Which of the following proposed reactions would take place quickly under mild conditions?

The chemical reaction will be successful if the reaction proceeds from the compound containing a more reactive functional group to the compound containing a less reactive functional group.

This type of reaction is called a downhill reaction. These types of reactions occur readily without any disturbances.

The given reaction contains amide as the reactant and acid chloride as the product. The amide functional group is less reactive than the acid chloride. Thus, it is the reverse of downhill transformation. So, this reaction will not occur.

The given reaction is the transformation from acid chloride to an amide. The acid chloride is stronger than amide. So, this reaction occurs rapidly.

The given reaction contains amide as the reactant and ester as the product. The amide functional group is less reactive than the ester. Thus, it is the reverse of downhill transformation. So, this reaction will not occur.

The given reaction is the transformation from acid chloride to an anhydride. The acid chloride is stronger than anhydride. So, this reaction occurs rapidly.

The given reaction is the transformation from anhydride to an amide. The anhydride is stronger than amide. So, this reaction occurs rapidly.