On the Mechanism of the Vitamin B₁ Activities. III

The Cleavage of Thiazole Rings

Abstract

Examinations were made as to whether vitamin B₁ when treated with alkali to cleave its thiazole nucleus takes the thiol form.
As a model experiment, two kinds of thiazolium compounds were synthesized. Calculated amount of NaOH was added to each and 2, 4-dinitrochlorobenzene was respectively applied by which corresponding 2, 4-dinitrophenylmercapto compounds were formed. In order to determine the structure of these thioethers, they were hydrolyzed by mineral acids and the decomposition products (especially those containing sulfur) were examined and proved. Moreover, similar 2, 4-dinitrophenylmercapto compound was obtained in the case of vitamin B₁ but its hydrolyzed product was an oily substance and the structure could not be determined. However, pyrimidine portion and formic acid were obtained. From these results, it has been made clear that the thiazole nucleus of vitamin B₁ is cleaved by 3mol. NaOH to become Nasalt of a thiol compound.