VERY HIGH ISOTOPE INCORPORATION IN THE C-1 POSITION OF GLUCOSE BY EXCHANGE WITH DEUTERIUM OR TRITIUM GAS

The experimental conditions which control the exchange from deuterium or tritium gas into the C-1 proton position of glucose in aqueous solu tion have been studied in detail, with a view to determining the facto rs which maximize exchange into glucose, but minimize exchange into th e solvent water. The favoured conditions for producing glucose with cl ose to 100% isotope labelling in the C-1 position, and with negligible formation of labelled byproducts, were a reaction time of 6 to 8 hour s, a temperature of 60 degrees C, and a pH of 7 or higher. Pd/BaSO4 wa s the preferred catalyst and slow pre-addition of the deuterium or tri tium gas to the catalyst bed was essential to maximize the subsequent isotope exchange into the substrate.