Selective deuterium exchange during superheated heavy water chromatography–nuclear magnetic resonance spectroscopy–mass spectrometry of sulfonamides

Superheated deuterium oxide has been investigated as an eluent for reversed-phase HPLC on a polystyrene–divinylbenzene column with UV, 1H NMR and MS detection using a series of sulfonamides as model compounds. In the course of these studies, a selective, specific and efficient deuteration of the methyl groups on a pyrimidine ring was observed during chromatography of certain of the sulfonamides. The potential of this methodology for producing deuterium-labelled compounds from substances bearing suitable substituents is considered. The utility of HPLC–NMR–MS as a means for studying on-column reactions is discussed.