Abstract
Physical and chemical properties of deoxythiamine (DOB_1) were almost similar to those of thiamine. Prebulda and formaldehyde azo methods of thiamine determination were tried to DOB_1 and it was found that the color substances which were produced from DOB_1 were very similar to those from thiamine in UV spectrum and in paper partition chromatography. DOB_1 was completely oxidized with BrCN to deoxythiochrome and when reacted with benzenesulfonyl chloride, it was changed to a thiochrome-negative compound as thiamine was. In nonenzymatic system of thiamine which produces acetoin through acetolactate from pyruvate, DOB_1 produced about 70% of acetoin which thiamine did.