22. Carboxylic Acid Derivatives: NAS

When a student treated butanedioic acid with thionyl chloride, she was surprised to find that the product she obtained was an anhydride rather than an acyl chloride. Propose a mechanism to explain why she obtained an anhydride.

Phosgene (COCl₂) was used as a poison gas in World War I. What product would be formed from the reaction of phosgene with each of the ­following reagents?

c. excess propylamine

d. excess water

Propose a mechanism for the reaction of benzoic acid with oxalyl chloride. This mechanism begins like the thionyl chloride reaction, to give a reactive mixed anhydride. Nucleophilic acyl substitution by chloride ion gives a tetrahedral intermediate that eliminates a leaving group, which then fragments into carbon dioxide, carbon monoxide, and chloride ion.

What reagents are required to carry out the following synthesis?

Predict the product of the following reactions.

(a)

Predict the product of the following reactions.

(c)

Suggest a series of steps involving a cuprate reagent that would convert the reactant on the left to the product on the right. The ideal number of steps is shown.

(a)

Draw structures for A-D for each of the following:

b.

How could you convert N-methylbenzamide to the following compounds?

c. methyl benzoate

How could you synthesize the following compounds starting with a carboxylic acid?

b.

Using an alcohol for one method and an alkyl halide for the other, show two ways to make each of the following esters:

d. methyl phenylethanoate (odor of honey)

What are the products of the following reactions?

c.

Identify A through O: