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141.
Tietze LF Redert T Bell HP Hellkamp S Levy LM 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(8):2527-2535
The Pd-catalyzed domino Tsuji-Trost-Heck-Mizoroki reactions of compounds 18, 27, and 34, respectively, each containing an allyl acetate and a halogen aryl moiety, lead to the formation of hexahydronaphthacenes 2 and 3 and octahydroanthracene 4 in 62-81 % yield. The octahydroanthracene and hexahydronaphthacene motifs are found in many natural products, for example, the tetracycline antibiotics. 相似文献
142.
We conducted a series of experiments investigating decomposition of secondary explosives PETN and TATB at varying static pressures and temperatures using synchrotron radiation. As seen in our earlier work, the decomposition rate of TATB at ambient temperature slows systematically with increasing pressure up to at least 26 GPa but varies little with pressure in PETN at ambient temperature up to 15.7 GPa, yielding important information pertaining to the activation complex volume in both cases. We also investigated the radiation-induced decomposition rate as a function of temperature at ambient pressure and 26 GPa for TATB up to 403 K, observing that the decomposition rate increases with increasing temperature as expected. The activation energy for the TATB reaction at ambient temperature was experimentally determined to be 16 +/- 3 kJ/mol. 相似文献
143.
Francisco Guerra Vázquez Hubertus Th. Jongen Vladimir Shikhman Maxim Ivanov Todorov 《Mathematical Methods of Operations Research》2009,70(1):35-46
We consider unconstrained finite dimensional multi-criteria optimization problems, where the objective functions are continuously
differentiable. Motivated by previous work of Brosowski and da Silva (1994), we suggest a number of tests (TEST 1–4) to detect,
whether a certain point is a locally (weakly) efficient solution for the underlying vector optimization problem or not. Our
aim is to show: the points, at which none of the TESTs 1–4 can be applied, form a nowhere dense set in the state space. TESTs
1 and 2 are exactly those proposed by Brosowski and da Silva. TEST 3 deals with a local constant behavior of at least one
of the objective functions. TEST 4 includes some conditions on the gradients of objective functions satisfied locally around
the point of interest. It is formulated as a Conjecture. It is proven under additional assumptions on the objective functions,
such as linear independence of the gradients, convexity or directional monotonicity.
This work was partially supported by grant 55681 of the CONACyT. 相似文献
144.
Nils Helge Schebb Helene Faber Ronald Maul Ferry Heus Jeroen Kool Hubertus Irth Uwe Karst 《Analytical and bioanalytical chemistry》2009,394(5):1361-1373
Abstract A novel method for the identification of glutathione/electrophile adducts that are inhibiting glutathione-S-transferase (GST) activity was developed and applied for the analysis of the mycotoxin patulin. The method is based on high-performance
liquid chromatography (HPLC) coupled to a continuous-flow enzyme reactor serving as biochemical detector (BCD) in parallel
to electrospray mass spectrometric detection (ESI-MS). This HPLC-BCD technique combines a separation step and the detection
of the inhibition and is therefore ideally suited for the analysis of the activity of single patulin/glutathione adducts within
a complex mixture of adducts. Two out of at least 15 detected patulin–glutathione adducts showed strong GST inhibition. In
ESI-MS, the inhibitory active adducts were characterized by [M + H]+ ions with m/z 462.1138 and m/z 741.2011, respectively. They could be identified as a dihydropyranone adduct containing one molecule glutathione and a ketohexanoic
acid bearing two glutathione molecules.
Graphical Abstract OnlineAbstractFigure
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
145.
Oskar Nuyken Hubertus Krner Gisbert Rieß Saehoon Oh Stefan Ingrisch 《Macromolecular Symposia》1996,101(1):29-42
Scope and limitation of the vinyl ether polymerization initiated by NR4ClO4(KClO4;LiClO4)/CH3CHI-OR was discussed. Besides isobutyl vinyl ether (IBVE), N-vinylcarbazole (NVC) and 2-chloroethyl vinyl ether (CEVE) were initiated by NR4ClO4/CH3CHI-OR. These polymerizations exhibited the characteristics of a living polymerization. However, in order to observe narrow molar mass distribution NVC was initiated with CH3CHI-OR, without salts. Block copolymers were synthesized by the method of sequential monomer addition (NVC, IBVE, CEVE). The PCEVE segment was modified by nucleophilic substitution, which allowed the synthesis of amphiphilic block copolymers. 相似文献