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61.
G Uccello-Barretta R Bernardini F Balzano P Salvadori 《The Journal of organic chemistry》2001,66(1):123-129
Ionic complexes [PtCl3(C2H4)]-[AmH]+, containing chiral secondary amines, constitute a versatile class of chiral derivatizing agents (CDAs) for the enantiomeric purity determination of chiral unsaturated compounds via 195Pt NMR spectroscopy. The NMR conformational analysis allows us to search for the stereochemical basis of their enhanced versatility. 相似文献
62.
A multicomponent reaction that employs an unsaturated carboxylic acid, a 1,2 or 1,3 amino alcohol and gaseous CO and H2 has been discovered. Thus, hydrocarbonylation of the carboxylic acid double bond generates a linear aldehyde, that is, immediately transformed into an oxazolidine. Further microwave assisted intramolecular lactamization delivers oxazolopiperidines with the generation of six new bonds in a one-pot single step. Bicylic, tricyclic, tetracyclic, and spirocyclic oxazolopiperidines can be prepared in good yields and acceptable stereoselection. The reaction did not occur under conventional heating even at higher temperature and pressure and for longer time, showing that microwave heating is indispensable to the process. 相似文献
63.
Marilena Di Valentin E. Salvadori S. Ceola D. Carbonera 《Applied magnetic resonance》2010,37(1-4):191-205
The photoexcited triplet state of the carotenoid peridinin in the peridinin–chlorophyll a–protein (PCP) of the dinoflagellate Heterocapsa pygmaea has been investigated by pulsed electron paramagnetic resonance (EPR) and pulsed electron-nuclear double resonance (ENDOR) spectroscopies. The α- and β-protons hyperfine couplings of the peridinin-conjugated chain have been derived from Davies and Mims ENDOR experiments. The spectroscopic results have been compared to those obtained for the main form of the PCP complex and for the high-salt PCP form from Amphidinium carterae. The EPR features of the peridinin triplet state are very similar in the antenna complexes belonging to the two different dinoflagellate species, proving that the triplet formation pathway and the triplet localization on one specific peridinin per subcluster are common features of different PCP antennas. No significant variation of the hyperfine couplings of the peridinin triplet state has been detected between the main form of the PCP complex from A. carterae and H. pygmaea. The spectroscopic results confirm the close relationship between the Amphidinium PCP and the corresponding Heterocapsa complex at least in terms of mutual arrangement of the chlorophyll a–peridinin pair involved in photoprotection and in terms of conformation of the peridinin-conjugated chain. 相似文献
64.
Angela Cuzzola Antonella Petri Francesco Mazzini Piero Salvadori 《Rapid communications in mass spectrometry : RCM》2009,23(18):2975-2982
Alteration of levels of glucocorticoids in plasma and urine can be related to several diseases. In particular, the determination of endogenous glucocorticoids in urine has been reported to provide information on cortisol and cortisone status, on the activities of steroid hormone enzymes and on glucocorticoid metabolism. In this study, the application of hyphenated mass spectrometry techniques (GC/MS without derivatization and LC/MS) for the simultaneous analysis of free urinary cortisol (F), cortisone (E), tetrahydrocortisol (THF), allo‐tetrahydrocortisol (A‐THF) and tetrahydrocortisone (THE) was evaluated. A sample preparation protocol by solid‐phase extraction, mass spectrometry parameters and chromatographic conditions for both techniques were carefully optimized in terms of extracting phase and solvents, matrix effects, recovery, sensitivity and compound resolution. Baseline separation was achieved for the five underivatized analytes both in GC and LC. The LC/MS/MS technique was more suitable for the analysis of urine samples, being less influenced by matrix effects and showing excellent sensitivity and selectivity. A preliminary application of the reported method for the diagnosis of metabolic diseases was also described. The determination of each analyte in its free form, described for the first time in the paper, offers new perspectives in the application of glucocorticoid analysis for diagnostic purposes. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
65.
Over the past few years, quantitative determination of alpha- and gamma-CEHC, main urinary metabolites of vitamin E, has been becoming more and more important as a key parameter in assessing oxidative stress and supplementation of tocopherols. The use of deuterated analogues of these metabolites allows their accurate determination even in complex matrixes. While preparation of gamma-CEHC-d(2) has already been described, here we report the first synthesis of alpha-CEHC-d(3) together with alpha-tocopheronolactone-d(3), its oxidation product. 相似文献
66.
We extend the weak Burkill-Cesari integral of a vector valued set function, with values in a Banach space, to a measure, following an idea developed by Cesari ([4], [5]) in Euclidean spaces. 相似文献
67.
Uccello-Barretta G Balzano F Quintavalli C Salvadori P 《The Journal of organic chemistry》2000,65(12):3596-3602
The stereochemistries in solution of the diastereoisomeric complexes formed by quinines modified at the hydroxyl site (9-O-acetylquinine; 9-O-(3,5-dimethoxyphenylcarbamate)quinine) or quinuclidine nitrogen (N-benzylquininium chloride) and each enantiomer of 2-(3', 5'-dinitrobenzamido)-1-phenylethanol have been compared to those of the free compounds by (1)H NMR investigations. Completely different interaction models, also involving changes of the free state conformations, have been obtained. 相似文献
68.
Summary The primary exposure standard for medium-energy X-rays of the Istituto Superiore di Sanità (ISS) is described with particular
attention to some innovatory details. Methods for intercalibrating exposure standards from various national primary-standard
laboratories are discussed. The results of a comparison between the ISS exposure standard and that of the Bureau International
des Poids et Mesures performed in 1983 are presented.
Riassunto Si descrive il campione primario dell'unità di esposizione per raggi X di media energia dell'Istituto Superiore di Sanità (ISS), con particolare attenzione ad alcuni dettagli innovativi. Si discutono le metodiche d'intercalibrazione tra campioni primari di esposizione di diversi laboratori metrologici primari. Sono infine presentati i risultati di un confronto effettuato nel 1983 tra il campione primario di esposizione dell'ISS e l'analogo campione del Bureau International des Poids et Mesures.
Резюме Описывается первичный эталон экспозиции для рентгеновских лучей промежуточных энергий, предложенный Высщим институтом здравоохраненуя Италии. Особое внимание уделяется некоторым новым техническим деталам. Обсуждаются методы взаимной калибровки эталонов экспозиции из различных националъных метрологических лабораторий. В заключение приводятся результаты сравнения первичного эталона экспозиции Высщего института здравоохранения и первичного эталона экспозиции Международного Ъюро Мер и Весов, которое было проведено в 1983 году.相似文献
69.
Summary
We prove that the Weierstrass integral over a variety ([5]),in Banach spaces, can be represented as a Bochner integral. This result was given by Cesari ([6])in Euclidean spaces.
Lavoro eseguito nell'ambito del Gruppo Nazionale per l'Analisi Funzionale e le sue Applicazioni del C.N.R.Desideriamo ringraziare i Proff. L.Cesari e C.Vinti per le conversazioni avute con loro sull'argomento. 相似文献
Lavoro eseguito nell'ambito del Gruppo Nazionale per l'Analisi Funzionale e le sue Applicazioni del C.N.R.Desideriamo ringraziare i Proff. L.Cesari e C.Vinti per le conversazioni avute con loro sull'argomento. 相似文献
70.
F. Marchetti P. Negrini L. Salvadori M. Scalia 《Annali di Matematica Pura ed Applicata》1976,108(1):211-226
Summary A concept of total stability for continuous or discrete dynamical systems and a generalized definition of bifurcation are
given: it is possible to show the link between an abrupt change of the asymptotic behaviour of a family of flows and the arising
of new invariant sets, with determined asymptotic properties. The theoretical results are a contribution to the study of the
behaviour of flows near an invariant compact set. They are obtained by means of an extension of Liapunov's direct method.
A Dario Graffi nel suo 70° compleanno
Entrata in Redazione il 9 febbraio 1975.
Work performed under the auspices of the Italian Council of Research (C.N.R.). 相似文献