Isolation and characterization of a coupled compound of thiamin with catechol.

Equimolecular amounts of thiamin and catechol incubated under suitable conditions produced an unknown reaction product isolated as a light yellow powder from the reaction mixture by reverse-phase ODS column chromatography. Elemental analysis of the purified powder showed the molecular formula to be C18H22N4O4S X HCl X H2O in agreement with a molecular ion peak found at m/e 390 in the mass spectrum. These results together with the data of IR and NMR spectrometry possibly show that this material consists of an isomeric mixture of S-3,4- and S-2,3-dihydroxyphenylthiamin (I and II) which probably arise as a result of oxidative addition of the thiol group of thiamin to catechol.