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NEET levelSingle correct optionDifficulty 1 of 3bm236

Does the compound shown give a positive Tollens test?

  1. AYes, because it is an aldose
  2. BYes, because it has several OH groups
  3. CNo, because the anomeric carbon is an acetal and cannot open to an aldehyde
  4. DNo, because it is a ketose

Answer: C

The anomeric carbon carries the ring oxygen and an OCH3 group, so it is an acetal (a glycoside, methyl beta-D-glucopyranoside). Without a free hemiacetal OH the ring cannot open to the CHO group, so it does not reduce Tollens' reagent.
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