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Thiamine and its three phosphorylated derivatives (mono-, di- and triphos-phate) occur naturally in most cells. Recently, we reported the presence of a fourth thiamine derivative, adenosine thiamine triphosphate, produced in Escherichia coliin response to carbon starvation. | Thiaminylated adenine nucleotides Chemical synthesis structural characterization and natural occurrence 2 2 r2 3 Michel Frederich David Delvaux Tiziana Gigliobianco Marjorie Gangolf Georges Dive Gabriel Mazzucchelli4 Benjamin Elias5 Edwin De Pauw4 Luc Angenot1 Pierre Wins2 and Lucien Bettendorff2 1 Laboratory of Pharmacognosy Université de Liege Belgium 2 GIGA-Neurosciences Universite de Liege Belgium 3 Center for Protein Engineering Universite de Liege Belgium 4 PhysicalChemistry GIGA-Research Universite de Liege Belgium 5 Organic and MedicinalChemistry Universite catholique de Louvain Louvain-la-Neuve Belgium Keywords adenosine thiamine diphosphate adenosine thiamine triphosphate cofactor metabolism nucleotides Correspondence L. Bettendorff GIGA-Neurosciences University of Liege Bat. B36 Tour de Pathologie 2 etage 1 Avenue de l Hopital 1 B-4000 Liege 1 Sart-Tilman Belgium Fax 32 4 366 59 53 Tel 32 4 366 59 67 E-mail l.bettendorff@ulg.ac.be These authors contributed equally to this work Received 12 February 2009 revised 2 April 2009 accepted 6 April 2009 doi 10.1111 j.1742-4658.2009.07040.x Thiamine and its three phosphorylated derivatives mono- di- and triphosphate occur naturally in most cells. Recently we reported the presence of a fourth thiamine derivative adenosine thiamine triphosphate produced in Escherichia coli in response to carbon starvation. Here we show that the chemical synthesis of adenosine thiamine triphosphate leads to another new compound adenosine thiamine diphosphate as a side product. The structure of both compounds was confirmed by MS analysis and 1H- 13C-and 31P-NMR and some of their chemical properties were determined. Our results show an upfield shifting of the C-2 proton of the thiazolium ring in adenosine thiamine derivatives compared with conventional thiamine phosphate derivatives. This modification of the electronic environment of the C-2 proton might be explained by a through-space interaction with the adenosine moiety suggesting .