New Chemical Compound from Caraganajubata （pall.） Poir.

<正>A new pterocarpan glycoside,(-)-maackiain 3-O-6'-O-acrylyl-β-D-galactopyranoside(1) was isolated from the whole parts of Caragana jubata(pall.) Poir.,together with three known pterocarpan glycosides,(-)-maackiain 3-O-6'-O-acetyl-β-D-glucopyranoside(2),(-)-maackiain 3-O-β-D-glucopyranoside(3) and(-)-maackiain 3-O-β-D-galactopyranoside(4).All the compounds were isolated from the title plant for the first time.The structure of the new compound was established on the basis of detailed 1D,2D NMR and circular dichroism spectroscopic analyses.All the compounds were evaluated for their cytotoxic activities against three tumor cell lines,A549,HL-60 and P388.     

AFFINITY LABELLING OF E.coil LEUCYL-tRNA SYNTHETASE WITH 3''''-OXIDIZED tRNA~(Leu)

The E.coli leucyl-tRNA synthetase (E. C. 6. 1. 1. 4) was specifically labelled with 3'-oxidized tRNA~(Leu) (tRNA_(ox)~(Leu)).The procedure involves a Schiff's base formation and its subsequent reduction by sodium cyanoborohydride. Stoichiometric inactivation of aminoacylation was achieved with the incorporation of 1 mol of tRNA_(ox)~_(Leu) per mol LeuRS.On the other hand, the amino acid activation activity of LeuRS-tRNA_(ox) complex was partially inhibited. After extensive digestion of the complex by pancreatic ribonuclease, the amino acid activation activity was fully recovered, while the aminoacylation activity was not restored at all.The results suggest that the active sites responsible for the activities of LeuRS correlate with each other as well as differ from each other.     

Chiral Borated Esters in Asymmetric Synthesis： 1. The First Asymmetric Reaction Catalyzed by Chiral Spiroborated Esters with an O3BN Framework

The first asymmetric reaction catalyzed by chiral spiroborated esters with an O3BN framework was reported. In the presence of 0.1 equivalent of (R,S)-1 or (S,S)-1, acetophenone was reduced by 0.6 equivalent of borane in THF at 0-5℃ for 2 h to give (R)-1-phenylethanol of up to 76% ee and 73% isolated yield. Influence of reaction conditions on the stereoselectivity of the reduction was investigated and a possible catalytic mechanism of the chiral spiroborated esters toward the reduction was also suggested.     

Sebiferone,a New Triterpenoid from Stem Bark of Sapium sebiferum （L.）Roxb.

From the stem bark of Sapium sebiferum a new triterpenoid,anmed sebiferone (1),was isolated.The structure of the new compound was clucidated as 3β-acetoxy-D-friedoolen-14-en-1-one-28-oic acid on the basis of spectral and chemical methods.     

A New Chromone Derivative from Stellera chamaejasme L.

A new chromone derivative,3-[1-(2,4,6-trihydroxyphenyl)3-di-(4-hydroxyphenyl) 1-propanone-2-yl]5,7-dihydroxy-8-di(4-hydroxyphenyl)methyl-4H-1-benzopyran-4-one,named as isomohsenone was isolated from the roots of Stellera chamaejasme L.together with known chamaechromone. Its structure was determined by the analysis of MS and NMR data,especially 2D NMR spectra.     

A New Bisxanthone from Hypericumjaponicum Thunb. ex Murray

A new bisxanthone, named bijaponicaxanthone C, was isolated from the whole plant of Hypericum japonicum. The structure was elucidated as 6-[1″,5″,6″-trihydroxy-2″′-(β-hydroxy-β-methylethyl)-2″′,3″′dihydrofuran(5″′,4″′，3″′,4″′)xanthone-3″′-oxyl]- 1,3,5-trihydroxy-4-isoprenylxant-hone (1) on the basis of the spectral and chemical evidences.     

Cr^3^+的水解聚合作用IV.两种"根+节"体系之间的过渡状态

The hydrolytic polymerization of chromium (III) ion in 0.040, 0.060, 0.080 and 0.160M Cr(NO3)3 solutions was studied pH-metrically in the medium of 0.5M NaNO3 at 40+/-1 C. The average number of OH- bound per Cr^3^+ at different pH was designated as Z, the gighest value of Z was found to be about 1.0. A family of curves of Z(pH)B, each at a definite concentration B of Cr(NO3)3, was obtained. The values of both B and pH were determined from the curves and a linear relationship between -lgB and pH was found for each value of Z. From the slope of each curve of-lgB(pH)z, a value of t was obtained, which increased from 1.51 to 2.06 when Z increased from 0.10 to 1.0. This implied that the polymerized hudrolysis products were of mixed types. The data of different Z value were treated by three different methods, namely, "core + links" method, project strip method and "homoligand formation constant" method. The results obtained showed the existence of "core + links" compounds not only with two hydroxyl bridges as Cr (Cr(OH)2)n^(^3^+^n^)^+(n = 1,2,3) but also with both one and two hydroxy bridges as Cr3(OH)3, indicating that the present system was a transition from t = 2 to t = 1. The hydrolysis constants of the above compounds are as follows: lgβ = -4.19, lgβ33 = -5.28, lgβ = -8.23, lgβ64 = 12.28. The above results are in agreement with those obtained at low and medium concentration of Cr(NO3)3. Furthermore, the constants obtained by means of different methods are in good agreement with each other as well as with those reported in previous papers.     

BICYCLO[2. 2. 1] HEPT-5-ENE-2,3-DICARBOXYLIC ANHYDRIDE CAPPED ‘PMR'''' TYPE POLYAMIDE-IMIDE

The resin solution of NA capped ‘PMR' type polyamide-imide was prepared from bicyclo [2.2.1]-hept-5-ene-2, 3-dicarboxylic acid ethyl ester,1, 2, 4-trimellitic acid-2-(or-1-) ethyl ester and 4,4'-methylenedianiline in ethanol. This resin solution is specially suitable for the preparation of compo-sites. The fiexural strength of the glass cloth reinforced plastics was 6000--7000 kg/cm~2 (RM) and4000--kg/cm~2 (260°--300℃), respectively. The result of isothermal aging for 800 hours in-dicated that this composite can be used at 26℃. The mechanism of the formation of polyamide-imide was discussed by using appropriate model compounds.     

ENHANCEMENT OF THE SALT EFFECT ON THE CONFORMATION OF M. L. DNA MOLECULES BY METHYLATION

Methylated Micrococcus luteus DNA (M. L. DNA) in which the DNA methylation level was 2.39% was prepared by using Hhal DNA methylase. (The natural M. L. DNA is completely unmethylated.) The [θ]_(275) value of M. L. DNA was decreased and the —[θ]_(220-250) value was increased with increasing concentration of MgC1_2. The UV spectra of M. L. DNA at different concentration of MgCl_2 showed that a hypochromisity happens at 260nm with increasing concentration of MgC1_2. The heat-releasing of M. L. DNA also increased with increasing concentration of MgC1_2. A11 these results showed that the M. L. DNA molecules tend to shrink in space, The difference between methylated DNA and unmethylated DNA was compared. The sensitivity of methylated DNA to MgC1_2 is 40—70 fold higher than that of the unmethylated M. L. DNA.     

SYNTHESIS OF FUNCTIONAL UNSATURATED POLYESTER BY USING RARE EARTH CATALYSTS 2.TERPOLYMERIZATION OF EPICHLOROHYDRINMALEIC ANHYDRIDE-CARBON DIOXIDE WITH Y(P_(204))_3-Al(i-Bu)_3

Teroolymerization of enichlorohydrin(ECH)-maleic anhydride(MAn)-carbon dioxide(CO_2) was carried out by using Y(P_(204))_3-Al(i-Bu)_3 as catalyst for the first time.The terpolymersobtained were characterized by IR and ~1H-NMR.It was foundthat the composition of the teroolymer was influenced by theaddition mode,initial monomer charge ratio,etc.     

Structural characterisation of a water-soluble polysaccharide from tissue-cultured Dendrobium huoshanense C.Z. Tang et S.J. Cheng

A water-soluble polysaccharide TC-DHPA4 with a molecular weight of 8.0 × 10⁵ Da was isolated from tissue-cultured Dendrobium huoshanense by anion exchange and gel permeation chromatography. Monosaccharide analysis revealed that the homogeneous polysaccharide was made up of rhamnose, arabinose, mannose, glucose, galactose and glucuronic acid with a molar ratio of 1.28:1:1.67:4.71:10.43:1.42. The sugar residue sequence analysis based on the GC-MS files and NMR spectra indicated that the backbone of TC-DHPA4 consisted of the repeated units:→6)-β-Galp-(1→6)-β-Galp-(1→4)-β-GlcpA-(1→6)-β-Glcp-(1→6)-β-Glcp-(→. The sugar residue sequences β-Glcp-(1→)-α-Rhap-(1→3)-β-Galp-(1→, β-Glcp-(1→4)-α-Rhap-(1→3)-β-Galp-(1→, β-Galp-(1→6)-β-Manp-(1→3)-β-Galp-(1→, and α-l-Araf-(1→2)-β-Manp-(1→3)-β-Galp-(1→ were identified as the branches attached to the C-3 position of (1→6)-linked galactose in the backbone.     

ICP—AES法测定菜头肾中多种微量元素

为探讨测定菜头肾中多种微量元素的方法,采用HNO3-HC lO4体系湿法消化,运用ICP-AES法测定了菜头肾中的多种微量元素。结果表明,菜头肾中K、Ca、Mg、P、S、A l、Na、Fe、Mn等元素含量相对较高,变异系数范围在0.23%~8.92%之间,元素的回收率在82.9%~106.1%之间。该法简便快速,可同时测定菜头肾中多种微量元素。     

HPLC测定河套大黄中的土大黄苷含量

从河套大黄中分离纯化出活性成分土大黄苷,作为自制的标准品,利用KromasilTM C(18)(250 mm×4.6 mm I.d.,5μm)反相色谱柱,以V(甲醇):V(乙腈):V(水)=35:5:60为流动相,以320mm为检测波长,对河套大黄中土大黄苷进行测定.土大黄苷在0.427～4.190μg范围内与峰面积呈良好线性关系(r=0.9994),平均回收率为99.12%.该方法为河套大黄的质量控制奠定了基础.     

瓯柑中微量元素的测定

采用电感耦合等离子体原子发射光谱仪(ICP-AES)，对瓯柑籽、果皮、果肉汁中10种微量元素进行了测定。结果表明，瓯柑籽、果皮、果肉汁中含有丰富的人体必需微量元素，且瓯柑籽、果皮中的微量元素含量普遍高于肉汁中的微量元素的含量，这为瓯柑药效功能的进一步研究和资源综合开发利用提供科学依据。     

A New Flavonoid Ketohexofuranoside from Leaves of Crataegus pinnatifida Bge.var. major N.E.Br.

Crataegus pinnatifida Bge.var.major N.E.Br. is widely distributed in the northeast part of China. It is used as a medicinal plant to improve digestion, remove retention of food, promote blood circulation and resolve blood stasis both in traditional and folk medicine 1. Preparations of Crataegus leaves improve the heart function, the coronary blood supply and arrhythmia2. Up to now, fifty flavonoids have been isolated from Crataegus3,4. In our previous paper, some new flavonoid glycosides we…     

十六烷基三甲基氯化铵与直接蓝199的相互作用

采用吸收光谱法和电导率法,研究了阳离子表面活性剂十六烷基三甲基氯化铵（CTAC）与直接蓝199(DB199)的相互作用。 实验结果表明,当CTAC的浓度低于临界胶束浓度（CMC）时,混合溶液的电导率随CTAC浓度变化曲线与理论计算曲线基本吻合;高于CMC时,CTAC溶液中有80.88%的Cl-吸附在胶束的表面,当加入染料之后数量会降至78.48%。 混合溶液的最大吸收波长（λmax）随着CTAC浓度的增加先发生蓝移后红移。λmax处吸光度随着CTAC的浓度增大先下降后上升。     

Application of R.O.P. in polymerization of furanic oligoesters with cyclic esters: Synthesis,characterization and degradation

Furano-Aliphatic copolyesters, such as poly(propylene furanic)-co-(polycaprolactone) (PPF-co-PCL), Poly(propylene furanic)-co-(polylactide) (PPF-co-PLA) and Poly(propylene furanic)-co-(polyglycolide) (PPF-co-PGA) were prepared by ring opening polymerization (R.O.P.) using monomers derived from renewable resources. These copolyesters were characterized by ¹H-NMR, DSC and TGA. The degree of randomness determined by ¹H-NMR is close to 1, reflecting a random distribution, sometimes less than one. This indicates that these polyesters have a character to block. The hydrolytic degradation of polymers was performed at pH 4.35 at 37°C over a period of four weeks. The oxidative degradation proved a mass loss of about 50%.     

Determination of Saponins in Leaf of Panax Ginseng C. A. Mey. by High Performance Liquid Chromatography

A high performance liquid chromatography(HPLC) with UV detection was established for simultaneous determination of saponins in the leaf of Panax ginseng C. A. Mey. Nine ginsenosides(Rb1,Rb2,Rb3,Rc,Rd,F1,F2,F3,F5) and notoginsenoside Fe(NFe) were studied. Among the saponins,the ginsenosides F1,F2,F3,F5 and NFe were determined by HPLC-UV method for the first time. The determination of the ginsenosides via the HPLC-UV method was performed on a reversed-phase C18 column with gradient elution in 40 min. The line...     

珠子参化学成分分析

从珠子参根茎中分离得到7个化合物. 利用核磁共振、 质谱和红外等手段, 并结合其理化性质, 鉴定了其结构, 它们分别是24(R)-珠子参苷R1, 6-O-[β-D-吡喃葡萄糖基(1→2)-β-D-吡喃葡萄糖基]-20-O-[β-D-吡喃葡萄糖基(1→4)-β-D-吡喃葡萄糖基]-20(S)-原人参三醇、 6″-乙酰基-人参皂苷Rd、 人参皂苷Rf、 竹节参皂苷Ⅳa、 人参皂苷Rd和竹节参皂苷Ⅴ. 其中, 24(R)-珠子参苷R1和6-O-[β-D-吡喃葡萄糖基(1→2)-β-D-吡喃葡萄糖基]-20-O-[β-D-吡喃葡萄糖基(1→4)-β-D-吡喃葡萄糖基]-20(S)-原人参三醇为2个新化合物, 6″-乙酰基-人参皂苷Rd 和人参皂苷Rf为首次从珠子参根茎中得到.     

A new coumarin from Wikstroemia indica （L.） C. A. Mey

A new coumadn was obtained from the stems and roots of Wikstroemia indica (L.) C.A.Mey.Its structure was elucidated as methyl 3-(2-hydroxy-4-(7-hydroxy-6-methoxy-2-oxo-2H-chromen-3-yloxy) phenyl) propanoate by spectroscopic methods.