d-Fructose–l-sorbose interconversions. Access to 5-thio-d-fructose and interaction with the d-fructose transporter, GLUT5 Original Research Article

Epimerisation and subsequent functionalization at C-5 of d-fructopyranose derivatives under Mitsunobu and Gareggʹs conditions provided efficient access to 5-thio-d-fructose (2) as well as to 5-azido-5-deoxy-1,2-O-isopropylidene-β-d-fructopyranose (19), a known precursor to 2,5-deoxy-2,5-imino-d-mannitol (3). The interaction of 2 with the d-fructose transporter GLUT5, was found to be weaker than that of d-fructose, a result that suggests involvement of the ring oxygen atom in the recognition of d-fructose by GLUT5.