Abstract
Reaction of thiamine analogues lacking the 5-hydroxyethyl group (6a-e) with diethyl benzoylphosphonate (7) was carried out. Comparison of reactivity in 4'-substituted thiamine analogues and those lacking the hydroxyethyl group suggests the presence of an interaction in the thiamine molecule between the pyrimidine ring and the hydroxyethyl group in an aprotic solvent. Reactivity at the 2 position (the active center in enzymatic decarboxylation) in 4'-substituted thiamine analogues may be affected by this interaction.
