22. Carboxylic Acid Derivatives: NAS

There are many methods for activating a carboxylic acid in preparation for coupling with an amine. The following method converts the acid to an N-hydroxysuccinimide (NHS) ester.

(b) Propose a mechanism for the reaction shown.

Write the mechanism for the reaction of an amino acid with di-tert-butyl dicarbonate.

Starting with methyl acetate, what neutral nucleophile would you use to synthesize each of the following compounds? b. acetamide

In each part, rank the compounds in order of increasing rate of nucleophilic attack at C=O by a strong nucleophile like methoxide.

(b)

a. When a carboxylic acid is dissolved in isotopically labeled water (H₂O₁₈) and an acid catalyst is added, the label is incorporated into both oxygens of the acid. Propose a mechanism to account for this.

Determine the major product for the following reaction.

Determine the major product for the following reaction.

Determine the major product for the following reaction.

Determine the major product for the following reaction.

What compounds are formed from the reaction of benzoyl chloride with the following reagents?

g. excess benzylamine

h. 4-chlorophenol

What acyl chloride and amine are required to synthesize the following amides?

a. N-ethylbutanamide

b. N,N-dimethylbenzamide