SAJC 2026 Halogen Derivatives Assignment (Students)

1 St Andrew’s Junior College H2 Chemistry 2026 Assignment: Halogen Derivatives 1. 2015/2/4(b) – Modified Adrenaline is formed from noradrenaline in the body by an SN2 reaction between the amine and group of noradrenaline and a suitable methyl compound. (a) Draw a mechanism for the reaction between an amine, R-NH2 and methyl iodide to form R-NHCH3 and any other products. Show relevant lone pairs and dipoles, and use curly arrows to indicate the movements of electron pairs [4] (b) Explain why this reaction proceeds mainly via an SN2 mechanism rather than an SN1 mechanism. [2] Criteria of Success for SN2 mechanism:  Name of mechanism: Nucleophile Substitution, SN2  3D representation of reactant and product  δ+ on C, δ– on X  Lone pair of electrons on Nu–  Nu– attack from the side opposite to X  Curly arrows to show flow of a pair of electrons  Bond breaking and bond forming in transition state  Overall charge on transition state if Nu− was used  Inverted product

2 (c) State and explain how the rate of this reaction changes when methyl iodide is replaced by methyl chloride. [2] 2. 2019/3/5(c) – Modified Compound K can be made using only dibromoethane and appropr iate inorganic reagent by the following 3-step synthesis. HO2CCH2CH2NHCH2CH2CO2H K BrCH2CH2Br L M K (a) Suggest the structures of compounds L and M and the reagents and conditions for the three steps. [4] (b) Identify one possible organic side product of your chosen reactions in (a), and suggest one way to minimise its formation. [2] Step 1 Step 2 Step 3

3 3. 2022/1/23