钯(Ⅱ)类抗肿瘤药物研究进展

20世纪60年代,美国密执安州立大学Rosenberg发现了顺铂具有抗癌活性,开辟了金属类抗肿瘤药物研究的新领域.经过40余年的研究,已相继成功开发了卡铂、奈达铂、奥沙利铂、舒铂、洛铂和双环铂等铂类抗肿瘤药物.虽然对于铂类抗肿瘤药物研究取得了一定的成绩,但在临床使用过程中也存在一些问题,如其毒副作用和抗药性,限制了其在临床上的进一步广泛应用.为了解决这些问题,科研工作者开始寻找新的金属类抗肿瘤药物以弥补现有铂类抗肿瘤药物的不足.在金属元素中,唯有钯(II)与铂(II)配合物具有相似或相同的结构特征,进而表现出相近或相似的化学性质.因此,继铂类抗肿瘤配合物后,钯(II)配合物作为潜在抗肿瘤药物成为一个诱人的领域.本文综述了近年来钯(II)类抗肿瘤药物的研究进展,并探讨了其构效关系,这对于指导新型钯(II)类抗肿瘤药物的合成具有重要的参考价值.     

Magnetic solid‐phase extraction of angiotensin II receptor antagonists in human urine and plasma with a reversed‐phase/cation‐exchange mixed‐mode sorbent

Biocompatible magnetic nanoparticles that featured divinylbenzene and sulfonate functionalities were used for the magnetic solid‐phase extraction of five angiotensin II receptor antagonists from human urine and plasma samples based on a reversed‐phase and cation‐exchange mixed‐mode mechanism. Under the optimized extraction conditions, coupled to high‐performance liquid chromatography with fluorescence detection, this proposed method was found to be accurate and precise with relative standard deviations of less than 11.7%, and a good recovery of 80.1–119.5% for both samples. The linear ranges were 0.2–2000 and 0.2–2500 ng/mL along with correlation coefficients above 0.9923 and 0.9928 for urine and plasma samples, respectively. Limits of detection were 0.01–5.74 and 0.01–1.31 ng/mL, respectively. The proposed magnetic solid‐phase extraction based on the magnetic nanoparticles functionalized with divinylbenzene and sulfonate was a reliable and convenient sample pretreatment method and had the potential for isolating and enriching the angiotensin II receptor antagonists in biological samples.     

Photophysics of Hypericin and Hypocrellin A in Complex with Subcellular Components: Interactions with Human Serum Albumin

Time-resolved fluorescence and absorption measurements are performed on hypericin complexed with human serum albumin, HSA (1:4, 1:1 and approximately 5:1 hypericin: HSA complexes). Detailed comparisons with hypocrellin A/HSA complexes (1:4 and 1:1) are made. Our results are consistent with the conclusions of previous studies indicating that hypericin binds to HSA by means of a specific hydrogen-bonded interaction between its carbonyl oxygen and the N1-H of the tryptophan residue in the IIA subdomain of HSA. (They also indicate that some hypericin binds nonspecifically to the surface of the protein.) A single-exponential rotational diffusion time of 31 ns is measured for hypericin bound to HSA, indicating that it is very rigidly held. Energy transfer from the tryptophan residue of HSA to hypericin is very efficient and is characterized by a critical distance of 94 A, from which we estimate a time constant for energy transfer of approximately 3 x 10(-15) s. Although it is tightly bound to HSA, hypericin is still capable of executing excited-state intramolecular proton (or hydrogen atom) transfer in the approximately 5:1 complex, albeit to a lesser extent than when it is free in solution. It appears that the proton transfer process is completely impeded in the 1:1 complex. The implications of these results for hypericin (and hypocrellin A) are discussed in terms of the mechanism of intramolecular excited-state proton transfer, the mode of binding to HSA and the light-induced antiviral and antitumor activity.     

Circular threshold quantum secret sharing

This paper proposes a circular threshold quantum secret sharing （TQSS） scheme with polarized single photons. A polarized single photon sequence runs circularly among any t or more of n parties and any t or more of n parties can reconstruct the secret key when they collaborate. It shows that entanglement is not necessary for quantum secret sharing. Moreover, the theoretic efficiency is improved to approach 100% as the single photons carrying the secret key are deterministically forwarded among any t or more of n parties, and each photon can carry one bit of information without quantum storage. This protocol is feasible with current technology.     

Synthesis and photoluminescence properties of novel europium complexes of 2'-hydroxyacetophenone and 4,6-diacetylresorcinol

Novel europium (III) complexes of the formulae Eu(OHAP)(3).2H2O, Eu(OHAP)(3)Phen, Eu2(DAR)(3).4H2O and Eu2(DAR)(3)Phen2 (HOHAP=2'-hydroxyacetophenone, H2DAR=4,6-diacetylresorcinol, Phen=1,10-phenanthroline) have been designed and synthesized in this paper. These complexes were characterized by elemental analysis, FT-IR, and UV-vis. Based on these observations, the ligands are coordinated to Eu(III) via the acetyl and phenolic oxygens, and H2DAR is concluded to be bis-bidentate donor. Photoluminescence studies showed that the several complexes emitted red luminescence. Thermo-gravimetric analysis showed that the complexes possess good thermal stability. Also, it was found that Phen as a synergic ligand, coordinated to Eu(III) in a composite system like 2'-hydroxyacetophenone and 4,6-diacetylresorcinol, could enhance the complexes luminescence intensity, quantum yield and lifetime.     

Sodium nitrite catalyzed aerobic oxidative deoximation under mild conditions

A mild, simple process for the effective deoximation of a wide range of ketoximes and aldoximes has been developed, which utilizes available NaNO(2) as the catalyst and molecular oxygen as the green oxidant. Notably Amberlyst-15, which acts as the initiator of NaNO(2), can be reused without regeneration. This environmentally benign protocol could provide a valuable synthetic method for practical applications.     

Thermotropic copolyamides from triethyleneglycol bis (4-carboxyphenyl) ether,aromatic diamines,and p-aminobenzoic acid

It is proposed that depression of the transition temperatures, especially the melting point (T_m), can be achieved by the introduction of a different amide bond structure into the copolyamides of dicarboxylic acids and diamines by copolymerization of aminocarboxylic acids, such as p-aminobenzoic acid. The effect was examined by the amount and distribution of the structure in the copolylamindes. Copolycondensations of PEG₃, p-aminobenzoic acid, and diamines with different chain lengths showed that the structural change of the amide bond in the copolymers, especially its distribution, was more important than its total amount in them. Several types of aminocarboxylic acids were briefly examined to study the effect. © 1994 John Wiley & Sons, Inc.     

{3,3′‐[2,2′‐(Ethylenedioxy)dibenzyl­idene]bis(S‐methyl dithiocarbazate)}­nickel(II)

The tetradentate N₂S₂ Schiff base ligand 3,3′‐[2,2′‐(ethyl­ene­di­oxy)di­benzyl­idene]­bis­(S‐methyl di­thio­car­ba­zate) (H₂L), prepared by the condensation of S‐methyl di­thio­carb­aza­te with 1,4‐bis(2‐formyl­phenyl)‐1,4‐dioxa­butane in a 1:2 molar ratio, reacts with nickel acetate to form the title neutral metal complex, [Ni(C₂₀H₂₀N₄O₂S₄)]. The X‐ray structure of the complex shows a distorted square‐planar geometry around the Ni atom. The monomeric units are weakly associated into dimers via a long Ni?S interaction [3.569 (1) Å]. These dimeric units are then linked by C—H?S intermolecular contacts to form a polymeric chain along the a axis.     

溶胶-凝胶法合成有机/无机杂化材料进展——1.组分间以化学键作用的有机/无机杂化材料

介绍了溶胶－凝胶法（Sol-gel process)制备组分间以化学键作用的有机／无机杂化材料的基本情况,根据合成方法进行分类,并指出其发展趋势。     

Highly efficient and diastereoselective synthesis of 1,3-oxazolidines featuring a palladium-catalyzed cyclization reaction of 2-butene-1,4-diol derivatives and imines

A palladium-catalyzed protocol for effective synthesis of 1,3-oxazolidines has been reported. This method is featured by the high diastereoselectivity (dr up to >98/2) and using the readily available 2-butene-1,4-diol derivatives and imines as substrates.