The role of the pyrimidine 4-amino-group in thiamine

Abstract

A number of analogues of thiamine, bearing 4- or 4,6-substituents, have been synthesised in order to establish whether there is a relation between their ability to catalyse the decarboxylation of pyruvic acid and the electron-withdrawing inductive effect of their substituted 5-pyrimidylmethyl groups as exemplified by the pK_a of the corresponding substituted 5-pyrimidylmethylamines. It has been established that no such correlation exists and that the 5-pyrimidylmethyl groups are therefore unlikely to be influencing catalytic ability by an inductive effect.