Home About us Contact
|
Home About us Contact | ||
|
|
||
Pyridine Complex (pyridine + complex)
Selected AbstractsSynthesis of [14C]- and [35S]-labelled PI-88 for pharmacokinetic and tissue distribution studiesJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 9 2002Vito Ferro Abstract PI-88, uniformly labelled with [14C] was prepared by incorporating D -[14C]glucose into the fermentation of Pichia (Hansenula) holstii NRRL Y-2448 under controlled conditions to produce [14C]-labelled extracellular phosphomannan. Subsequent acid catalyzed hydrolysis gave the [14C]-labelled oligosaccharide phosphate fraction which was sulfonated with excess sulfur trioxide pyridine complex to give [14C]PI-88. [35S]-labelled PI-88 was similarly prepared by the sulfonation of unlabelled oligosaccharide phosphate fraction with [35S] sulfur trioxide pyridine complex. Copyright © 2002 John Wiley & Sons, Ltd. [source] FT-Raman, FTIR and density functional theory studies of a hydrogen-bonded formamide:pyridine complexJOURNAL OF RAMAN SPECTROSCOPY, Issue 11 2009Filipe S. F. Jacinto Abstract Raman and IR experiments have been carried out on formamide (FA) and pyridine (Py) mixtures at different compositions. The appearance of a new Raman band at 996 cm,1 (,1 region of Py), whose intensity depends on the FA concentration, is assigned to an FA:Py adduct and this result is in excellent agreement with those of other authors who employed noisy light-based coherent Raman scattering spectroscopy (I(2) CARS). Another band at 1587 cm,1 (,8 region of Py) has been observed for the first time by using Raman and IR spectroscopies. Its intensity shows the same dependence on the FA concentration and this fact allows us to also attribute it to an FA:Py adduct. The good relationship between the Raman and IR data demonstrates the potential of the vibrational spectroscopy for this kind of study. Owing to higher absolute Raman scattering cross section, the ,1 region of Py has been chosen for the quantitative analysis and a stoichiometry of 1:1 FA:Py is reported. The experimental data are very well supported by the density functional theory (DFT) calculation, which was employed for the first time to the present system. Furthermore, the actual investigation shows an excellent agreement with those reported from computational calculations for similar systems. A comparison with our previous studies confirms that the solvent dielectric constant determines the stoichiometry of a given Lewis acid,base adduct in the infinite dilution limit. Copyright © 2009 John Wiley & Sons, Ltd. [source] Facile synthesis of pyridinium aryltetrachlorotellurates: crystal and molecular structure of [C5H6N][RTeCl4] (R = m -O2NC6H4, p -NCC6H4)APPLIED ORGANOMETALLIC CHEMISTRY, Issue 11 2005Jens Beckmann Abstract Arylation of TeCl4 with arylboroxine,pyridine complexes [(RBO)3·C5H5N, where R = m -O2NC6H4 (1), p -O2NC6H4 (2), m -NCC6H4 (3), p -NCC6H4 (4)] and advantageous moisture provided good yields of the pyridinium aryltetrachlorotellurates [C5H6N][RTeCl4] [R = m -O2NC6H4 (5), p -O2NC6H4 (6), m -NCC6H4 (7), p -NCC6H4 (8)]. Compounds 5 and 8 have been investigated by X-ray crystallography. Key features of both crystal structures are intermolecular secondary Te,,,Cl interactions between the aryltetrachlorotellurate anions and weak association of the cations and anions. Electrospray mass spectra of compound 5 reveal that the associative interactions also play a role in solution. Copyright © 2005 John Wiley & Sons, Ltd. [source] Syntheses of cyclodextrin,3,-azido-3,-deoxythymidine conjugates and their sulfates with improved anti-HIV activitiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2006Ildoo Chung Abstract New anti-HIV agents, cyclodextrin,3,-azido-3,-deoxythymidine (CD,AZT) conjugates, were synthesized and characterized. A succinate diester spacer was used to covalently couple 3,-azido-3,-deoxythymidine (AZT) onto cyclodextrin. In addition, their sulfates were prepared by the reaction of CD,AZT conjugates and a sulfur trioxide/pyridine complex at 80 °C. The degree of AZT substitution of the synthesized conjugates and the sulfur contents of their sulfates were calculated from elemental analysis and ranged from 1.3 to 4.7 and from 8.4 to 12.1, respectively. These resulting sulfated conjugates were expected to have a synergistic effect against HIV because of the two anti-HIV active agents (sulfate group and AZT) by the inhibition of virus attachment to cells and that of reverse transcriptase. The in vitro antiviral activity of these conjugates was determined and used to evaluate the potential applications in anti-AIDS drugs. The in vitro anti-HIV activities indicated that the synthesized conjugates and their sulfates against HIV-1 and HIV-2 strains were much better inhibitors than AZT. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 295,303, 2006 [source] | ||||||||||