An Efficient Synthesis of O-Methyl Protected Emodin Aldehyde and Emodin Nitrile

An efficient synthesis of tri-O-methylemodin aldehyde was achieved via bromination of tri-O-methylemodin utilizing N-bromosuccinimide yielding the monobromo and dibromo derivatives. Sommelet reaction of the monobromomethyl derivative as well as hydrolysis of the dibromomethyl analog with aqueous silver nitrate afforded the protected aldehyde in good yield. Accordingly, both bromo derivatives can be used even when they are obtained as a mixture of the bromination reaction, which could not be controlled easily to yield the bromo products selectively. From the aldehyde the tri-O-methylemodin nitrile was prepared in a one-pot reaction using hydroxylamine-O-sulfonic acid.     

大黄素的吸附溶出伏安研究

研究了大黄素在甲醇、二氧六环和水的混合溶剂中以１％硼砂为支持电解质在静汞电极上的吸附伏安行为。建立了用微分脉冲吸附溶出伏安法测定其含量的新方法。在－０３０Ｖ（ｖｓＡｇ／ＡｇＣｌ）电位下吸附富集，可得一灵敏的还原溶出峰，峰电位－０７５Ｖ，浓度在５×１０－８～５×１０－９ｍｏｌ／Ｌ范围内与峰电流具有良好的线性关系，最低检出限为１×１０－９ｍｏｌ／Ｌ。该法用于含有大黄素体系的测定简便、快速、可靠。     

反相高效液相色谱法同时测定决明子中芦荟大黄素和大黄素

用反相高效液相色谱法分离并测定了决明子中芦荟大黄素和大黄素，建立了该中药中芦荟大黄素、大黄素分离、测定的色谱方法。色谱条件：ＯＤＳ柱，甲醇－水（８０∶２０Ｖ／Ｖ）为流动相，检测波长２２３ｎｍ。本研究为决明子的质量评价提供了科学依据。     

Combination of Methotrexate and Emodin Interacting with DNA

Abstract

The study on interaction of dsDNA with the combination of methotrexate and emodin demonstrated that emodin and methotrexate can form intermolecular hydrogen bonds that enhance the anticancer effect of methotrexate and decrease the side effects. The results show that a combination of synthetic and herbal medicines in treating cancer is very effective and can be used to select other effective combination uses of antitumor drugs. At the same time, according to different interaction models of methotrexate with dsDNA and ssDNA, methotrexate can be used to discriminate between dsDNA and ssDNA in a DNA biosensor as hybridization indicator.     

大黄素的化学合成及结构修饰研究进展

大黄素是中药大黄的主要成分,也存在于虎杖、芦荟等药用植物中,是分布广泛的一种羟基蒽醌类化合物.其药理作用表现为抗肿瘤、扩张血管、抗菌、导泻、利尿等,具有很好的临床应用价值.结合本研究组的工作综述了大黄素的化学合成方法、结构修饰和生物活性等方面的新进展.     

循环伏安法研究大黄素的电化学行为

采用循环伏安法研究了大黄素在滴汞电极上的电化学行为,应用线性扫描法提出了药用植物大黄中大黄素不需分离的直接测定方法。大黄素在pH 5.72 B-R缓冲溶液中,在-0.434 V(vs.Ag/AgCl)处产生一灵敏的极谱峰,峰电流与大黄素浓度在1×10-6~1.5×10-5mol.L-1范围内呈线性关系。试验结果表明:该体系属具有吸附性的准可逆过程体系。     

反相胶束增稳室温荧光法测定血浆中的大黄素

利用高灵敏度的气溶胶ＯＴ／环己烷／水反相胶束增稳定温荧光法，研究了中草药有效成分大黄素的荧光性质。并在最佳的实验条件下，将该法应用于血浆中痕量大黄素含量的测定。     

An Efficient Synthesis of <Emphasis Type="Italic">O</Emphasis>-Methyl Protected Emodin Aldehyde and Emodin Nitrile

Summary. An efficient synthesis of tri-O-methylemodin aldehyde was achieved via bromination of tri-O-methylemodin utilizing N-bromosuccinimide yielding the monobromo and dibromo derivatives. Sommelet reaction of the monobromomethyl derivative as well as hydrolysis of the dibromomethyl analog with aqueous silver nitrate afforded the protected aldehyde in good yield. Accordingly, both bromo derivatives can be used even when they are obtained as a mixture of the bromination reaction, which could not be controlled easily to yield the bromo products selectively. From the aldehyde the tri-O-methylemodin nitrile was prepared in a one-pot reaction using hydroxylamine-O-sulfonic acid.Received February 18, 2003; accepted March 3, 2003 Published online June 2, 2003     

Extrakte aus Seeigeleiern

Ohne Zusammenfassung     

Bis-Trifluormethansulfonate aus Monoacyl-Yliden

Tetrahydrothiopyranium-trifluoroacetyl-methylide (1) and trimethylammonium-trifluoroacetyl-methylide (2) give, in a surprising reaction, with trifluoromethane-sulfonic acid anhydride (3) the bis-trifluoromethane-sulfonate-ylides4 and5.

Herrn Prof. Dr.M. Tiler, Edvard-Kardelj-Universität Ljubljana, zum 60. Geburtstag gewidmet.     

Fasern aus Polyvinylalkohol

Ohne Zusammenfassung     

Filmbildung aus Emulsionen

Zusammenfassung Die Frage der Filmbildung aus Emulsionen, die zum Oberfl?chenschutz dienen, wird besprochen. Die entstehenden Filme werden beschrieben. Es wird zwischen leimartigen (L)-Filmen, einschichtigen Harzleim- oder HL-Filmen, zweischichtigen, „gebrochenen“ OL-Filmen und ?lartigen (O)-Filmen unterschieden. Letztere entstehen aus WO-Emulsionen. Einen Spezialfall bilden die wachshaltigen C-Filme. Einige Prüfungsmethoden werden beschrieben, die zusammen mit der mikroskopischen Filrnprüfung eine für die Technik wichtige Haltbarkeitsprognose erm?glichen.     

Wasserluftpumpen aus Aluminiumbronze

Ohne Zusammenfassung     

Filter aus Asbestpapier

Ohne Zusammenfassung     

Schmelztiegel aus Speckstein

Ohne Zusammenfassung