The following three nitrogen mustards were studied for possible clinical use. One is now used clinically, one was found to be too unreactive, and one was found to be too insoluble in water to be injected intravenously. Which is which? (Hint: Draw resonance contributors.)

Indicate the type of catalysis that is occurring in the slow step in each of the following reaction sequences:

a.

Indicate the type of catalysis that is occurring in the slow step in each of the following reaction sequences:

b.

Why is melphalan a good cancer drug?

Indicate which species in each pair gives a higher substitution-product-to-elimination-product ratio when it reacts with isopropyl bromide:

c. Cl⁻ or Br⁻

Finish Solved Problem 7-3 by showing how the rearranged carbocations give the four products shown in the problem. Be careful when using curved arrows to show ­deprotonation and/or nucleophilic attack by the solvent. The curved arrows always show ­movement of electrons, not movement of protons or other species.

Give the substitution and elimination products you would expect from the following reactions.

c. 1-bromo-2-methylcyclohexane + silver nitrate in water (AgNO₃ forces ionization)

Make models of the following compounds, and predict the products formed when they react with the strong bases shown.

(a)

Deuterium (D) is the isotope of hydrogen of mass number 2, with a proton and a neutron in its nucleus. The chemistry of deuterium is nearly identical to the chemistry of hydrogen, except that the C―D bond is slightly (5.0 kJ/mol, or 1.2 kcal/mol) stronger than the C―H bond. Reaction rates tend to be slower if a C―D bond (as opposed to a C―H bond) is broken in a rate-limiting step. This effect on the rate is called a kinetic isotope effect. (Review Problem 4-57)

b. When the following deuterated compound reacts under the same conditions, the rate of formation of the substitution product is unchanged, while the rate of formation of the elimination product is slowed by a factor of 7.

Explain why the elimination rate is slower, but the substitution rate is unchanged.