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61.
W. Adam J. Halász Z. Jámbor A. Lévai C. Nemes T. Patonay G. Tóth 《Monatshefte für Chemie / Chemical Monthly》1996,127(6-7):683-690
Summary Oxidation of the (E) and (Z) isomers of 2-arylidene-1-indanones (1) and 2-arylidene-1-benzosuberones (4) by alkaline hydrogen peroxide (methodi) afforded the spiroepoxidestrans-2a–g andtrans-5a–g from both isomers as sole products in high yields. On the other hand, dimethyldioxirane epoxidation(methodii) of the (E) isomers1a–g and4a–g gave the correspondingtrans spiroepoxides in good yields, whereas the (Z) isomers1a,c,e and4a,c,e led to thecis spiroepoxides in moderate yields. Dimethyldioxirane oxidation (methodii) of (Z)-1c and (Z)-4c,e gave diones3c and6c,e as by-products as well. Epoxidation of (Z)-1a,c,e and (Z)-4a,c,e bym-chloroperoxybenzoic acid (methodiii) resulted inca. 6:1 mixtures ofcis-2a,c,e andtrans-2a,c,e orcis-5a,c,e andtrans-5a,c,e spiroepoxides.Dedicated to Prof.W. Fleischhacker on the occasion of his 65th birthday 相似文献
62.
63.
Anikó Nemes 《Journal of fluorine chemistry》2010,131(12):1368-1376
2,2,2-Trifluoroethanol, 1,1,1,3,3,3-hexafluoro-2-propanol, and nonafluoro-tert-butyl alcohol were used as precursors for the preparation of the appropriate bis(polyfluoroalkoxymethyl)carbinols [(RFHOCH2)2CHOH, 1a-c, RFH = (a) CF3CH2, (b) (CF3)2CH, and (c) (CF3)3C] and the corresponding mesylates [(RFHOCH2)2CHOSO2CH3, 2a-c]. This novel design paradigm is introduced to eliminate the persistence and bioaccumulation problems of fluorous chemistry, which are associated with the use of longer linear perfluoroalkyl groups (e.g. Rfn ≥ n-C8F17, n-C7F15). Secondary mesylates 2a,b and the primary tosylate [(CF3)3COCH2CH2OTs, 2d] displayed acceptable reactivity towards azide and imidazole nucleophiles to allow the syntheses of novel fluorous azides, which on hydrogenolysis with H2/Pd-C offered fluorous amines [(RFHOCH2)2CHNH2, 8a,b], and 1-(polyfluoroalkyl)imidazoles (5a,b,d), respectively, while 2c showed no reactivity due to steric hindrance. The reaction of 8a,b with formaline, glyoxal and hydrochloric acid gave symmetrical 1,3-dialkylated imidazolium chlorides (9a,b), while 5a,b,d were effectively alkylated using n-C8F17(CH2)3I, methyl iodide, 2-bromoethanol, and 2d to yield the corresponding 1,3-dialkylimidazolium iodides, bromides, and tosylates (7aa-ec). Some physical properties of new compounds including mp, bp and solubility patterns were also analyzed; and the fluorophilicity values of 1a-c, and 2a-c were experimentally determined by GC and/or 19F NMR spectroscopy. 相似文献
64.
65.
C.R. Pontes A.P. Baêta Scarpelli Marcos Sampaio J.L. Acebal M.C. Nemes 《The European Physical Journal C - Particles and Fields》2008,53(1):121-131
Constrained differential renormalization (CDR) and the constrained version of implicit regularization are two regularization
independent techniques that do not rely on dimensional continuation of the space-time. These two methods, which have rather
distinct bases, have been successfully applied to several calculations, which show that they can be trusted as practical,
symmetry invariant frameworks (gauge and supersymmetry included) in perturbative computations even beyond one-loop order.
In this paper, we show the equivalence between these two methods at one-loop order. We show that the configuration space rules
of CDR can be mapped into the momentum-space procedures of implicit regularization, the major principle behind this equivalence
being the extension of the properties of regular distributions to regularized ones.
PACS 11.10.Gh; 11.15.Bt; 11.15.-q 相似文献
66.
Summary A new HPLC-UV method has been developed and validated for the pharmacokinetic linearity study of Telviran? tablets containing 200, 400, and 800 mg acyclovir. RP-18 solid phase extraction has been developed for sample preparation.
Guanosine (9-[β-D-ribofuranosyl]-guanine) was used as internal standard. The separation was carried out on an ODS Hypersil
(5 μm, 200×4.5 mm) analytical column, supplied with a 20 mm guard column containing the same packing material. A column switching
technique was applied for the elimination of the endogenous compounds eluting with longer retention times than the investigated
compounds, so the analysis time was considerably shorter compared with the time of gradient elution. The eluent was 0.5% triethylamine
in water, the pH was adjusted with orthophosphoric acid (85%) to pH5. The detection was performed at 254 nm. The calibration
curve was linear in the concentration range 10–5000 ng mL−1. The new bioanalytical method was successfully applied for a pharmacokinetic linearity study in dogs.
Presented at Balaton Symposium on High Performance Separation Methods, Siófok, Hungary, September 1–3, 1999 相似文献
67.
68.
Bruno FY Garcia-Barriocanal J Varela M Nemes NM Thakur P Cezar JC Brookes NB Rivera-Calzada A Garcia-Hernandez M Leon C Okamoto S Pennycook SJ Santamaria J 《Physical review letters》2011,106(14):147205
We report on the magnetic coupling of La0.7Sr0.3MnO3 layers through SrTiO3 spacers in La0.7Sr0.3MnO3/SrTiO3 epitaxial heterostructures. Combined aberration-corrected microscopy and electron-energy-loss spectroscopy evidence charge transfer to the empty conduction band of the titanate. Ti d electrons interact via superexchange with Mn, giving rise to a Ti magnetic moment as demonstrated by x-ray magnetic circular dichroism. This induced magnetic moment in the SrTiO3 controls the bulk magnetic and transport properties of the superlattices when the titanate layer thickness is below 1 nm. 相似文献
69.
Gergő Nemes 《Constructive Approximation》2013,38(3):471-487
Laplace’s method is one of the fundamental techniques in the asymptotic approximation of integrals. The coefficients appearing in the resulting asymptotic expansion arise as the coefficients of a convergent or asymptotic series of a function defined in an implicit form. Due to the tedious computation of these coefficients, most standard textbooks on asymptotic approximations of integrals do not give explicit formulas for them. Nevertheless, we can find some more or less explicit representations for the coefficients in the literature: Perron’s formula gives them in terms of derivatives of an explicit function; Campbell, Fröman and Walles simplified Perron’s method by computing these derivatives using an explicit recurrence relation. The most recent contribution is due to Wojdylo, who rediscovered the Campbell, Fröman and Walles formula and rewrote it in terms of partial ordinary Bell polynomials. In this paper, we provide an alternative representation for the coefficients that contains ordinary potential polynomials. The proof is based on Perron’s formula and a theorem of Comtet. The asymptotic expansions of the gamma function and the incomplete gamma function are given as illustrations. 相似文献
70.
We show in a diagrammatic and regularization independent analysis that the quadratic contribution to the beta function which has been conjectured to render quantum electrodynamics asymptotically free near the Planck scale has its origin in a surface term. Such surface term is intrinsically arbitrarily valued and it is argued to vanish in a consistent treatment of the model. 相似文献