26. Amines

Triethylenemelamine (TEM) is an antitumor agent. Its activity is due to its ability to cross-link DNA.

b. Explain why it can cross-link DNA.

In Section 10.12, we saw that S-adenosylmethionine (SAM) methylates the nitrogen atom of noradrenaline to form adrenaline, a more potent hormone. If SAM methylates an OH group attached to the benzene ring instead, it completely destroys noradrenaline's activity.

b. Which reaction is more apt to occur, methylation on nitrogen or methylation on oxygen?

Dimethylamine, (CH₃)₂NH, has a molecular weight of 45 and a boiling point of 7.4 °C. Trimethylamine, (CH₃)₃N, has a higher molecular weight (59) but a lower boiling point (3.5 °C). Explain this apparent discrepancy.

Rank the following substituted anilines from most basic to least basic:

Rank each set of compounds in order of increasing boiling points.

(a) triethylamine, di-n-propylamine, n-propyl ether

(b) ethanol, dimethylamine, dimethyl ether

(c) diethylamine, diisopropylamine, trimethylamine

In each pair of compounds, select the stronger base, and explain your choice.

(a) HOCH₂CH₂NH₂ or CH₃CH₂NH₂

(b) PhNH₂ or PhCH₂NH₂

Within each structure, rank the indicated nitrogens by increasing basicity.

(c)

Within each structure, rank the indicated nitrogens by increasing basicity.

(a)

(b)

Rank each set of compounds in order of increasing basicity.

(d) pyrrole, imidazole, 3-nitropyrrole

Rank each set of compounds in order of increasing basicity.

(c) aniline, pyrrole, pyridine, piperidine

Rank each set of compounds in order of increasing basicity.

(b) aniline, p-methylaniline, p-nitroaniline

Predict the products of the following reactions:

(a) excess NH₃ + Ph–CH₂CH₂CH₂Br →

Propose a mechanism to show the individual alkylations that form this quaternary ammonium salt.

What is the major product of the following reactions?

c.

Draw the product formed when pyridine reacts with ethyl bromide