Chapter 15
An Introduction to Medicinal Chemistry · 6 exercises
Problem 2
What is meant by a placebo and what sort of issues need to be considered in designing a suitable placebo?
5 step solution
Problem 3
Usually, a 'balancing act' of priorities is required during chemical development. Explain what this means.
4 step solution
Problem 4
Discuss whether chemical development is simply a scale-up exercise.
4 step solution
Problem 5
The following synthetic route was used for the initial synthesis of
fexofenadine \(\left(\mathrm{R}=\mathrm{CO}_{2} \mathrm{H}\right)\) - an
analogue of terfenadine \(\left(\mathrm{R}=\mathrm{CH}_{3}\right)\). The
synthesis was suitable for the large-scale synthesis of terfenadine, but not
for fexofenadine. Suggest why not. (Hint: consider the electronic effects of
R.)
4 step solution
Problem 8
What considerations do you think have to be taken into account when choosing a solvent for scale up? Would you consider diethyl ether or benzene as a suitable solvent?
5 step solution
Problem 9
Phosphorus tribromide was added to an alcohol to give an alkyl bromide, but
the product was contaminated with an ether impurity. Explain how this impurity
might arise and how the reaction conditions could be altered to avoid the
problem.
$$
\mathrm{R}-\mathrm{OH} \stackrel{\mathrm{PBr}_{3}}{\longrightarrow}
\mathrm{R}-\mathrm{Br}
$$
5 step solution