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151.
Tagat JR McCombie SW Nazareno DV Boyle CD Kozlowski JA Chackalamannil S Josien H Wang Y Zhou G 《The Journal of organic chemistry》2002,67(4):1171-1177
Aryl carboxamides are useful structural units found in several biologically active compounds. Unlike their benzoic acid counterparts, fluorinated versions of naphthoic acids are relatively unknown. In connection with a recent project, we needed viable syntheses of several mono- and difluorinated naphthoic acids. Herein we describe the synthesis of 5-, 6-, 7-, and 8-fluoro-1-naphthalenecarboxylic acids and 5,7-, 5,8-, 6,7-, and 4,5-difluoro-1-naphthalenecarboxylic acids. The 5-fluoro derivative 1was obtained from the corresponding 5-bromo compound via electrophilic fluorination of the lithio-intermediate. The rest of the monofluoro (2, 3, and 4) and the difluoro acids (5, 6, and 7) were prepared by a new, general route which entailed the elaboration of commercial fluorinated phenylacetic acids to 2-(fluoroaryl)glutaric acids with differential ester groups; selective hydrolysis to a mono acid, intramolecular Friedel-Crafts cyclization, and aromatization furnished the target structures. An alternative process to assemble a naphthalene skeleton is also presented for the difluoro acids 5 and 6. Finally, 4,5-difluoro-1-naphthalenecarboxylic acid (8) was prepared expeditiously from 1,8-diaminonaphthalene by adapting classical reactions. 相似文献
152.
A highly selective and flexible route to 1,5-ene-ynes is provided by the reactions of [(propargyl) dicobalt hexacarbonyl] cations with allyl silanes. 相似文献
153.
A metal-segregated layered compound, containing square nets of Cu(pyz)(2)(2+) and buckled V(6)O(16)(2)(-) layers, has been synthesized using hydrothermal techniques to have the composition V(6)O(16)Cu(C(4)H(4)N(2))(2) x (H(2)O)(0.22(1)) (C(4)H(4)N(2) = pyrazine, pyz). The Cu(II) square nets are nearly regular and undergo an antiferromagnetic transition at 8 K. In contrast to the plethora of recently synthesized metal-oxide clusters, chains, and networks in the VO(x)/M/L (M = late transition element; L = organonitrogen ligand) system, this compound is a relatively rare example that contains two different metals distributed into distinct layers. An application of charge density matching to form layered structures is postulated. 相似文献
154.
PHOTOBLEACHING OF PORPHYRINS USED IN PHOTODYNAMIC THERAPY AND IMPLICATIONS FOR THERAPY 总被引:5,自引:0,他引:5
Thomas S. Mang Thomas J. Dougherty William R. Potter Donn G. Boyle Stein Somer Johan Moan 《Photochemistry and photobiology》1987,45(4):501-506
Abstract— The development of an extraction procedure to quantitate dihematoporphyrin ether (DHE) concentration in tissues correlated to fluorescence measurements from instrumentation developed for in vivo fluorimetry was examined. In vivo fluorometric results from mouse mammary carcinoma (SMT-F) were calibrated against results of the chemical extraction assay quantitated spectrophotometrically. Fluorescence and drug extractable levels increase in a linear fashion with injected dose. Loss of porphyrin fluorescence (photobleaching) and intra-tumoral porphyrin level has been demonstrated both in vitro (NHIK cells) and in vivo (SMT-F tumor) during illumination with light following exposure to Hpd or DHE. This process is essentially independent of porphyrin tumor level in vivo and could lead to tumor protection at very low porphyrin levels. On the other hand, this photobleaching process which occurs concurrent with cellular inactivation and tissue damage due to the photodynamic process can be exploited to protect normal tissue during photodynamic therapy (PDT) and thus greatly enhance the therapeutic ratio. This has been demonstrated in patients undergoing PDT. 相似文献
155.
Copper, nickel, and cadmium can be determined in 100 ml of sea water by coprecipitation with cobalt pyrrolidinedithiocarbamate and graphite atomizer atomic absorption spectrometry. Concentration ranges likely to be encountered and estimated (1 σ ) analytical precisions are 1–6 nmol kg-1 (±0.1) for copper, 3–12 nmol kg-1 (±0.3) for nickel and 0.0–1.1 nmol kg-1 (±0.1) for cadmium. The technique may be applied to fresh-water samples with slight modification. 相似文献
156.
Boyle Timothy J. Clem Paul G. Rodriguez Mark A. Tuttle Bruce A. Heagy Michael D. 《Journal of Sol-Gel Science and Technology》1999,16(1-2):47-55
We have recently isolated the neo-pentoxide (HOCH2CMe3, ONp) derivatives of Ba, Sr, and Ti as Ba4(ONp)8(HONp)6(py)2, Sr5(O)(ONp)8(Solv)5 (Solv = solvent), and Ti2(ONp)8, respectively. The combination of these precursors were found to be readily soluble in a wide range of solvents and thus were excellent candidates for preparation of barium strontium titanate ((Ba,Sr)TiO3 or BST) thin films using spin-cast deposition techniques. The highest quality BST films for this system were generated from ternary mixtures dissolved in either pyridine or pyridine/toluene. By in situ VT-GIXRD analysis it was determined that the perovskite phase of BST was readily formed at 650°C. The electronic properties of films crystallized at 700°C indicated that the thin films (300 nm) possessed a dielectric constant of 120 (tan = 0.03) with a tunability of 29% at ±10 V. 300 nm films (700°C) which had been generated from a standard BST solution modified with a novel tridentate ligand, had a higher dielectric constant of 180 and a tunability of 35% at ±10 V. The collective characteristics of these precursors offer an attractive alternative to the more complex, less stable sol-gel precursors currently in use. 相似文献
157.
Wohlleben W Bartels FW Boyle M Leyrer RJ 《Langmuir : the ACS journal of surfaces and colloids》2008,24(10):5627-5635
We report opal photonic crystals that are self-assembled from functional polymer particles. We randomly copolymerized functional side-chain monomers containing motifs that form homodimers or heterobridges. These include ether or methylene bridges, hydrazone bridges, acids for anhydride formation, low- T g copolymers or physical cross-links by hydrogen bonds and/or polarity. To generate particles that are monodisperse, spherical, and functionalized, we combined emulsifier-free synthesis with swelling synthesis steps. Laser diffraction from centimeter-sized beams, white-light interferometry, and atomic force microscopy demonstrates symmetry and homogeneity across the entire crystal without the loss of interstitial volume. Compared to the stability of nonfunctional particles, the stability of the crystal against immersion in water and isopropanol was enhanced from 10 to a perfect 100%. One of the successful approaches (methylene bridges from N-methylolmethacrylamid) is triggered by thermal activation, but as shown, this is operative far from the trivial regime of sintering. We demonstrate successful infiltration with and solvation of a laser-polymerizable resin, thus enabling the processing of 3D photonic waveguide structures. 相似文献
158.
An asymmetric synthesis of (−)-N-acetylcolchinol is described based on a Suzuki-Miyaura coupling to generate the biaryl pharmacophore. The sole asymmetric centre was introduced by an asymmetric reduction of a dibenzosuberone derivative 24 using lithium borohydride in the presence of stoichiometric amounts of a chiral Lewis acid (TarB-NO2). A conjugate between an αVβ3 integrin-binding cyclic peptide c[RGDfK] and colchinol (adipoyl linker) was synthesised with an aim to deliver colchinol to solid tumours selectively. 相似文献
159.
Klok M Boyle N Pryce MT Meetsma A Browne WR Feringa BL 《Journal of the American Chemical Society》2008,130(32):10484-10485
A combination of cryogenic UV-vis and CD spectroscopy and transient absorption spectroscopy at ambient temperature is used to study a new class of unidirectional rotary molecular motors. Stabilization of unstable intermediates is achieved below 95 K in propane solution for the structure with the fastest rotation rate, and below this temperature measurements on the rate limiting step in the rotation cycle can be performed to obtain activation parameters. The results are compared to measurements at ambient temperature using transient absorption spectroscopy, which show that behavior of these motors is similar over the full temperature range investigated, thereby allowing a maximum rotation rate of 3 MHz at room temperature under suitable irradiation conditions. 相似文献
160.
Munro-Leighton C Feng Y Zhang J Alsop NM Gunnoe TB Boyle PD Petersen JL 《Inorganic chemistry》2008,47(14):6124-6126
Synthesis and isolation of the monomeric octahedral platinum(IV) amido complex (NCN)PtMe2NHPh have been accomplished upon deprotonation of the amine complex [(NCN)PtMe2(NH2Ph)][OTf]. The preliminary reactivity of the amido ligand has been explored. 相似文献