Chemistry 9701 · AS & A Level · Organic synthesis

Organic synthesis — practice question

Procaine serves as a local anaesthetic in medicine. It is prepared from methylbenzene in five steps, as illustrated in Fig. 7.1.
(a(i))[1]

Name the functional groups present in procaine.

(a(ii))[1]

Procaine contains 13 carbon atoms. State how many carbon atoms in procaine are $sp$, $sp^2$ and $sp^3$ hybridised.

(b)[1]

The proton ($^1\text{H}$) NMR spectrum of procaine in $\text{D}_2\text{O}$ is obtained. Predict how many peaks will be seen.

(c)[1]

State why procaine can act as a base.

(d(i))[1]

Draw the structure of compound W in the space provided.

(d(ii))[2]

State the reagents and conditions for step 1 and step 2.

(e)[3]

Procaine is made from X in three steps. Suggest the reagents and conditions for step 4 and for step 5 in Fig. 7.1.

(f(i))[2]

Explain what is meant by partition coefficient, $K_{pc}$.

(f(ii))[2]

The partition coefficient of procaine between octan-1-ol and water is 1.77. Octan-1-ol and water do not mix. A solution containing 0.500 g of procaine in $75.0\,\text{cm}^3$ of water is shaken with $50.0\,\text{cm}^3$ of octan-1-ol. Calculate the mass of procaine extracted into the octan-1-ol.

Worked solution & mark scheme

This 14-mark question has a full step-by-step worked solution and mark scheme. One marking point: phenylamine group, amine group and ester group

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