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61.
De Luca L Giacomelli G Porcheddu A Salaris M Taddei M 《Journal of combinatorial chemistry》2003,5(4):465-471
The synthesis of libraries of substituted pyrazoles and isoxazoles has been developed via in situ generation of polymer-bound enaminones. The synthetic protocol makes use of commercially available aniline cellulose, a low-cost and versatile biopolymer, under very mild conditions. This new support allowed us to carry out reactions in polar solvents under both conventional heating and MW irradiation without degradation of the polymer. The reaction between cellulose-bound enaminone and hydroxylamine or hydrazines to afford the target heterocycles in high yields directly in solution is the key step. The support can be conveniently recycled. 相似文献
62.
Francesco?FerranteEmail author Giampaolo?Barone Dario?Duca 《Theoretical chemistry accounts》2012,131(3):1165
Potential energy curves of NgH+ cations (Ng = Kr, Xe, Rn) were obtained by using four-component relativistic CCSD(T) coupled cluster calculations. Dissociation
energies, equilibrium bond lengths, electronic properties, such as dipole moments and electric field gradients at the nuclei,
and the related spectroscopic parameters of the electronic ground state have been determined. The results obtained for KrH+ and XeH+ are in good agreement with available experimental data, while those for RnH+ have been determined for the first time at this level of theory. 相似文献
63.
Giovanni Meazza Giampaolo Zanardi Paolo Piccardi 《Journal of heterocyclic chemistry》1993,30(2):365-371
Trifluoromethyl-substituted pyrazoles were synthesized via 1,3-dipolar cycloaddition from sydnones 2a-j and 1-aryl-3,3,3-trifluoro-propynes 5a-f. The regioselectivity of the reaction and the spectroscopic characteristics of the products are discussed. 相似文献
64.
Pier Luigi Ferrarini Giuliana Biagi Oreste Livi Giampaolo Primofiore Marino Carpen 《Journal of heterocyclic chemistry》1981,18(5):1007-1010
Some 3-substituted-5,6-dihydro[1,8]naphthyrido[3,2-c][1,8]naphthyridines (V) were obtained by the condensation of 7-substituted-2,3-dihydro-1,8-naphthyridin-4-(1H)ones (IV) with 2-aminonicotinaldehyde. All of the 5,6-dihydro derivatives V were transformed into the fully aromatic compounds VI by refluxing with nitrobenzene. 相似文献
65.
Antonio Da Settimo Anna Maria Marini Giampaolo Primofiore Federico Da Settimo Daniele Bertini 《Journal of heterocyclic chemistry》1998,35(1):57-60
The synthesis of derivatives of two new heterocyclic systems, purino[8,7-b][1,3]benzothiazine and pyrido[3′,2′:5,6][1,3]thiazino[3,2-f]purine, was effected by the Ullmann reaction between 8-mercaptotheophylline or 8-bromotheophylline with the appriopriately substituted benzoic or nicotinic acid, respectively. The 8,8′-dithiobistheophylline is also reported. 相似文献
66.
M. Barbui A. Andrighetto C. Antonucci S. Carturan F. Cervellera S. Cevolani M. Cinausero P. Colombo A. Dainelli P. Di Bernardo F. Gramegna G. Maggioni G. Meneghetti C. Petrovich L. Piga G. Prete V. Rizzi M. Santana-Leitner M. Tonezzer P. Zanonato D. Zafiropoulos 《The European physical journal. Special topics》2007,150(1):275-276
A Direct Target for a mid-term RIB ISOL-type facility is being developed at LNL, in the framework of the R&D for the SPES
project [1]. Using a 40 MeV proton beam impinging on a UCx thick target of 2.5 g/cm3 density, a production rate of 1013 in target fissions per second is expected [2]. The crucial point, when short-lived isotopes are produced in the target, is
to build systems (target + ion source) with good release properties and high efficiency.
Monte Carlo simulations were performed using the GEANT4 toolkit [3] and the RIBO code [4] in order to optimize our target
geometry and to estimate the average release time. 相似文献
67.
We here report that the formation and breakdown of an intramolecular cytosine-thymine (CT) motif DNA triple-helix can be performed repeatedly, quickly and independently of its local concentration without performance reduction over successive cycles; as a consequence, we propose that this set of characteristics makes the DNA duplex-triplex transition an ideal candidate to power simple nanometer-scale devices capable of maintaining effective performance regardless of their local concentration. 相似文献
68.
69.
Giampaolo Cicogna 《Mathematical Methods in the Applied Sciences》2014,37(12):1819-1827
This paper describes the notion of σ‐symmetry, which extends the one of λ‐symmetry, and its application to reduction procedures of systems of ordinary differential equations (ODEs) and of dynamical systems (DS) as well. We also consider orbital symmetries, which give rise to a different form of reduction of DS. Finally, we discuss how DS can be transformed into higher order ODEs, and how these symmetry properties of the DS can be transferred into reduction properties of the corresponding ODEs. Many examples illustrate the various situations. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
70.
Sgobba V Giancane G Conoci S Casilli S Ricciardi G Guldi DM Prato M Valli L 《Journal of the American Chemical Society》2007,129(11):3148-3156
Thin films consisting of two fulleropyrrolidine derivatives 1 or 2 and a water-soluble porphyrin, TPPS4, were prepared by the Langmuir-Sch?fer (LS, horizontal lifting) method. In particular, a solution of the fulleropyrrolidine in chloroform and dimethyl sulfoxide was spread on the water surface, while the porphyrin (bearing peripheral anionic sulfonic groups) was dissolved into the aqueous subphase. To the best of our knowledge, such a versatile method for film fabrication of fullerene/porphyrin mixed composite films has never been used by other researchers. Evidence of the effective interactions between the two components at the air-water interface was obtained from the analysis of the floating layers by means of surface pressure vs area per molecule Langmuir curves, Brewster angle microscopy, and UV-visible reflection spectroscopy. The characterization of the LS films by UV-visible spectroscopy reveals that in each case the two constituents behave as strongly interacting pi systems. The use of polarized light suggests the existence of a preferential direction of the TPPS4 macrocyclic rings with an edge-on arrangement with respect to the substrate surface, regardless which fulleropyrrolidine derivative is in the composite film. Atomic force microscopy investigations give evidence of morphologically flat layers even for LS transfer at low surface pressures. Photoaction spectra were recorded from films deposited by only one horizontal lifting onto indium-tin-oxide (ITO) electrodes, and the observed photocurrent increased notably with increasing transfer surface pressure for both 1/TPPS4 and 2/TPPS4 composite films. IPCE values are larger for 2/TPPS4 systems in comparison with 1/TPPS4 composite layers. Finally, a nonconventional approach to photoinduced phenomena is proposed by differential spectroscopy in the FT-IR attenuated total reflectance (ATR) mode. 相似文献