胀果皂甙Ⅲ和Ⅴ的结构鉴定

从胀果甘草根茎中获得２个皂甙（１和３），依其理化性质和波谱分析，将其结构确定为：异甘草次酸－３－Ｏ－β－Ｄ－６＂－正丁基－吡喃葡萄糖醛酸基－（１→２）－β－Ｄ－６＇－乙基－吡喃葡萄糖醛酸甙（１）、异甘草次酸－３－Ｏ－β－Ｄ－６＂－正丁基－吡喃葡萄糖醛酸基－（１→２）－β－Ｄ－６＇－正丁基－吡喃葡萄糖酸甙（３），分别命名为胀果皂甙Ⅲ、胀果皂甙Ⅴ。     

茯苓菌核多糖的分离和结构分析

分别用０．９％ＮａＣｌ不溶液，热水，０．５ｍｏｌ／Ｌ ＮａＯＨ水溶液和８８％甲酸从新鲜茯苓菌核体中提取出５种多糖：ＰＣ１，ＰＣ２，ＰＣ２－Ａ，ＰＣ３和ＰＣ４．用ＩＲ，ＨＰＬＣ，ＧＣ，＾１ＨＮＭＲ和＾１３Ｃ ＮＭＲ等方法分析了它们的组成和结构。结果表明，ＰＣ１，ＰＣ２和ＰＣ２－Ａ由Ｄ－葡萄糖，Ｄ－木糖，Ｄ－甘露糖和Ｄ－半乳糖组成，ＰＣ１和ＰＣ２－Ａ含葡萄糖醛酸，其葡萄糖含量随提取过程的进行逐渐增加。     

2D-NMR归属1,1,1-Kestopentaose的^1H和^1^3C共振谱线

１,１,１－Ｋｅｓｔｏｐｅｎｔａｏｓｅ是菊粉（Ｉｎｕｌｉｎ）类中的一个葡果糖化合物（β－Ｄ－果糖－（２→１）－β－Ｄ－果糖（２→１）－β－Ｄ－果糖－（２→１）－α→Ｄ－葡萄糖）本文采用各种２Ｄ－ＮＭＲ技术,包括Ｈ－ＨＣＯＳＹＦ１－去偶Ｈ－ＨＣＯＳＹ ＨＭＱＣ和ＨＭＢＣ等,归属了它的Ｈ和Ｃ的谱线,并得到了有关质子间的偶合常数,为进一步分析其在溶液中的三维空间结构打下了基础。     

罂粟花粉中阿拉伯半乳聚糖的结构及圆二色性的研究

从罂粟花粉中纯化得到由等量阿啦伯和半乳糖基组成的阿拉伯半乳聚糖ＰＳ（１），经ＮＭＲ和甲基化分析，证明ＰＳ（１）分子中含有β（１→３），β（１→６），β（１→３，６）半乳吡喃糖苷键和α（１→５），β（１→３）阿拉伯呋喃糖苷键。在２００ｎｍ处，ＰＳ（１）具有正圆二色性。     

沙棘果皮水溶性多糖Hn的结构研究

沙棘果皮水溶性多糖经酸性乙醇分级和ＤＥＡＥ－ＳｅｐｈａｄｅｘＡ－２５ｓｙｇｇ层析纯化,得到多糖Ｈｎ,经ＳｅｐｈａｒｏｓｅＣＬ－４Ｂ柱层析、玻璃纤维纸电泳、比旋光度测定等方法鉴定Ｈｎ为均一多糖。经唾液淀粉酶解、部分酸水解、高碘酸氧化、Ｓｍｉｔｈ降解、甲基化分析及ＩＲ,＾１３Ｃ－ＮＭＲ,ＧＣ和ＧＣ－ＭＳ等方法,确定其基本结构中主链由１→４ｌｃ基,１→６Ｍａｎ基和１→６Ｇａｌ基构成。三者摩尔比为ｎＧｌｃ     

硫酸化高山红景天多糖(RSASL)的制备及鉴定

从高山红景天中分离出一种酸性杂多糖（ＲＳＡ）．该多糖由阿拉伯糖（Ａｒａ）、鼠李糖（Ｒｈａ）、半乳糖（Ｇａｌ）、木糖（Ｘｙｌ）、葡萄糖（Ｇｌｃ） 与半乳糖醛酸（ＧａｌＡ）组成,其单糖摩尔比为１．００∶３ ．２３∶０ ．２６∶０ ．３４∶０ ．８４∶１０．２４．用氯磺酸－吡啶法制备硫酸化高山红景天多糖（ＲＳＡＳＬ）．用离子色谱法测定ＲＳＡＳＬ 中Ｓ的质量分数为１１．０１％ ,其硫酸基取代度为０．８５．用红外光谱,紫外光谱,Ｓｅｐｈａｒｏｓｅ ＣＬ－４Ｂ柱层析,激光解吸电离飞行时间质谱等方法鉴定,ＲＳＡＳＬ均显示了多糖硫酸酯的特征     

（四甲基二硅撑）双（3－三甲硅基环戊二烯基）－四羰基二铁的反应性

标题化合物（Ｍｅ_２ＳｉＳｉＭｅ_２）［η￣５－（３－Ｍｅ_３ＳｉＣ_５Ｈ_３）Ｆｅ（ＣＯ）_２］_２／（μ－ＣＯ）_２（Ａ）分子中的Ｆｅ－Ｆｅ键被钠汞齐还原断裂，生成相应的双铁负离子，分别与ＭｅＣＯＣｌ、ＰｈＣＯＣｌ、ＰｈＣＨ_２Ｃｌ、ＣｌＣＨ_２ＣＯＯＣ_２Ｈ_５和Ｐｈ_３ＳｎＣｌ进行亲核取代反应，生成在铁原子上引入相应取代基的产物（Ｍｅ_２ＳｉＳｉＭｅ_２）［η￣５－（３－Ｍｅ_３ＳｉＣ_５Ｈ_３）Ｆｅ（ＣＯ）_２Ｒ］_２（Ｒ：ＭｅＣＯ（１），ＰｈＣＯ（２），ＰｈＣＨ_２（３），ＣＨ_２ＣＯＯＣ_２Ｈ_５（４），Ｐｈ_３Ｓｎ（５），Ｉ（６））。Ａ在氯仿中与碘反应，得到Ｆｅ－Ｆｅ断裂的双铁碘化物，但在苯中与过量碘反应，则得到Ｆｅ－Ｉ－Ｆｅ桥联的离子型化合物（Ｍｅ_２ＳｉＳｉＭｅ_２）［η￣５－（３－Ｍｅ_３ＳｉＣ_５Ｈ_３）Ｆｅ（ＣＯ）_２］_２Ｉ·Ｉ（７）。化合物６的晶体和分子结构经Ｘ射线衍射测定，６属单斜晶系，Ｐ２１／ｃ空间群，ａ＝１．７２１７（４）ｎｍ，ｂ＝０．７７５３（２）ｎｍ，Ｃ＝１．３６２９（７）ｎｍ，β＝１０３．８０（３）°，Ｖ＝１．７６７（２）ｎｍ３，Ｚ＝４，Ｄｃ＝１．６２９９·ｃｍ－１，最终偏差因子Ｒ＝０．０５４。     

（四甲基二硅撑）二（3－三甲硅基环戊二烯基）四羰基二铁及其相关化合物的合成及结构

１，２－二（三甲硅基环戊二烯基）四甲基二硅烷与Ｆｅ（ＣＯ）_５在二甲苯中于１０５～１１０℃反应除分离到少量标题化合物（Ｍｅ_２ＳｉＳｉＭｅ_２）［η－（３－Ｍｅ_３ＳｉＣ_５Ｈ_３Ｆｅ（ＣＯ）］_２（μ－ＣＯ）_２（５）外，主要是生成了脱Ｍｅ_３Ｓｉ基的产物（Ｍｅ_２ＳｉＳｉＭｅ_２）［η－Ｃ_５Ｈ_４Ｆｅ（ＣＯ）］_２（μ－ＣＯ）_２（１）及１的热重排异构体［Ｍｅ_２ＳｉＣ５Ｈ４－Ｆｅ（ＣＯ）_２］_２（２）．将５的二甲苯溶液加热回流１８ｈ，则转化为其异构体［Ｍｅ_２Ｓｉ（Ｍｅ_３ＳｉＣ_５Ｈ_３）Ｆｅ（ＣＯ）_２］_２（６）．脱硅基发生在由相应反应物制备５的过程中。且脱硅基是与反应物中（Ｍｅ_２ＳｉＳｉＭｅ_２）桥的存在有关．５的晶体结构经Ｘ射线衍射测定属单斜晶系，Ｐ２_１／ｍ空间群，晶体学数据：ａ＝０．６７８０（１）ｎｍ，ｂ＝２．２３０３（９）ｎｍ，ｃ＝０．９９８８（１）ｎｎ，；β＝９８．９６（１）°，Ｖ＝１．４９６０ｎｍ~３．Ｚ＝２，Ｄ_ｃ＝１．３６ｇ／ｃｍ~３．     

RS－联萘酚膦酰胺晶体结构及与其SS体分子力学计算结果的比较

测定了Ｏ，Ｏ（２，２′－联萘基）－Ｎ－（α－苯基乙基）膦酰胺（简称联萘酚膦酰胺，ＤＮＰＡ）ＲＳ体与乙醇形成的分子化合物晶体结构。晶体学数据为：Ｃ＿（２８）Ｈ＿（２２）ＮＯ＿３Ｐ·Ｃ＿２Ｈ＿５ＯＨ，Ｍｒ＝４９７．５，单斜晶系，Ｐ２＿１空间群，α＝９．３５９（２），ｂ＝１２．８０６（３），ｃ＝１１．６４１（Ａ），β＝１１１．６２（３）°，Ｚ＝２，Ｖ＝１２９４．０（５）（Ａ）３，Ｄｃ＝１．２７７ｇ／ｃｍ￣３，ＭｏＫａ（λ＝０．７１０７３Ａ）射线，μ＝０．１３６ｍｍ￣（－１），可观测数据３８７１个，Ｆ（０００）＝５２４，Ｒ＝０．０３５，Ｒｗ＝０．０４２。分子间以氢键相连接。ＲＳ体晶体结构与分子力学方法计算得到的ＳＳ体构象比较，发现这一对非对映体构象的差别由联萘基一边的构型决定。     

超大孔Fe和V－Ti分子筛的合成

水热法合成了具有超大孔ＭＣＭ－４１分子筛结构的含Ｐｅ和Ｖ－Ｔｉ分子筛，通过ＸＲＤ、骨架ＩＲ、ＥＳＲ、￣（２９）ＳｉＭＡＳＮＭＲ、紫外漫反射等测试表征证实，Ｆｅ原子在ＦｅＭＣＭ－４１分子筛骨架上，Ｖ和Ｔｉ同时进入Ｖ－ＴｉＭＣＭ－４１分子筛骨架。ＦｅＭＣＭ－４１的骨架红外谱除Ｆｅ分子筛的特征吸收峰６６０ｃｍ￣（－１）外，还显示９６０ｃｍ￣（－１）峰，ＥＳＲ谱出现高对称八面体环境Ｆｅ（Ⅲ）信号（ｇ＝２．０）和扭曲四面体环境Ｆｅ（Ⅲ）信号（ｇ＝４．２），而Ｖ－ＴｉＭＣＭ－４１的骨架红外９６０ｃｍ￣（－１）峰强度分别随分子筛中钛或钒的含量线性增强。约在ｇ＝１．９８处出现的超精细结构ＥＳＲ信号表明Ｖ以分散的不流动的Ｖ￣（４＋）形式存在，化学分析结果表明骨架上Ｔｉ和Ｖ原子相互间不排斥。     

Structural investigation and biological activity of the lipooligosaccharide from the psychrophilic bacterium Pseudoalteromonas haloplanktis TAB 23

Pseudoalteromonas haloplanktis TAB 23 is a Gram-negative psychrophilic bacterium isolated from the Antarctic coastal sea. To survive in these conditions psychrophilic bacteria have evolved typical membrane lipids and "antifreeze" proteins to protect the inner side of the microorganism. As for Gram-negative bacteria, the outer membrane is mainly constituted by lipopoly- or lipooligosaccharides (LPS or LOS, respectively), which lean towards the external environment. Despite this, very little is known about the peculiarity of LPS from Gram-negative psychrophilic bacteria and what their role is in adaptation to cold temperature. Here we report the complete structure of the LOS from P. haloplanktis TAB 23. The lipid A was characterized by MALDI-TOF MS analysis and was tested in vitro showing a significant inhibitory effect on the LPS-induced pro-inflammatory cytokine production when added in culture with LPS from Escherichia coli. The product obtained after de-O-acylation of the LPS was analyzed by MALDI-TOF MS revealing the presence of several molecular species, differing in phosphorylation degree and oligosaccharide length. The oligosaccharide portion released after strong alkaline hydrolysis was purified by anion-exchange chromatography-pulsed amperometric detection (HPAEC-PAD) to give three main fractions, characterized by means of 2D NMR spectroscopy, which showed a very short highly phosphorylated saccharidic chain with the following general structure. α-Hepp3R,6R,4R'-(1→5)-α-Kdop4P-(2→6)-β-GlcpN4R-(1→6)-α-GlcpN1P (R=-H(2)PO(3) or -H; R'=α-Galp-(1→4)-β-Galp-(1→ or H-).     

Synthesis of Rhus succedanea lacquer film and analysis by pyrolysis-gas chromatography/mass spectrometry

Laccol, a major component of lacquer sap from Rhus succedanea, was synthesized by a Witting reaction, and then mixed with acetone powder separated from raw lacquer sap to synthesize lacquer films. The resulting lacquer films were analyzed by pyrolysis gas chromatography/mass spectrometry (Py-GC/MS), and the results were compared with that of natural lacquer film to evaluate the polymerization mechanism and film structure. The results showed that saturated and monoenyl laccol components were present only in the natural lacquer film, but not in the synthesized lacquer films. Meanwhile, alkylphenols, alkebulphenols, alkanes, and alkenes having longer carbon chains than the side chains were detected in the synthesized laccol, suggesting that the polymerization of synthetic laccol proceeds through the laccase-catalyzed nucleus-side chain CO coupling and autoxidative side chain to side chain CC coupling like natural lacquer film. The synthesized laccol films showed shallow color and hardness, which would make them useful as good preservative surface-coating materials.     

Steroid saponins and sapogenins ofAllium. XVI. Turoside C fromAllium turcomanicum

From a methanolic extract of the bulbs ofAllium turcomanicum Rgl. we have isolated a new furostanol glycoside, turoside C (I). An acid hydrolysate was found to contain the aglycone — neoagigenin (II) — and the sugars D-xylose, D-glucose, and D-galactose in a ratio of 1:4:1. The structure of the furostanol (I) has been established by methylation, enzymatic hydrolysis, and oxidative cleavage, and also by the oxidative cleavage of (II), as (25S)-5α-furostan-2α,3β,6β,22α,26-pentaol 26-O-β-D-glucopyranoside 3-O-{[O-β-D-xylopyranosyl-(1→3)]-[O-β-D-glucopyranosyl-(1→2)-O-β-D-glucopyranosyl-(1→2)]-O-β-D-glucopyranosyl-(1→4)-β-D-galacto-pyranoside}.     

An acidic polysaccharide having immunological activities from the rhizome of Cnidium officinale.

An acidic polysaccharide, designated as cnidirhan AG, was isolated from the rhizomes of Cnidium officinale Makino. It was homogeneous on electrophoresis and gel chromatography, and its molecular mass was estimated to be 5.1 x 10(4). It showed pronounced reticuloendothelial system-potentiating activity in a carbon clearance test, and had a remarkable effect on both anti-complementary and alkaline phosphatase-inducing activities. It is composed of L-arabinose: D-galactose: D-glucuronic acid in the molar ratio of 2:6:1, in addition to small amounts of O-acetyl groups. Methylation analysis, carbon-13 nuclear magnetic resonance, controlled Smith degradation and limited acid hydrolysis indicated that the core structural features of cnidirhan AG include a backbone chain composed of beta-1,3-linked D-galactose residues. Some of the galactose units in the backbone carry beta-D-galactosyl side chains at position 6. Both alpha-L-arabinosyl arabinose side chains and terminal beta-D-glucuronic acid residues are linked to the core galactan units.     

Preparation and Characterization of the Enzymatic Degradation Products of the Exopolysaccharide From Klebsiella K13

Oligosaccharides were prepared from the exopolysaccharide of Klebsiella K13 by enzymatic degradation and characterized. A phage-borne depolymerase enzyme was used to degrade the exopolysaccharide of Klebsiella K13. Bio-Gel P4 and P6 were used to purify the oligosaccharide products. The purified oligosaccharides were characterized by HPLC, mass spectroscopy, infrared spectroscopy, and NMR spectroscopy. The monosaccharide constituents of these enzymatic degradation products include D-glucose, D-galactose, D-mannose, and D-glucuronic acid. It was concluded that a pentasaccharide repeating unit with the following structure, as well as its dimer and trimer, was released from the exopolysaccharide: 3,4-O-(1-carboxyethylidene)-β-D-Galp-(1→4)-α-D-GlcpA-(1→3)-β-D-Manp-(1→4)-α-D-Glcp-(1→3)-D-Glcp     

Stereochemical Aspects of Acid-Catalyzed Cyclopropane Ring-Opening Reactions. A Stereospecific Pathway to Crinosterol and Brassicasterol

It is shown that the acid-catalyzed ring-opening of the two diastereoisomeric 23:24-methylenecholesterols 3 and 5 on treatment with gaseous HCl in acetic acid leads stereospecifically to the naturally occurring crinosterol ( 4 ) and brassicasterol ( 6 ), respectively (Scheme 1). This isomerization can be viewed as a biomimetic model of an in vivo methylation process of the type already known in plant sterol metabolism (cf. cycloeucalenol → obtusifoliol, 1 → 2 ). The synthetic application of this method provides a convenient labelling of sterol side chains for tracer experiments. The mechanistic features of the reaction with respect to its particular stereospecificity are discussed.     

Steroid saponins and sapogenins ofAllium. XV. Eruboside B fromAllium erubescens

A new steroid glycoside of the spirostan series — eruboside B (I) — has been isolated from an ethanolic extract of the bulbs ofAllium erubescens C. Koh. In an acid hydrolysate, the aglycone β-chlorogenin (II) and the sugars D-glucose and D-galactose in a ratio of 3:1 have been found. By methylation, partial hydrolysis, and oxidation the structure of the spirostanol (I) has been established as (25R)-5α-spirostan-3β,6β-diol 3-O-{[O-β-D-glucopyranosyl-(1→3)]-[O-β-D-glucopyranosyl-(1→2)]-O-β-D-glucopyranosyl-(1→4)-β-D-galactopyranoside}.     

GEL PERMEATION CHROMATOGRAPHIC ANALYSIS OF LACQUER POLYSACCHARIDE

Ten fractionated samples of Chinese lacquer polysaccharide in aqueous 0.1M NaC1 solution were studied by aqueous-phase gel permeation chromatography (GPC). The universal calibration, broad MWD calibration and corrected column dispersion were adopted to the analysis of GPC chromatograms of the polysaccharide. The molecular weights M_w, M_n and polydispersity index M_w/M_n obtained from GPC are in good agreement with the results of light scattering and membrane osmometry. It is verified that the universal calibration concept is applicable to the lacquer polysaccharide having a number of side chains.     

The predicted unfolding order of the β-strands in the starch binding domain from Aspergillus niger glucoamylase

The unfolding of the β-strands in the starch binding domain from Aspergillus niger glucoamylase was predicted to follow the order of β3→β2→β6→β5→β4→β1→β7 by 600 ps molecular dynamics simulations at 300, 400, and 600 K. The interior region around β-strands 2 and 3 acts as the initiation site for unfolding. β-Strands 1 and 7 are probably stabilized by the disulfide bond formed between Cys509 and Cys604. β-Strand 4 is stabilized by forming an antiparallel β-sheet with β-strand 1. Hydrophobic and electrostatic interactions between side chains instead of the hydrogen bonds are important in stabilizing these β-strands, thus the entire starch binding domain.     

Reticuloendothelial system-activating polysaccharides from rhizomes of Panax japonicus. I. Tochibanan-A and -B

From rhizomes of Panax japonicus (Araliaceae), two polysaccharides named tochibanan-A and -B, which show reticuloendothelial-potentiating activity in the carbon clearance test in mice, were isolated. The structure of tochibanan-A (molecular mass: 23,000) was elucidated as a linear beta-1,4-D-galactan. Tochibanan-B (molecular mass: 40,000) consists of D-galactose (87.1%), L-arabinose, D-glucose and D-galacturonic acid and has a beta-D-(1----4)-linked galactopyranosyl backbone possessing GalA-(1----6)-Gal, Ara-(1----5)-Ara, Gal, and Glc side chains. The structure around the branching points and the repeating unit were investigated and a possible structure of tochibanan-B is proposed.