Oxidation Product of Thiamine Anhydride and the Metabolite of Thiamine Anhydride in Rats.

As shown in the previous paper, a metabolite of thiamine anhydride (TA) (I) was isolated as crystals melting at 172-173•‹ from the urine when TA was given parenterally to rats and it was assumed to be thiamine anhydride sulfoxide (TAO) (II) from its analytical data. It is known, however, that TA can be oxidized to TA sulfone (III) besides its sulfoxide by hydrogen peroxide according to the con ditions of the reaction. Furthermore, the RF values of the two compounds, II and III, using three kinds of solvent systems as given in the previous paper, were almost the same ; this makes their differentiation very difficult. Moreover, the melting-points of the compounds have been reported to be different according to several workers. The author has obtained thiamine anhydride sulfoxide melting at 132•‹ by treatment of TA with H2O2 in 50% acetic acid, but Motoyama (3) obtained thiamine anhydride sulfone (TAO2) melting at 164•‹ by the same treatment, and Yonemoto (4) obtained also TAO2 melting at 132•‹ by oxidation with H2O2 in glacial acetic acid. The identification of these compounds was made by elementary analyses and infrared spectra. Utsumi (5) differentiated TAO (mp 176-8•‹) from TAO2 by comparison of oxygen consumption by lead dioxide. The authors rein vestigated the oxidation of TA and the product was compared with the metabolite of TA i n vivo.