The structure of butamben is shown. butamben [Figure of butamben structure]

1. (a)(i)Butamben can act as a base. Complete the equation for a reaction in which butamben acts as a base.[1]
2. (a)(ii)Predict whether butamben is a stronger or weaker base than ammonia. Give a reason for your answer.[1]
3. (b)Complete the reaction scheme below to show the structural formulae of the products formed when butamben is treated separately with the stated reagent. [Reaction scheme with Br₂(aq), HNO₂(aq) + HCl(aq) at 5°C, NaOH(aq) under reflux][3]
4. (c)(i)The proton NMR spectrum of butamben in CDCl₃ contains one or more peaks that show a triplet splitting pattern. State the number of peaks in the spectrum that show a triplet splitting pattern.[1]
5. (c)(ii)On the diagram of butamben below, circle the protons responsible for the peak or peaks you identified in (c)(i).[1]
6. (c)(iii)Describe and explain how the proton NMR spectrum of butamben in D₂O would differ from the proton NMR spectrum of butamben in CDCl₃.[2]
7. (d)The mass spectrum of butamben includes peaks at m/e 92 and 57. Identify the fragments responsible for these peaks.[1]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.