Selenotrisulphides from mercaptopurines

Abstract

Products from the reaction of selenium dioxide with 2-mercapto-(2-MP) and 6-mercapto-purines (6-MP) were studied. The molar ratio of selenium dioxide to mercaptopurines was evaluated from u.v. absorption spectra obtained according to a modification of the method of continuous variations. From the results of the stoicheiometric calculations the products were shown to be seleno-trisulphides and -disulphides. From electrophoretic data equilibrium constants were computed for both reactions. In the presence of an excess of 6-MP the derived selenotrisulphide was stable in alkaline solution.