2,3,4, 6-Tetra-o-benzyl-α-D-Glucopyranose method for preparing partial benzylated aldopyranose

Introduction of 2,3,4, 6-Tetra-o-benzyl-α-D-Glucopyranose

2,3,4, 6-Tetra-o-benzyl-α-D-Glucopyranose is an intermediate of voglibose/dagliflozin, which is mainly used in the glucosylation reaction, but also as a reagent for the synthesis of 1-C-alpha-D-glucopyranose derivatives, and it is capable of synthesising some of the partially benzylated aldopyranose. 

Synthesis method of benzylated aldopyranose

2,3,4, 6-Tetra-o-benzyl-α-D-Glucopyranose for the synthesis of some Partial benzylated aldopyranose by specific methods. In preparation, methyl α-d-glucopyranoside is suspended in 150 ml of dry dioxane with 250 g of powdered potassium hydroxide, and the mixture is stirred and gently boiled under a reflux condenser while 318 ml of benzyl chloride is added in dropwise fashion over a period of ∼ 40 min. The residue is cooled and sufficient water is added to dissolve the crystalline mass, the methyl 2,3,4,6-tetra-O-benzyl-α-d-glucopyranoside then being extracted with ether. Methyl α-d-glucopyranoside is the preferred starting material due to its favourable commercial availability and affordability.