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Fast-atom-bombardment mass spectrometry and 1H-NMR spectrometry in studies of the transformations of thiamine in strongly basic solutions

✍ Scribed by Ian Horman

Publisher
John Wiley and Sons
Year
1984
Tongue
German
Weight
341 KB
Volume
67
Category
Article
ISSN
0018-019X

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✦ Synopsis

Abstract

Fast‐atom‐bombardment (FAB) mass spectra have been used to establish or confirm the nature of the yellow‐product and open‐chain forms of thiamine produced in the presence of excess (5 mol‐equivb.) of strong base. Time‐dependent changes in ^1^H‐NMR spectra show that the rates of disappearance of the yellow form and of formation of the open‐chain form are the same at pH 12.5, having a pseudo‐first‐order rate constant of k = 2.2 × 10^−3^ sec^−1^. The implications of these results are discussed in the light of current ideas on the acid‐base dependence of thiamine structures.

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