HYDROLYSIS OF THIAMINE (VITAMIN-B-1) IN THE PRESENCE OF DIMETHYLTHALLIUM(III) HYDROXIDE - THE NOVEL CRYSTAL-STRUCTURE OF A THIAMINE THIOLATE DERIVATIVE

The hydrolysis of thiamine (vitamin B-1) in basic media containing the dimethylthallium(III) cation afforded the compound [TlMe2TS]. 3H(2)O (TS- = 'thiamine thiol') which was characterised in the solid state by mass and C-13 CPMAS spectrometry and in solution by H-1 and C-13 NMR spectrometry. X-ray diffraction showed that in the crystal the TS- lig and is bound to the metal mainly via its sulfur atom (Tl-S = 2.986(3) Angstrom), although secondary interaction via an oxygen atom gives the ligand an anisobidentate character. The influence of the thallirum-su lfur bond on the mechanism of the basic hydrolysis of thiamine is disc ussed on the basis of the kinetics of the reactions in the presence of sodium and dimethylthallium(III) cations. (C) 1998 Elsevier Science S .A. All rights reserved.