Studies on Vitamin B₁ and Related Compounds.CVII.Synthesis of Hydroxyethylthiamine Homologs

Abstract

Two types of dihydrothiamine derivatives, IV, VI, VIII, and V, VII, IX, were obtained by the reaction of I, II, and phenylglyoxal derivatives. On treatment with mineral acids both of those underwent hydrolysis in the presence of water, but in non-aqueous solutions thiamine was afforded under room temperature. Treatments of them with weak acids such as phosphoric acid, formic acid and acetic acid effected the conversion to the aryl homologs of hydroxyethylthiamine, XI, XII and XIII.