Answers to Concept Checks

9.1

Carboxylic  Acid    Derivative Formed   from    –COOH   by... Suffix Cyclic Naming

Amide Ammonia   or  an  amine –amide Lactam

Ester An    alcohol –oate Lactone

Anhydride Another   carboxylic  acid anhydride Anhydride

A   condensation    reaction    is  one in  which   two molecules   are joined  with    the loss    of  a   small

molecule.   In  all of  the examples    in  this    section,    the small   molecule    lost    was water.

9.2
Anhydrides are the most reactive to nucleophiles, followed by esters, and then amides.
Therefore, acetic anhydride will be the most reactive, followed by ethyl acetate, and finally
acetamide.
β-lactams are susceptible to hydrolysis due to the high level of ring strain, which is due to both
torsional strain (eclipsing interactions) and angle strain (deviation from 109.5°).
Electronic effects like induction have some effect on the reactivity of the carbonyl in these
three functional groups. Differences in resonance also explain the increased reactivity of
anhydrides, in particular. Steric effects could also be significant, depending on the specific
leaving group present.

9.3
Ammonia acts as the nucleophile. One of the carbonyl carbons of the anhydride serves as the
electrophile.
Transesterification is the exchange of one esterifying group for another in an ester. This
reaction requires an alcohol as a nucleophile.
Strongly acidic conditions catalyze amide hydrolysis by protonating the oxygen in the carbonyl.
This increases the electrophilicity of the carbon, making it more susceptible to nucleophilic