19. Reactions of Aromatics: EAS and Beyond

Predict the product of the following substitution/addition reactions involving phenoxides. [Because this problem represents a review of current and previous material, section numbers have been provided for your reference.]

(d)

What are the products of the following reactions?

e.

Using the given starting material, any necessary inorganic reagents and catalysts, and any carbon-containing compounds with no more than two carbons, indicate how each of the following compounds can be prepared:

b.

(a) Propose a mechanism for the reaction of 2-bromopyridine with sodium amide to give 2-aminopyridine.

(b) When 3-bromopyridine is used in this reaction, stronger reaction conditions are required and a mixture of 3-aminopyridine and 4-aminopyridine results. Propose a mechanism to explain this curious result.

Show how the substituents containing the azo group (N=N) can facilitate both electrophilic and nucleophilic aromatic substitution.

(b)

Show how you would accomplish the following syntheses.

(c) benzene → p-methoxybenzaldehyde

Explain why hydroxide ion catalyzes the reaction of piperidine with 2,4-dinitroanisole but has no effect on the reaction of piperidine with 1-chloro-2,4-dinitrobenzene.

Rank the following compounds from greatest tendency to least tendency to undergo nucleophilic aromatic substitution:

chlorobenzene 

1-chloro-2,4-dinitrobenzene 

p-chloronitrobenzene

Propose a mechanism for each of the following reactions:

b.