| Popis: |
Penta-O-acetyl-β-D-galactopyranose was converted in two steps into pentabromophenyl 1,2,3,4-tetra-O-acetyl-β-D-galactopyranoside. Short treatment of the latter with tetra-n-butylammonium hydroxide at 20°C, followed by acetylation, afforded crystalline 2,3,4-tri-O-acetyl-1,6-anhydro-β-D-galactopyranose. The same procedure could also be applied to the synthesis of the per-O-acetates of 1,6-anhydro-β-cellobiose and 1,6-anhydro-β-D-glucopyranose. 2,3,4-Tri-O-acetyl-1,6-anhydro-β-D-glucopyranose could also be obtained in a one-flask procedure by selective tosylation of D-glucose at the primary hydroxyl group, followed by treatment with base and subsequent acetylation. |
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