Acetylation of glucose with acetic anhydride gives 

 $$\begin{gathered} \mathrm{CHO}{\left(\mathrm{CHOH}\right)}_4{\mathrm{CH}}_2\mathrm{OH}\stackrel{\mathrm{aceticanhydride}}{\to } \mathrm{CHO}{\left({\mathrm{CHOCOCH}}_3\right)}_4{\mathrm{CH}}_2{\mathrm{OCOCH}}_3 \\ \mathrm{glucose} \mathrm{glucose} \mathrm{pentaacetate} \end{gathered}$$

Glucose reacts with 5 molecules of acetic anhydride to form glucose pentaacetate or penta acetyl glucose.