Capsaicin is found in chilli peppers. [Structure of capsaicin] You should assume the CH3O group is unreactive in the reactions involved in this question.

1. (a)Name all the functional groups in capsaicin in addition to the CH3O group.[1]
2. (b)Complete the equation for the reaction of capsaicin with an excess of Br2(aq) in the dark. Draw the structure of the organic product in the labelled box. [Equation with capsaicin + .........Br2 → organic product box + .........][3]
3. (c)Capsaicin is heated with an excess of hydrogen gas in the presence of platinum metal. The six-membered ring reacts in the same way as benzene under these conditions. Draw the structure of the organic product formed.[2]
4. (d)(i)When capsaicin is treated with reagent J under suitable conditions one of the products is methylpropanoic acid, CH3CH(CH3)COOH. Identify reagent J and any necessary conditions.[1]
5. (d)(ii)There are three different peaks in the proton (¹H) NMR spectrum of CH3CH(CH3)COOH in CDCl3. [Table 8.1 with chemical shift ranges] Use Table 8.1 to complete Table 8.2 and state: • the typical proton (¹H) chemical shift values (δ) for the protons • the splitting pattern (singlet, doublet, triplet, quartet or multiplet) shown by each peak • the explanation for the splitting patterns of the CH3 protons and the CH proton. [Table 8.2 with environment, δ/ppm, splitting pattern, explanation for splitting pattern columns, and rows for CH3, CH, COOH][3]
6. (e)(i)Capsaicin is heated with an excess of hot aqueous NaOH. Draw the structures of the two organic products H and K. [Boxes for H and K with molecular formulas given][2]
7. (e)(ii)Name the two types of reaction occurring in (e)(i).[1]
8. (f)Draw the structure of the organic product L formed when capsaicin is treated with LiAlH4 in dry ether. [Box for L][1]

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