Rimantadine was among the fi rst antiviral drugs to be

Chapter 7, Problem 7.19

(choose chapter or problem)

Rimantadine was among the fi rst antiviral drugs to be licensed in the United States for use against the infl uenza A virus and in treating established illnesses. It is synthesized from adamantane by the following sequence (we discuss the chemistry of Step 1 in Chapter 8 and the chemistry of Step 5 in Section 16.8A). Adamantane 1-Bromoadamantane Br Br2 (1) CH2"CHBr, AlBr3 (2) Br Br O Rimantadine (3) NH2 (4) (5) Rimantidine is thought to exert its antiviral effect by blocking a late stage in the assembly of the virus. (a) Propose a mechanism for Step 2. Hint: As we shall see in Section 21.1A, reaction of a bromoalkane such as 1-bromoadamantane with aluminum bromide (a Lewis acid, Section 4.7) results in the formation of a carbocation and AlBr4 2. Assume that adamantyl cation is formed in Step 2 and proceed from there to describe a mechanism. (b) Account for the regioselectivity of carbon-carbon bond formation in Step 2. (c) Describe experimental conditions to bring about Step 3. (d) Describe experimental conditions to bring about Step 4.