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1 H NMR study of cis ‐ trans isomerization in two analogs of the thiol form of thiamine
Author(s) -
Chriss Derald,
Miller Robert H.,
Echols Richard E.,
Vessel Ellen
Publication year - 1984
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270220204
Subject(s) - chemistry , isomerization , formamide , reagent , propenyl , oxygen , resonance (particle physics) , thiol , proton nmr , benzene , double bond , thiamine , photochemistry , medicinal chemistry , stereochemistry , organic chemistry , catalysis , physics , particle physics
Proton magnetic resonance ( 1 H NMR) was used to study cis ‐ trans isomerization in N ‐methyl‐ N ‐(1‐methylthio‐2‐propenyl)formamide and N ‐benzyl‐ N ‐(1‐methylthio‐2‐propenyl)formamide, 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 CC bond trans to the carbonyl oxygen. Shift reagent studies, using Pr(fod) 3 in CCl 4 or CDCl 3 , suggest that the reagent may be bonding to both the nitrogen and oxygen atoms of the substrate. For some of the systems studied, varying ρ at constant temperature had the same spectral effect as varying temperature at constant ρ.