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111.
112.
Adriano Mollica Federica Feliciani Ivana Cacciatore Gino Lucente 《Tetrahedron letters》2010,51(9):1333-1335
In this Letter we present a simple reaction pathway which allows the conversion of the glutamic acid residue of a tripeptide into a proline residue. The reaction was performed by using Boc-Val-Glu-Phe-NH2 as a starting material and is based on a NaH-induced intraresidue alkylation under reaction conditions analogous to that adopted during the Freidinger lactams formation. 相似文献
113.
Adriano D'Addio Juraj Malinčik Dr. Olaf Fuhr Prof. Dr. Dieter Fenske Prof. Dr. Daniel Häussinger Prof. Dr. Marcel Mayor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(56):e202201678
Orthogonal joints, understood as connections with an angle of 90°, were introduced in the design of the “Geländer” model compounds 1 and 2 . The banister, consisting of a conjugated carbazole dimer linked by either 1,3-butadiyne ( 2 ) or a single thiophene ( 1 ), wraps around an axis composed of a phthalimide dimer due to the dimensional mismatch of both subunits, which are interconnected by phenylene rungs. The “Geländer” structure was assembled from a monomer comprising the 1,4-diaminobenzene rung with one amino substituent as part of a 4-bromo phthalimide subunit forming the orthogonal junction to the axis, and the other as part of a masked 2-ethynyl carbazole as orthogonal joint to the banister. The macrocycle was obtained by two sequential homocoupling steps. A first dimerization by a reductive homocoupling assembled the axis, while an oxidative acetylene coupling served as ring-closing reaction. The formed butadiyne was further derivatized to a thiophene, rendering all carbons of the model compound sp2 hybridized. Both helical structures were fully characterized and chirally resolved. Assignment of the enantiomers was achieved by simulation of chiroptical properties and enantiopure synthesis. 相似文献
114.
In this paper we show that a complete characterization of the controllability property for linear control system on three-dimensional solvable nonnilpotent Lie groups is possible by the LARC and the knowledge of the eigenvalues of the derivation associated with the drift of the system. 相似文献
115.
Adriano Bigotto 《光谱学快报》2013,46(6):355-362
The properties and molecular structure of the metal complexes of Schiff-bases of the type N-alkyl- and N-aryl-salicylaldimine have elicited considerable interest:in particular their vibrational spectra have been the subject of many investigations 1,2. Earlier assignments were made empirically, but recently the 15 N isotopic shift technique has also been used. 相似文献
116.
In this article, we will address the complexity of non-identical components in multi-component systems. Most technical systems can be described as such since either component types or component functions within the system vary amongst components. While most reliability related work resorts to the assumption of homogeneous components, we aim to address the often more realistic assumption of heterogeneous components extending the model of Extended Sequential Order Statistics by two inferential methods. Firstly, the derivation of Maximum Likelihood Estimates including a simulation study demonstrating their good performance for large enough sample size. Secondly, we introduce a likelihood ratio test to test whether components can be assumed identical accompanied by a power study. Both methods are powerful tools in reliability contexts. The former increases our understanding of component behaviour, especially upon failure of other components. This knowledge empowers system operators to make better decisions regarding maintenance schedules and failure time prediction. The latter supports operators in their quest of identifying component equivalence. Therefore, both methods can be used to achieve meaningful results in real life applications. 相似文献
117.
118.
Adriano Polican Ciena Isabela Ugo Luques Fernando José Dias Sonia Regina Yokomizo de Almeida Mamie Mizusaki Iyomasa Ii-sei Watanabe 《Micron (Oxford, England : 1993)》2010,41(8):1011-1014
The myotendon junction (MTJ) is a specialised area into the muscle fibers where the sarcoplasmic membranes connect to the collagen fibers bundles. There are few data about plasticity of the MTJ in aging processes. The aim of this study is to analyse the ultrastructure characteristics of MTJ of medial pterygoid muscle of adult and aged rats. Employing the transmission electron microscopy method, twenty male rats Wistar (Rattus norvegicus) were divided into two groups: A (n = 10) with 12 months of age; B (n = 10) 24 months of age. The animals were anaesthetised with overdose the urethane (3 g/kg, i.p.) and sacrified during the perfusion with modified Karnovsky solution. The specimens were post-fixed in a 1% osmium tetroxide solution, dehydrated in ascending concentration of ethanol and embedded in Spurr resin. The thin sections, of 90 nm thick, were counterstained with uranyl acetate and lead citrate solution, and examined in a Jeol 1010 transmission electron microscope. The fine structure of the MTJ of group A revealed the defined interdigitations and disposed in several levels of deep formations containing the collagen fibers. In the group B, such structures did not observed, detecting the projections irregular in shape, and large of extra matrix with in aspect of remodelling. In conclusion it was possible to identify the plasticity of MTJ in the group B which presented several morphological alterations comparing to the adult animals. These data of group B suggested the occurrence of aging processes in the MTJ in rats. 相似文献
119.
Adriano Boni Riccardo Peloso Claudia Graiff 《Journal of organometallic chemistry》2006,691(26):5602-5609
The chemistry of bis(3,5-dimethylpyrazolyl)methane complexes of copper(I) has been investigated and a dinuclear copper(I) derivative of formula {Cu2[μ-CH2(3,5-Me2Pz)2]2}(TfO)2 [TfO = trifluoromethanesulphonate anion, ], characterized by an uncommon bridging coordination of the bis(pyrazolyl)methane ligands, has been isolated and characterized by X-ray diffraction methods. Moreover, new olefin derivatives of general formula [Cu[CH2(3,5-Me2Pz)2](olefin)]TfO have been prepared (olefin: coe = cyclooctene, van = 4-vinylanisole, nbe = norbornene), their carbonylation reactions, {Cu[CH2(3,5-Me2Pz)2](olefin)}TfO + CO ? {Cu[CH2(3,5-Me2Pz)2](CO)}TfO + olefin, have been studied gas volumetrically and the thermodynamical parameters of the equilibria for the displacement of the coordinated olefin by carbon monoxide have been determined. 相似文献
120.
[reaction: see text] A novel synthetic pathway to benzoquinazolines from naphthylamines is reported. Benzoquinazoline nucleus was cyclized in good yield from N-protected naphthylamines using hexamethylenetetramine in TFA and potassium ferricyanide in aqueous ethanolic KOH. This method is efficient and convenient with respect to previously reported synthetic pathways. 相似文献