Two New ent-Kaurane Diterpenoids from Isodon xerophilus

In continuation of our research on diterpenoids in the Isodon species, several newcompounds"' were obtained from the leaves oflsodon xerophilus (C. Y. Wu et H. W. Li)H. Hara (Labiatae), a perennial shrub native to Yunnan province. Further fractionation ofthe EtOAc extract led to the isolation of tWo new enl-kauranoids, xerophilusin E (l) andxerophilusin F (2). This paper deals with the structUral elucidation of the newcompounds.Xerophilusin E (l), a minor constitUent, was obtained as p…     

Analysis of functional groups on the surface of plasma-treated carbon nanofibers

Plasma chemically modified carbon nanofibers were characterized by X-ray photoelectron spectroscopy with regard to the content of carbon, oxygen, and nitrogen and the contribution of carboxylic groups or ester, carbonyl and hydroxylic groups or ether on the surface. Unfortunately, X-ray photoelectron spectroscopy only provides an average value of the first 10 to 15 molecular layers. For comparison, depth profiles were measured and wet chemical methods were applied to estimate the thickness of the functionalized layer and the distribution of oxygen-containing functional groups within the near-surface layers. The results indicate that the fiber surface is covered by a monomolecular oxygen-containing layer and that plasma treatment allows a complete oxygen functionalization of the uppermost surface layer. The best conditions for plasma treatment found within the set of parameters applied to generate complete functionalization are: plasma gas O(2)/Ar ratio 1:1, gas pressure 1-1.5 hPa, plasma power 80 W, treatment time >or= 5 min. Additionally, three quick and easy methods are presented to estimate the efficiency of plasma treatment with regard to surface functionalization: pyrolysis, contact angle measurements, and light permeability measurements of aqueous carbon nanofiber suspensions.     

Novel photopolymerizable biodegradable triblock polymers for tissue engineering scaffolds: synthesis and characterization

For use in micro-patterned scaffolds in tissue engineering, novel diacrylated triblock macromers (PLA-b-PCL-b-PLA, PGA-b-PCL-b-PGA and PCL-b-PEO-b-PCL) were synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). All diacrylated polymers were designed as triblock copolymers and involved biodegradable blocks of relatively non-polar epsilon-caprolactone (CL) and polar monomers such as glycolide (GA), lactide (LA) or ethylene oxide (EO). All triblock polymers were prepared in molecular weights of a few kilo daltons via the anionic ring-opening polymerization (ROP) of the corresponding lactide, glycolide or caprolactone using stannous octoate [Sn(Oct)(2)] as catalyst. The polymers had low polydispersity indices, ranging from 1.23 to 1.56. Biodegradable polymeric networks were prepared with conversions of 72-84% via photopolymerization of the triblock diacrylated polymers with 2,2-dimethoxy-2-phenylacetophenone (DMPA) as photoinitiator. PLA-b-PCL-b-PLA copolymers crumbled easily and were not suitable for micro-patterning. PGA-b-PCL-b-PGA copolymers had higher water contact angles than PCL-b-PEO-b-PCL and were also cytocompatible with Fibroblasts 3T3.     

Preliminary study on dual fluorescence behavior of porphyrin

It is well known that porphyrin derivatives play a key role in the primary process of photo-synthesis[1], in which porphyrins directly absorb the sunlight or indirectly acquire excitation en-ergy from light-harvesting antenna system to reach their excited state, and then donate electrons to quinone acceptors to yield a series of charge-separated species. In general, only first singlet ex-cited state of porphyrins is involved in energy transfer process[2]. However, highly excited state (S2 stat…     

Enantioselective iodolactonization catalyzed by chiral quaternary ammonium salts derived from cinchonidine

Chiral quaternary ammonium salts derived from cinchonidine have been applied to catalyze the stereoselective iodolactonizations of trans-5-aryl-4-pentenoic acids leading to a mixture of two regioselectively iodolactonized products with fair to excellent yield (37-98%) and moderate enantioselectivity (exo = 42.0% ee, endo = 31.0% ee) under mild conditions. This work is the first example of asymmetric iodolactonization reaction in the presence of less than a stoichiometric amount of chiral reagent.     

硼化合物的研究XX:乙醇胺合三(2-呋喃基)硼烷的合成及其转化

2-呋喃基锂与(N,N-二乙胺基)二氯硼烷的反应是以三烃基化的方式发生,因而可用于制取三(2-呋喃基)硼烷,并可以得到乙醇胺配合物1的稳定形式。乙醇胺合三(2-呋喃基)硼烷(1)可在稀酸中游离出三(2-呋喃基)硼烷,可与吡啶形成吡啶合三(2-呋喃基)硼烷2;化台物1中的呋喃环被8-羟基喹啉或8-羟基喹哪啶裂开以后,分别形成含 B-N 内配键的二呋喃基硼螯合物3及4。化合物1～4均经元素分析及有关波谱鉴定。     

周岁内幼儿头发中锌钙含量的动态分析

对合肥市16671名1－12个月幼儿的发锌，钙含量进行了测定，并对测定值进行了统计分析。结果表明，锌，钙的含量随着月龄的增加呈直线递减。并给出了发锌，钙含量的趋势线方程，丰富了目前文献给出的发锌，钙的标准值，为及时准确判断周岁内幼儿微量元素锌，钙缺乏程度提出依据。     

Über die thermischen Eigenschaften von Heteropolysäuren des Typs H3+n[PVnMo12−nO40] · x H2O (n = 0, 1, 2, 3) II. Raman- und IR-spektroskopische Untersuchungen

On the Thermal Behaviour of Heteropoly Acids of the Type H_3+n[PV_nMo_12?nO₄₀] · x H₂O (n = 0, 1, 2, 3). II. Raman and Infrared Spectroscopic Investigations The investigation of de- and rehydratization of the heteropoly acids H_3+n[PV_nMo_12?nO₄₀] · x H₂O (n = 0, 1, 2, 3) shows typical changes in the region of valence and bridging vibrations in the Raman and infrared spectra, in particular during the existence of ?anhydrous”? forms. The time dependence of rehydratization is also demonstrated well with a special Raman sample technique.     

硼化合物的研究——Ⅴ.氢硼酸π-芳烃-π-环戊二烯基铁的合成和性质

本文研究了氢硼酸根(B_(12)H_(12)~(2-)、B_(10)H_(10)~(1-)、B_(11)H_(14)~-)和π-芳烃-π-环戊二烯基铁阳离子的反应,合成了36个氢硼酸π-芳烃-π-环戊二烯基铁化合物。通过元素分析和红外光谱测定确定了化合物的组成。部份化合物还作了~1H NMR鉴定。对化合物的性质,包括它们的热行为,进行了较详细的研究。DTA仪测得的结果表明,(1)当阳离子相同时,化合物的热稳定性的顺序为:[ArFeC_5H_5]_2B_(12)H_(12)>[ArFeC_5H_5]_2B_(10)H_(10)>[ArFeC_5H_5]B_(11)H_(14);(2)当氢硼酸根相同时,其热稳定性受芳环上取代基的影响。     

水相法合成二氯二甲茂钛与水杨酸类配合物

Ｃｐ2 ＴｉＣｌ2 具有很好的抗癌活性 ,已成为第三代抗癌药物[1 - 3] 。为了寻求活性更高的抗癌药物 ,探索抗癌机理 ,我们用 (ＭｅＣｐ) 2 ＴｉＣｌ2 、水杨酸或其衍生物 ,按水相法合成了甲茂钛的水杨酸类配合物。合成路线如下图所示 :其中 :Ⅰ为ｐＨ <4 ,Ｘ =Ｈ ,Ｙ =Ｈ的产物 ;Ⅱ为ｐＨ <4 ,Ｘ =Ｈ ,Ｙ =ＮＯ2 的产物 ;Ⅲ为ｐＨ >6 ,Ｘ =ＮＯ2 ,Ｙ =ＮＯ2 ,Ｚ =Ｏ的产物 ;Ⅳ为ｐＨ >6 ,Ｘ =Ｈ ,Ｙ =Ｈ ,Ｚ =Ｓ的产物。 (Ⅰ～Ⅳ为新化合物 )1　实验部分1 .1　仪器与试剂水杨酸、ＴｉＣｌ4,ＡＲ ;5 -硝基水杨酸、3,5 -二硝基水杨酸、5 -磺基…