Synthesis of 2-deoxy-D-arabino-(6-13C)hexose

2-Deoxy-D-arabino-[6-13C]hexose (10), to be used to test the stability of 2-deoxy-D-arabino-hexose 6-phosphate in brain tissue, was prepared. 2-Deoxy-D-arabino-hexose was labeled at C-6 because of the large difference in chemical shift between C-6 in the free sugar and C-6 in the 6-phosphate. The synthetic scheme resembled that used for the synthesis of D-[6-13C]glucose that involved the removal of C-6 from D-glucose followed by its replacement with 13C. The protected derivative methyl 2-deoxy-alpha-D-arabino-hexofuranoside was prepared, using trifluoroacetic acid in methanol. This was treated with periodate, which cleaves only between C-5 and C-6, to afford an aldehyde which reacted directly with K13CN to give a mixture of the D-arabino and L-xylo nitriles. The enriched nitriles were reduced with hydrogen in the presence of 5% Pd-carbon catalyst to a mixture of 6-aldehydo sugars. These were reduced with NaBH4 to a mixture of the two labeled methyl furanosides. Acid hydrolysis followed by ion-exchange chromatography on AG-50(Ca2+) resin at 65 degrees gave 10 in an overall yield of 16% from K13CN.