Thienocoumarin derivatives: interaction with nucleic acids and synthetic polydeoxyribonucleotides

This paper reports the photobiological properties of two new thienocoumarins, 4,6,9-trimethyl-2H-thieno[3,2-g]-1-benzopyran-2-one (compound I) and the 6,9-dimethyl-4-methoxymethyl-2H-thieno[3,2-g]-1-benzopyran-2-one (compound II). Cell growth inhibition studies have revealed significant antiproliferative potency on human tumor cell lines. The photoaddition process of these tritium-labeled derivatives was investigated using various nucleic acid structures (calf thymus DNA, bacterial DNA, and synthetic polydeoxyribonucleotides). The results obtained show that both compounds photobind to DNA to a higher extent than 8-MOP, taken as the reference drug. The capacity to form interstrand crosslinks into DNA helix was also evaluated. Interestingly, notwithstanding the lack of cutaneous phototoxicity, II revealed a good ability to induce diadduct formation.     

卟啉钴分子筛的制备,表征和催化性能的研究

用液－固相分步合成法将新型四卤四甲基卟啉诱捕在经Ｃｏ＾２＋交换的ＮａＸ分子筛超笼内，利用索式提取器洗净分子筛外表面吸附的卟啉后，采用ＵＶ－Ｖｉｓ、ＩＲ、ＳＥＭ、ＤＴＡ、Ｘ射线衍射分析、吸附等手段对诱捕在超笼内的卟啉予以表征。进一步对比研究了卟啉、分子筛和诱捕卟啉分子筛的催化性能。结果表明，卟啉与分子筛结合后，催化活性大大提高。     

Synthesis of secondary and tertiary aminofurazans

Reactions of nitrofurazans with primary and secondary amines were studied. Conditions were found which allow the efficient replacement of the nitro group with these nucleophiles. Transformations of the amidoxime fragment, which is bound to the furazan ring and contains an amino substituent, enable one to substantially expand the spectrum of polyfunctional derivatives. The structures of the amines synthesized were studied by X-ray diffraction analysis.     

Structures and conformations of metabolites of antitumor cyclic hexapeptides, RA-VII and RA-X.

Metabolites of antitumor cyclic hexapeptides, RA-VII and -X which were isolated from Rubia cordifolia were studied by hepatic microsomal biotransformation in rats and in bile juice of rabbits to which these drugs were administered intravascularly. Their structures and conformations were elucidated by two-dimensional nuclear magnetic resonance techniques, temperature effect on NH protons and nuclear Overhauser effect experiments. Specific N-demethylation of Tyr-3, O-demethylation and hydroxylation at aromatic rings of Tyr-3 and -5 were observed. Compared with metabolites of RA-VII, most of RA-X was excreted unchanged in the bile juice. Relationship among their structures, conformations and antitumor activities is also discussed.     

Synthesis and cytotoxic activity of 11-nitro and 11-amino derivatives of acronycine and 6-demethoxyacronycine

Condensation of 2-chloro-3-nitrobenzoic acid with either 5-amino-7-methoxy-2,2-dimethyl-2H-chromene or 5-amino-2,2-dimethyl-2H-chromene afforded diphenylamines 14 and 15. Trifluoroacetic anhydride mediated cyclization gave the corresponding acridones 16 and 17, which were subsequently N-methylated and reduced to 11-aminoacronycine and 11-amino-6-demethoxyacronycine. These two amino compounds, which gave stable water soluble salts, were 2- to 3-fold more potent than acronycine or 6-demethoxyacronycine in inhibiting L1210 cell proliferation.     

支化聚乙烯的合成及结构与性能

以[ArNC(An)-C(An)NAr]NiBr₂[An=acenaphthyl, Ar=2,6-C₆H₃(ⁱPr)₂]为主催化剂, 以改性甲基铝氧烷(MMAO)和常规的甲基铝氧烷(MAO)为助催化剂, 研究了压力、 温度和时间等条件对乙烯聚合制备支化聚乙烯的影响, 采用高温核磁、 高温凝胶渗透色谱(GPC)及差示扫描量热仪(DSC)等对所得的聚乙烯结构进行表征. 研究发现, 以MMAO为助催化剂时, 催化活性比以MAO为助催化剂时高约1个数量级, 达到10⁷ g/(mol Ni·h); 所得聚乙烯的支化度为(45~64)/1000C, 而以MAO为助催化剂时所得聚乙烯的支化度达(82~88)/1000C. 对支化聚乙烯的力学性能进行了分析, 并与低密度聚乙烯(LDPE)和二元乙丙橡胶(EPM)进行比较. 结果表明, 支化聚乙烯拉伸强度达27.90 MPa, 比LDPE(14.40 MPa)和EPM(5.44 MPa)高, 但支化聚乙烯的弹性模量仅为2.10 MPa, 与EPM(2.11 MPa)相近; 支化聚乙烯的断裂伸长率为774.6%, 略高于LDPE的断裂伸长率(725.6%), 比EPM的断裂伸长率(1770.1%)低.     

Preparations of anthraquinone and naphthoquinone derivatives and their cytotoxic effects

Chrysophanol and 1,8-di-O-hexylchrysophanol derivatives having nucleic acid bases at position 5 were synthesized. Furthermore, derivatives of menadione substituted at position 11 (type A naphthoquinone derivatives) or methylmenadione substituted at position 7 (type B naphthoquinone derivatives) modified with nucleic acid bases, amines and thiocyano, selenocyano or thioacetyl groups were synthesized. The cytotoxic effects of these derivatives on HCT 116 cells, which poorly express P-glycoprotein (P-gp), and Hep G2 cells, which stably express P-gp, were evaluated by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results were compared with those obtained using 5-fluorouracil (5-FU), which has been used clinically. Several of these derivatives exhibited markedly higher potent cytotoxic effects not only on HCT cancer cells but also Hep G2 cancer cells as compared with 5-FU.     

他克林及其衍生物的合成与表征

以廉价的靛红为起始原料,经靛红-3-肟和邻氨基苯甲腈两个中间体合成了他克林,并对其进行衍生化合成。所有新化合物的结构均经^1H NMR,IR,MS和元素分析确证。     

噻吩并嘧啶酮衍生物的合成及其抑菌活性

利用三组分氮杂Wittig反应,以磷亚胺2、对氯苯基异氰酸酯和酚,合成了16个未见文献报道的2-芳氧基-3-对氯苯基-3,5,6,7-四氢-4H-环戊二烯并[4,5]噻吩并[2,3-d]-嘧啶-4-酮衍生物,产率52～74%。通过IR、1H NMR、MS和元素分析对目标化合物的结构进行了表征。初步探讨了所合成化合物的抑菌活性,结果显示所合成的化合物对真菌的抑制活性优于对细菌的抑制活性,对桔青霉菌的抑制活性在65.2%以上,其中5n的抑菌率最高,达到89.1%。在化合物对细菌的抑制活性中,对绿脓杆菌的抑菌率较好,在52.8～73.0%之间,对金黄色葡萄球菌的抑制活性最低,在43.3～65.5%之间。     

Preparation and properties of polymer and quantum dot composites

Quantum dots (QDs) were prepared in an organic system through a simple and low-cost wet chemistry method. Polymer beads with a diameter of 60–70 nm and specific functional groups were synthesized by a particular seeded emulsion polymerization technique. QDs were embedded in the polymer beads with the specific functional groups through dissolving and swelling method, which provided the condition for the conjunction of biomolecules and QDs as fluorescent probes. The prepared composites were characterized with UV-Vis, PL, TEM, FTIR, CLSM and conductance titration etc. The results show that QDs are successfully embedded in polymer beads, which breaks the limitation that the conjunction of biomolecules and QDs can be achieved only for those synthesized in aqueous system. __________ Translated from Journal of Shanghai Jiaotong University, 2005, 39(1) (in Chinese)     

Ignition and combustion characteristics of compound of magnesium and boron

Compound of magnesium and boron (MB) is promising to be the ideal substitute of amorphous boron which is usually used as the raw material of boron-based fuel-rich propellants. In this study, the physical characteristics of MB and amorphous boron were studied by the scanning electron microscope, X-ray diffraction and X-ray photoelectron spectroscopy. The thermal reaction characteristics and the ignition and combustion characteristics were investigated through TG/DSC experiments and laser ignition experiments. The experimental results show that the MB particle is much more regular than amorphous boron, which favors for the preparation of boron-based fuel-rich propellants. Magnesium exists in the form of elementary substance, and boron oxide is produced during the preparation of MB which results in the longer ignition delay time of MB. The content of magnesium and the pressure have effects on the MB combustion performance. Although the combustion of magnesium can provide much heat for the combustion of boron, MB with moderate content of magnesium shows the best combustion performance. On the contrast, the ignition delay time of MB is independent on the content of magnesium and the pressure.     

Spectral parameters and Hamaker constants of silicon hydride compounds and organic solvents

Cyclopentasilane (CPS) and polydihydrosilane, which consist of hydrogen and silicon only, are unique materials that can be used to produce intrinsic silicon film in a liquid process, such as spin coating or an ink-jet method. Wettability and solubility of general organic solvents including the above can be estimated by Hamaker constants, which are calculated according to the Lifshitz theory. In order to calculate a Hamaker constant by the simple spectral method (SSM), it is necessary to obtain absorption frequency and function of oscillator strength in the ultraviolet region. In this report, these physical quantities were obtained by means of an optical method. As a result of examination of the relation between molecular structures and ultraviolet absorption frequencies, which were obtained from various liquid materials, it was concluded that ultraviolet absorption frequencies became smaller as electrons were delocalized. In particular, the absorption frequencies were found to be very small for CPS and polydihydrosilane due to σ-conjugate of their electrons. The Hamaker constants of CPS and polydihydrosilane were successfully calculated based on the obtained absorption frequency and function of oscillator strength.     

Simulation of IR and Raman spectra of p-hydroxyanisole and p-nitroanisole based on scaled DFT force fields and their vibrational assignments

This work deals with the vibrational spectroscopy of p-hydroxyanisole (PHA) and p-nitroanisole (PNA) by means of quantum chemical calculations. The mid and far FT-IR and FT-Raman spectra were recorded in the condensed state. The fundamental vibrational frequencies and intensity of vibrational bands were evaluated using density functional theory (DFT) with the standard B3LYP/6-31G* method and basis set combination and were scaled using various scale factors which yield a good agreement between observed and calculated frequencies. The vibrational spectra were interpreted with the aid of normal coordinate analysis based on scaled density functional force field. The results of the calculations were applied to simulate infrared and Raman spectra of the title compounds, which showed excellent agreement with the observed spectra.     

Solubilization of steviolbioside and steviolmonoside with gamma-cyclodextrin and its application to selective syntheses of better sweet glycosides from stevioside and rubusoside

1,4-alpha-Glucosylation at the 13-O-glycosyl moiety of stevioside (S) and rubusoside (RU) results in a significant increase of sweetness. Saponification of the 19-COO-beta-glucosyl linkage of S and RU yielded steviolbioside (SB) (= 13-O-beta-sophorosyl-steviol) and steviolmonoside (SM) (= 13-O-beta-glucosyl-steviol), respectively, both of which are poorly soluble in an acetate buffer. It was found that the solubilities of SM and SB in the buffer solution were remarkably increased in the presence of gamma-cyclodextrin (gamma-CD). SB was solubilized in the buffer solution with the aid of gamma-CD, and the solution was subjected to 1,4-alpha-transglucosylation by using a cyclodextrin glucanotransferase-starch system to give a mixture of products which were glucosylated at the 13-O-glycosyl moiety. This mixture was acetylated, and the acetate was subjected to chemical beta-glucosylation of 19-COOH followed by deacetylation to afford compounds which have superior sweetness to S. In the same way, derivatives with superior sweetness were selectively prepared from RU through SM.     

Structure of cholesteric gels and their electrically induced light scattering and colour changes

Abstract

Networks with a helical structure containing large amounts of low mass liquid crystal molecules (gels) were produced by photopolymerization of a nematic diacrylate in the presence of low mass cholesteric mixtures. Prior to polymerization the systems selectively reflected a band of circularly polarized light. Upon polymerization, the gels obtained gave rise to two reflection peaks which were subsequently associated with polymer rich and polymer poor phases. At high network concentrations (>40 per cent w/w) one of the peaks did not appear, indicating that the behaviour of the molecules which were not chemically attached to the network was totally dominated by the network. From the gap required for the suppression of the rotation of the director, it was estimated that the molecules, which were not crosslinked, were confined in layers thinner than 85 nm. The gels were very transparent and did not give rise to excess light scattering as compared with the monomeric state. Upon application of an electric field, colour changes as well as light scattering were induced. These efffects were found to be highly dependent on the state of the polarization of the light as well as the kind of field applied. The response times were very short and they depended strongly on the structure of the network.     

Studies on formic acid-catalyzed dimerization of isorhapontigenin and of resveratrol to tetralins

The formic acid-catalyzed dimerization of stilbenes, isorhapontigenin and resveratrol, offers a route to tetralin derivatives. Seven products have been obtained, four of which were trisubstituted tetralins and three of which were formed from tetralins by losing substituted benzene groups and methoxy groups during the Diels-Alder reaction. The structures and configurational assignments of the compounds were elucidated mainly by spectroscopic analysis and a possible mechanism is proposed for the reaction. The anti-inflammatory activities of some derivatives obtained were also evaluated.     

氰基取代的含杂环烯酮缩胺的合成及其波谱和结构特性

由氰基乙酸酯或丙二腈先制得氰基取代的烯酮缩硫醇, 然后与二胺反应合成了氰基取代的含杂环烯酮缩胺, 测定了它们的UV、IR、^1H及^1^3C NMR等波谱, 并测定了其中两个化合物的晶体结构, 对所得的波谱和结构特性进行了讨论。     

维生素A在胶束溶液中衰变动力学及机理研究

利用紫外光谱方法测定了维生素A及其乙酸酯在不同胶束水溶液中的衰变速率常数和衰变活化参数. 数据显示, 维生素A及其乙酸酯在阴离子胶束溶液SDS中的衰变速度要远大于在阳离子胶束溶液CTAB和中性胶束溶液TX-100中的衰变速度. 机理分析表明, 维生素A及其乙酸酯在水溶液中的衰变是经过先质子化, 再脱去一分子水或乙酸生成碳正离子中间体, 碳正离子再脱去质子, 经重排后得到最终产物脱水维生素A.     

两种络合剂对Ce-Sn-O复合氧化物结构与性能的影响

分别以柠檬酸、葡萄糖为络合剂, 用溶胶-凝胶法制备了CeO2和掺杂少量Sn的Ce-Sn-O复合氧化物, 利用XRD、TPR、FT-IR、比表面法、TEM等方法表征了四种催化剂的物理化学性质, 同时以甲烷催化燃烧反应为探针对其进行了活性评价. 结果表明, 以葡萄糖为络合剂合成的掺杂锡后的样品其甲烷完全转化温度较低, 比表面积较大, 通过透射电子显微镜观察, 平均晶粒大小为14 nm 左右, 且分散性良好, 而相比之下柠檬酸为络合剂合成的样品出现明显的团聚现象.     

Development and Evaluation of Sampling and Analytical Techniques for Investigating Air-Water Exchange of Chemicals

Abstract

Gas exchange across the air-water interface is one of the three major transport pathways for atmospheric inputs of organic pollutants in the Great Lakes. It is essential to advance our knowledge of the air-water exchange processes to improve our understanding of the environmental pathways and fate of a variety of persistent and toxic chemicals. Two complementary prototype devices were developed and tested for direct characterization of air-water exchange processes. One was a sparger device which was used to determine the (truly) dissolved concentration of a given chemical in water, and hence its potential for diffusive transfer at the air-water interface. The other was a flux chamber with which the chemical mass transfer rate from the water surface to the atmosphere (or vice versa) was determined. Ambient air and air from the sparger and flux chamber were collected/concentrated on multi-bed adsorbent tubes, followed by thermal desorption GC-MS analysis. Collected water samples were filtered and then concentrated on adsorbent tubes which were subject to similar thermal desorption GC-MS analytical procedures. The combination of these techniques provides a useful means for the estimation of the mass transfer rates of chemicals across the air-water interface.