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31.
Yves L. Janin Anne-Marie Aubertin Angéle Chiaroni Claude Riche Claude Monneret Emile Bisagni David S. Grierson 《Tetrahedron》1996,52(48):5109-15170
The imidazo[1,5-g][1,4]diazepine derivatives 7a and 7b, analogues of TIBO lacking the aromatic ring, were prepared as part of a research program to find compounds displaying antiviral activity against HIV-2 and resistant strains of HIV-1. Condensation of N-trityl and N-tosyl 4-(2-chloroethyl)-imidazole with the appropriate amino alcohols gave compounds 10a-c and 16a-e. The hydroxyl group in these intermediates was activated toward closure of the [1,4]diazepine ring by either conversion to the corresponding chloro derivative, or by N → O transfer of the tosyl group. However, only cyclization to compounds 13a and 13b proved efficient. These products were converted to the target molecules 7 by reaction of their C-2 anion with S8. In vitro evaluation of compounds 7a,b and 13,a,b in cell culture (CEM SS/HIV-1-LAI and CEM SS/HIV 1 nevirapine resistant cells) revealed that only 13b displayed minimal activity. 相似文献
32.
The setup for Simultaneous Triple Radiation Mössbauer Spectroscopy (STRMS) is described. The arrangement allows an independent and simultaneous recording of conversion electron Mössbauer spectra (CEMS) and of conversion X-ray Mössbauer spectra (CXMS), both in backscattering geometry, and-in addition-of γ-ray absorption spectra in transmission (TMS). Due to the different escape or penetration ranges of the three radiations involved, the spectra give information on phases, depth and orientation. From a practical point of view the counter for γ-rays, X-rays and electrons must be separated and shielded to minimize the mutual perturbation. 相似文献
33.
Gaucher B Rouquayrol M Roche D Greiner J Aubertin AM Vierling P 《Organic & biomolecular chemistry》2004,2(3):345-357
With the aim of improving the pharmacological properties of current protease inhibitors (PIs), the synthesis of various acyl and carbamate amino acid- or diglyceride-containing prodrugs derived from saquinavir, indinavir and nelfinavir, their in vitro stability with respect to hydrolysis and their anti-HIV activity in CEM-SS and MT4 cells have been investigated. l-Leucine (Leu) and l-phenylalanine (Phe) were connected through their carboxyl to the PIs while l-tyrosine (Tyr) was conjugated through its aromatic hydroxyl via various spacer units. Hydrolysis of the prodrug with liberation of the active free drug was crucial for antiviral activity. The Leu- and Phe-PI prodrugs released the active free drug very rapidly (half-lives of hydrolysis in buffer at 37 degree C of 3-4 h). The Tyr-PI conjugates with a -C(O)(CH(2))(4)- linker exhibited half-lives in the 40-70 h range and antiviral activities in the 21-325 nM range (from 2 to 22 nM for the free PIs). The chemically very stable carbamate "peptidomimetic" Tyr-PI prodrugs (no hydrolysis detected after 7 days in buffer) displayed a very low anti-HIV activity or were even inactive (EC(50) from 2300 nM to >10 microM). A very low antiviral activity was measured for the diglyceride-substituted saquinavir and for all of the disubstituted indinavir and nelfinavir prodrugs. All these prodrugs probably released the active parent PI too slowly under the antiviral assay conditions. These results combined with those from transepithelial transport studies (Rouquayrol et al., Pharm. Res., 2002, 19, 1704-1712) indicate that conjugation of amino acids (through their carboxyl) to the PIs constitutes a most appealing alternative which could improve the intestinal absorption of the PIs and reduce their recognition by efflux carriers. 相似文献
34.
J. Balogh L. Bottyán I. Dézsi K. Papp F. Aubertin S. M. Fries U. Gonser 《Hyperfine Interactions》1986,28(1-4):803-806
Hydrogen desorption during heat treatments of (crystalline) Zr3FeH5.5 was studied by Mössbauer spectroscopy (MS), X-ray (powder) diffraction (XRD) and thermal gravimetry (TG). In case of sufficiently slow heating rate all hydrogen effuses below 650°K and no phase segregation occurs. At higher temperatures retained hydrogen induce phase separation into Fe2Zr (or more likely Fe2ZrHx) and zirconium hydride. The existence of a highly disordered f.c. tetragonal ternary hydride phase was also detected both by XRD (ao=4.76 Å, c=4.96 Å) and MS
. 相似文献
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38.
Munshi G Mustafa Sudhir Raniwala T Awes B Rai RS Bhalerao JG Contreras RV Gavai SK Ghosh P Jaikumar GC Mishra AP Mishra H Mishra B Mohanty J Nayak J-Y Ollitrault SC Phatak L Ramello R Ray PK Sahu AM Srivastava DK Srivastava VK Tiwari 《Pramana》2006,67(5):961-981
This is the report of Heavy Ion Physics and Quark-Gluon Plasma at WHEPP-09 which was part of Working Group-4. Discussion and
work on some aspects of quark-gluon plasma believed to have created in heavy-ion collisions and in early Universe are reported. 相似文献
39.
The phase composition at the surface of plasma nitrocarborized carbon steel was measured in backscattering geometry. The hyperfine
parameters of the various iron sites in cementite, γ′-iron nitride and ε-carbonitride reflect the variation of composition
with distance from the sample surface in a similar way as in the fractional areas of the respective phases.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
40.
An assessment of the phases present in the Hf?Fe system agress well with the phase diagram and yields parameters in general agreement with previous Mössbauer studies. The Hf2Fe phase exhibits a quadrupole split spectrum whereas the HfFe2 compound shows magnetic hyperfine splitting. 相似文献