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11.
Baltrusaitis RM Becker JJ Blaylock GT Brown JS Bunnell KO Burnett TH Cassell RE Coffman D Cook V Coward DH Cui H Del Papa C Dorfan DE Duncan AL Einsweiler KF Eisenstein BI Fabrizio R Gladding G Grancagnolo F Hamilton RP Hauser J Heusch CA Hitlin DG Köpke L Mockett PM Moss L Mozley RF Nappi A Odian A Partridge R Perrier J Plaetzer SA Richman JD Roehrig JR Russell JJ Sadrozinski HF Scarlatella M Schalk TL Schindler RH Seiden A Sleeman JC Spadafora AL Thaler JJ Toki W Unno Y Villa F Wattenberg A 《Physical review letters》1985,55(17):1723-1726
12.
Mario Sechi Luciano Sannia Maria Orecchioni Fabrizio Carta Giuseppe Paglietti Nouri Neamati 《Journal of heterocyclic chemistry》2003,40(6):1097-1102
HIV‐1 integrase (IN) is a very promising and validated target for the development of therapeutic agents against AIDS. In an effort to design and synthesize biological isosteric analogs of β‐diketoacid‐containing inhibitors of IN, we prepared a series of substituted isoxazole carboxylic acids. Several of these compounds inhibited catalytic activities of purified IN at micromolar concentration range. With an aim to prepare a large number of analogues based on the isoxazole pharmacophore we focused our study on a series of 3,5‐disubstituted isoxazole isomers. For a rapid structural analysis we discovered a convenient 1H‐nmr method for distinguishing between isomeric structures based on their H‐4 assignments. This “finger print” approach to isomer identification will be useful in combinatorial chemistry settings where a mixture can be further derivatized. 相似文献
13.
Fundueanu G Constantin M Bortolotti F Ascenzi P Cortesi R Menegatti E 《Macromolecular bioscience》2005,5(10):955-964
Despite the large number of publications and patents concerning pH/thermoresponsive polymers, few data are available concerning the preparation of thermoresponsive cross-linked microspheres from preformed polymers. Therefore, N-isopropylacrylamide-co-acrylamide-co-(2-hydroxyethyl acrylate) copolymers were obtained as a new thermoresponsive material with a lower critical solution temperature (LCST) around 36 degrees C, in phosphate buffer at pH 7.4, and with a cross-linkable OH group in their structure. The LCST value was determined both by UV spectroscopy and microcalorimetric analysis. These copolymers were solubilised in acidified aqueous solution below their LCST, dispersed in mineral oil, and transformed into stable microspheres by cross-linking with glutaraldehyde. The thermoresponsive microspheres were characterised by optical and scanning electron microscopy, degree of swelling, and water retention. The pore dimensions of the microspheres and the retention volumes of some drugs and typical compounds were evaluated at different temperatures by liquid chromatography. Indomethacin, as a model drug, was included in the microspheres by the solvent evaporation method. Finally, the influence of temperature and of temperature cycling on drug release was investigated. 相似文献
14.
Amadei A Marinelli F D'Abramo M D'Alessandro M Anselmi M Di Nola A Aschi M 《The Journal of chemical physics》2005,122(12):124506
In this paper we extend the perturbed matrix method by explicitly including the nuclear degrees of freedom, in order to treat quantum vibrational states in a perturbed molecule. In a previous paper we showed how to include, in a simple way, nuclear degrees of freedom for the calculation of molecular polarizability. In the present work we extend and generalize this approach to model vibroelectronic transitions, requiring a more sophisticated treatment. 相似文献
15.
The intermolecular cyclotrimerisation of terminal and internal alkynes can be catalysed by simple cobalt complexes such as a CoBr2(diimine) under mild reaction conditions when treated with zinc and zinc iodide with high regioselectivity in excellent yields. 相似文献
16.
Badorrey R Cativiela C Díaz-de-Villegas MD Díez R Galbiati F Gálvez JA 《The Journal of organic chemistry》2005,70(24):10102-10105
[reaction: see text] Addition of trimethylsilyl cyanide to ketimines derived from (R)-2,2-dimethyl-1,3-dioxolan-4-yl methyl ketone to generate a quaternary stereocenter has been achieved with high yields and excellent diastereoselectivity. The stereoselectivity was found to be temperature and solvent dependent. The beta-hydroxy-alpha-amino nitrile of syn configuration was the major compound in kinetically controlled reactions, whereas the anti stereoisomer was obtained in excess in thermodynamically controlled reactions. Double stereodifferentiation under kinetic control conditions was successful, and the cyanation reaction occurred with complete syn diastereoselectivity using the matched pair. The versatility of the resulting amino nitrile as a synthetic intermediate was tested by performing the synthesis of orthogonally protected (R)-(2-aminomethyl)alanine. 相似文献
17.
Massimo Di Vaira Fabrizio Mani Piero Stoppioni 《Journal of organometallic chemistry》2004,689(10):1757-1762
The reaction of [CpRu(CH3CN)3]PF6 with the bidentate ligands L-L=1,2-bis(diphenylphosphino)ethane, dppe, and (1-diphenylarsino-2-diphenylphosphino)ethane, dpadppe, affords mononuclear or dinuclear complexes of formula [CpRu(η2-L-L)(CH3CN)]PF6, [{CpRu(CH3CN)2}2(μ-η1:1-L-L)](PF6)2 and [{CpRu(CH3CN)}2(μ-η1:1-L-L)2](PF6)2 (L-L=dppe, dpadppe). All of the compounds are characterized by microanalysis and NMR [1H and 31P{1H}] spectroscopy. The crystal structure of [{CpRu(CH3CN)2}2(μ-η1:1-dppe)](PF6)2 has been determined by X-ray diffraction analysis. The complex exhibits a dppe ligand bridging two CpRu(CH3CN)2 fragments. 相似文献
18.
Garavelli M Ruggeri F Ogliaro F Bearpark MJ Bernardi F Olivucci M Robb MA 《Journal of computational chemistry》2003,24(11):1357-1363
MMVB is a QM/MM hybrid method, consisting of a molecular mechanics force field coupled to a valence bond Heisenberg Hamiltonian parametrized from ab initio CASSCF calculations on several prototype molecules. The Heisenberg Hamiltonian matrix elements Q(ij) and K(ij), whose expressions are partitioned here into a primary contribution and second-order correction terms, are calculated analytically in MMVB. When the original MMVB force field fails to produce potential energy surfaces accurate enough for dynamics calculations, we show that significant improvements can be made by refitting the second-order correction terms for the particular molecule(s) being studied. This "local" reparametrization is based on values of K(ij) extracted (using effective Hamiltonian techniques) from CASSCF calculations on the same molecule(s). The method is demonstrated for the photoisomerization of s-cis butadiene, and we explain how the correction terms that enabled a successful MMVB dynamics study [Garavelli, M.; Bernardi, F.; Olivucci, M.; Bearpark, M. J.; Klein, S.; Robb, M. A. J Phys Chem A 2001, 105, 11496] were refitted. 相似文献
19.
Stefan Furegati Walter Ganci Fabrizio Gorla Urs Ringeisen Peter Rüedi 《Helvetica chimica acta》2004,87(10):2629-2661
Phosphorylation of suitable piperidine precursors yielded a series of novel decalin‐type O,N,P‐heterocycles. The title compounds, P(3)‐axially and P(3)‐equatorially X‐substituted, cis‐ and trans‐configurated 2,4‐dioxa‐7‐aza‐, 2,4‐dioxa‐8‐aza‐, and 2,4‐dioxa‐9‐aza‐3‐phosphabicyclo[4.4.0]decane 3‐oxides (X=Cl, F, 4‐nitrophenoxy, and 2,4‐dinitrophenoxy), are configuratively fixed and conformationally constrained P‐analogues of acetylcholine and as such represent acetylcholine (7‐aza and 9‐aza isomers) or γ‐homo‐acetylcholine mimetics (8‐aza isomers). Being irreversible inhibitors of acetylcholinesterase (AChE), the compounds are considered to be suitable probes for the investigation of the stereochemical course of the inhibition reaction by 31P‐NMR spectroscopy. Moreover, the design of these mimetics will enable studies of molecular interactions with AChE, in particular, the recognition conformation of acetylcholine. 相似文献
20.
Fabrizio Casarini Luigi Marcheselli Andrea Marchetti Lorenzo Tassi Giuseppe Tosi 《Journal of solution chemistry》1993,22(10):895-905
The relative permittivities for the ternary 1,2-ethanediol (component 1) + 2-methoxyethanol (2) + water (3) solvent system have been measured for 66 mixtures covering the whole mole fraction composition 0X1/X2/X3 1 range at –10, –5 and 0 °C. The experimental data were used to test some empirical relations stating the dependence of = (X1, X2, X3). A comparison between the calculated and experimental data show that these equations can be usefully employed to predict values in correspondence of the experimental data gaps. 相似文献