Studies on Relation between Vitamin B₁ and Metals. II : Reaction of Vitamin B₁ with Copper (II), Cadmium (II) and Zinc (II).

Abstract

Previous study has shown that red-fluorescent product was formed by reaction of vitamin B₁ with cupric ion, and could be applied to the detection of vitamin B₁. The present report deals with the synthesis and the structure of the product of vitamin B₁ with copper, cadmium and zinc, respectively. In order to find the condition for the synthesis of the product, the effect of metal ion on the stability of vitamin B₁ was examined by determining vitamin B₁. When respective ion of copper (II), cadmium (II) and zinc (II) was reacted with thiolized vitamin B₁ at pH 10∼11, vitamin B₁ was decomposed only by copper vigorously at 37°and slowly at 0°, but the decomposition of vitamin B₁ was hardly observed by any other metal under the experimental conditions. Therefore, their metal salts of vitamin B₁ were synthesized as follows : vitamin B₁-HCl solution (1 mol) was added into NaOH solution (3 mol) at room temperature, after about 45 minutes, the metal ion solution (1 mol) was added to the mixture at pH 10∼11 under cooling and stirring. The precipitate was recrystallized from iso-butanol or iso-propanol. The molar ratio of metal to vitamin B₁ of the crystal was found to be 1 to 2 by chemical analysis. The measurements of U.V. and I.R. spectra of their salts showed the structure of metal chelate.