Synthesis of D-glucose pentamethyl esters (D-Glu) and L-glucose
pentamethyl esters (L-Glu)
The glucose (4.10 g, 22.51 mmol) was first dissolved in acetic acid (100
mL) and acetic anhydride (400 mL), then 1.5 mL of concentrated sulfuric
acid was added to the reaction flask, and the reaction was carried out
in ice bath for 2 hours. After the reaction was completed, 200 mL of DCM
was added to dilute the mixture, and then the mixture was washed
successively with ice water (3 × 300 mL), saturated
Na2CO3 solution, and saturated brine
until the aqueous solution was neutral. The organic phase was dried over
anhydrous sodium sulfate, and then DCM was removed under reduced
pressure to obtain D-Glu. L-Glu was also synthesized with the same
procedure.27