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161.
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Gabriella Ieronimo Alessandro Mondelli Francesco Tibiletti Angelo Maspero Giovanni Palmisano Simona Galli Stefano Tollari Norberto Masciocchi Kenneth M. Nicholas Silvia Tagliapietra Giancarlo Cravotto Andrea Penoni 《Tetrahedron》2013
The thermal reaction between nitrosoarenes and alkynes under alkylating conditions produces N-alkoxyindoles as the major products in moderate to good yields and excellent regioselectivity. Various electrophiles are used affording different N–O-protected hydroxyindoles in a multi-component fashion. Privileged acetylenic substrates used in reactions with substituted nitrosoarenes are arylalkynes or propiolates. Potentially bioactive compounds and other classes of highly functionalizable indole products were prepared. Reactions between o-carbomethoxy-nitrosoarenes and arylacetylenes provided tricyclic compounds containing an acylaziridine indoline skeleton. 相似文献
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Beaumont Jonathan S. Lee Tae Hoon Mayorov Mikhail Tintori Carlo Rogo Francesco Angelucci Bruno Corbo Matteo 《Journal of Radioanalytical and Nuclear Chemistry》2017,314(2):803-812
Journal of Radioanalytical and Nuclear Chemistry - The IAEA has developed a liquid scintillator-based system for the non-destructive assay of 235U in fresh fuel assemblies. The fast neutron... 相似文献
165.
Dr. Gabriel Menendez Rodriguez Dr. Francesco Zaccaria Leonardo Tensi Prof. Cristiano Zuccaccia Prof. Paola Belanzoni Prof. Alceo Macchioni 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(6):2050-2064
The degradation pathways of highly active [Cp*Ir(κ2-N,N-R-pica)Cl] catalysts (pica=picolinamidate; 1 R=H, 2 R=Me) for formic acid (FA) dehydrogenation were investigated by NMR spectroscopy and DFT calculations. Under acidic conditions (1 equiv. of HNO3), 2 undergoes partial protonation of the amide moiety, inducing rapid κ2-N,N to κ2-N,O ligand isomerization. Consistently, DFT modeling on the simpler complex 1 showed that the κ2-N,N key intermediate of FA dehydrogenation ( INH ), bearing a N-protonated pica, can easily transform into the κ2-N,O analogue ( INH2 ; ΔG≠≈11 kcal mol−1, ΔG ≈−5 kcal mol−1). Intramolecular hydrogen liberation from INH2 is predicted to be rather prohibitive (ΔG≠≈26 kcal mol−1, ΔG≈23 kcal mol−1), indicating that FA dehydrogenation should involve mostly κ2-N,N intermediates, at least at relatively high pH. Under FA dehydrogenation conditions, 2 was progressively consumed, and the vast majority of the Ir centers (58 %) were eventually found in the form of Cp*-complexes with a pyridine-amine ligand. This likely derived from hydrogenation of the pyridine-carboxiamide via a hemiaminal intermediate, which could also be detected. Clear evidence for ligand hydrogenation being the main degradation pathway also for 1 was obtained, as further confirmed by spectroscopic and catalytic tests on the independently synthesized degradation product 1 c . DFT calculations confirmed that this side reaction is kinetically and thermodynamically accessible. 相似文献
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Several new constitutive models are formulated for the planar interface of a soft body sliding on a rigid soil, describing stick-slip phenomena due to friction, and wear due to abrasion. Attention is focused on damage at the interface, by neglecting any interaction with damage of body and any propagation of damage inside the body. Models are formulated in the general framework of the Thermodynamics of the irreversible processes and account for suitable defined internal variables of phenomenological type, namely gap, isotropic friction hardening and wear. The main feature of the new presented models is that the formulation of the wear process at the interface is obtained in the contest of Damage Mechanics, and it is based on the formal analogy between abrasion of a soft body and ductile damage of an elastic-plastic material. By following this approach, a scalar wear field, an effective stress and appropriate state and dissipation potentials are defined, able to describe a tangential isotropic wear process due to stick-slip and to hardening mechanism. Both cases of linear and nonlinear friction hardening are formulated; moreover, wearable and no-wearable bodies are considered. Numerical results relevant to one-dimensional problems are illustrated for monotonic, forward-backward and cyclic displacement time-histories, showing evolution for stress, gap and wear. Results furnished by different models are compared and discussed. 相似文献
169.
Angelo Ranise Francesco LucchesiniMatteo Caviglia Silvana AlfeiAndrea Spallarossa Chiara Caneva 《Tetrahedron》2013
A simple one-pot procedure for the stereoselective synthesis of Knoevenagel-type indoles is described. The method is based on the in situ reaction of indole iminium salts (four of them are fully characterized) with acyclic symmetrical and unsymmetrical active methylene reagents in the presence of triethylamine. In general, the overall yields are moderate to good. Some of relevant reaction parameters and steric effects affecting stereoselectivity are discussed. 相似文献
170.
Massimo Curini Francesco Epifano Maria Carla Marcotullio Ornelio Rosati Monia Rossi André Tsadjout 《合成通讯》2013,43(17):3181-3187
Layered zirconium hydrogen phosphonate exchanged with the potassium ion was found to be an efficient heterogeneous catalyst for the hydrolysis of sterically hindered phenolic silyl ethers. 相似文献