Does glucose react with Brady's reagent?
From Wikipedia:


  The reaction of $\ce{NH2OH}$ with an aldehyde or ketone produces an oxime.
  $$\ce {R2C=O + NH2OH·HCl + NaOH → R2C=NOH + NaCl + H2O}$$


For the penta-acetate ester of glucose not to react with hydroxylamine would indicate that the ester is more stable, or there is steric hindrance to the reaction. Since hydroxylamine is heat sensitive, I am guessing that you did not heat the reaction. Given time, you should see the oxime form.

From Wikipedia:


  A positive test is signaled by a yellow, orange or red precipitate (known as a dinitrophenylhydrazone).
  $$\ce {RR'C=O + C6H3(NO2)2NHNH2 → C6H3(NO2)2NHNCRR' + H2O}$$


2,4-DNP also reacts with an aldehyde (or ketone), so both glucose and the penta-acetate ester of glucose should react. If you get a different color for the penta-acetate ester, it is due to the substituents on the glucose.