Abstract
Direct introduction of substituents of organic groups to the hydroxyl group of thiamine was achieved by the use of phosgene. O-Chlorocarbonylthiamine (VI) thus prepared was converted into O-carbamoylthiamine and O-alkoxycarbonylthiamine. The free bases of O-carbamoyl derivatives were assigned dihydrothiochrome structures (XV) and (XVI). S-Carbamoylthiamine derivatives were also prepared. Application of S→O rearrangement of the carbamoyl group gave various O, S-bis substituted thiamine derivatives.
