A-Level CAIE Chemistry A2 36.1 Organic synthesis Question Bank

(a)

Benzocaine is used as a local anaesthetic. It can be synthesised from 4-nitromethylbenzene by the route shown.

4-nitromethylbenzene

benzocaine

step 4
step 3

[ 6 ]

(i)

Suggest the reagents and conditions for steps 1-5.
step 1
step 2
step 3
step 4
step 5

[ 6 ]

(b)

Benzocaine can also be used to synthesise the dyestuff S by the following route.

[ 2 ]

(i)

Suggest structures for compounds R and S and draw them in the boxes.

[ 2 ]

(a)

The reaction of phenylethanone with 1,4-dibromobutane, $\mathrm{BrCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}$ , in the presence of $\mathrm{FeBr}_{3}$ is shown in Fig. 6.2.
phenylethanone

Fig. 6.2

The mechanism of this reaction is similar to that of the alkylation of benzene.

[ 2 ]

(i)

The reaction shown in Fig. 6.2 forms small amounts of two by-products, $\mathbf{Y}\left(\mathrm{C}_{20} \mathrm{H}_{22} \mathrm{O}_{2}\right)$ and $\mathbf{Z}\left(\mathrm{C}_{12} \mathrm{H}_{14} \mathrm{O}\right)$ .

Suggest structures for Y and Z in the boxes in Fig. 6.4.

Fig. 6.4

[ 2 ]

[Maximum number: 9]

The anti-inflammatory drug ketoprofen can be synthesised from benzene via the following five steps.

(a)

Suggest the structures of compounds T and U and draw them in the boxes above.

[ 2 ]

(b)

Suggest reagents and conditions for steps 1-5.
step 1
step 2
step 3
step 4
step 5

[ 5 ]

(c)

What types of reaction are steps 1 and 5?
step 1
step 5

[ 2 ]

[Maximum number: 10]

The anti-inflammatory drug ibuprofen can be synthesised from benzene via the following six steps.

(a)

Suggest the structures of compounds H and J and draw them in the boxes above.

[ 2 ]

(b)

Suggest reagents and conditions for steps 1-6.
step 1
step 2
step 3
step 4
step 5
step 6

[ 6 ]

(c)

Name the mechanism of step 1 and state the type of reaction for step 6. step 1
step 6

[ 2 ]

0 selected