26. Amines

Predict the products of the following reactions:

(h)

Show how to synthesize the following amines from the indicated starting materials by reductive amination.

(a) benzylmethylamine from benzaldehyde

(b) N-benzylpiperidine from piperidine

(c) N-cyclohexylaniline from cyclohexanone

Propose mechanisms for the following reactions.

(a)

Excess ammonia must be used when a primary amine is synthesized by reductive amination. What product will be obtained if the reaction is carried out with excess carbonyl compound?

The two most general amine syntheses are the reductive amination of carbonyl compounds and the reduction of amides. Show how these techniques can be used to accomplish the following syntheses.

(b) benzaldehyde → benzylamine

Show how you would use the same sulfonyl chloride as used in the sulfanilamide synthesis to make sulfathiazole and sulfapyridine.

Show how m-toluidine can be converted to the following compounds, using any necessary reagents.

(f)

Show how you can synthesize the following compounds starting with benzene, toluene, and alcohols containing no more than four carbon atoms as your organic starting materials. Assume that para is the major product (and separable from ortho) in ortho, para mixtures.

(d) N-benzylpropan-1-amine

Using cyclohexanone as the starting material, describe how each of the following compounds can be synthesized:

d.

Show how to synthesize the following amines from the indicated starting materials by reductive amination.

(e)

Show how you can synthesize the following compounds starting with benzene, toluene, and alcohols containing no more than four carbon atoms as your organic starting materials. Assume that para is the major product (and separable from ortho) in ortho, para mixtures.

(c) N-ethyl-N-propylbutan-2-amine

The compounds commonly known as 'amino acids' are actually α-aminocarboxylic-aminocarboxylic acids. What carbonyl compounds should be used to synthesize the two amino acids shown here?

a.

The two most general amine syntheses are the reductive amination of carbonyl compounds and the reduction of amides. Show how these techniques can be used to accomplish the following syntheses.

(d) cyclohexanone → N-cyclohexylpyrrolidine

Show how you can synthesize the following tertiary amine three different ways, each using a different secondary amine and adding the final substituent by

(a) reductive amination (3 ways).