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51.
Colantoni D Fioravanti S Pellacani L Tardella PA 《The Journal of organic chemistry》2005,70(23):9648-9650
[Reaction: see text]. One-pot aziridinations were obtained starting from substituted 2,2,2-trifluoroethyl beta-dicarbonyl compounds with nosyloxycarbamates in the presence of an excess of CaO as base. The unexpected ring closure reaction takes place at room temperature, leading to the N-protected alpha-trifluoromethyl aziridines with good yields. The reaction pathway seems to be influenced by the choice of the base. 相似文献
52.
Eleonora Truzzi Caterina Durante Davide Bertelli Benedetta Catellani Samuele Pellacani Stefania Benvenuti 《Molecules (Basel, Switzerland)》2022,27(17)
In the present work, the applicability of attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, coupled with chemometric tools in recognizing essential oils (EOs) for routine control, was evaluated. EOs belonging to Mentha, Cymbopogon, and Lavandula families and to S. rosmarinus and T. vulgaris species were analyzed, and the performance of several untargeted approaches, based on the synergistic combination of ATR-FTIR and Partial Least Squares Discriminant Analysis (PLS-DA), was tested to classify the species and chemotypes. Different spectra pre-processing methods were employed, and the robustness of the built models was tested by means of a Receiver Operating Characteristic (ROC) curve and random permutations test. The application of these approaches revealed fruitful results in terms of sensitivity and specificity, highlighting the potentiality of ATR-FTIR and chemometrics techniques to be used as a sensitive, cost-effective, and rapid tool to differentiate EO samples according to their species and chemotype. 相似文献
53.
(E)-O-Arylsulfonyl-N-(2-nitroalk-2-enyl)hydroxylamines were easily obtained in good yields starting from (E)-nitro allylic alcohols, the crucial step being an inorganic base-catalyzed decarboxylative rearrangement of proposed labile unsaturated carbamates. A possible mechanism for the outcome of the reaction, characterized by the unusual retention of the sulfonyloxy group, is proposed. 相似文献
54.
In this paper we propose a continuous-time Markov chain to describe the spread of an infective and non-mortal disease into a community numerically limited and subjected to an external infection. We make a numerical simulation that shows tendencies for recurring epidemic outbreaks and for fade-out or extinction of the infection. 相似文献
55.
Stefania delle Noci Marco Frasconi Gabriele Favero Marina Tosi Tommaso Ferri Franco Mazzei 《Electroanalysis》2008,20(2):163-169
One of the main drawbacks affecting first‐generation electrochemical biosensors in the analysis of real matrices is the interference of electroactive species present in the sample under investigation. Several approaches have been attempted to overcome this problem in the past ten years but the best results were achieved by using mediated based electrochemical biosensors. Despite this, the kinetic of the redox mediators‐enzymatic proteins interaction has not been studied deeply enough. In this work we have developed a theoretical‐methodological approach for the characterization of the kinetic of interaction between redox enzymes and substrates and/or redox mediators. Particularly, the interaction of glucose oxidase (GOx) with several commercially available redox mediators has been studied by means of amperometry and cyclic voltammetry. The main kinetic parameters for different mediators were exploited and discussed with the aim of finding the best mediator for a glucose biosensor to be used on real samples. 相似文献
56.
3,5-Dicyano-1,4-dihydropyridines underwent ring contraction to give functionalized cyclopentadienes upon treatment with trifluoroacetic anhydride. 相似文献
57.
Short malonyl dehydro peptides have been epoxidized using H2O2/Na2WO4 dihydrate. The obtained diastereomeric epoxides were separated by HPLC and successfully tested in the ring opening reaction with N-Boc l-cysteine methyl ester, to indicate their electrophilic behavior. Moreover, by a simple two-step reaction, the epoxy malonyl peptides can be converted into the corresponding aziridino malonyl peptides. 相似文献
58.
59.
Frank Lenzen Florian Becker Jan Lellmann Stefania Petra Christoph Schnörr 《Computational Optimization and Applications》2013,54(2):371-398
We introduce a class of adaptive non-smooth convex variational problems for image denoising in terms of a common data fitting term and a support functional as regularizer. Adaptivity is modeled by a set-valued mapping with closed, compact and convex values, that defines and steers the regularizer depending on the variational solution. This extension gives rise to a class of quasi-variational inequalities. We provide sufficient conditions for the existence of fixed points as solutions, and an algorithm based on solving a sequence of variational problems. Denoising experiments with spatial and spatio-temporal image data and an adaptive total variation regularizer illustrate our approach. 相似文献
60.
Stefania Tomasiello 《Numerical Algorithms》2011,57(3):289-312
In this paper, the solution of one-dimensional (1D) wave problems, by means of the Iterative Differential Quadrature method is discussed in terms of stability and accuracy. The 1D-wave equation with different boundary and initial conditions is considered. The time advancing scheme is here presented in a form, particularly suitable to support the discussion about stability both by the matrix method and by the energy method. The stability analysis, performed by means of these two methods, confirms the conditionally stable nature of the method. The accuracy of the solutions is discussed too. 相似文献