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1H NMR study of cis-trans isomerization in two analogs of the thiol form of thiamine

✍ Scribed by Derald Chriss; Robert H. Miller Jr; Richard E. Echols; Ellen Vessel

Publisher
John Wiley and Sons
Year
1984
Tongue
English
Weight
445 KB
Volume
22
Category
Article
ISSN
0749-1581

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✦ Synopsis

Proton magnetic resonance ('H NMR) was used to study cis-trans isomerizatiOn in N-methyl-N-(1methylthio-2-propeny1)formamide and N-benzyl-N-(1-methylthio-2-propenyl)fonnamide, two analogs of the thiol form of thiamine. Benzene dilution studies and shift reagent studies were used to make resonance assignments, which indicate that the predominant isomer for each analog has the C=C bond trans to the carbonyl ozqgen. Shift reagent studies, using Pr(f0d)3 in CCI, or CDCI,, suggest that the reagent may be bonding to both the nitrogen and oxygen atoms of the substrate. For some of the systems studied, varying p at constant temperature had the same spectral effect as varying temperature at constant p.

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