ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 13C solid-state nuclear magnetic resonance spectroscopy  (1)
  • hydrates  (1)
Collection
Keywords
Publisher
Years
  • 1
    Electronic Resource
    Electronic Resource
    Crystal structure and physical characterization of neotame methanol solvate (1999)
    Springer
    Journal of chemical crystallography 29 (1999), S. 967-975 
    Details
    ISSN: 1572-8854
    Keywords: neotame ; crystal structure ; methanol solvate ; thermal analysis ; powder X-ray diffractometry ; 13C solid-state nuclear magnetic resonance spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal structure of the methanol solvate (empirical formula: 2C20H30N2O5·3CH3OH) of a new dipeptide sweetener, neotame (N-(3,3-dimethylbutyl)-L-α-aspartyl-L-phenylalanine 1-methyl ester), has been determined. Crystal data: a = 9.8989(1), b = 18.1331(1), c = 27.5725(1) Å, orthorhombic, space group P212121, with Z = 4. Each unit cell includes 8 neotame and 12 methanol molecules. Disorder exists in one neotame molecule and one methanol molecule. The crystals were characterized by the following techniques: hot-stage microscopy (HSM), Karl-Fischer titrimetry (KFT), powder X-ray diffractometry (PXRD), differential scanning calorimetry (DSC), thermogravimetry (TGA), 13C solid-state nuclear magnetic resonance (SSNMR) spectroscopy. Under HSM at a heating rate of 10°C/min in silicone oil, the sample melts at 64–84°C and liberates bubbles at 71–86°C. DSC in open pans shows two overlapping endotherms at 56 and 71°C, probably due to melting and desolvation, respectively. TGA in open pans shows 5.9% weight loss due to desolvation below 70°C. Under house vacuum (23 mm Hg) over phosphorus pentoxide at 23°C, the methanol solvate produces pure amorphous anhydrate, which converts to crystalline neotame monohydrate in the presence of moisture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009542515709
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Nuclear Magnetic Resonance and Infrared Spectroscopic Analysis of Nedocromil Hydrates (2000)
    Springer
    Pharmaceutical research 17 (2000), S. 619-624 
    Details
    ISSN: 1573-904X
    Keywords: NMR ; infrared ; nedocromil ; hydrates ; solvate ; methanol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. Nedocromil sodium (NS), which is used in the treatment ofreversible obstructive airway diseases, such as asthma, has been foundto exist in the following solid phases: the heptahemihydrate, thetrihydrate, a monohydrate, an amorphous phase, which contains variableamounts of water, and a recently discovered methanol + water (MW)solvate. Our aim was to apply 13C solid-state nuclear magneticresonance (NMR) spectroscopy and solid-state Fourier transform infrared(FTIR) spectroscopy to the study of specific interactions in the varioussolid forms of NS. Methods. The 13 solid-state NMR and FTIR spectra of the varioussolid forms of NS were obtained and were related to the crystalstructures of NS, the conformations of the nedocromil anion, and theinteractions of the water molecules in these crystals. Results. The 13C solid-state NMR spectrum is sensitive to theconformation of the nedocromil anion, while the solid-state FTIR spectrumis sensitive to interactions of water molecules in the solid state. In NSmonohydrate, for which the crystal structure has not yet been solved,and in the amorphous phase, the information about the conformationsof the nedocromil anion and the interactions of the water moleculesare deduced from the 13C solid-state NMR spectra and solid-state FTIRspectra, respectively. Conclusions. 13C solid-state NMR spectroscopy and solid-state FTIRspectroscopy are shown to be powerful complementary tools forprobing the chemical environment of molecules in the solid state,specifically the conformation of the nedocromil anion and the interactions ofwater-molecules, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007533419711
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...