22. Carboxylic Acid Derivatives: NAS

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)

Show how you would accomplish the following syntheses using amides as intermediates. You may use any necessary reagents.

(a) benzoic acid → benzyldimethylamine

(b) pyrrolidine → N-ethylpyrrolidine

(c) cyclopentanecarboxylic acid → cyclopentanecarbonitrile

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

b.

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

b.

Predict the product of the following reactions.

(c)

Show how you would use an acid chloride as an intermediate to synthesize

(b) phenyl propionate (CH₃CH₂COOPh) from propionic acid and phenol.

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

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.

What are the products of the following reactions?

c.

Show how you would accomplish the following syntheses efficiently (you may use any necessary reagents).

(d) hexanoic acid → hexanal

Using any necessary reagents, show how you would accomplish the following syntheses.

(g)

What reagents are required to carry out the following synthesis?

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.

Identify A through O: