共查询到19条相似文献,搜索用时 656 毫秒
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3-疏基香豆素及其衍生物的研究 总被引:1,自引:0,他引:1
研究了3-疏基香豆素(8)、3,3'-二硫代双香豆素的合成及8与一系列Michael受体的反应.按受体结构不同,除都能发生分子间的加成反应外,有些还可进一步发生第二次分子内的加成反应,关环后得到一系列四氢噻吩并[2,3-C][1]苯并吡喃-4(H)-酮的衍生物.对这些化合物的立体化学及结构进行了鉴定.8分别和烯丙基溴、肉桂基溴缩合,前者在N,N-二甲苯胺内发生正常的Claisen重排,得到1,2-二氢-2-甲基噻吩并[2,3-C][1]苯并吡喃-4-(H)-酮及1,2,3,5-四氢硫代吡喃并[2,3-C][1]苯并吡喃-5-酮,但后者的反应产物是3-(ρ-N,N-二甲氨基)苄硫基香豆素. 相似文献
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<正> 前文报道了含芳香叔胺基丙烯酸酯-甲基丙烯酸4-N,N-二甲氨基苄酯(DMABMA)的合成和聚合。这种在分子中既含有二甲氨基苯基,又含有双键的单体为“可聚合芳香叔胺”,在过氧化二酰如过氧化苯甲酰(BPO),过氧化月桂酰(LPO)引发下,芳香叔胺残基参与氧化还原引发体系,进而双键发生聚合反应。本文报道了二甲氨基苯基取代丙烯酰胺,即N-(4-N,N‘-二甲氨基苯基)丙烯酰胺(DMAPAA)和N-(4-N,N-二甲氨基苯基)甲基丙烯酰胺(DMAPMA)的合成及聚合。 相似文献
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<正> 我们曾报道过甲基丙烯酸-4-N,N-二甲氨基苄酯(DMABMA),4-N,N-二甲氨基苯乙烯(DMAS)等含芳香叔胺基的烯类衍生物不仅可以作为氧化还原引发体系组分引发烯类单体如甲基丙烯酸甲酯(MMA)的聚合,而且还进入MMA的聚合物链中。在另文中报道了两个芳香叔胺取代的丙烯酰胺:N-(4-N′,N′-二甲氨基苯基)丙烯酰胺(DMAPAA)和N-(4-N′,N′-二甲氨基苯基)甲基丙烯酰胺(DMAPMA)的合成及其聚合的研究,本文研究了这两个丙烯酰胺衍生物与过氧化苯甲酰(BPO)组成的氧化还 相似文献
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B. Szajáni Aranka Molnár Gabriella Klámar M. Kálmán 《Applied biochemistry and biotechnology》1987,14(1):37-47
A simple, one-step process, using 0.25Mp-benzoquinone dissolved in 20% dioxane at 50°C for 24 h was applied to the activation of polyacrylamide beads. The activated
beads were reacted with glucose oxidase isolated fromAspergillus niger. The coupling reaction was performed in 0.1M potassium phosphate at pH 8.5 and 0–4°C for 24 h. The protein concentration was
50 mg/mL. In such conditions, the highest activity achieved was about 100 U/g solid. The optimum pH for the catalytic activity
was shifted by about 1 pH unit in the acidic direction to pH 5.5. Between 35 and 50°C, the activity of the immobilized form
depends on the temperature to a smaller extent than that of the soluble form. Above 50°C, the activity of immobilized glucose
oxidase shows a sharper heat dependence. The enzyme-substrate interaction was not profoundly altered by the immobilization
of the enzyme. The heat resistance of the immobilized enzyme was enhanced. The immobilized glucose oxidase is most stable
at pH 5.5. The practical use of the immobilized glucose oxidase was tested in preliminary experiments for determination of
the glucose concentration in blood sera. 相似文献
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《Analytical letters》2012,45(10):2007-2017
ABSTRACT We describe a spectrophotometric analytical method for the detection of polyphenol oxidase activity in an aqueous solution. The assay is based on the coupling reaction between 4-tert-butyl-o-benzoquinone, generated during the enzyme-catalyzed reaction acting on 4-tert-butylcatechol, and the aromatic amine, 4-amino-N,N-diethylaniline to yield a blue adduct (λmax 625 nm). This blue adduct exhibited spectral features different from the parent phenol and from the o-quinone. Polyphenol oxidase activities extracted from potatoes, and sunflower seedlings were assayed. The proposed method presents several advantages over the spectrophotometric measurement of 4-tert-butyl-o-benzoquinone. The duration of the linear period was increased, allowing a better determination of its value. The molar extinction coefficient of the blue adduct was higher than that of the 4-tert-butyl-o-benzoquinone; therefore the limitation i8542948 by the comparatively low ? for the 4-tert-butyl-o-benzoquinone is overcome. This is of great importance when considering the inertness of the 4-tert-butyl-o-benzoquinone towards some common coupling agents such as 3-methyl-benzothiazolin-2-one hydrazone. 相似文献
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4-n-Butylamino-5-ethyl-1,2-benzoquinone (1(ox)) has been synthesized as a model compound for the LTQ (lysine tyrosyl quinone) cofactor of lysyl oxidase (LOX). At pH 7, 1(ox) has a lambda(max) at 504 nm and exists as a neutral o-quinone in contrast to a TPQ (2,4,5-trihydroxyphenylalanine quinone) model compound, 4, which is a resonance-stabilized monoanion. Despite these structural differences 1(ox) and 4 have the same redox potential (ca. -180 mV vs SCE). The structure of the phenylhydrazine adduct of 1(ox) (2) is reported, and 2D NMR spectroscopy has been used to show that the position of nucleophilic addition is at C(1). UV-vis spectroscopic pH titration of phenylhydrazine adducts of 1(ox) and 4, 2, and 11, respectively, reveals a similar red shift in lambda(max) at alkaline pH with the same pK(a) (approximately 11.8). In contrast, the red shift in lambda(max) at acidic pH conditions yields different pK(a) values (2.12 for 2 vs -0.28 for 11), providing a means to distinguish LTQ from TPQ. Reactions between in situ generated 4-ethyl-1,2-benzoquinone and primary amines give a mixture of products, indicating that the protein environment must play an essential role in LTQ biogenesis by directing the nucleophilic addition of the epsilon-amino group of a lysine residue to the C(4) position of a putative dopaquinone intermediate. Characterization of a 1,6-adduct between an o-quinone and butylamine (3-n-butylamino-5-ethyl-1,2-benzoquinone, 13) confirms the assignment of LTQ as a 1,4-addition product. 相似文献
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M Holzinger M Singh S Cosnier 《Langmuir : the ACS journal of surfaces and colloids》2012,28(34):12569-12574
The formation of stable supramolecular interactions between biotin and β-cyclodextrin was studied. An association constant of 3 × 10(2) M(-1) could be determined by NMR measurements by mapping the high field shift differences of the β-cyclodextrin protons (H-3) at different biotin concentrations. With the aim to demonstrate a new alternative for the immobilization of bioreceptors, biotin and β-cyclodextrin tagged biomolecules were immobilized on transducer surfaces, which were functionalized with the correspondent host-guest partner. The reliability of this new affinity system was investigated using two enzymes (glucose oxidase and polyphenol oxidase) as biomolecule models. This supramolecular inclusion complex shows clear advantages to the classic biotin-(strept)avidin-biotin system due to a detrimental effect of the additional avidin layer reducing the transduction efficiency. A 7-fold increase in the maximum current density and an almost 20 times higher sensitivity were exhibited by the immobilized biological layer obtained using this new host-guest system. 相似文献
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Akira Hasegawa Takatoshi Murase Keisuke Adachi Minoru Morita Hideharu Ishida Makoto Kiso 《Journal of carbohydrate chemistry》2013,32(2-3):181-199
ABSTRACT Ganglioside GM3 analogs, containing 5-acetamido-3, 5-dideoxy-L-arabino-heptulosonic acid and 5-acetamido-3, 5-dideoxy-D-galacto-octulosonic acid have been synthesiyed. Glycosylation of 2-(trimethylsilyl)ethyl 0-(6-0-benzoyl-ß-D-galactopyranosyl)-(l→4)-2, 6-di-0-benzoyl-ß-D-glucopyranoside (5), with methyl (methyl 5-acetamido-4, 7-di-0-acetyl-3, 5-dideoxy-2-thio-ß-L-arabino-2-heptulo-pyranosid)onate (2) or with methyl (methyl 5-acetamido-4, 7, 8-tri-0-acetyl-3, 5-dideoxy-2-thio-α-D-galacto-2-octulopyranosid)onate (4), which were respectively prepared from the corresponding 2-S-acetyl derivatives (1 and 3) by selective 2-S-deacetylation and subsequent S-methylation, using dimethyl(methylthio)sulfonium triflate as a glycosyl promoter, gave 2-(trimethylsilyl)ethyl 0-(methyl 5-acet-amido-4, 7-di-0-acetyl-3, 5-dideoxy-ß-L-arabino-2-heptulopyranosyl-onate)-(2→3)-0-(6-0-benzoyl-ß-D-galactopyranosyl)-(1→4)-2, 6-di-0-benzoyl-ß-D-glucopyranoside (6) and 2-(trimethylsilyl)ethyl (0)-(methyl 5-acetamido-4, 7, 8-tri-0-acetyl-3, 5-dideoxy-α-D-galacto-2-octulopyranosylonate)-(2→3)-0-(6-0-benzoyl-ß-D-galactopyranosyl)-(l-4)-2, 6-di-0-benzoyl-ß-D-glucopyranoside (10), respectively. Compounds 6 and 10 were converted, via 0-acetylation, selective removal of the 2-(trimethylsilyl)ethyl group, and subsequent imidate formation, into the corresponding trichloroacetimidates 9 and 13, respectively. Glycosylation of (2S, 3R, 4E)-2-azido-3-0-benzoyl-4-octadecen1, 3-duik (14) with 9 or 13 affored the ß-glcosides (15 and 18), which were converted, via selective reduction of the azide group, coupling with octadecanoic acid, 0-deacylation, and deesterification, into the title compounds, respectively. 相似文献
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An enzymatic reactor was constructed by the immobilization of polyphenol oxidase (PPO) from avocado (Persea americana) crude extract in an inorganic support of controlled pore silica (CPS), after a previous step of silanization. This inorganic support has been used as an excellent carrier to immobilize this enzyme and the enzymatic reactor was used in a flow injection system for the determination of isoproterenol in pharmaceutical products. The procedure is based on the oxidation reaction of this drug with immobilized PPO and the product obtained was monitored at 492 nm. This system presented an analytical curve from 1.23x10(-4) to 7.38x10(-4) mol l(-1) isoproterenol with a detection limit of 6.25x10(-5) mol l(-1). Recoveries of isoproterenol between 98.5 and 103.1%, a relative standard deviation (R.S.D.) less than 1% (n=10) and 36 determinations per h were obtained. 相似文献
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Vladimir K. Cherkasov Georgy K. Fukin Yury A. Kurskii Ludmila G. Abakumova Gleb A. Abakumov 《Journal of organometallic chemistry》2005,690(5):1273-1281
New catecholate Sb(V) complexes triphenyl(3,6-di-tert-butylcatecholato)antimony(V) Ph3Sb(3,6-DBCat) (1) and triphenyl(perchloroxanthrenecatecholato)antimony(V) Ph3Sb(OXCatCl) (2) were synthesized by the oxidative addition reaction of corresponding o-quinones (3,6-di-tert-butyl-o-benzoquinone and perchloroxanthrenequinone-2,3) with triphenylantimony. Catecholates 1 and 2 can alternatively be synthesized by reacting the appropriate thallium catecholate with triphenylantimony dichloride. The oxidative addition reaction of an equimolar ratio of 4,4′-di-(3-methyl-6-tert-butyl-o-benzoquinone) and triphenylantimony yielded 4-(2-methyl-5-tert-butyl-cyclohexadien-1,5-dion-3,4-yl)-(3-methyl-6-tert-butyl-catecholato)triphenylantimony(V) Ph3Sb(Cat-Q) (3); in the case of a 1:2 molar ratio, complex 4,4′-di-[(3-methyl-6-tert-butyl-catecholato)triphenylantimony(V)] Ph3Sb(Cat-Cat)SbPh3 (4) resulted. Complexes 1-4 were characterized by IR- and 1H NMR spectroscopy. Molecular structures of 1, 2 and 4 were determined by X-ray crystallography to be a distorted tetragonal-pyramidal. 相似文献
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The reaction of CpMoMn(mu-S(2))(CO)(5), 1, with 1,4-benzoquinone in the presence of irradiation with visible light yielded the quinonedithiolato complex CpMoMn(CO)(5)(mu-S(2)C(6)H(2)O(2)), 2. The new complex CpMoMn(CO)(5)(mu-S(2)C(6)Cl(2)O(2)) (4) was synthesized similarly from 1 and 2,3-dichloro-1,4-benzoquinone. Compounds 2 and 4 were reduced with hydrogen to yield the hydroquinone complexes CpMoMn(CO)(5)[mu-S(2)C(6)H(2)(OH)(2)], 3, and CpMoMn(CO)(5)[mu-S(2)C(6)Cl(2)(OH)(2)], 5. UV-vis irradiation of solutions of Fe(2)(CO)(6)(mu-S(2)) and 1,4-benzoquinone yielded the hydroquinone complex Fe(2)(CO)(6)[mu-S(2)C(6)H(2)(OH)(2)], 6. Compound 6 was oxidized to the quinone complex Fe(2)(CO)(6)(mu-S(2)C(6)H(2)O(2)), 7, by using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. Substitution of the CO ligands on 6 by PPh(3) yielded the derivatives Fe(2)(CO)(5)(PPh(3))[mu-S(2)C(6)H(2)(OH)(2)], 8, and Fe(2)(CO)(4)(PPh(3))(2)[mu-S(2)C(6)H(2)(OH)(2)], 9. The electrochemical properties of 3, 5, 6, 8, and 9 were measured by cyclic voltammetry. The molecular structure of each of the new compounds 2-9 was established by single-crystal X-ray diffraction analyses. 相似文献