Two New C—21 Steroidal Glycosides from Cynanchum aurichulatum

Two new C-21 steroidal glycosides, cynanauriculoside I and cynanauriculoside Ⅱ, were isolated from the roots of Cynanchum aurichulatum. Their structures were established using spectroscopic methods including one and two-dimensional NMR.     

A Novel Preprocessing Algorithm for Three-Way HPLC Data

Orthogonal signal correction (OSC) was a data preprocessing algorithm. It ensured that the filtered information was irrelevant to concentration data while using it to filter the noise from the original data. This paper extended the OSC application range from two-way data to three-way data. Two drug data sets, Enoxacin, Norfloxacin, Ciprofloxacin and Betamethasone, cortisone acetate, prednisone acetate, showed that the application of the OSC algorithm to three-way HPLC data was feasible and needed further research.     

Preparation and characterization of trans-RhCl(CO)(TPPTS)2-intercalated layered double hydroxides

trans-RhCl(CO)(TPPTS)₂ (TPPTS=tris(m-sulfonatophenyl)phosphine) has been intercalated into Zn-Al layered double hydroxides (LDHs) by the method of ion exchange. The structure, composition and thermal stability of the composite material have been characterized by powder X-ray diffraction, Fourier transform infrared and ³¹P solid-state magic-angle spinning nuclear magnetic resonance spectroscopy, elemental analysis, thermogravimetry, and differential thermal analysis. The geometry of trans-RhCl(CO)(TPPTS)₂ was fully optimized using the PM3 semiempirical molecular orbital method, and a schematic model for the intercalated species has been proposed. The thermal stability of trans-RhCl(CO)(TPPTS)₂ is significantly enhanced by intercalation, which suggests that such materials may have prospective application as the basis of a supported catalyst system for the hydroformylation of higher olefins.     

Separation and preconcentration of ultratrace lead in biological organisms and its determination by graphite furnace atomic absorption spectrometry

A biological organism (chitosan) was utilized to preconcentrate lead ions from tap water. This preconcentration was achieved by mixing 0.8 ml of chitosan slurry with 10-50 ml of lead-containing solution and subsequently separating by centrifugation. The chitosan paste was then dissolved in 1 ml of 0.2% nitric acid and analysed by graphite furnace atomic absorption spectrometry. The extraction efficiency can approach 100% in the pH range 4-10. The amount of chitosan used was not critical. The effect of some impurities was also investigated. If six samples were prepared simultaneously, the time needed to preconcentrate each sample was less than 3 min. Two different modes of standard addition (the standard lead solutions being added before and after preconcentration) were used for analysis of tap water samples, and the results obtained by the two modes were found to be quite consistent.     

PEO／PBHE共混体系X射线散射研究

在聚环氧乙烷(PEO)/聚双酚A羟基醚(PBHE)共混体系中PEO是一个强质子受体,而PBHE是一个强质子给体,两者极易形成氢键,十分有利于形成互容对。笔者研究了PEO/PBHE共混体系的相容性,等温及非等温结晶动力学,本文根据Vonk提出的一维电子密度相关函数,分析了PEO/PBHE的SAXS现象,求得了共混体系的结晶度,片晶层厚度,过渡层厚度及长周期等结构参数。     

Separation of dideoxyribonucleosides in trace amounts by automated liquid chromatography and capillary electrophoresis.

No satisfactory high-performance liquid chromatographic (HPLC) method is currently available for the separation of the major dideoxyribonucleosides (ddNs) and their derivatives. A method involving HPLC has been developed for the separation of five major ddNs [ddA, ddC, ddI, azT and 2',3'-dideoxy-2',3'-didehydrothymidine (d4T)]. Elution of the common and modified components of DNA was also examined under the selected separation conditions of HPLC. The elution characteristics of these compounds were studied using serum plasma samples spiked with ddN derivatives. In addition, capillary electrophoresis (CE) was investigated for the separation of ddNs and their derivatives. Picomolar amounts of the five major ddNs and the metabolic product of azT [5'-O-glucuronide-3'-azido-3'-deoxythymidine (Glo-azT)] were satisfactorily resolved in 10 min by using a modification of CE. The spectral properties of the ddNs were characterized under different pH conditions and compared with those of their parent deoxyribonucleosides (dNs) because these compounds are commonly measured in HPLC by their spectral properties. The spectra of ddC and ddT derivatives resemble very closely those of dC and dT, but those of ddA and ddI differ to some extent from their parent dNs. The HPLC method was extensively examined for satisfactory resolutions of these compounds. For example, an isocratic elution method, although simple, failed to resolve these compounds and ion-pair chromatography did not offer any advantage. Gradient elution involving buffered solutions and increasing amounts of an organic modifier yielded satisfactory results. Methanol appeared to be the organic modifier of choice. A reversed-phase matrix with smaller than octadecyl alkyl chains did not produce the necessary interactions. Uniform spherical beads of smaller diameter produced superior resolutions. The separation of these compounds on three commercially available columns is discussed. The separation of human plasma samples spiked with dideoxynucleoside derivatives by HPLC was accomplished in ca. 16 min. The presence of the dNs did not interfere in their separations.     

单向拉伸聚偏氟乙烯的取向结构

本文用X射线衍射法测定了单向拉伸聚偏氟乙烯的(110)和(020)晶面的极图,拉伸温度为100℃和160℃,拉伸比从250％—420％。利用衍射强度分布数据I(φ、ψ)计算出晶面均方余弦(cos~2(?)),经坐标转换并借助Wilchin-sky方法,得到c轴相对拉伸方向的均方余弦(cos~2φ_(c,y))。当T=100℃时,拉伸伴随有晶型转化,表现为晶面衍射峰强度和位置的变化,在此基础上对α晶型和β晶型的取向分别进行了分析。     

Sesquiterpene esters from the fruits of Celastrus orbiculatus

Three new beta-dihydroagarofuran sesquiterpene esters, 6 alpha-acetoxy-9 beta-benzoyloxy-1 beta-cinnamoyloxy-8 beta-butanoyloxy-beta-dihydroagarofuran (1), 6 alpha-acetoxy-9 beta-benzoyloxy-1 beta-cinnamoyloxy-8 beta-(2-methylbutanoyloxy)-beta-dihydroagarofuran (2), and 6 alpha-acetoxy-1 beta,8 beta-dibenzoyloxy-9 beta-hydroxy-beta-dihydroagarofuran (6), together with three known compounds (3-5) were isolated from the fruits of Celastrus orbiculatus THUNB. Their structures were elucidated on the basis of spectroscopic methods. Compound 4 showed moderate activity in inhibiting LPS-induced nitric oxide production in murine macrophage RAW264.7 cells with an IC(50) value of 43.7 microM.     

丙酮一步法合成甲基异丁基酮催化剂研究

用浸渍法制备了丙酮一步法合成甲基异丁基酮负载型催化剂，考察了载体的预处理温度、添加镧助剂对催化剂性能的影响；用BET法测定了催化剂的表面积；采用H2-O2滴定法测定Pd的分散度．结果发现，用经过1．023K焙烧过的Al2O3为载体的催化剂具有较好的催化性能，添加镧助剂后催化剂的分散度、活性有较大的提高．     

Synthesis of 2,2＇-（Substituted Arylmethylene）bis（1,6,6-trimethyl 6,7,8,9-tetrahydrophenanthro[1,2-b]furan-10,11-dione） Derivatives

The reactions of tanshinone IIA with aromatic aldehydes have been investigated and several 2, T-（substituted arylmethylene） bis （1,6,6-trimethyl-6,7,8,9-tetrahydrophenanthro[1,2-b]- furan- 10, 11-dione） derivatives were obtained,