枸杞子糖缀合物的LbGp4糖链的结构及其免疫活性的研究

枸杞子糖缀合物LbGp4经β-消除、柱层析分离后得到一条分子量高达180800的分支多糖化合物LbGp-OL.LbGp4-OL糖基组成分为n(Rha):n(Ara):n(Gal)=0.05:1.33:1，根据甲基化、部分酸水解及^1HNMR、^13CMR分析，确定了其主要的结构，并对LbGp4和LbGp4-OL的免疫活性进行了研究。     

三种不同碳桥联双核茂钛配合物的合成及催化乙烯聚合研究

合成了3种不同结构的CnH₂n桥联双核茂钛配合物(CH₃)₂C[(C₅H₄)TiCl₂(C₅H₅)]₂(3),(CH₂)_n[(C₅H₄)TiCl₂(C₅H₅)]₂(6,n=3;7,n=4),并用1HNMR进行了表征.发现以甲苯为溶剂时,不仅提高了产率,而且有效地避免了副产物Cp₂TiCl₂的生成.研究了化合物7/MAO(甲基铝氧烷)催化乙烯聚合的反应,考察了反应条件对催化体系的影响.结果表明,催化活性随着n(Al)/n(Cat.)比的增大而提高,聚乙烯的分子量在n(Al)/n(Cat.)=500和50℃时达到最高值9.0102×10⁴;随着聚合时间的延长,催化活性下降,而产物分子量不断升高;随着温度的上升,50℃时催化活性和聚乙烯的分子量最高,分别为2.4074×10⁵gPE/(molTi·h)和6.8679×10⁴.随着桥联双核茂钛配合物碳桥的增长,催化活性增加,所得聚乙烯的分子量降低.     

三(三甲基硅)环戊二烯与六羰基钼的反应

三(三甲基硅)环戊二烯与六羰基钼在二甲苯中回流8h,反应停留在生成中间物η⁵-[(Me₃Si)_NC₅H_5-n]Mo(CO)₃H(n=2,3)(I)的阶段.不经分离,I随即分别与CCl₄·NBS及MeI反应,生成其相应的钼卤化物η-⁵[(Me₃Si)_NC₅H_5-n]Mo(CO)₃X[n=3,X=Cl(1),Br(2),I(3);n=2,X=Cl(4),Br(5),I(6)].4-6是由于茂环上脱掉1个Me₃Si基.经元素分析和IR及¹H NMR谱表征了化合物1-6的结构,并用X射线衍射测定了1的晶体结构.     

花青醛的合成工艺优化

以3-异丙基苯乙酮(1)为原料,经3步反应合成了花青醛[3-(3-异丙基苯基)丁醛(4)],并优化了反应条件。确定合成3-(3-异丙基苯基)-2-丁烯酸乙酯(2)的最优条件为：n(1)/n(磷酰基乙酸三乙酯)/n(氢化钠)=5/6/6,于室温反应12 h,收率84.5%;合成3-(3-异丙基苯基)-1-丁醇(3)的最佳条件为:n(2)/n(硼氢化钠)/n(六水合二氯化钴)/n(二异丙基胺)=10/20/1/2,于55 ℃反应24 h,收率87.8%;合成4的最优条件为: n(3)/n(乙酸酐)/n(亚硝酸钠)=5/4/15,投料顺序为:乙酸酐、3、亚硝酸钠,反应时间为2 min,收率91.0%。产物结构经¹H NMR, ¹³C NMR和MS(ESI)确证。     

香菇多糖的成分及其分子量研究

从香菇子实体中用0.9%NaCl水溶液、85%乙醇、热水、1%草酸铵、5%NaOH/0.05%NaBH₄和2%NaOH/2%尿素分别提取出四种杂多糖(L-FⅠ-L-FⅣn)和两种葡聚糖(L-FⅤ和L-FⅥn).红外光谱和高效液相色谱分析结果表明杂多糖主要由葡萄糖、葡萄糖醛酸、木糖、甘露糖、半乳糖和鼠李糖组成,而且按照分离过程的进行多糖中葡萄糖含量递增.由光散射和膜渗透压法研究了多糖的重均分子量Mw、均方根旋转半径2>^1/2、第二维利系数A₂及数均分子量M_n.L-FⅡ、L-FⅢ、L-FⅤ及L-FⅥn的M_w值依次为19.7×10⁴、192.3×10⁴、136.4×10⁴和136.7×10⁴,它们的多分散系数-Mw/-Mn在3～5范围.     

四甲基双硅桥联环戊二烯基稀土金属有机配合物的合成及[Me4Si2(C5H4)2Sm(μ-Cl)(THF)]2的晶体结构研究

四甲基双硅桥联环戊二烯基钠与无水三氯化稀土在THF溶剂中反应合成了标题配合物Me₄Si₂(C₅H₄)₂LnCl[Ln:3Nd,4Sm,5Gd,6Y]和配合物Me₄Si₂(C₅H₄):Ln(C₅H₅)(THF)n[Ln:1La,n=1;2Pr,n=0].通过元素分析、¹HNMR、13CNMR和MS确证了配合物的结构,在THF溶液中重结晶获得配合物4的单晶,x射线衍射证明晶体结构为二聚体,4为单斜晶系,空间群为P2₁/c,晶体学数据a=1.2982(3)nm,b=1.2269(3)nm,c=1.3681(2)nm,β=96.79(2)°,V=2.162(1)nm³,Z=2,D_x=1.53g/cm³,偏差因子R=0.068.     

双(O,O-二芳基硫代磷酰基)多硫物的合成

双(O,O-二芳基硫磷酰基)多硫物(Ⅰ)具有杀虫作用^[1]、增效作用^[2,3]、杀菌作用^[4],亦可用作橡胶硫化剂^[5]。R为芳基的I,除几个双二硫物(I,n=2)^[6,7]外,文献中尚未有记载,为探索它们的杀菌活性,我们用下列反应由(Ⅱ)或(Ⅲ)合成了17个行为2,3和4,R为芳基、卤代芳基的I。     

杯芳烃钕配合物均相体系催化丁二烯聚合

应用新型配体杯芳烃钕配合物与三异丁基铝以及添加Al(i-Bu)₂Cl为第三组分构成二元、三元均相催化体系催化丁二烯聚合.研究结果表明,对于杯[6,8]芳烃钕(C[n]Nd_xCl_y)/Al(i-Bu)₃/汽油体系,当n(Al)/n(Nd)=40～100,50℃时具有中等催化聚合活性,所制得聚丁二烯的粘均分子量为1×10⁵～2×10⁵,顺-1,4结构含量为89%左右,添加适量Al(i-Bu)₂Cl能提高催化活性.杯芳烃钕(C[n]Nd)构成的三元体系在n(Al)/n(Nd)=30,n(Cl)/n(Nd)=1～3时不同杯芳烃的活性次序为:C6>C4>C8     

B4O分子异构化稳定性的理论研究

采用CCSD(T)/6-311+G(2df)//B3LYP/6-311+G(d)方法, 系统研究了B₄O体系各个异构体的结构和能量, 以及重要异构体的解离和异构化稳定性. 结果表明, 单态平面三角形含-BO单元的异构体cB₃-BO ¹1能量最低, 其次是带状的异构体B₄O ¹2(10.9 kJ/mol), 并且¹1和¹2结构都具有良好的动力学稳定性. 因此对于B₄O体系, ¹1和¹2都是有可能存在的. 而文献报道的三态直线型结构BBBBO(146.0 kJ/mol)的能量比异构体¹1和¹2高得多.     

2-甲硫基-4-羟基-5-嘧啶甲酸乙酯的工艺优化

以S-甲基异硫脲半硫酸盐和乙氧基亚甲基丙二酸二乙酯为主要原料,乙醇为溶剂,合成出2-甲硫基-4-羟基-5-嘧啶甲酸乙酯,研究了2-甲硫基-4-羟基-5-嘧啶甲酸乙酯的工艺优化,考察了投料比、反应温度、反应时间等因素对产率的影响。 获得较好的反应条件:n(C₂H₆N₂S·1/2H₂SO₄):n(C₁₀H₁₆O₅):n(NaOH)=1.2:1:1.8,在室温下缓慢滴加NaOH溶液,搅拌反应6 h,酸化得白色固体产物,产率为81.1%。产物结构经熔点测定仪、¹H NMR、ESI-MS、FT-IR等技术手段得到验证。     

Complete assignment of the 13C n.m.r. spectrum of mutarotated D-ribose by integration and specific deuteration

The ¹³C n.m.r. spectrum of mutarotated D -ribose is completely assigned by using 2- and 3-deuterio-D -ribose as reference compounds. The signal intensities of the largely relaxed ¹³C n.m.r. spectrum are evaluated, and the equilibrium mixture of mutarotated D -ribose is found to consist of 6·1% α-furanose, 11·6% β-furanose, 20·3% α-pyranose and 62% β-pyranose.     

Structural features of an acidic polysaccharide with the potential of promoting osteoblast differentiation from Lycium ruthenicum Murr.

Abstract

The enhanced osteoblast differentiation is beneficial to the prevention of osteoporosis. In this study, a homogeneous polysaccharide (LRP-S2A) with the potential of promoting osteoblast differentiation was obtained from the fruits of Lycium ruthenicum, a traditional herb for treatment of postmenopausal metabolic disorders. Structural identification indicated that LRP-S2A, with a relative molecular weight of 2.65 × 10⁶ Da and an uronic acid content of 41.8%, contained Rha, Ara, Gal, Glc and GlcA in a molar ratio of 1.00 : 2.07 : 0.57 : 2.59 : 4.33 and was composed of a backbone consisting of 6-O-Me-α-(1→4)-D-GlcpA, 2-O-acetyl-α-(1→4)-D-Glcp, α-(1→2,4)-L-Rhap, β-(1→3)-D-Galp andα-(1→3,5)-L-Araf, and some branches consisting of 6-O-Me-α-(1→4)-D-GlcpA and terminal α-L-Araf. These results suggested that LRP-S2A with the potential of promoting osteoblast differentiation was a new acidic polysaccharide.     

A new hybrid (experimental–theoretical) quantitative method for detection of relative anomer concentrations in water

A novel and inexpensive hybrid (combined experimental and theoretical) approach was used to quantitatively identify anomer proportions of d-glucose, d-galactose and d-mannose in water. The study involves three parts: recording of experimental FT-IR spectra of monosaccharides in water, calculation of vibrational frequencies of all stable anomers of monosaccharides and regression analysis of theoretical and experimental intensities. No expensive experimental processes and high-level calculations were needed during the study. The results were compared with the data from pure experimental and molecular dynamic studies. It has been concluded that in water while d-glucose and d-mannose have two stable anomers, α-pyranose and β-pyranose, d-galactose has four stable anomers, α-pyranose, β-pyranose, α-furanose and β-furanose. Comparison of detected results with the literature data showed that the developed method is working for the quantitative detection of anomer proportions of monosaccharides in water.     

Structure Analysis of Pectin SB1-1 from the Root of Panax ginseng

A water-soluble pectin SB1-1 was isolated and purified from the root of Panax ginseng C. A. Mey. The HPLC analysis indicates that SB1-1 is homogenous. Its molecular weight was estimated via gel filtration to be 10000. The GC analysis indicated that it contains the monosaccharides of GalA, Gal, Ara and Rha. Their molar ratio is 2.10 : 1.00 : 0.12 : 0.13. Partial hydrolysis with acid, pectinase treatment, periodate oxidation, Smith degradation, methylation analyses, GC/MS analyses and NMR analyses were used for the structure analyses of SB1-1. The results reveal that SB1-1 has a lower branched structure. The main chain is composed of GalA and Gal; the inner part is a-1,4-linked-GalA; the border is 1,4-linked-Gal. Some of the 1,4-linked-GalA and 1.4-linked-Gal residues are substituted at O6. On an average, there is one branch for every ten hexose residues. The side chain is composed of 1,6-linked-Gal and 1,3,6-linked-Gal. The nonreduced end is composed of Rha, Ara and Gal. The main glycosidic link of SB1-1 has an a configuration.     

Analysis of the ring-form tautomers of psicose with MM3 (92)

By nuclear magnetic resonance (NMR), the four ring forms of psicose, α-and β-pyranose and α- and β-furanose, have almost equal concentrations in aqueous solution. Prediction of this equilibrium by molecular mechanics tests both the balance within the force field and the methods for including the many degrees of freedom in the system. For both the α- and β-furanoses, each of 410 different ring shapes was studied in combination with 3⁷ combinations of staggered side-group orientations. Of these, 48 and 57 initial combinations of side-group orientations contributed to the α- and β-furanose energy surfaces. The pyranoses were analyzed in two steps. First, the 38 characteristic ring conformations were optimized with the 6³ staggered side-group combinations. All combinations that gave the lowest energy at one or more of the 38 shapes (20 combinations for α-pyranose, 15 for β-pyranose) were then optimized with 4912 different ring forms. Ring conformations were generated by fixing nonadjacent ring atoms (two for furanose rings, three for pyranoses) at increments of 0.1 Å from the plane of the remaining three atoms. At a dielectric constant of 4.0, prediction was in fair agreement with the NMR results. Model northern and southern conformers contribute to the furanose equilibrium, and both chairs are important for α-psicopyranose. © 1994 by John Wiley & Sons, Inc.     

Synthesis of homochiral 2-C-perfluoroalkyl substituted d- and l-riboses

Homochiral 2-C-perfluoroalkyl substituted d- and l-riboses were synthesized via Barbier, Grignard and Ruppert type reactions. The influence of the size of the perfluoroalkyl groups, attached to C-2, on the furanose/pyranose as well as on the α-furanose/β-furanose and α-pyranose/β-pyranose ratio in solution was studied.     

肉苁蓉茎水溶性多糖SPA的结构分析

肉苁蓉为稀有的名贵中药材 ,具有补肾、益精、润肠及抗衰老等功效 [1] .研究表明 ,肉苁蓉多糖具有延缓皮肤衰老、增强机体免疫功能、促进人体外成纤维细胞的生长及促进创伤愈合 [2 ] 等生理活性作用 .对于肉苁蓉多糖的深入研究尚未见报道 ,为探讨多糖的生物活性与结构的关系 ,本文对肉苁蓉茎水溶性多糖 SPA组分进行结构分析 .有关肉苁蓉茎水溶性多糖 SPA组分的分离纯化过程见文献 [3].1　实验部分1 .1　试剂与仪器　 Sephadex G- 75 ( Pharmacia公司 ) ;二甲基亚砜 (江苏洪声化工厂 ) ;Shimadzu高压液相色谱 (日本岛津 ) ;Vavian 340 0…     

Two-Dimensional Proton Chemical Shift Correlated NMR Spectroscopy of Digitoxose1

Abstract

The hydroxyl proton coupled ¹H NMR spectra of solutions of β-d-digitoxopyranose and of an equilibrated mixture of the four ring forms of d-digitoxose in dimethylsulfoxide-d ₆ have been assigned completely by two-dimensional, proton chemical shift correlated NMR spectroscopy and spin decoupling at 400 MHz. Analysis of resolution enhanced, one-dimensional ¹H NMR spectra yielded an almost complete set of CH and OH proton-proton coupling constants for the four ring forms. The free aldehydo form of d-digitoxose in dimethylsulfoxide-d ₆ solution has been detected by means of its characteristic H-l quartet at 6 9.687. Quantitative analysis of the equilibrated mixture of the five forms of d-digitoxose gave the composition:- α-pyranose, β-pyranose, α-furanose, β-furanose, aldehydo form, 11.2, 67.3, 8.4, 13.0, and 0.1%, respectively. The ⁴ C ₁ chair conformations have been assigned to the α- and β-pyranose forms by analysis of the coupling constants and are discussed qualitatively in terms of their relative stabilities.     

Studies on chemistry and immuno‐ modulating mechanism of a glycoconjugate from Lycium barbarum L.

The detailed structure of an O‐glycan derived from the fruit of Lycium barbarum L. was elucidated based on glycosidic linkage analysis, complete and partial acid hydrolysis, ¹H‐NMR and ¹³C NMR spectroscopy. According to the experiments, the carbohydrate was in the form of polysacchride (arabinogalactan) chains with highly branched 3, 4‐galactans and terminal arabinofuranosyl substituents. The immuno‐modulating mechanism of glycoconjugate and its glycan were investigated using tritium thymidine incorporation assay, flow cytometry assay and electrophoretical mobility shift assay (EMSA). The results suggested that the immunoactive components of the fruit of Lycium barbarum L. could enhance the splenocyte proliferation in normal mice and the effects of glycan chain were stronger than those of glycoconjugate. The target cell was most likely to be B‐lymphocyte, on which existed receptor binding site acting with the glycan. In addition, the immuno‐stimulatory effect of glycoconjugate (LbGp4) and its glycan (LbGp4‐OL) was associated with activating the expression of nuclear factor KB (NF‐KB) and activator protein 1 (AP‐1).     

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