抄録
In the synthesis of O-benzoylthiamine disulfide (BTDS) by the benzoylation of thiamine disulfide, crystals showing 2 spots (Rf 0.57 and 0.75 on paper chromatography using acetic acid・n-butanol・water=1 : 4 : 5 system) were often isolated and they had a lower melting point and a higher growth-stimulating activity on L.fermensi than the authentic sample of Rf 0.75. The Rf 0.57 and 0.75 substances were separated fom the crystals by the means of similar chromatography and their activities on L.fermenti in the broth containing cysteine were compared with that of thiamine. The Rf 0.57 substance was found to have 1/2,the crude BTDS 1/40 and the authentic BTDS about 1/70 activity of thiamine, while the Rf 0.75 substance was proved to have no growth-stimulating activity. As the Rf 0.57 substance was reduced to thiamine and O-benzoylthiamine and the Rf 0.75 substance was reduced to O-benzoylthiamine by the incubation with cysteine or Na_2S_2O_3,it was suggested that the Rf 0.57 substance was monobezoate of thiamine disulfide and the Rf 0.75 substance having no microbiological activity was the purest sample of BTDS free from the Rt 0.57 substance
