ビタミンB_1類の安定性に関する研究(第12報) : 中性水溶液中のO-, S-, およびO, S-Bis (ethoxycarbonyl) thiaminesの安定性

概要

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Comparative studies were made on the stabilities of ethoxycarbonylthiamines, benzoylthiamines, and related thiamine derivatives in aqueous solutions of pH 7.4 at 37.4°. Each of these compounds was degraded by a pseudo-first-order reaction. The time necessary for a 10% decrease in the residual fraction was 12.5 hours for O-ethoxycarbonylthiamine, 0.66 hours for S-ethoxycarbonylthiamine, and 87.1 hours for O, S-bis (ethoxycarbonyl) thiamine. Comparison of these values with those of other compounds is shown in Table I. Of the derivatives having one or more substituents of the same type, an S-monosubstituted derivative was the least stable, followed by the O-monosubstituted, and the O, S-disubstituted compound was the most stable. Both the S-ethoxycarbonyl- and S-benzoyl-thiamines were easily converted into thiamine. The major part of O-ethoxycarbonyl-, and O-benzoyl-thiamines was decomposed to thiochrome reaction-negative compounds, and minor amounts were hydrolysed to thiamine. Parts of disubstituted derivatives were hydrolysed to thiamine and the corresponding thiamine-O-ester, the latter of which resulted mainly from the cleavage of the thioester linkage. When the period of storage was extended beyond about 30 days for thiamine disulfide and about 85 days for thiamine propyl disulfide, the residual fractions decreased markedly, showing a deviation from the pseudo-first-order character.
社団法人日本薬学会の論文
1969-03-25