1,3—戊二烯／苯乙烯阳离子共聚合反应

本文研究了以甲苯为溶剂,ＡｌＣｌ３和ＢＦ３·ＯＥｔ２为引发剂,１,３－戊二烯（ＰＤ）与苯乙烯（Ｓｔ）的阳离子共聚合反应,并用红外光谱测定聚合物的微观结构。由共聚单体ＰＤ和Ｓｔ加入顺序的不同可生成无规共聚物Ｐ（ＰＤ－ｃｏ－Ｓｔ）和接枝共聚物Ｐ（ＰＤ－ｇ－Ｓｔ）和Ｐ（Ｓｔ－ｇ－ＰＤ）。无论是由ＡｌＣｌ３引发聚合反应,还是由ＢＦ３·ＯＥｔ２引发聚合反应,Ｓｔ上的碳阳离子的活性都高于ＰＤ上碳阳离子的活性。由ＡｌＣｌ３首先引发ＰＤ进行聚合反应,结束后再引入Ｓｔ时,聚合体系不能引发Ｓｔ聚合反应;相反ＡｌＣｌ３首先引发Ｓｔ聚合后的体系能继续引发ＰＤ的聚合反应。ＢＦ３·ＯＥｔ２无论先引发Ｓｔ或是ＰＤ,都能在聚合反应完成后接着引发另一单体而生成接枝共聚物Ｐ（ＰＤ－ｇ－Ｓｔ）和Ｐ（Ｓｔ－ｇ－ＰＤ）。二苯醚与烯丙基氯的加入,提高了碳阳离子的稳定性,增加了聚合物的分子量,但降低了碳阳离子的活性,使得聚合反应的产率降低,同时对Ｓｔ和ＰＤ碳阳离子的活性次序无明显影响     

RUTHENIUM COORDINATION COMPOUBNDS WITH POLYPYRIDINES Ⅳ SYNTHESIS AND CHARACTERIZATION OF （2－PHENYL）IMIDAZO［f］ 1， 10－PHENANTHROLINE AND THEIR Ru（Ⅱ） COORDINATION COMPOUNDS

ＲＵＴＨＥＮＩＵＭＣＯＯＲＤＩＮＡＴＩＯＮＣＯＭＰＯＵＢＮＤＳＷＩＴＨＰＯＬＹＰＹＲＩＤＩＮＥＳⅣＳＹＮＴＨＥＳＩＳＡＮＤＣＨＡＲＡＣＴＥＲＩＺＡＴＩＯＮＯＦ（２－ＰＨＥＮＹＬ）ＩＭＩＤＡＺＯ［ｆ］１，１０－ＰＨＥＮＡＮＴＨＲＯＬＩＮＥＡＮＤＴＨＥＩ...     

Ga^3＋的新萃取体系的界面特性和胶团化作用研究

研究了Ｇａ~（３＋）协萃体系（Ｇａ~（３＋）－Ｄ_２ＥＨＰＡ－Ｈ_２ＭＰＡ－正十二烷－Ｈ_２ＳＯ_４）的界面吸附和胶团形成热力学，发现该萃取体系中［Ｈ_２ＭＰＡ］影响Ｄ_２ＥＨＰＡ和Ｈ_２ＭＰＡ的界面吸附性质。在中、高［Ｈ_２ＭＰＡ］范围内Ｄ_２ＥＨＰＡ与Ｈ_２ＭＰＡ的界面吸附行为相反，Ｄ_２ＥＨＰＡ的存在也影响Ｈ_２ＭＰＡ的界面吸附行为。研究了界面张力与各因素关系的数学模型，并获得某些胶团形成和界面吸附特性的物化参数。     

CuZSM-5分子筛上苯酚羟化制苯二酚

在Ｎａ２Ｏ－ＳｉＯ２－ＣｕＯ－Ｈ２Ｏ体系中以１５％ＴＰＡＢｒ－８５％ＨＭＤＡ为模板剂合成了ＣｕＺＳＭ－５分子筛，并用ＸＲＤ，ＩＲ及ＳＥＭ等方法进行了表征，考察了ＣｕＺＳＭ－５分子筛催化苯酚与过氧化氢的羟化活性，研究了催化剂用量、反应温度、反应时间及ｎ（ＰｈＯＨ）／ｎ（Ｈ２Ｏ２）等对羟化活性的影响．     

SYNTHESIS OF 6，6＇＇＇＇－DIMETHYL－4＇，4＇＇＇－DIPHENYL－2，2＇：6＇，2＇＇：6＇＇，2＇＇＇：6＇＇＇，2＇＇＇－QUINQUE PYRIDINE AND ITS BINUCLEAR DOUBLE HELICAL COPPER COMPLEX

ＳＹＮＴＨＥＳＩＳＯＦ６，６＇＇＇＇－ＤＩＭＥＴＨＹＬ－４＇，４＇＇＇－ＤＩＰＨＥＮＹＬ－２，２＇：６＇，２＇＇：６＇＇，２＇＇＇：６＇＇＇，２＇＇＇－ＱＵＩＮＱＵＥＰＹＲＩＤＩＮＥＡＮＤＩＴＳＢＩＮＵＣＬＥＡＲＤＯＵＢＬＥＨＥＬＩＣＡＬＣＯＰＰＥＲ...     

A NEW APPROACH TO SYNTHESIZING 2－ALKOXYCARBONYL －2－METHYL ETHYL TIN TRICHLORIDES AND THEIR COMPLEXES WITH DBSO AND HMPA

ＡＮＥＷＡＰＰＲＯＡＣＨＴＯＳＹＮＴＨＥＳＩＺＩＮＧ２－ＡＬＫＯＸＹＣＡＲＢＯＮＹＬ－２－ＭＥＴＨＹＬＥＴＨＹＬＴＩＮＴＲＩＣＨＬＯＲＩＤＥＳＡＮＤＴＨＥＩＲＣＯＭＰＬＥＸＥＳＷＩＴＨＤＢＳＯＡＮＤＨＭＰＡ￥ＬａｉＪｉｎＴＩＡＮ（Ｄｅｐａｒｔｍｅｎｔ...     

CuZSM—5分子筛上苯酚羟化制苯二酚

在Ｎａ２Ｏ－ＳｉＯ２－ＣｕＯ－Ｈ２Ｏ体系中以１５％ＴＰＡＢｒ－８５％ＨＭＤＡ为模板剂合成了ＣｕＺＳＭ－５分子筛，并用ＸＲＤ，ＩＲ及ＳＥＭ等方法进行了表征，考察了ＣｕＺＳＭ－５分子筛催化苯酚与过氧化氢的羟化活性，研究了催化剂用量，反应温度，反应时间及ｎ（ＰｂＯＨ）／ｎ（Ｈ２Ｏ２）等对羟化活性的影响。     

SYNTHESIS OF LINEAR POLYSILOXANE WITH PENDANT BENZO－15－C－5 MOIETIES AND ITS TRANPORT PROPERTIES IN BULK LIQUID MEMBRANE SYSTEM

ＳＹＮＴＨＥＳＩＳＯＦＬＩＮＥＡＲＰＯＬＹＳＩＬＯＸＡＮＥＷＩＴＨＰＥＮＤＡＮＴ　ＢＥＮＺＯ－１５－Ｃ－５ＭＯＩＥＴＩＥＳＡＮＤＩＴＳＴＲＡＮＰＯＲＴＰＲＯＰＥＲＴＩＥＳＩＮＢＵＬＫＬＩＱＵＩＤＭＥＭＢＲＡＮＥＳＹＳＴＥＭＣＨＥＮＹｕａｎｙｉｎ；Ｌｕ...     

RUTHENIUM COORDINATION COMPOUNDS WITH POLYPYRIDINES V．DNA－BINDING STUDIES OF Ru（Ⅱ）COORDINATION COMPOUNDS WITH（2－PHENYL－）IMIDAZO［f］1，10－PHENANTHROLINE

ＲＵＴＨＥＮＩＵＭＣＯＯＲＤＩＮＡＴＩＯＮＣＯＭＰＯＵＮＤＳＷＩＴＨＰＯＬＹＰＹＲＩＤＩＮＥＳＶ．ＤＮＡ－ＢＩＮＤＩＮＧＳＴＵＤＩＥＳＯＦＲｕ（Ⅱ）ＣＯＯＲＤＩＮＡＴＩＯＮＣＯＭＰＯＵＮＤＳＷＩＴＨ（２－ＰＨＥＮＹＬ－）ＩＭＩＤＡＺＯ［ｆ］１，１０－...     

EVIDENCE FOR AROMATIC sp~2 C－H…O＝C INTRAMOLECULAR INTERACTION IN PYRIDINO AND BENZOBENZANTHRONE SKELETONS

ＥＶＩＤＥＮＣＥＦＯＲＡＲＯＭＡＴＩＣｓｐ~２Ｃ－Ｈ…Ｏ＝ＣＩＮＴＲＡＭＯＬＥＣＵＬＡＲＩＮＴＥＲＡＣＴＩＯＮＩＮＰＹＲＩＤＩＮＯＡＮＤＢＥＮＺＯＢＥＮＺＡＮＴＨＲＯＮＥＳＫＥＬＥＴＯＮＳ￥ＺｅｐｅｒＡＢＬＩＺ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔ?..     

硒对铅诱发动物体内变化的效应

综述了实验动物体内硒和铅的相互作用。研究结果表明,硒有拮抗铅毒的作用。全文包括上部分：（１）硒对铅诱发动物生长变化的效应;（２）硒对铅诱发动物血和器官中变化的效应;（３）三对铅诱发组织脂质过氧化的效应;（４）硒对抗铅毒性的可能机理。     

The antioxidant profile of 2,3-dihydrobenzo[b]furan-5-ol and its 1-thio, 1-seleno, and 1-telluro analogues

A novel synthesis of 2,3-dihydrobenzo[b]thiophene-5-ol based on intramolecular homolytic substitution on sulfur was reported. The "antioxidant profile" of the series of 2,3-dihydrobenzo[b]furan-5-ol (2a) its 1-thio (2b), 1-seleno (2c) and 1-telluro (2d) analogues was determined by studies of redox properties, the capacity to inhibit stimulated lipid peroxidation, the reactivity toward tert-butoxyl radicals, the ability to catalyze decomposition of hydrogen peroxide in the presence of glutathione, and the inhibiting effect on stimulated peroxidation in liver microsomes. The one-electron reduction potentials of the aroxyl radicals corresponding to compounds 2a-2d, E degrees (ArO(*)/ArO(-)) were 0.49, 0.49, 0.49, and 0.52 V vs NHE, respectively, as determined by pulse radiolysis. With increasing chalcogen substitution the compounds become slightly more acidic (pK(a) = 10.6, 10.0, 9.9, and 9.5, respectively, for compounds 2a-2d). By using Hess' law, the homolytic O-H bond dissociation enthalpies of compounds 2a-2d (340, 337, 336, and 337 kJ mol(-)(1), respectively) were calculated. The reduction potentials for the proton coupled oxidation of compounds 2a-2d (ArOH --> ArO(*) + H(+)) as determined by cyclic voltammetry in acetonitrile were 1.35 (irreversible), 1.35 (quasireversible) 1.13 (reversible), and 0.74 (reversible) V vs NHE, respectively. As judged by the inhibited rates of peroxidation, R(inh), in a water/chlorobenzene two-phase lipid peroxidation system containing N-acetylcysteine as a thiol-reducing agent in the aqueous phase, the antioxidant capacity increases (2d > 2c = 2b > 2a) as one traverses the group of chalcogens. Whereas the times of inhibition, T(inh), were slightly reduced for the oxygen (2a) and sulfur (2b) derivatives in the absence of the thiol-reducing agent, they were drastically reduced for the selenium (2c) and tellurium (2d) derivatives. This seems to indicate that the organochalcogen compounds are continuously regenerated at the lipid aqueous interphase and that regeneration is much more efficient for the selenium and tellurium compounds. The absolute rate constants for the oxidation of compounds 2a-2b by the tert-butoxyl radical in acetonitrile/di-tert-butyl peroxide (10/1) were the same-2 x 10(8) M(-)(1) s(-)(1). Whereas the oxygen, sulfur, and selenium derivatives 2a-2c were essentially void of any glutathione peroxidase-like activity, the organotellurium compound 2d accelerated the initial reduction of hydrogen peroxide, tert-butyl hydroperoxide, and cumene hydroperoxide in the presence of glutathione 100, 333, and 213 times, respectively, as compared to the spontaneous reaction. Compounds 2a-2d were assessed for their capacity to inhibit lipid peroxidation in liver microsomes stimulated by Fe(II)/ADP/ascorbate. Whereas the oxygen, sulfur, and selenium compounds showed weak inhibiting activity (IC(50) values of approximately 250, 25, and 13 microM, respectively), the organotellurium compound 2d was a potent inhibitor with an IC(50) value of 0.13 microM.     

Cyclodextrin-derived chalcogenides as glutathione peroxidase mimics and their protection of mitochondria against oxidative damage

A series of novel glutathione peroxidase (GPx) mimics based on organochalcogen cyclodextrin (CD) dimer were synthesized. Their GPx-like antioxidant activities were studied using hydrogen peroxide H₂O₂, tert-butylhydroperoxide (BHP), and cumene hydroperoxide (CHP) as substrates and glutathione as thiol co-substrate. The results showed that 6A,6B-ditelluronic acid-A,6B′-tellurium bridged γ-cyclodextrin (6-diTe-γ-CD) had the highest peroxidase activity, which was ~670-fold higher than ebselen, a well-known GPx mimic. Reduction of lipophilic CHP often proceeded much faster than reduction of the more hydrophilic H₂O₂ or BHP, which cannot bind into the hydrophobic interior of the CD. The biological activities were also evaluated for their capacity to protect mitochondria against ferrous sulfate/ascorbate-induced oxidative damage. 6-diTe-γ-CD was the best inhibitor which significantly suppressed ferrous sulfate/ascorbate-induced cytotoxicity as determined by swelling of mitochondria, lipid peroxidation and cytochrome c oxidase activity. Our data suggests that 6-diTe-γ-CD has potential pharmaceutical application in the treatment of ROS-mediated diseases.     

Regenerable Antioxidants—Introduction of Chalcogen Substituents into Tocopherols

To improve the radical‐trapping capacity of the natural antioxidants, alkylthio‐, alkylseleno‐, and alkyltelluro groups were introduced into all vacant aromatic positions in β‐, γ‐ and δ‐tocopherol. Reaction of the tocopherols with electrophilic chalcogen reagents generated by persulfate oxidation of dialkyl dichalcogenides provided convenient but low‐yielding access to many sulfur and selenium derivatives, but failed in the case of tellurium. An approach based on lithiation of the appropriate bromo‐tocopherol, insertion of chalcogen into the carbon‐lithium bond, air‐oxidation to a dichalcogenide, and final borohydride reduction/alkylation turned out to be generally applicable to the synthesis of all chalcogen derivatives. Whereas alkylthio‐ and alkylseleno analogues were generally poorer quenchers of lipid peroxyl radicals than the corresponding parents, all tellurium compounds showed a substantially improved radical‐trapping activity. Introduction of alkyltelluro groups into the tocopherol scaffold also caused a dramatic increase in the regenerability of the antioxidant. In a two‐phase lipid peroxidation system containing N‐acetylcysteine as a water‐soluble co‐antioxidant the inhibition time was up to six‐fold higher than that recorded for the natural antioxidants.     

Spectrophotometric determination of trace amounts of selenium with catalytic reduction of bromate by hydrazine in hydrochloric acid media

A method is presented for the determination of selenium, based on the catalytic effect of selenium(IV) on the reduction reaction of BrO(-)(3) by N(2)H(4).2HCl. The decolourization of Methyl Orange by the reaction products was used to monitor the reaction spectrophotometrically at 525 nm. This method is precise, highly sensitive, simple, rapid, widely applicable and selective for the determination of selenium(IV) and total selenium. The variables which affected the reaction rate were fully investigated and the optimum conditions were established. Selenium, as low as 1 ng/ml, can be determined by this method. The relative standard deviation of 20 ng of selenium was 0.94% (N = 10). The method was applied to the determination of Se(IV) in a health-care product.     

由从头算Hartree-Fock MO法对叔丁基过氧化氢与N,N-二甲苯胺反应机理的探讨

本文由从头算Hartree-Fock(STO-3G)MO法来探讨叔丁基过氧化氢(BHP)与N,N-二甲苯胺(DMA)的反应机理。该反应是由如下三种反应组成的。(1)DMA的N攻击BHP的O~1而形成N-氧化物(方式1);(2)生成氢键复合物(方式2);(3)由DMA的N攻击BHP的O~2而生成自由基(方式3)。上列三种的微挠能量经计算结果分别为0.2276、0.1687、0.2056 eV。因此,我们可得此三种反应机理的结论。     

3-O-alkylascorbic acids as free radical quenchers. II. Inhibitory effects on some lipid peroxidation models.

We previously found that 3-O-dodecylcarbomethylascorbic acid (3-RASA,3,HX-0112) exhibited a potent inhibitory effect on biochemical lipid peroxidation and that 3-RASA (3) alleviated myocardial lesions induced by ischemia-reperfusion treatment in rats. In this study we examined the mode of action of 3-RASA (3) on the inhibition of lipid peroxidation. There was no reducing activity by 3-RASA (3) (i.e., no oxide was produced) against ferric ions and superoxide anion radicals. The low reducing activity of 3-RASA (3) against a radical as compared to that of alpha-tocopherol was obtained by using a stable radical. However, 3-RASA (3) had a potent inhibitory effect, almost equal to that of alpha-tocopherol, in the model of lipid peroxidation dependent on enzymatic superoxide generation. 3-RASA (3) very strongly inhibited the chain-reaction of the peroxidation induced by Fe(2+)-linoleic acid hydroxyperoxide. On the basis of these findings, it appears that the anti-lipid-peroxidative effects of 3-RASA (3) are due to the inhibition of the radical chain-reaction, as a chain-breaking antioxidant.     

Studies on the biological activity of tocotrienols

Tocotrienols were evaluated for activity against transplantable murine tumors inoculated i.p. into mouse, and the activities of two tocotrienols and alpha-tocopherols were compared. When the compounds were injected i.p., alpha- and gamma-tocotrienols were effective against sarcoma 180, Ehrlich carcinoma, and IMC carcinoma, and gamma-tocotrienol showed a slight life-prolonging effect in mice with Meth A fibrosarcoma, but the tocotrienols had no antitumor activity against P388 leukemia at doses of 5-40 mg/kg/d. On the other hand alpha-tocopherol had only a slight effect against sarcoma 180 and IMC carcinoma. The antitumor activity of gamma-tocotrienol was higher than that of alpha-tocotrienol. Tocotrienols showed growth inhibition of human and mouse tumor cells when the cells were exposed to these agents for 72 h in vitro, whereas tocopherol did not show any marked cytotoxic activity. Alpha- and gamma-tocotrienols had inhibitory effects on lipid peroxidation of murine microsomes by adriamycin.     

Mechanism of antioxidant action of pueraria glycoside (PG)-1 (an isoflavonoid) and mangiferin (a xanthonoid).

The antioxidant activities of pueraria glycoside (PG)-1 (isoflavonoid) and mangiferin (xanthonoid) were studied and compared with PG-3 and daidzein (isoflavonoids) and with wogonin (flavonoid). PG-1 and mangiferin rapidly scavenged 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and inhibited lipid peroxidation which was initiated enzymatically by reduced nicotinamide adenine dinucleotide phosphate (NADPH) or non-enzymatically by ascorbic acid or Fenton's reagent (H2O2 + Fe2+) in rat liver microsomes. Wogonin inhibited the enzymatically induced lipid peroxidation but had no scavenging effect on DPPH radical or on the non-enzymatic peroxidation. PG-3 and daidzein did not show any of these effects. Formation of Fe2+ by NADPH-dependent cytochrome P-450 reductase was inhibited by wogonin, but not by PG-1 or mangiferin. PG-1 and mangiferin had no effect on terminating radical chain reaction during the lipid peroxidation in the enzymatic system of microsomes or in the linoleic acid hydroperoxide-induced peroxidation system. These results suggest that PG-1 and mangiferin have an antioxidant activity, probably due to their ability to scavenge free radicals involved in initiation of lipid peroxidation. In contrast, wogonin may affect NADPH-dependent cytochrome P-450 reductase action, since it inhibited only the enzymatically induced lipid peroxidation.     

Chromanols from Sargassum siliquastrum and their antioxidant activity in HT 1080 cells

Six meroterpenoids (compounds 1-6) of chromene class, including three known compounds (1-3), were isolated from Sargassum siliquastrum. The structure of these compounds was established by extensive 2D-NMR experiments such as (1)H gradient double quantum filtered correlation spectroscopy (gDQCOSY), total correlation spectroscopy (TOCSY), nuclear Overhauser effect spectroscopy (NOESY), gradient heteronuclear multiple quantum coherence (gHMQC), and gradient heteronuclear multiple bond correlation (gHMBC), and by comparison with published spectral data. The antioxidant activity of these compounds was evaluated by various antioxidant tests, such as scavenging effects on generation of intracellular reactive oxygen species (ROS), increments of intracellular glutathione (GSH) level, and inhibitory effects on lipid peroxidation in human fibrosarcoma HT 1080 cells. Compounds (1-6) significantly decreased generation of intracellular ROS and inhibited lipid peroxidation while they increased levels of intracellular GSH at a concentration of 5 μg/ml.