New polyfluorinated porphyrazine complexes: synthesis,characterization, aggregation,and solubility

By cyclotetramerization of 2,3-bis(2,3,5,6-tetrafluoro-4-methylbenzylthio)maleonitrile in the presence of magnesium butoxide, magnesium porphyrazinate (MgPz) carrying eight (2,3,5,6-tetrafluoro-4-methylbenzylthio) functional units on the periphery positions has been synthesized. Conversion of MgPz into the metal-free derivative was achieved upon addition of a strong acid such as trifluoroacetic acid. Further reaction of this product with different metal(II) acetates led to metallo porphyrazines (MPz). The monomeric bisaxial complex FePz(py)₂ as well as the bridged complex [FePz(pyz)]_n were formed as stable complexes by reacting FePzCl with pyridine or pyrazine, respectively. These complexes were characterized by elemental analysis, together with FT-IR, ¹H NMR, ¹³C NMR, ¹⁹F NMR, UV–vis, and mass spectral data.     

Reactions of Polyhalopyridines. 16. Synthesis and Reactions of 2,3,5,6-Tetrafluoro-4-perfluoroalkylthiopyridines

Identical reaction products, viz. 2,3,5,6-tetrafluoro-4-perfluoroalkylthiopyridines 3a-c, were obtained on thermal decomposition of Xe(II) bisperfluoroalkylcarboxylates in the presence of mercaptotetrafluoropyridine and bis(2,3,5,6-tetrafluoro-4-pyridyl) disulfide. Compounds 3a-c readily interact with N-, O-, and S-containing nucleophiles, though with the first two types of reactant only with substitution of fluorine atoms in position 2 of the pyridine ring. In the latter case products are obtained both with retention of the perfluoroalkylthio group on interaction with sodium N,N-dimethyldithiocarbamate, and with total fission of that group in the case of alkali metal methanethiolate and toluenethiolate.     

Synthesis and reactions of 2-hydroxy-4-oxo-4-(2,3,5,6-tetrafluoro-4-methoxyphenyl)-but-2-enoic acid methyl ester

2-Hydroxy-4-oxo-4-(2,3,5,6-tetrafluoro-4-methoxyphenyl)-but-2-enoic acid methyl ester (1) was synthesized by the reaction of pentafluoroacetophenone with dimethyl oxalate in the presence of sodium methylate. Subsequently, reactions of compound 1 with aniline, o-phenylenediamine, and o-aminophenol were investigated. In addition, the thermal cyclization of ester 1 was studied and led to the formation of 5,6,8-trifluoro-7-methoxy-4-oxo-4H-chromene-2-carboxylic acid methyl ester (6) due to nucleophilic substitution of the 3-fluoro group. Hydrolysis of compound 1 and subsequent cyclization by treatment with SOCl₂ gave 5-(2,3,5,6-tetrafluoro-4-methoxyphenyl)-furan-2,3-dione (3). Thermal decarbonylation of compound 3 under mild conditions resulted in the formation of 3-(2,3,5,6-tetrafluoro-4-methoxyphenyl)-propene-1,3-dione (4) which dimerized to pyranone 5.     

Colorimetric detection of D-amino acids based on anti-aggregation of gold nanoparticles

A new method has been proposed to realize the visual detection of D-amino acids(DAAs) via the antiaggregation of 4-mercaptobenzoic acid modified gold nanoparticles(AuNPs) in the presence of D-amino acid oxidase(DAAO). The negatively charged AuNPs were prepared using sodium citrate as a reducer and stabilizer. The presence of 4-mercaptobenzoic acid(4-MBA) and Cu2+induces the aggregation of AuNPs,resulting in a color change from ruby red to royal purple. However, DAAO could oxidize DAAs to generate H2O2. In the presence of H2O2, the mercapto(–SH) group in 4-mercaptobenzoic acid can be oxidized to form a disulfide(–S–S–) bond. Based on these facts, the pre-incubation of DAAs and 4-mercaptobenzoic acid with DAAO would significantly reduce the concentration of free 4-mercaptobenzoic acid molecules,thus the aggregation of AuNPs was interrupted since due to the lack of inducer. As the concentration of DAAs increases, the color of the AuNPs solution would progress from royal purple to ruby red.Consequently, DAAs could be monitored by the colorimetric response of AuNPs using a UV–vis spectrophotometer or even naked eyes. This DAAO mediated visual detection method could determine Dalanine(D-Ala) as a representative DAA with concentrations ranging from 1.5×10~(-7)mol L~(-1) to 3.0×10~(-5)mol L~(-1), and the detection limit was as low as 7.5×10~(-8)mol L~(-1). The proposed method is convenient, low-cost and free of complex equipment, making it feasible to analyze the concentration of D-Ala in real samples of b-amyloid peptide(Aβ1–42).     

Synthesis of Vinylsulfanyl-Substitued Polyfluorobenzenes from Perfluorotoluene

The reaction of octafluorotoluene in DMF with vinylthiolate ion generated from divinyl sulfide by the action of sodium in liquid ammonia afforded 2,3,5,6-tetrafluoro-4-trifluoromethylaniline, 3,6-difluoro-4-trifluoromethyl-1,2,5-tris(vinylsulfanyl)benzene, and 3,6-difluoro-N, N-dimethyl-4-trifluoromethyl-2,5-bis-(vinylsulfanyl)aniline. Under the same conditions, 2,3,5,6-tetrafluoro-4-trifluoromethylaniline gave rise to 3,6-difluoro-4-trifluoromethyl-2,5-bis(vinylsulfanyl)aniline.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 3, 2005, pp. 411–414.Original Russian Text Copyright © 2005 by Amosova, Gavrilova, Afonin.     

Determination of penicillamine, penicillamine disulfide and penicillamine-glutathione mixed disulfide by high-performance liquid chromatography with electrochemical detection

Methodology is described for the simultaneous determination of D-penicillamine, penicillamine disulfide and the penicillamine-glutathione mixed disulfide, as well as glutathione and glutathione disulfide, in human plasma, erythrocytes and urine. The various thiols and disulfides are separated by reversed-phase ion-pairing liquid chromatography with detection by an electrochemical detector with dual gold/mercury amalgam electrodes in series. The thiols are detected at the downstream electrode; the disulfides are reduced at the upstream electrode and then detected as the thiols at the downstream electrode. Detection limits (at a signal-to-noise ratio of 2.0) are in the picomole range for 20 microliters of injected solution for all compounds except penicillamine disulfide, which has a detection limit of 600 pmol in 20 microliters. A convenient method is described for preparation of the penicillamine-glutathione mixed disulfide by thiol/disulfide exchange with standardization of the solution by 1H NMR spectroscopy.     

exo-N-[2-(4-Azido-2,3,5,6-tetrafluorobenzamido)ethyl]-dC: a novel intermediate in the synthesis of dCTP derivatives for photoaffinity labelling

An alternative route for the synthesis of a photoaffinity labelling (PAL) dCTP derivative is reported. This method involves the intermediacy of exo-N-[2-(4-azido-2,3,5,6-tetrafluorobenzamido)ethyl]-dC. The latter is prepared from the coupling of known N-(2-aminoethyl)-4-azido-2,3,5,6-tetrafluorobenzamide, prepared in an improved three-step sequence, with an activated 4-triazolyl derivative of dU, followed by deprotection. ¹⁹F NMR spectroscopy proved extremely useful in following the synthetic transformations, and enabled control of any adventitious reduction of the azides.     

ROLE OF THIOL-DISULFIDE EXCHANGE IN INSULIN BINDING TO ITS RECEPTOR

The effects of reduction by DTT, oxidation by DTNB and treatment with NEM on the thiol contents and insulin binding to its receptor in mice liver membranes were studied. Reduction with DTT leads to a parallel increase in the thiol content and the speciflc binding of insulin to the membrane. Scatchard analysis of the results shows little change in the number of binding sites but a twofold increase of the binding constant. Washing the membrane with bound insulin by a DTT containing buffer results in a more marked increase in the release of bound insulin than washing with buffer alone, suggesting that part of the insulin is bound to its receptor by covalent disulfide linkages through a thIol-disulfide exchange reaction and reduction with DTT leads to a marked increase in this "disulfide-linked" insulin. Treatment with DTNB or NEM of the DTT-reduced membrane seems to reverse the effect of DTT reduction, although the reaction of the untreated membrane with DTNB or NEM had little or no effect on the specific     

Molecular diodes and ultra-thin organic rectifying junctions: Au-S-CnH2n-Q3CNQ and TCNQ derivatives

Attempts to obtain derivatives of the molecular diode, 2-{4-[1-cyano-2-(1-(omega-acetylsulfanylalkyl)-1H-quinolin-4-ylidene)-ethylidene]-cyclohexa-2,5-dienylidene}-malonitrile [1, CH(3)CO-S-C(n)H(2n)-Q3CNQ], from either 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-quinodimethane (TCNQF(4)) or 2,3,5,6-tetramethyl-7,7,8,8-tetracyano-p-quinodimethane (TMTCNQ) result in ring closure via the cyano group of the pi-bridge and yield di-substituted analogues: 2-{2,3,5,6-tetrafluoro-4-[6-(10-acetylsulfanyldecyl)-3-(1-(10-acetylsulfanyldecyl)-1H-quinolin-4-ylidenemethyl)-6H-benzo[f][1,7]naphthyridin-2-ylidene]-cyclohexa-2,5-dienylidene}-malonitrile (2a) and the 2,3,5,6-tetramethyl derivative (2b). Self-assembled monolayers (SAMs) of these donor-(pi-bridge)-acceptor molecular diodes exhibit asymmetric current-voltage characteristics with electron flow at forward bias from the top contact to surface C(CN)(2) groups. Comparison is made with I-V curves from ultra-thin films of an organic rectifying junction in which TCNQ(-) is electron-donating and a donor-(sigma-bridge)-acceptor diode in which TCNQ degrees is electron-accepting.     

Regiospecific photohydroxyalkylation of pentafluoropyridine

Irradiation of 1-hydroxyalkane solutions of pentafluoropyridine in the presence of benzo-phenone resulted in regiospecific substitution at position 4, thus forming 2,3,5,6-tetrafluoro-4-(1-hydroxyalkyl)pyridine.     

“黑洞型”缺电子联吡啶环蕃的合成

利用2,3,5,6-四氟-1,4-苯二甲酸为原料, 经过酯化、还原及溴代, 合成1,4-二溴甲基-2,3,5,6-四氟苯. 以其为原料在低温下利用模板效应合成高度缺电子的“黑洞型”缺电子联吡啶环蕃化合物, 经过连续液液萃取及离子交换得到“黑洞型”缺电子联吡啶环蕃单体. 产品经¹H NMR, ¹³C NMR, MS表征. 利用变温核磁共振技术研究“黑洞型”缺电子联吡啶环蕃与经典的双环(百草枯-对苯撑)型缺电子联吡啶环蕃在溶液中的变化.     

Kinetic analyses of disulfide formation between thiol groups attached to linear poly(acrylamide)

Kinetic analyses were carried out for formation of disulfide crosslinkages between thiol groups on linear polymers, poly(acrylamide‐co‐N‐acrylcysteamine) (P‐SH). Disulfide crosslinkages were formed by auto‐oxidation of pendant thiol groups or through the thiol‐disulfide exchange reaction induced by addition of disulfide compounds gluthathione. In the auto‐oxidation reaction, the rate constant for disulfide formation highly depended on pH values of the reaction mixtures and the P‐SH concentrations. Gelation rate is too slow to enclose living cells into hydrogel under physiological pH 7.4. The hydrogel formation rate can be accelerated by addition of disulfides, such as oxidized glutathione. In the later case, oxygen in the reaction mixture is not consumed. The thiol‐disulfide exchange reaction is much more suitable for the cell encapsulation than the thiol auto‐oxidation reaction. These findings give a basis for enclosure of living cells in a hydrogel. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Spectrophotometric Label-Free Determination of Lead Using Thiol-Functionalized Gold Nanoparticles

A method for the determination of lead is described using thiol-functionalized gold nanoparticle. The detection method is based on the prevention of thiol-induced aggregation of gold nanoparticles by lead. Among six thiols, e.g., 4-mercapto-1-butanol, meso-2, 3-dimercaptosuccinic acid, mercaptosuccinic acid, 6-mercapto-1-hexanol, 4-(methylthio)-1-butanol, 1-propanethiol, four (4-mercapto-1-butanol, 6-mercapto-1-hexanol, 4-(methylthio)-1-butanol and 1-propanethiol) induced the aggregation of the gold nanoparticles which was measured by the change in absorbance at 520 and 650?nm. Prior incubation of the gold nanoparticles with lead decreased the 4-(methylthio)-1-butanol-induced aggregation of gold nanoparticles in a dose-dependent manner. A linear inverse relationship between the logarithmic concentration of lead and the ratio of absorbance at 650 to 520 was noted. The method has a dynamic range from 10?nM to 100?µM. However, metals such as mercury and chromium were more effective in comparison with lead in preventing the 4-methylthio-1-butanol-induced aggregation of gold nanoparticles. The method can be used for assessing the heavy metal load in water samples.     

On the Orthogonality of Two Thiol‐Based Modular Ligations

The chemoselectivity of two thiol‐based modular ligations operating under mild conditions is assessed. For this purpose, a macromolecular scaffold possessing allyl and pentafluorophenyl groups in two distinct parts is employed, which enables facile characterization by NMR spectroscopy (¹H and ¹⁹F) and size‐exclusion chromatography. By using appropriate triggers (introduction of a base or light irradiation), it is possible to direct thiols to an arbitrarily chosen part of the scaffold, without any change to the other part and with no involvement of protecting group chemistry. Dual functionalization experiments are achieved by applying these triggers consecutively with no consideration of the reaction sequence order, evidencing full bidirectionality. A set of one‐pot, purification‐free procedures that enable near‐quantitative to full dual functionalization in (very) short reaction times (17–180 min) is also presented.     

Synthesis and Characterization by (19)F and (125)Te NMR and Raman Spectroscopy of cis-ReO(2)(OTeF(5))(3) and cis-ReO(2)(OTeF(5))(4)(-), and X-ray Crystal Structure of [N(CH(3))(4)(+)][cis-ReO(2)(OTeF(5))(4)(-)

The pentafluorooxotellurate compound ReO(2)(OTeF(5))(3) has been synthesized from the reaction of ReO(2)F(3) with B(OTeF(5))(3) and structurally characterized in solution by (19)F and (125)Te NMR spectroscopy and in the solid state by Raman spectroscopy. The NMR and vibrational spectroscopic findings are consistent with a trigonal bipyramidal arrangement in which the oxygen atoms and an OTeF(5) group occupy the equatorial plane. The (19)F and (125)Te NMR spectra show that the axial and equatorial OTeF(5) groups of ReO(2)(OTeF(5))(3) are fluxional and are consistent with intramolecular exchange by means of a pseudorotation. The Lewis acid behavior of ReO(2)(OTeF(5))(3) is demonstrated by reaction with OTeF(5)(-). The resulting cis-ReO(2)(OTeF(5))(4)(-) anion was characterized as the tetramethylammonium salt in solution by (19)F and (125)Te NMR spectroscopy and in the solid state by Raman spectroscopy and X-ray crystallography. The compound crystallizes in the triclinic system, space group P&onemacr;, with a = 13.175(7) ?, b = 13.811(5) ?, c = 15.38(1) ?, alpha = 72.36(5)(o), beta = 68.17(5)(o), gamma = 84.05(4)(o), V = 2476(2) ?(3), D(calc) = 3.345 g cm(-)(3), Z = 4, R = 0.0547. The coordination sphere about Re(VII) in cis-ReO(2)(OTeF(5))(4)(-) is a pseudooctahedron in which the Re-O double bond oxygens are cis to one another.     

含氟天麻素的合成

A本文报道了三个含氟天麻素及其衍生物的合成,即2-氟-4-羟甲苯基-β-D-葡萄吡喃糖苷,2-三氟甲基-4-羟甲苯基-β-D-葡萄吡喃糖苷,2,3,5,6-四氟-4-羟甲苯基-β-D-葡萄吡喃糖苷及其五乙酰衍生物等.这些新化合物的结构经元素分析,^1H和^1^9F NMR,IR,和MS等测试确证.     

Synthesis and characterization of poly(2,3,5,6-tetrafluoro-1,4-phenylenevinylene)

Poly(2,3,5,6-tetrafluoro-1,4-phenylenevinylene) (PTFPV) was prepared for the first time by the Stille cross-coupling reaction and the resulting material was characterized through MALDI-TOF mass spectrometry, employing a novel sample preparation protocol suitable for insoluble compounds; preliminary optical and electrooptical measurements were performed.     

Coordination networks with fluorinated backbones

Fluorine-containing ligands 2,3,5,6-tetrafluoro-1,4-bis(imidazol-1-yl-methyl)benzene (1) and 2,3,5,6-tetrafluoro-1,4-bis(2-methylimidazol-1-yl-methyl)benzene (2) were prepared and coordinated with AgNO3, Co(ClO4)2 x 6 H2O, and Cd(NO3)2 x 4 H2O, respectively, to form the following structures: 3D channel polymer [Ag2(1)2(NO3)2 x H2O x MeOH]n (3), 2D sheet polymer [Co(1)3(ClO4)2]n (4), 1D chain polymer [Cd(1)3(NO3)2 x 4 H2O]n (5), and a 2D herringbone sheet polymer [Ag(2)NO3 x 1.5 MeOH]n (6). The solid-state crystal structures of 3-6 were studied by single-crystal X-ray crystallography.     

硫酸酯型氟表面活性剂的合成与表面活性

以4-全氟壬烯氧基苯磺酰氯和2-甲氨基乙醇为主要原料,经酰胺化、酯化和中和反应制备了硫酸2-（N-甲基-4-全氟壬烯氧基苯磺酰胺基）乙酯钠（I）,用红外光谱和19F NMR,1H NMR对中间体和产物分子结构进行了表征,借助正交试验法优化了反应条件。酰胺化反应较佳工艺条件：n（4-全氟壬烯氧基苯磺酰氯）: n（2-甲氨基乙醇）＝1.0 : 2.0,以三乙胺为缚酸剂,在THF溶剂中,室温下搅拌反应3.0 h,收率93.4 ％;酯化反应较佳工艺条件：n（ N-羟乙基-N-甲基-4-全氟壬烯氧基苯磺酰胺）: n（氯磺酸）＝1.0 : 2.0,在THF溶剂中,室温下反应0.5 h,收率97.1 ％。硫酸2-（N-甲基-4-全氟壬烯氧基苯磺酰胺基）乙酯钠表面活性剂的临界胶束浓度 8.0×10-4mol/L,γcmc 23.1 mN/m (25℃)。     

RAFT polymerization of vinyl methacrylate and subsequent conjugation via enzymatic thiol‐ene chemistry

The polymerization of vinyl methacrylate (VMA) allows the synthesis of polymers with pendant double bonds. When this polymerization was undertaken in the presence of 2‐cyanopropyl dithiobenzoate as reversible addition–fragmentation chain transfer agent, it led almost exclusively to vinylester functional sidegroups, which were available for further reactions. The vinylester functionality could not be functionalized using common thiol‐ene catalysts, but could be activated using Candida antarctica lipase B (CAL‐B) (Novozyme 435). The reaction between PVMA and various thiols in N, N‐dimethyl formamide in the presence of CAL‐B led exclusively to the formation of the anti‐Markovnikov product. The rate of reaction between PVMA and 1‐butanethiol was monitored using ¹H NMR. The reaction was complete within 72 h. Similar results were obtained with other small‐sized thiols such as 2‐mercaptoethanol, 3‐mercaptopropionic acid, and 2‐(trimethylsilyl)ethanethiol, while more bulky thiols, such as secondary thiols, thiols with long alkyl chains, and sterically demanding thiols, such as mono(6‐deoxy‐6‐mercapto)‐β‐cyclodextrin, only led to lower conversions. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012