Studies on Pyrimidine Derivatives and Related Compounds. LIV. Reactions of Thiamine with α-Ketoaldehydes

Abstract

Reaction of thiamine-sodium salt (III) with phenylglyoxal in the presence of carbon dioxide yielded 2-phenyloxalylthiamine (Va) which underwent facile air oxidation to thiamine thiazolone (VI) and phenylglyoxylic acid. Thiamine hydrochloride (I) was also condensed with phenylglyoxal in the presence of triethylamine or sodium hydroxide to give Va. The reaction was applied to a number of α-ketoaldehydes including some heterocyclic glyoxals to give corresponding 2-oxalylthiamine derivatives (Vb-1) which were shown to be convertible into stable acyl derivatives (XIa-r).