Abstract
Oxidation of thiamine sodium salt (I) with iodine in the presence of amines (II) gave S-aminothiamines (III). When III was treated with weak acids, oxathiolane derivative (VIII) was obtained. From VIII, some new thiamine derivatives, pyrimido [4, 5-c] [1, 2, 6]-10H-thiadiazocine (XIII), S-phosphate (XVI) derivatives and so forth, were derived. An analogue of XVI, cyclic O, S-phosphate (XVIII) was also synthesized.