抄録
The effect of N-methanesulfonate compounds such as sulpyrine and isoniazid methanesulfonate sodium (I) on the stability of four typical thiamine derivatives of the thiol-type was examined. Thiamine disulfide in solution was easily decomposed by these N-methanesulfonate compounds to give thiamine, thiamine-S-sulfonic acid, 2-methyl-4-aminopyrimidyl-5-methanesulfonic acid, 4-methyl-5-β-hydroxyethylthiazole, and the corresponding replacement reaction products of thiamine. The stability of thiamine propyldisulfide was also affected in a similar manner, whereas O, S-bisbenzoylthiamine and O, S-bisethoxycarbonylthiamine were not decomposed by sulpyrine and I. The decomposition products indicated that the disulfide derivatives were reductively decomposed by bisulfite from N-methanesulfonate compounds, and that thiamine resulting from the decomposition of the disulfides was successively decomposed through the replacement reaction with N-methanesulfonate compounds. Results were also obtained which indicated that thiamine-S-sulfonic acid derived from the disulfides changed slightly into thiamine when heated for a long period at pH 5 and 80℃. Instability of thiamine disulfide in the presence of I was markedly decreased when formaldehyde, a dissociation product of I, was added to the system.
