Production of 1,4:3,6-dianhydro-α-d-glucopyranose from methyl 3,6-anhydro-α-d-glucopyranoside and its taste identification.

1,4:3,6-Dianhydro-α-d-glucopyranose (DGP) is one of important biomass pyrolysis anhydro sugar products that derive from the cellulose and hemicellulose components. There is no reliable method for the preparation of DGP at present, which contributed to its high cost with limited market supply and restricted applied research. In this study, we provided a novel method for the synthesis of DGP from methyl 3,6-anhydro-α-d-glucopyranoside for the first time. A mild and environmentally friendly synthetic approach for 3,6-anhydro glucopyranoside was developed the intramolecular cyclization of 6--tosyl glucopyranoside, promoted by a catalytic amount of TBAF. And the preparation of DGP was achieved through the stabilization effect on carbocation intermediates by HFIP in the intramolecular cyclization of 3,6-anhydro glucopyranoside. Further sensory evaluation studies revealed that DGP had a sweetness similar to that of sucrose.