Abstract
A dihydrothiamine derivative (VI) was prepared by the reaction of IV, V and methylglyoxal. On treatment with hydrochloric acid VI underwent hydrolysis in the presence of water, but in non-aqueous solutions thiamine was afforded under room temperature. Treatment of VI, however, with weak acids such as phosphoric acid, formic acid or acetic acid effected the conversion to hydroxyethylthiamine in fairly good yields.
