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141.
scar M. Bautista‐Aguilera Lhassane Ismaili Isabel Iriepa Daniel Diez‐Iriepa Fakher Chabchoub Jos Marco‐Contelles Marta Prez 《Chemical record (New York, N.Y.)》2021,21(1):162-174
Herein we have reviewed our recent developments for the identification of new tacrine analogues for Alzheimer's disease (AD) therapy. Tacrine, the first cholinesterase inhibitor approved for AD treatment, did not stop the progression of AD, producing only some cognitive improvements, but exhibited secondary effects mainly due to its hepatotoxicity. Thus, the drug was withdrawn from the clinics administration. Since then, many publications have described non‐hepatotoxic tacrines, and in addition, important efforts have been made to design multitarget tacrines by combining their cholinesterase inhibition profile with the modulation of other biological targets involved in AD. 相似文献
142.
Copia Lorenzo Plastino Wolfango Nisi Stefano Ciarletti Marta Povinec Pavel P. 《Journal of Radioanalytical and Nuclear Chemistry》2017,311(1):385-393
Journal of Radioanalytical and Nuclear Chemistry - Groundwater samples, collected into the deep underground facilities of Gran Sasso National Laboratory of the National Institute of Nuclear Physics... 相似文献
143.
Giuseppe Spedalotto Dr. Robert Gericke Marta Lovisari Dr. Erik R. Farquhar Dr. Brendan Twamley Dr. Aidan R. McDonald 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(51):11983-11990
Hydroxide-bridged high-valent oxidants have been implicated as the active oxidants in methane monooxygenases and other oxidases that employ bimetallic clusters in their active site. To understand the properties of such species, bis-μ-hydroxo-NiII2 complex ( 1 ) supported by a new dicarboxamidate ligand (N,N′-bis(2,6-dimethyl-phenyl)-2,2-dimethylmalonamide) was prepared. Complex 1 contained a diamond core made up of two NiII ions and two bridging hydroxide ligands. Titration of the 1 e− oxidant (NH4)2[CeIV(NO3)6] with 1 at −45 °C showed the formation of the high-valent species 2 and 3 , containing NiIINiIII and NiIII2 diamond cores, respectively, maintaining the bis-μ-hydroxide core. Both complexes were characterised using electron paramagnetic resonance, X-ray absorption, and electronic absorption spectroscopies. Density functional theory computations supported the spectroscopic assignments. Oxidation reactivity studies showed that bis-μ-hydroxide-NiIII2 3 was capable of oxidizing substrates at −45 °C at rates greater than that of the most reactive bis-μ-oxo-NiIII complexes reported to date. 相似文献
144.
P. De March M. Moreno-Maas J. L. Roca G. Germain J. F. Piniella O. Dideberg 《Journal of heterocyclic chemistry》1986,23(5):1511-1513
The structure of 3-acetoacetyl-2-chromenone has been definitely assigned to the product resulting from the reaction of 4-hydroxy-6-methyl-2-pyrone, 1 , with 2-hydroxybenzaldehyde. Also, the reaction of the pyrone 1 with pentane-2,4-dione in a 2:1 molar ratio gives 3,6,9,12-tetramethyl-1H,6H,7H,12H-6,12-methanodypirano[4,3-b:4,3-f]dioxocin-1,7-dione. X-Ray analyses of both products are presented. 相似文献
145.
Roca M Marcos MD Amorós P Beltrán-Porter A Edwards AJ Beltrán-Porter D 《Inorganic chemistry》1996,35(19):5613-5621
A general synthetic approach to rationalize the solution preparative chemistry of oxovanadium phosphates containing organic species as structural directing agents is presented. Careful attention is payed to the hydrolysis and condensation processes involving the ionic species in solution, and a simple restatement of the partial charge model (PCM) has been used in order to organize the experimental results. The structure of a new V(IV)-Fe(III) bimetallic oxovanadium phosphate, [H(3)N(CH(2))(2)NH(3)](2)[H(3)N(CH(2))(2)NH(2)] [Fe(III)(H(2)O)(2)(V(IV)O)(8)(OH)(4)(HPO(4))(4)(PO(4))(4)].4H(2)O, has been determined by X-ray single crystal diffraction methods. This compound crystallizes in the monoclinic system, space group P2(1)/n and the cell dimensions are as follows: a = 14.383(3) ?, b = 10.150(2) ?, c = 18.355(4) ?, and beta = 90.39(3) degrees (Z = 2). The existence of a complex intercrossing channel system, including a very large channel of 18.4 ? of diameter (in which both water molecules and ethylenediamine species are located), is the more interesting feature of this structure. Thermal decomposition, including the dehydration/rehydration process, has been studied by thermal analysis and variable temperature X-ray powder diffraction techniques. A complementary SEM study of the different intermediate decomposition products is presented. 相似文献
146.
Fustero S Navarro A Díaz D de La Torre MG Asensio A Sanz F González ML 《The Journal of organic chemistry》1996,61(25):8849-8859
Reaction of azaenolates of 2-alkyl-oxa(thia)zolines 6 with imidoyl chlorides 7 as electrophiles to furnish masked N-substituted beta-enamino acid derivatives 1-2 in 70-90% yield is described. Alternative routes are discussed. Compounds 1-2 generally appear in one tautomeric form, imino or enamino, depending on the nature of the imidoyl chloride. The configuration of the enamino moiety (Z) and the conformation (s-cis) of compounds 1-2 obtained were established by an NMR study and unequivocally set by nuclear Overhauser effect difference experiments. An X-ray structure of compound 1e is also reported, showing a strong intramolecular NH.N hydrogen bond. Ab initio calculations (HF/3-21G and HF/3-21+G) have been carried out on several representative examples (1e, 1p, and 1l) in an attempt to support and provide the correct geometry of these derivatives. Structural considerations among the possible isomers of compounds 1 are discussed. From these studies it was concluded that the theoretical calculations agree with the experimental results. In addition, a very simple one-pot procedure for the preparation of masked N-substituted alpha-alkylated beta-enamino acid derivatives 2 from 6, 7, and different alkyl halides (R(3)Y) is described. 相似文献
147.
Josef Bartos Marta Klimov 《Journal of polymer science. Part A, Polymer chemistry》1996,34(9):1741-1746
For a series of five amorphous polymers with a broad range of Tg values the kinetics of macroradical decay was measured by ESR technique and evaluated by the second-order kinetic model. It was found that the temperature Ttr of the transition between two regions of different reactivity in free radical decay reaction agrees quite well with the temperature parameter T0 of the Vogel-Fulcher-Tamman-Hesse (VFTH) equation for α-segmental dynamics. This parameter represents the onset of α-segmental mobility in glassy state below Tg. A nontraditional way of the estimation of T0 values for α-segmental dynamics through study of the macroradical decay in glassy state of amorphous polymers has been suggested. © 1996 John Wiley & Sons, Inc. 相似文献
148.
In this work we analyze how the choice of the active space in the CASSCF (the complete-active-space multiconfiguration self-consistent-field method) and CASPT2 (the second-order perturbation theory based on the CASSCF reference wave function) calculations affects the computed potential energy curves (PECs) for the intramolecular proton transfer reaction in the ground state and the two lowest lying singlet excited states of 1-amino-3-propenal. As anticipated, the results revealed that, qualitatively, the proton transfer in the different states can be correctly described even by minimal active spaces, which include the orbitals involved in the electronic excitation of the considered state and the antibonding sigma orbital corresponding to the bond formed by the molecule with the migrating hydrogen atom. However, quantitatively, the relative energies of the two tautomers and the energy barriers computed at the CASSCF level change when the active space is increased, indicating importance of the dynamic electron correlation. Introducing the dynamic correlation effects via CASPT2 makes the calculated energy parameters more uniform among the different active spaces. The analysis suggested certain optimal active spaces for studying proton transfer reactions in systems similar to 1-amino-3-propenal. The PEC calculations for excited states showed that the results are sensitive to the molecular geometries used in the calculations, particularly near the transition point. ©1999 John Wiley & Sons, Inc. J Comput Chem 20: 1422–1431 (1999) 相似文献
149.
Fila Karolina Grochowicz Marta Podkościelna Beata 《Journal of Thermal Analysis and Calorimetry》2018,133(1):489-497
Journal of Thermal Analysis and Calorimetry - The paper presents the synthesis, structure and polymerization of S-phenyl 2-methylprop-2-enethioate (PSM). This compound was prepared in the reaction... 相似文献
150.
Koltsov Iwona Prześniak-Welenc Marta Wojnarowicz Jacek Rogowska Anna Mizeracki Jan Malysa Maria Kimmel Giora 《Journal of Thermal Analysis and Calorimetry》2018,131(3):2273-2284
Journal of Thermal Analysis and Calorimetry - Industrially relevant nanopowder was synthesised by microwave hydrothermal synthesis to obtain well-controlled composition (ZrO2–AlO(OH) system)... 相似文献