Synthesis of Acridine–Quinone Systems—A Potential Electrochemical Fluorescent Switch

The synthesis of various acridine-quinones is reported. The fluorescence-quenching quinone moiety has been incorporated into various acridine molecules, each having a different functionality at the ninth position of the acridine ring. It is envisaged that the quenching nature of the quinone will lead to the fluorescent properties of the acridine being controlled in a way similar to turning on a light switch.     

3-亚甲基苯并吡喃-2,4-二酮与烯醇硅醚的Diels-Alder反应合成3,4- 二氢-2H,5H-吡喃并[3,2-c][1]苯并吡喃-5-酮衍生物

通过4-羟基香豆素与苯甲醛、甲醛和戊醛缩合产生的quinone methide与烯醇硅醚的Diels-Alder反应, 以较高产率合成了一系列含有硅氧基的3,4-二氢-2H,5H-吡喃并[3,2-c][1]苯并吡喃-5-酮衍生物. 用X射线单晶衍射确定了其中5个化合物的空间构型. 利用密度泛函(DFT)方法计算反应物之间的前线分子轨道相互作用, 对反应的区域选择性进行了研究, 计算结果与实验值相符.     

Enzyme‐Free Quinone Crosslinking Reaction for Proteins: A Macromolecular Characterization Study Using Gelatin

To mimic the quinone hardening of extracellular proteins in invertebrates, we investigated an enzyme‐free crosslinking of gelatin by HQ in a neutral aqueous phase. The mixture was rapidly transformed to a yellowish brown, thermally and mechanically stable hydrogel in the presence of a simple copper(II) salt. A dehydrated thin film made of the mixture was flexible, tough, and showed a large ultimate breaking force. Physicochemical examination of the gel suggested that the basic amino acid residues (lysine, hydroxylysine, and histidine) of the protein were modified by the quinone ring to form 2–6 crosslinks per protein. The enzyme‐free crosslinking reaction is discussed with consideration of a copper(II) ion‐catalyzed oxidation of HQ and the hydroquinone/protein adducts.

     

Detection of V-type nerve agent degradation products at electrodes modified by PPy/PQQ using CaCl2 as supporting electrolyte

Electrochemical detection without derivatization was used to detect thiol-containing degradation products of V-type nerve agents. Electropolymerization of pyrrole was used for entrapment of the biocatalyst PQQ to produce a sensor. Various parameters which affect the detection processes such as the type of the supporting electrolyte used during electrodeposition and the thickness of the polypyrrole film were examined and optimized. Electocatalytic oxidation of thiols by the PPy/PQQ electrode was strongly affected by the presence of Ca²⁺ cations during electrodeposition of the PPy/PQQ. Cyclic voltammetry, linear sweep voltammetry and amperometry have been used for electrode characterization. Amperometric detection of the V-type nerve agent thiol degradation products 2-(dimethylamino)ethanethiol (DMAET) and 2-(diethylamino)ethanethiol (DEAET) was performed at 0.38 V. Linear calibration plots were observed for these compounds. The detection limits of 4.5 and 3 μM were obtained for DMAET and DEAET respectively, with sensitivities of 1.18 and 1.37 nA μM⁻¹ cm⁻².     

Phthalocyanines formed from several precursors: synthesis,characterization, and comparative fluorescence and quinone quenching

Abstract

We have synthesized a new phthalonitrile with different substituents in 4- and 5-positions (1). Cyclotetramerization of 1 yielded phthalocyanines with cobalt(II) (2), zinc(II) (3), gallium(III)chloride (4), and indium(III)chloride (5) containing diethylamino-phenoxy and hexylsulfanyl substituents on each benzene unit. Elemental analyses, Fourier transform infrared spectra, ¹H-nuclear magnetic resonance spectra, mass spectra, and ultraviolet-visible spectra were used for characterization of the phthalocyanines. The aggregation behavior of the zinc phthalocyanine derivative was studied in different concentrations. Also four chloro and four diethyllaminophenoxy substituted zinc phthalocyanine (6) and octa-diethylaminophenoxy substituted zinc phthalocyanine (7) were synthesized. These phthalocyanines (3, 6, and 7) were compared for electronic absorption spectra, fluorescence quantum yields, fluorescent lifetimes, and fluorescence quenching in the presence of benzoquinone. The fluorescence quantum yield gives the efficiency of the fluorescence process. The fluorescence lifetime is an important parameter for practical applications of fluorescence such as fluorescence resonance energy transfer and fluorescence-lifetime imaging microscopy.     

Polymerization of 7-phenyl-2,6-dimethylquinone methide and its derivatives

7-Phenyl-, 7-chlorophenyl-,7-methylphenyl-, and 7-trifluoromethylphenylquinone methide were synthesized to investigate the anionic polymerization of quinone methide. Novel high molecular weight polymers have been prepared and the substitution effects of the monomers on polymerization kinetics were determined. © 1993 John Wiley & Sons, Inc.     

Orientational Waves in Cell Membranes

A theoretical analysis of various types of orientational waves in biological membranes is described. In particular, we consider nonlinear solitary waves (solitions) which may result from local membrane disorder in the presence of an electric field across the cell membrane. The non-dispersive waves could provide an efficient mechanism for the lateral spread of local perturbations in the membrane plane for solute transport across the membrane by modifying the orientation of the lipid molecules.     

新型吲哚苯醌衍生物的合成及抗肿瘤活性

基于醌类以及含"2-苯基萘型"结构单元的衍生物在临床上表现出良好的抗肿瘤活性,设计了取代吲哚苯醌衍生物。以2-取代吲哚衍生物为底物,乙腈为反应溶剂,在相转移催化剂苄基三乙基氯化铵和无水碳酸钾存在下,与四溴苯醌反应,合成了9个未见文献报道的2-取代吲哚-1,4-醌衍生物(2a^2c,3a^3c,4a^4c),其结构经1H NMR,13C NMR和HR-MS(ESI)表征。体外抗肿瘤活性实验表明,该类化合物对人肺癌细胞系(A549)、人乳腺癌细胞系(MDA-MB-231)及宫颈癌细胞系(Hela)具有抑制作用,其中化合物2b和3c对人乳腺癌细胞系MDA-MB-231具有良好的抑制活性。