Which type of nucleophilic substitution reaction is most likely to occur when pyrimidine dimers in DNA are repaired, potentially leading to mutations that can cause cancer?

Cardura, a drug used to treat hypertension, is synthesized as shown here.

a. Identify the intermediate (A) and show the mechanism for its formation.

Strawberry growers have used large quantities of methyl bromide (b.p. 4 °C) to sterilize the soil before planting their crops. Like some of the freons, methyl bromide can diffuse up into the stratosphere, where it damages the protective ozone layer. Agricultural chemists have suggested using methyl iodide (b.p. 43 °C) as a replacement for methyl bromide. Why is methyl iodide likely to be more toxic to agricultural pests (and people) than methyl bromide? Why is methyl iodide less likely to reach the stratosphere than methyl bromide?

Which substitution reaction takes place more rapidly?

a. CH₃CH₂Br + H₂O or CH₃CH₂Br + HO⁻

Draw all the products of the following reaction:

In contrast to the results of Assessment 13.18, when a secondary haloalkane is treated with sodium ethanethiolate, we predict formation of a thioether. How is this rationalized?

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)