moreover, through the modified Niementowski reaction of pyruvic acid, new derivatives of quiazoline were produced in the presence of SBA-Pr-SO₃H. The obtained products are important due to their potentially biological active skeletons.     

Abietane Quinones from Rabdosia serra

Rabdosiu Serra (M4-YId Hara is a chinese traditional medicine for the treatment ofhepatitis. enteritis. acute cholecystitis and dysentery'. The present communicationdescribes the first isolation of three abietane quinone diterpenoids from the herb (Figure1 ). The new abietane quinone, 16-acetoxy-7Q-ethoxyroyleanone I was elucidated. Inaddition. two known abietane quinones, horminone 2, 16-acetoxy-7-0-acetylhorminone 3and 6-sitosterol. stigmasterol. ursolic acid. palmitic acid were identifie…     

Biologically active metabolites from fungi, 19: new isocoumarins and highly substituted benzoic acids from the endophytic fungus, Scytalidium sp

Six known metabolites, two new isocoumarins 4 and 8, and one new highly substituted benzoic acid derivative 9 were isolated from the ethyl acetate culture extract of a fungal endophyte, Scytalidium sp. In addition, another new benzoic acid 10 with an unusual 1,2-dicarbonyl side chain was indirectly identified from its methylated derivatives 10a-10d.     

A new water soluble 3,6,9-trioxaundecanedioic acid-based linker and biotinylating reagent

Biotinylated peptides often have low solubility in water. In this Letter, we describe a new method to synthesize a biotinylating reagent for water-solubilizing hydrophobic peptides. The biotinyl-6-aminohexanoic derivatives prepared contain a hydrophilic 3,6,9-trioxaundecanedioic acid linker moiety between the biotin and the peptide to improve the water solubility, and also to function as a spacer. The monoesterified derivative of 3,6,9-trioxaundecanedioic acid was synthesized, and the Fmoc-protected ethylenediamine was used to link to the carboxylic group of biotin. The hydrophilic nature of this new biotin-peptide conjugate was also demonstrated in a comparative analysis of compounds containing a biotinyl-6-aminohexanoic acid or 3,6,9-trioxaundecanedioic acid derivative.     

Studies on the Chemical Structure of llexolide A

A new tritcrpene glycoside,ilexolidc-A(Ⅰ),exhibiting cardiac activity,has been isolated from the root of ilex publcscens HorJk et Am.(Ⅰ) has been determined as a β-xyloside of iicxolic acid(Ⅱ),(Ⅱ) is also a new triterpenic acid,and its structure has been assigned as 18-dehydro-20-epi-ursolic acid by chemical reactions and physical methods.The stcreochcnrstry of iicxolic acid was mainly confirmed by X-ray single crystal diffraction method.     

Beta-orcinol metabolites from the lichen Hypotrachyna revoluta

Four new beta-orcinol metabolites, hypotrachynic acid (1), deoxystictic acid (2), cryptostictinolide (3) and 8'-methylconstictic acid (4) along with the metabolites 8'-methylstictic acid (5), 8'-methylmenegazziaic acid (6), stictic acid (7), 8'-ethylstictic acid (8) and atranorin (9), that have been previously described, were isolated for the first time from the tissue extracts of the lichen Hypotrachyna revoluta (Fl?rke) Hale. The structures of the new metabolites were elucidated on the basis of extensive spectroscopic analyses. Radical scavenging activity (RSA) of the metabolites isolated in adequate amounts, was evaluated using luminol chemiluminescence and comparison with Trolox.     

Highly stable foams from block oligomers synthesized by enzymatic reactions

We have synthesized a new amphiphilic block oligomer by the enzymatic linking of a fatty acid (lauric acid) to a fructan oligomer (inulin) and tested the functionality of this carbohydrate derivative in foam stabilization. The structure of the modified oligosaccharide was found to be (Fruc)n(Glc)1CO-C11H23, which implies that on average one lauric acid molecule was linked to one inulin molecule. The new component produces foams with exceptional stability. Our results show that enzymatic acylation can produce an entirely new class of amphiphilic materials, with functionality comparable to that of synthetic block copolymers.     

Novel One-component Positive-tone Chemically Amplified I-Line Molecular Glass Photoresist Based on Tannic Acid

Molecular glass resist has been considered as one of the best choices for a new generation of lithography. In this work, a new type of photoactive compound was obtained by the esterification of tannic acid with 2-diazo-1- naphthoquinone-4-sulfonyl chloride(2,1,4-DNQ-Cl) and ditertbutyl dicarbonate. The new obtained compound possessed both a photosensitive group of diazonaphthoquinone sulfonate(2,1,4-DNQ) and a group of acidolytic protection. Upon the irradiation of the compound under 365 nm light, the former group was photolyzed and converted into indene carboxylic acid along with a small amount of sulfonic acid, which could lead to the deprotection of the latter group. As a result, a novel i-line molecular glass photoresist was formed with the chemical modification of tannic acid. The experimental results show that the modificated compound had a fair solubility in many organic solvents. The lithographic performance of the resist was evaluated on an i-line exposure system with high photosensitivity and resolution as well.     

19-epi-okadaic acid, a novel protein phosphatase inhibitor with enhanced selectivity

A new protein phosphatase inhibitor, 19-epi-okadaic acid, was isolated from the marine dinoflagellate Prorocentrum belizeanum. Its structure and conformation in solution has been determined, and important differences were found when compared with the lead compound okadaic acid. The new metabolite showed nanomolar activities, and its selectivity for PP2A versus PP1 surpasses that shown by okadaic acid 10-fold, making it one of the most selective inhibitors of this class.     

Oleanane acid from Myrica cerifera

From the twigs of Myrica cerifera L. (Myricaceae), a new oleanane triterpenic acid named myrica acid was isolated along with myricalactone and several other known constituents. The structure of the acid was determined as 3beta-hydroxy-1-oxoolean-11,13(18)-dien-28-oic acid on the basis of chemical and spectral evidence.